Dietary biomarkers: advances, limitations and future directions

Metabolic pathway and network analysis integration for discovering the biomarkers in pig feces after a controlled fruit-vegetable dietary intervention

This study aimed to establish a strategy for identifying dietary intake biomarkers using a non-targeted metabolomic approach, including metabolic pathway and network analysis. The strategy was successfully applied to identify dietary intake biomarkers in fecal samples from pigs fed two doses of a polyphenol-rich fruit and vegetable (FV) diet following the Dietary Guidelines for Americans (DGA) recommendations. Potential biomarkers were identified among dietary treatment groups using liquid chromatography-high resolution mass spectrometry (LC-HRMS) based on a non-targeted metabolomic approach with metabolic pathway and network analysis. Principal component analysis (PCA) results showed significant differences in fecal metabolite profiles between the control and two FV intervention groups, indicating a diet-induced differential fecal metabolite profile after FV intervention. Metabolites from common flavonoids, e.g., (epi)catechin and protocatechuic acid, or unique flavonoids, e.g., 5,3',4'-trihydroxy-3-methoxy-6,7-methylenedioxyflavone and 3,5,3',4'-tetrahydroxy-6,7-methylenedioxyflavone, were identified as highly discriminating factors, confirming their potential as fecal markers for the FV dietary intervention. Microbiota pathway prediction using targeted flavonoids provided valuable and reliable biomarker exploration with high confidence. A correlation network analysis between these discriminatory ion features was applied to find connections to possible dietary biomarkers, further validating these biomarkers with biochemical insights. This study demonstrates that integrating metabolic pathways and network analysis with a non-targeted metabolomic approach is highly effective for rapid and accurate identification and prediction of fecal biomarkers under controlled dietary conditions in animal studies. This approach can also be utilized to study microbial metabolisms in human clinical research.

Assessing and Monitoring Nutrition Security in the United States: A Narrative Review of Current Measures and Instruments

PURPOSE OF REVIEW

Because nutrition plays a crucial role in the development of chronic diseases, ensuring nutrition security is important for promoting population health. Nutrition security is defined as having consistent and equitable access to healthy, safe, affordable foods essential to optimal health and well-being. Distinguished from food security, nutrition security consists of two constructs: healthy diets and nutritional status. The study aimed to identify population measures that reflect the important constructs of nutrition security (i.e., healthy diets and nutritional status) to inform U.S. nutrition security assessment and monitoring.

RECENT FINDINGS

Through a narrative review conducted across multiple databases, associations between subconstructs of healthy diets and nutritional status were identified. Of the six subconstructs that constitute healthy diets, nutrient adequacy and moderation were most often used to assess and monitor healthfulness of U.S. population diets and were associated with health outcomes. There is little evidence of an association between health outcomes and macronutrient balance or diversity in the U.S. Thirteen instruments were identified as potentially suitable for measuring at least one subconstruct of healthy diet in the population. This review highlights the importance of nutrition security in addressing population health challenges. It emphasizes the potential use of multiple instruments and measures to comprehensively monitor population nutrition security and inform intervention strategies. Identifying feasible and practical measures for assessing and monitoring nutrition security is imperative for advancing population health and mitigating the burden of chronic diseases.

Plasma Metabolomics of Dietary Intake of Protein-Rich Foods and Kidney Disease Progression in Children

OBJECTIVE

Evidence regarding the efficacy of a low-protein diet for patients with CKD is inconsistent and recommending a low-protein diet for pediatric patients is controversial. There is also a lack of objective biomarkers of dietary intake. The purpose of this study was to identify plasma metabolites associated with dietary intake of protein and to assess whether protein-related metabolites are associated with CKD progression.

METHODS

Nontargeted metabolomics was conducted in plasma samples from 484 Chronic Kidney Disease in Children (CKiD) participants. Multivariable linear regression estimated the cross-sectional association between 949 known, nondrug metabolites and dietary intake of total protein, animal protein, plant protein, chicken, dairy, nuts and beans, red and processed meat, fish, and eggs, adjusting for demographic, clinical, and dietary covariates. Cox proportional hazards models assessed the prospective association between protein-related metabolites and CKD progression defined as the initiation of kidney replacement therapy or 50% eGFR reduction, adjusting for demographic and clinical covariates.

RESULTS

One hundred and twenty-seven (26%) children experienced CKD progression during 5 years of follow-up. Sixty metabolites were significantly associated with dietary protein intake. Among the 60 metabolites, 10 metabolites were significantly associated with CKD progression (animal protein: n = 1, dairy: n = 7, red and processed meat: n = 2, nuts and beans: n = 1), including one amino acid, one cofactor and vitamin, 4 lipids, 2 nucleotides, one peptide, and one xenobiotic. 1-(1-enyl-palmitoyl)-2-oleoyl-glycerophosphoethanolamine (GPE, P-16:0/18:1) was positively associated with dietary intake of red and processed meat, and a doubling of its abundance was associated with 88% higher risk of CKD progression. 3-ureidopropionate was inversely associated with dietary intake of red and processed meat, and a doubling of its abundance was associated with 48% lower risk of CKD progression.

CONCLUSIONS

Untargeted plasma metabolomic profiling revealed metabolites associated with dietary intake of protein and CKD progression in a pediatric population.

Neutrophil- and Platelet-Lymphocyte Ratio as Biomarkers of Severity in Complicated Diverticular Disease

INTRODUCTION

Diverticulitis is a prevalent gastrointestinal disease that may require surgical intervention. The aim of the study was to investigate the involvement of neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) as biomarkers of severity in complicated diverticular disease (CDD) in Mexican patients and their correlation with the need for surgical intervention, the length of hospital stay, and mortality.

MATERIAL AND METHODS

An observational, longitudinal, and retrospective study performed from 2017 to 2021 was considered in patients over 18 years of age, with a diagnosis of CDD by using computed tomography and with a hemogram taken in the first 24 hours upon admission to the emergency department to describe the sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) of NLR and PLR in the CDD.  Results: A total of 102 Mexican patients suffering from CDD, 54% women and 46% men with a mean of 59 years, were analyzed. According to Hinchey's classification, 79 (77.5%) patients showed type I, 12 (12.8%) type II, 5 (4.9%) type III, and 6 (5.9%) type IV. The mean hospital stay was 8.8 days, with a mortality rate of 3.9%. The cut-off value was established at 5.1 for NLR according to the results of the receiver operating characteristic (ROC) curve with an area under the curve (AUC) of 0.633, a sensitivity of 90%, a specificity of 43%, PPV of 21.8%, and NPV of 96% for the prediction of CDD. A cut-off value for PLR at 72 was established according to the results of the ROC curve with an AUC of 0.482, a sensitivity of 78%, a specificity of 40%, PPV of 96%, and NPV of 9% for the prediction of CDD.

CONCLUSION

The NLR and PLR are easily calculable and accessible biomarkers that can be part of the decision-making for the diagnosis and treatment of CDD in Mexican people as has been observed in other populations. However, more prospective, multicenter comparative studies are needed to assess the efficacy and safety of these biomarkers in relation to those already described.

Moderate wine consumption measured using the biomarker urinary tartaric acid concentration decreases inflammatory mediators related to atherosclerosis

OBJECTIVES

Several studies suggest that moderate wine consumption, particularly red wine, may have benefits for cardiovascular health. Red wine contains a variety of bioactive compounds, including polyphenols like phenolic acids, which have demonstrated anti-inflammatory effects in experimental models. The aim of this study was to assess the anti-inflammatory properties of wine, measured as urinary tartaric acid, a new biomarker of wine consumption.

DESIGN, SETTINGS, AND PARTICIPANTS

One-year longitudinal study that included 217 participants from the PREDIMED trial.

MEASUREMENTS

Plasma inflammatory biomarkers and urinary tartaric acid were analyzed using xMAP technology and high-performance liquid chromatography, respectively. Multivariable regression analyses were performed to assess the relationship between variations over 1-year in urinary tartaric acid concentrations and 1-year changes in serum inflammatory molecules, including adhesion cell molecules, interleukine-6, tumour necrosis factor alpha, and monocyte chemotactic protein 1. Three categories were built according to tertiles of 1-y changes in urinary tartaric acid.

RESULTS

Using a ROC curve, urinary tartaric acid was corroborated as a reliable biomarker of wine consumption (AUC = 0.818 (95% CI: 0.76; 0.87). In the continuous analysis, participants with higher increases in tartaric acid significantly reduced their concentrations in soluble vascular adhesion molecule (sVCAM-1) after 1-year of follow-up (-0.20 (-0.38; -9,93) ng/mL per 1-SD increment, p-value = 0.031). Moreover, tertiles 2 and 3 of 1-year changes in tartaric acid presented a significant reduction in soluble intercellular cell adhesion molecule (sICAM-1) as compared to tertile 1 (-0.31 (-0.52; -0.10) ng/mL, p-value = 0.014 and -0.29 (-0.52; -0.07) ng/mL, p-value = 0.023, respectively). Participants in the third tertile also exhibited a reduced concentration of sVCAM-1 compared to those in the first tertile (-0.31 (-0.55; -0.06) ng/mL, p-value = 0.035).

CONCLUSIONS

Our findings suggest that wine consumption is associated with lower levels of inflammation due to the anti-inflammatory properties of wine compounds.

Assessing Repeated Urinary Proline Betaine Measures as a Biomarker of Usual Citrus Intake during Pregnancy: Sources of Within-Person Variation and Correlation with Reported Intake

Proline betaine (Pro-B) has been identified as a biomarker of dietary citrus intake, yet gaps remain in its validation as a quantitative predictor of intake during various physiological states. This study quantified sources of within-individual variation (WIV) in urinary Pro-B concentration during pregnancy and assessed its correlation with the reported usual intake of citrus fruit and juice. Pro-B concentrations were determined by 1H-NMR spectroscopy in spot and 24-h urine specimens (n = 255) collected throughout pregnancy from women participating in the MARBLES cohort study. Adjusted linear or log mixed effects models quantified WIV and tested potential temporal predictors of continuous or elevated Pro-B concentration. Pearson or Spearman correlations assessed the relationship between averaged repeated biomarker measures and usual citrus intake reported by food frequency questionnaires. The proportion of variance in urinary Pro-B attributable to WIV ranged from 0.69 to 0.74 in unadjusted and adjusted models. Citrus season was a significant predictor of Pro-B in most analyses (e.g., adjusted β [95% CI]: 0.52 [0.16, 0.88] for non-normalized Pro-B), while gestational age predicted only non-normalized Pro-B (adjusted β [95% CI]: -0.093 [-0.18, -0.0038]). Moderate correlations (rs of 0.40 to 0.42) were found between reported usual citrus intake and averaged repeated biomarker measurements, which were stronger compared to using a single measurement. Given the high degree of WIV observed in urinary Pro-B, multiple samples per participant are likely needed to assess associations between citrus consumption and health outcomes.

Relationships between the maternal prenatal diet and epigenetic state in infants: a systematic review of human studies

Most human studies investigating the relationship between maternal diet in pregnancy and infant epigenetic state have focused on macro- and micro-nutrient intake, rather than the whole diet. This makes it difficult to translate the evidence into practical prenatal dietary recommendations.To review the evidence on how the prenatal diet relates to the epigenetic state of infants measured in the first year of life via candidate gene or genome-wide approaches.Following the PRISMA guidelines, this systematic literature search was completed in August 2020, and updated in August 2021 and April 2022. Studies investigating dietary supplementation were excluded. Risk of bias was assessed, and the certainty of results was analysed with consideration of study quality and validity.Seven studies were included, encompassing 6852 mother-infant dyads. One study was a randomised controlled trial and the remaining six were observational studies. There was heterogeneity in dietary exposure measures. Three studies used an epigenome-wide association study (EWAS) design and four focused on candidate genes from cord blood samples. All studies showed inconsistent associations between maternal dietary measures and DNA methylation in infants. Effect sizes of maternal diet on DNA methylation ranged from very low (< 1%) to high (> 10%). All studies had limitations and were assessed as having moderate to high risk of bias.The evidence presented here provides very low certainty that dietary patterns in pregnancy relate to epigenetic state in infants. We recommend that future studies maximise sample sizes and optimise and harmonise methods of dietary measurement and pipelines of epigenetic analysis.

Dietary biomarkers and food records indicate compliance to study diets in the ADIRA (Anti-inflammatory Diet In Rheumatoid Arthritis) trial

Background

In the ADIRA (Anti-inflammatory Diet In Rheumatoid arthritis) trial, compliance to the study diets has previously been described primarily with a score based on reported intake of trial foods from telephone interviews. The aim of this study was to evaluate compliance using objective dietary biomarkers for whole grain, fruit and vegetables, margarine and oil, seafood and overall fat quality, as well as reported intake from food records of key components of the study diets.

Methods

Fifty patients with rheumatoid arthritis were randomized to begin with the intervention diet (rich in whole grain, fruit and vegetables, margarine/oil and seafood) or the control diet (rich in meat and high-fat dairy) for 10 weeks, followed by a ~ 4 months wash-out period, and then switched diet. Compliance was evaluated using plasma alkylresorcinols (AR) as biomarkers for intake of whole grain wheat and rye, serum carotenoids for fruit and vegetables, plasma linoleic acid (LA, 18:2 n-6) and -α-linolenic acid (18:3, n-3) for margarine and cooking oil, plasma eicosapentaenoic acid (EPA, 20:5 n-3), -docosahexaenoic acid (DHA 22:6, n-3) and -docosapentaenoic acid (22:5 n-3) for seafood, and plasma fatty acid pattern for the overall dietary fat quality. Reported intake of whole grain, fruit, berries and vegetables, seafood, red meat, and fat quality was extracted from 3-d food records.

Results

Plasma AR C21:0 and C23:0, LA, EPA, and DHA were higher while total serum carotenoids were lower after the intervention diet period compared to the control diet period (AR and carotenoids: p = <0.05, fatty acids: p = <0.001). Reported intake of whole grain, fruit, berries and vegetables, and seafood was higher and reported intake of red meat was lower during the intervention diet period compared to the control diet period (p = <0.001). Plasma- and reported fatty acid pattern differed as intended between the diet periods.

Conclusion

This study indicates that the participants in the ADIRA trial were compliant to the study diets regarding intake of whole grain, cooking fat, seafood, and red meat, and the intended overall dietary fat quality. Compliance to instructions on fruit- and vegetable intake remains uncertain.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT02941055?term=NCT02941055&draw=2&rank=1, NCT02941055.

Biomarkers of seafood intake during pregnancy - Pollutants versus fatty acids and micronutrients

Intake of fish and seafood during pregnancy may have certain beneficial effects on fetal development, but measurement of intake using questionnaires is unreliable. Here, we assessed several candidate biomarkers of seafood intake, including long-chain omega 3 fatty acids (n-3 LCPUFA), selenium, iodine, methylmercury, and different arsenic compounds, in 549 pregnant women (gestational week 29) in the prospective birth cohort NICE (Nutritional impact on Immunological maturation during Childhood in relation to the Environment). Proportions of the fatty acids eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) in erythrocytes were measured using gas chromatography with flame ionization detector. Selenium was measured in blood plasma and erythrocytes, mercury and arsenic in erythrocytes, and iodine and several arsenic compounds in urine, using inductively coupled plasma mass spectrometry, arsenic compounds after first being separated by ion exchange high-performance liquid chromatography (HPLC). Each biomarker was related to intake of total seafood and to intake of fatty and lean fish, and shellfish in third trimester, estimated from a semi-quantitative food frequency questionnaire filled out in gestational week 34. The pregnant women reported a median total seafood intake of 184 g/week (5th-95th percentiles: 34-465 g/week). This intake correlated most strongly with erythrocyte mercury concentrations (rho = 0.49, p < 0.001), consisting essentially of methylmercury, followed by total arsenic in erythrocytes (rho = 0.34, p < 0.001), and arsenobetaine in urine (rho = 0.33, p < 0.001), the main form of urinary arsenic. These biomarkers correlated well with intake of both fatty fish, lean fish, and shellfish. Erythrocyte DHA and plasma selenium correlated, although weakly, mainly with fatty fish (rho = 0.25 and 0.22, respectively, both p < 0.001). In conclusion, elevated concentrations of erythrocyte mercury and urinary arsenobetaine can be useful indicators of seafood intake, more so than the n-3 LCPUFAs. However, the relative importance of the biomarkers may differ depending on the type and amount of seafood consumed.

Joint Microbiota Activity and Dietary Assessment through Urinary Biomarkers by LC-MS/MS

Accurate dietary assessment in nutritional research is a huge challenge, but essential. Due to the subjective nature of self-reporting methods, the development of analytical methods for food intake and microbiota biomarkers determination is needed. This work presents an ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method for the quantification and semi quantification of 20 and 201 food intake biomarkers (BFIs), respectively, as well as 7 microbiota biomarkers applied to 208 urine samples from lactating mothers (M) (N = 59). Dietary intake was assessed through a 24 h dietary recall (R24h). BFI analysis identified three distinct clusters among samples: samples from clusters 1 and 3 presented higher concentrations of most biomarkers than those from cluster 2, with dairy products and milk biomarkers being more concentrated in cluster 1, and seeds, garlic and onion in cluster 3. Significant correlations were observed between three BFIs (fruits, meat, and fish) and R24h data (r > 0.2, p-values < 0.01, Spearman correlation). Microbiota activity biomarkers were simultaneously evaluated and the subgroup patterns detected were compared to clusters from dietary assessment. These results evidence the feasibility, usefulness, and complementary nature of the determination of BFIs, R24h, and microbiota activity biomarkers in observational nutrition cohort studies.

Reflection Spectroscopy-Assessed Skin Carotenoids Are Sensitive to Change in Carotenoid Intake in a 6-Week Randomized Controlled Feeding Trial in a Racially/Ethnically Diverse Sample

BACKGROUND

Reflection spectroscopy, utilized by the Veggie Meter, is a less-expensive, noninvasive method to quantify skin carotenoids and is a valid approximation of fruit and vegetable (FV) intake. However, it is unknown to what degree Veggie Meter-assessed skin carotenoid score change is responsive to changes in carotenoid intake.

OBJECTIVES

This study aimed to evaluate Veggie Meter-assessed skin carotenoid score response in a 6-wk randomized controlled trial of a carotenoid-containing juice to determine whether the Veggie Meter can be used to detect nutritionally relevant changes in carotenoid intake; and to compare skin and plasma carotenoid responses with the 6-wk trial.

METHODS

In this 6-wk trial, participants (n = 162) who self-identified as one of 4 US racial/ethnic groups (25% Black, 25% Asian, 27% non-Hispanic White, 23% Hispanic) were randomized to a control group, receiving negligible carotenoids (177 mL apple juice/d), moderate-dose group, receiving 4 mg total carotenoids/d (177 mL orange-carrot juice/d), or high-dose group, receiving 8 mg total carotenoids/d (355 mL orange-carrot juice/d). Skin carotenoid score and plasma total carotenoid concentrations (α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein, zeaxanthin) were assessed at baseline, 3 wk, and 6 wk (n = 158 completed the trial). Repeated measures linear models were used to examine skin and plasma carotenoids over time and between groups.

RESULTS

At 6 wk, participants in the high-dose and moderate-dose groups had significantly higher mean skin carotenoid scores [414.0 (SD = 100.6) and 369.7 (SD = 100.3), respectively] compared with those in the control group [305.2 (100.5)]. In the high-dose group, there was a 42% change in skin carotenoids from baseline (mean = 290.4) to a 6-wk follow-up (increase of 123, 123/290 = 42.4%). There was a 61% change in the plasma carotenoids in the high-dose group.

CONCLUSIONS

The Veggie Meter is sensitive to increases in daily carotenoid intake in diverse racial/ethnic groups over 6 wk.

CLINICAL TRIALS REGISTRY NUMBER

This trial was registered at clinicaltrials.gov as ID: NCT04056624. Study URL: https://clinicaltrials.gov/ct2/show/NCT04056624.

Contribution of natural food environments to nutritional intake and biomarker status: insights from the women of indigenous santhal communities of Jharkhand, India

BACKGROUND

Many indigenous communities reside in biodiverse environments replete with natural food sources but show ​poor access and utilization.

METHODS

To understand the links between indigenous food access, dietary intakes, and biomarkers, we conducted a cross-sectional study among women of the Santhal Community (n = 211) from 17 villages in the Godda district of Jharkhand, India. Survey methods included household surveys, dietary intake assessment (24 HDR) and micronutrient and inflammatory biomarkers' estimation.

RESULTS

The diversity in access to foods from different natural sources expressed as Food access diversity index was low. This led to poor consumption and thus a low Minimum Dietary Diversity. The mean nutrient intake was less than the estimated average requirement for all nutrients. Women with higher dietary diversity scores had higher nutrient intakes. Thiamine and calcium intakes were significantly higher in women consuming indigenous foods than non-consumers. One-fourth of the women had elevated levels of inflammatory biomarkers. The prevalence of iron deficiency was approximately 70%. Vitamin A insufficiency (measured as retinol-binding protein) was observed in around 33.6% women, while 28.4% were deficient. Household access to natural food sources was associated with specific biomarkers. The access to kitchen garden (baari) was positively associated with retinol-binding protein levels and negatively with inflammatory biomarkers, while access to ponds was positively associated with ferritin levels.

CONCLUSION

The findings highlight the role of access to diverse natural foods resources, including indigenous foods, for improving nutrition security in indigenous communities. Nutrition and health programs promoting indigenous food sources should include the assessment of biomarkers for effective monitoring and surveillance.

Health associations of liver enzymes and inflammatory scores with urinary citrus flavonoid metabolites

Background: Dietary flavonoid intake is associated with a reduced risk of some cardiometabolic disorders, attributed in part to their claimed anti-inflammatory activity. Our aim was to investigate the potential association between specific urine flavonoid metabolites, liver enzymes, and inflammatory status in individuals with metabolic syndrome (MetS). Methods: In this cross-sectional study, clinical and dietary data from 267 participants, aged 55 to 75 years, participating in the PREDIMED Plus study (PREvención con DIeta MEDiterránea) were analyzed. At the baseline, spot urine samples were collected and seven urinary flavonoid metabolites were quantified using ultra-performance liquid chromatography coupled to triple quadrupole mass spectrometry (UPLC-Q-q-Q MS). Liver enzymes, inflammatory scores, and urinary flavonoid concentrations were inverse normally transformed. Results: Adjusted linear regression models showed an inverse association between urinary citrus flavanone concentrations and gamma-glutamyl transferase (GGT) (all p-values <0.05). Naringenin 7'-GlcUA was significantly associated with a lower aggregate index of systemic inflammation (AISI) (B_{per 1SD} = -0.14; 95% CI: -0.27 to -0.02; p-value = 0.025) and systemic inflammation index (SII) (B_{per 1SD} = -0.14; 95% CI: -0.27 to -0.02; p-value = 0.028). To investigate the relationship between flavanone subclasses and GGT levels, we fitted a score of citrus-flavanones, and subjects were stratified into quartiles. The highest values of the citrus-flavanone score (per 1-SD increase) were associated with lower GGT levels (B_{per 1SD} = -0.41; 95% CI: -0.74 to -0.07), exhibiting a linear trend across quartiles (p-trend = 0.015). Conclusion: This cross-sectional study showed that higher urinary excretion of citrus-flavanone metabolites was associated with lower GGT levels in subjects diagnosed with MetS and obesity.

Noninvasive Reflection Spectroscopy Measurement of Skin Carotenoid Score in Infants Is Feasible and Reliable

BACKGROUND

Skin carotenoid measurement by reflection spectroscopy (RS) offers a noninvasive biomarker of carotenoid intake, but feasibility, reliability, and validity are not established in infants.

OBJECTIVES

In this study we aimed to determine the feasibility and reliability of 4-mo-old infant skin carotenoid score (SCS) measurement and its correlation with total carotenoid intake and plasma concentrations.

METHODS

SCSs were measured in a prospective, observational study with a modified, portable RS device at the index finger and heel of the foot in 4-mo-olds (n = 21). Infant plasma, human milk, and formula carotenoid concentrations were measured by HPLC-photodiode array, and carotenoid intake was estimated from 7-d food diaries corrected for actual milk carotenoid content. Mean SCS, time to acquire measurements, replicate intraclass correlations, and bivariate correlations between SCS, carotenoid intake, and plasma carotenoids were examined. Exploratory analyses of returning 6- (n = 12) and 8-mo-old (n = 9) infants were conducted.

RESULTS

Mean ± SD finger and heel SCSs in 4-, 6-, and 8-mo-olds were 92 ± 57 and 92 ± 51; 109 ± 41 and 119 ± 44; and 161 ± 89 and 197 ± 128 units, respectively. Replicate SCS measurements were reliable, with high intraclass correlation (≥0.70) of within-subject visit measurements. Finger SCSs in 4-mo-olds were correlated with carotenoid intake (ρ = 0.48, P = 0.0033), and finger and heel SCS were correlated with total plasma carotenoid concentrations (ρ = 0.71, P < 0.0001 and ρ = 0.57, P = 0.0006, respectively). Eight-mo-olds' finger and heel SCSs were correlated with total carotenoid intake (ρ = 0.73, P < 0.001; ρ = 0.58, P = 0.0014, respectively), whereas SCSs in 6-mo-olds, in transition from exclusive milk to complementary feeding, did not correlate with plasma carotenoid or dietary carotenoids, despite correlation between plasma and dietary carotenoid intake (ρ = 0.86, P = 0.0137). Mixed models suggest plasma total carotenoid concentration, age, carotenoid intake, and age × carotenoid intake, but not measurement site, are determinants of infant SCS.

CONCLUSIONS

Infant skin carotenoids are feasibly and reliably measured by RS and may provide a biomarker of carotenoid intake in 4-mo-olds. This trial was registered at clinicaltrials.gov as NCT03996395.

A Review of Digital Innovations for Diet Monitoring and Precision Nutrition

This article provides an up-to-date review of technological advances in 3 key areas related to diet monitoring and precision nutrition. First, we review developments in mobile applications, with a focus on food photography and artificial intelligence to facilitate the process of diet monitoring. Second, we review advances in 2 types of wearable and handheld sensors that can potentially be used to fully automate certain aspects of diet logging: physical sensors to detect moments of dietary intake, and chemical sensors to estimate the composition of diets and meals. Finally, we review new programs that can generate personalized/precision nutrition recommendations based on measurements of gut microbiota and continuous glucose monitors with artificial intelligence. The article concludes with a discussion of potential pitfalls of some of these technologies.

Discovery of Food Intake Biomarkers Using Metabolomics

Due to the high impact of diet exposure on health, it is crucial the generation of robust data of regular dietary intake, hence improving the accuracy of dietary assessment. The metabolites derived from individual food or group of food have great potential to become biomarkers of food intake (BFIs) and provide more objective food consumption measurements.Herein, it is presented an untargeted metabolomic workflow for the discovery BFIs in blood and urine samples, from the study design to the biomarker identification. Samples are analyzed by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). A wide variety of compounds are covered by separate analyses of medium to nonpolar molecules and polar metabolites based on two LC separations as well as both positive and negative electrospray ionization. The main steps of data treatment of the comprehensive data sets and statistical analysis are described, as well as the principal considerations for the BFI identification.

Microfluidic assessment of nutritional biomarkers: Concepts, approaches and advances

Among various approaches to understand the health status of an individual, nutritional biomarkers can provide valuable information, particularly in terms of deficiencies, if any, and their severity. Commonly, the approach revolves around molecular sciences, and the information gained can support prognosis, diagnosis, remediation, and impact assessment of therapies. Microfluidic platforms can offer benefits of low sample and reagent requirements, low cost, high precision, and lower detection limits, with simplicity in handling and the provision for complete automation and integration with information and communication technologies (ICTs). While several advances are being made, this work details the underlying concepts, with emphasis on different point-of-care devices for the analysis of macro and micronutrient biomarkers. In addition, the scope of using different wearable microfluidic sensors for real-time and noninvasive determination of biomarkers is detailed. While several challenges remain, a strong focus is given on recent advances, presenting the state-of-the-art of this field. With more such biomarkers being discovered and commercialization-driven research, trends indicate the wide prospects of this advancing field in supporting clinicians, food technologists, nutritionists, and others.

Favorable fatty acid composition in adipose tissue in healthy Iraqi- compared to Swedish-born men - a pilot study using MRI assessment

Middle Eastern immigrants are at high-risk for insulin resistance. Fatty acid composition (FAC) plays an important role in the development of insulin resistance but has not been investigated in people of Middle Eastern ancestry. Here, the aim was to assess the FAC in visceral and subcutaneous adipose tissue (VAT and SAT) in healthy Iraqi- and Swedish-born men using a magnetic resonance imaging (MRI) method.This case-control study included 23 Iraqi- and 15 Swedish-born middle-aged men, without cardiometabolic disease. Using multi-echo MRI of the abdomen, the fractions of saturated, monounsaturated, and polyunsaturated fatty acids (fSFA, fMUFA, and fPUFA) were estimated in VAT and SAT. SAT was further analyzed in deep and superficial compartments (dSAT and sSAT).

In all depots, fPUFA was significantly higher and fSFA significantly lower in Iraqi men, independently of age and BMI. In both Iraqi- and Swedish-born men, higher fPUFA and lower fMUFA were found in sSAT vs. dSAT. Among Iraqi men only, higher fPUFA and lower fMUFA were found in SAT vs. VAT.Iraqi-born men presented a more favorable abdominal FAC compared to Swedish-born men. This MRI method also revealed different FACs in different abdominal depots. Our results may reflect a beneficial FAC in Middle Eastern immigrants.

  

Plasma metabolomic profiling of dietary patterns associated with glucose metabolism status: The Maastricht Study

BACKGROUND

Glucose metabolism has been reported to be affected by dietary patterns, while the underlying mechanisms involved remain unclear. This study aimed to investigate the potential mediation role of circulating metabolites in relation to dietary patterns for prediabetes and type 2 diabetes.

METHODS

Data was derived from The Maastricht Study that comprised of 3441 participants (mean age of 60 years) with 28% type 2 diabetes patients by design. Dietary patterns were assessed using a validated food frequency questionnaire (FFQ), and the glucose metabolism status (GMS) was defined according to WHO guidelines. Both cross-sectional and prospective analyses were performed for the circulating metabolome to investigate their associations and mediations with responses to dietary patterns and GMS.

RESULTS

Among 226 eligible metabolite measures obtained from targeted metabolomics, 14 were identified to be associated and mediated with three dietary patterns (i.e. Mediterranean Diet (MED), Dietary Approaches to Stop Hypertension Diet (DASH), and Dutch Healthy Diet (DHD)) and overall GMS. Of these, the mediation effects of 5 metabolite measures were consistent for all three dietary patterns and GMS. Based on a 7-year follow-up, a decreased risk for apolipoprotein A1 (APOA1) and docosahexaenoic acid (DHA) (RR 0.60, 95% CI 0.55, 0.65; RR 0.89, 95% CI 0.83, 0.97, respectively) but an increased risk for ratio of ω-6 to ω-3 fatty acids (RR 1.29, 95% CI 1.05, 1.43) of type 2 diabetes were observed from prediabetes, while APOA1 showed a decreased risk of type 2 diabetes from normal glucose metabolism (NGM; RR 0.82, 95% CI 0.75, 0.89).

CONCLUSIONS

In summary, this study suggests that adherence to a healthy dietary pattern (i.e. MED, DASH, or DHD) could affect the GMS through circulating metabolites, which provides novel insights into understanding the biological mechanisms of diet on glucose metabolism and leads to facilitating prevention strategy for type 2 diabetes.

Nontargeted and Targeted Metabolomics Identifies Dietary Exposure Biomarkers for Navy Bean and Rice Bran Consumption in Children and Adults

Dietary exposure biomarkers are needed for advancing knowledge on healthy foods. This study examined biomarkers for navy beans and rice bran in children and adults. Plasma, urine, stool, and study foods from dietary intervention studies were analyzed by metabolomics. A total of 38 children and 49 adults were assessed after consuming navy beans and/or rice bran for 2-, 4-, 6-, or 12 weeks. From the 138-175 metabolites modulated by diet, 11 were targeted for quantification. Trigonelline and pipecolate concentrations increased in children and adult plasma after 4 weeks compared to baseline. Increased xanthurenate (46%) was observed in children plasma after rice bran intake for 4 weeks. Study foods with navy beans had higher S-methylcysteine compared to control and supported the increased urine S-methylcysteine sulfoxide. Nontargeted metabolomics was moderately effective to identify target molecules as candidate biomarkers. Study limitations include interindividual metabolite variations before diet intervention. Validation is warranted using cross-over designs and larger sample sizes.

Biomarkers of Fruit Intake Using a Targeted Metabolomics Approach: an Observational Cross-Sectional Analysis of the ELSA-Brasil Study

BACKGROUND

Advances in technology have led to the identification of a greater number of metabolites related to diet. Although fruit intake biomarkers have been reported in some studies, these findings require further replication, considering the relevance of fruits for diet quality and health.

OBJECTIVES

The aim of this study was to explore the associations of a set of potential urinary biomarkers of diet, assessed using a targeted metabolomics approach, with self-reported fruit intake data in participants of a computer-assisted 24-h dietary recall (GloboDiet software) validation study.

METHODS

A total of 93 individuals aged 43-72 y, 54% female, participated in this study. The subjects were a subsample of the Longitudinal Study of Adult Health (ELSA-Brasil). A 24-h dietary recall was obtained with the aid of GloboDiet software matching a 24-h urine sample from each participant. Candidate biomarkers were selected in a literature search and identified in urine by LC coupled to high-resolution MS. Spearman correlation analyses were performed between fruit intake and each biomarker.

RESULTS

Spearman correlation analysis showed that total fruits intake was significantly correlated with citric acid (ρ = 0.213, P = 0.041), ferulic acid sulfate I (ρ = 0.240, P = 0.020), hesperetin glucuronide/homoeriodictyol glucuronide (ρ = 0.303, P = 0.003), hydroxyhippuric acid (ρ = 0.239, P = 0.021), homovanillic alcohol sulfate (ρ = 0.339, P = 0.001), methylgallic acid sulfate (ρ = 0.268, P = 0.009), naringenin glucuronide (NG; ρ = 0.278, P = 0.007), proline betaine (PB; ρ = 0.305, P = 0.003), syringic acid sulfate (ρ = 0.210, P = 0.044), and sinapic acid sulfate (ρ = 0.412, P < 0.001). Among them, 3 have been described in literature as promising biomarkers for intake of total fruit, oranges, and citrus fruit: NG, hesperetin glucuronide, and PB.

CONCLUSIONS

Associations of total fruits intake with urinary measurements indicate the potential usefulness of dietary biomarkers in the Brazilian population as a complement to self-reported dietary assessments.

Non-targeted metabolomics of cooked cowpea (Vigna unguiculata) and pigeon pea (Cajanus cajan) from Ghana using two distinct and complementary analytical platforms

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Cowpea varieties represent diverse staple foods in Sub-Saharan Africa.

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Cowpea metabolite composition is different from pigeon pea and common bean.

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Cowpea metabolites included tonkinelin, pheophytin A, and linoleoyl ethanolamide.

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Pheophytin A was only detected in the cowpea variety Sangyi.

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Pipecolic acid identification was confirmed for all three legumes.

Legumes are global staple foods with multiple human health properties that merit detailed composition analysis in cooked forms. This study analyzed cowpea [Vigna unguiculata] (three varieties: Dagbantuya, Sangyi, and Tukara), pigeon pea [Cajanus cajan], and common bean [Phaseolus vulgaris] using two distinct ultra-performance liquid chromatography mass spectrometry (UPLC-MS) platforms and analytical workflows. Comparisons between cowpea and pigeon pea consumed in Ghana, and common bean (navy bean) from USA, revealed 75 metabolites that differentiated cowpeas. Metabolite fold-change comparisons resulted in 142 metabolites with significantly higher abundance in cowpea, and 154 higher in abundance from pigeon pea. 3-(all-trans-nonaprenyl)benzene-1,2-diol, N-tetracosanoylphytosphingosine, and sitoindoside II are novel identifications in cowpea, with notably higher abundance than other legumes tested. Cowpea variety specific markers were tonkinelin (Dagbantuya), pheophytin A (Sangyi), and linoleoyl ethanolamide (Tukara). This study identified novel cowpea and pigeon pea food metabolites that warrant continued investigation as bioactive food components following consumption in people.

Postprandial Responses on Serum Metabolome to Milk and Yogurt Intake in Young and Older Men

The identification and validation of biomarkers of food intake (BFIs) is a promising approach to develop more objective and complementary tools to the traditional dietary assessment methods. Concerning dairy, their evaluation in terms of intake is not simple, given the variety of existing foods, making it difficult to establish the association between specific dairy products consumption and the effects on human health, which is also dependent on the study population. Here, we aimed at identifying BFI of both milk (M) and yogurt (Y) in 14 healthy young (20-35 years) and 14 older (65-80 years). After a 3-week run-in period of dairy exclusion from the diet, the subjects acutely consumed 600 ml of M or Y. Metabolomics analyses were conducted on serum samples during the following 6 h (LC-MS and GC-MS). Several metabolites showing increased iAUC after milk or yogurt intake were considered as potential BFI, including lactose (M > Y, 2-fold), galactitol (M > Y, 1.5-fold), galactonate (M > Y, 1.2-fold), sphingosine-1-phosphate (M > Y from 2.1-fold), as well as an annotated disaccharide (Y > M, 3.6-fold). Delayed serum kinetics were also observed after Y compared to M intake lysine (+22 min), phenylalanine (+45 min), tyrosine (+30min), threonine (+38 min) 3-phenyllactic acid (+30 min), lactose (+30 min), galactitol (+45min) and galactonate (+30 min). The statistical significance of certain discriminant metabolites, such as sphingosine-1-phosphate and several free fatty acids, was not maintained in the older group. This could be related to the physiological modifications induced by aging, like dysregulated lipid metabolism, including delayed appearance of dodecanoic acid (+60 min) or altered postprandial appearance of myristic acid (+70% Cmax), 3-dehydroxycarnitine (-26% Cmin), decanoylcarnitine (-51% Cmin) and dodecanoylcarnitine (-40% Cmin). In conclusion, candidate BFI of milk or yogurt could be identified based on the modified postprandial response resulting from the fermentation of milk to yogurt. Moreover, population specificities (e.g., aging) should also be considered in future studies to obtain more accurate and specific BFI.

The cure from within? a review of the microbiome and diet in melanoma

Therapy for cutaneous melanoma, the deadliest of the skin cancers, is inextricably linked to the immune system. Once thought impossible, cures for metastatic melanoma with immune checkpoint inhibitors have been developed within the last decade and now occur regularly in the clinic. Unfortunately, half of tumors do not respond to checkpoint inhibitors and efforts to further exploit the immune system are needed. Tantalizing associations with immune health and gut microbiome composition suggest we can improve the success rate of immunotherapy. The gut contains over half of the immune cells in our bodies and increasingly, evidence is linking the immune system within our gut to melanoma development and treatment. In this review, we discuss the importance the skin and gut microbiome may play in the development of melanoma. We examine the differences in the microbial populations which inhabit the gut of those who develop melanoma and subsequently respond to immunotherapeutics. We discuss the role of dietary intake on the development and treatment of melanoma. And finally, we review the landscape of published and registered clinical trials therapeutically targeting the microbiome in melanoma through dietary supplements, fecal microbiota transplant, and microbial supplementation.

Nutritional Assessment of Denture Wearers Using Matched Electronic Dental-Health Record Data

Purpose

To assess the nutritional profile of denture wearers through a retrospective cohort study using nutritional biomarkers from matched electronic dental and health record (EDR‐EHR) data.

Materials and methods

The case group (denture wearers) included matched EDR‐EHR data of patients who received removable partial, complete, and implant‐supported prosthodontic treatments between January 1, 2010 and December 31, 2018, study time. The control (nondenture wearers) group did not have recorded denture treatments and included patient records within 1 year of the denture index date (first date of case patients’ receiving complete or partial denture) of the matching cases. The qualified patients’ EDR were matched with their EHR based on the availability of laboratory reports within 2 years of receiving the dentures (index date). Nutritional biomarkers were selected from laboratory reports for complete blood count, comprehensive and basic metabolic profile, lipid, and thyroid panels. Summary statistics were performed, and general linear mixed effect models were used to evaluate the rate of change over time (slope) of nutritional biomarkers before and after the index date. Likelihood ratio tests were performed to determine the differences between dentures and controls.

Results

The final cohort included 10,481 matched EDR‐EHR data with 3,519 denture wearers and 6,962 controls that contained laboratory results within the study time. The denture wearers’ mean age was 57 ±10 years and the control group was 56 ±10 years with 55% females in both groups. Pre‐post analysis among denture wearers revealed decreased serum albumin (p = 0.002), calcium (p = 0.039), creatinine (p < 0.001) during the post‐index time. Hemoglobin (Hb) was higher pre‐index, and was decreasing during the time period but did not change post‐index (p < 0.001). Among denture wearers, completely edentulous patients had a significant decrease in serum albumin, creatinine, blood urea nitrogen (BUN), but increased estimated glomerular filtration rate (eGFR). In partially edentulous patients, total cholesterol decreased (p = 0.018) and TSH (p = 0.004), BUN (p < 0.001) increased post‐index. Patients edentulous in either upper or lower arch had decreased BUN and eGFR during post‐index. Compared to controls, denture wearers showed decreased serum albumin and protein (p = 0.008), serum calcium (p = 0.001), and controls showed increased Hb (p = 0.035) during post‐index.

Conclusions

The study results indicate nutritional biomarker variations among denture wearers suggesting a risk for undernutrition and the potential of using selected nutritional biomarkers to monitor nutritional profile.

Plasma Metabolites Associated with a Protein-Rich Dietary Pattern: Results from the OmniHeart Trial

Scope

Lack of biomarkers is a challenge for the accurate assessment of protein intake and interpretation of observational study data. The study aims to identify biomarkers of a protein‐rich dietary pattern.

Methods and Results

The Optimal Macronutrient Intake Trial to Prevent Heart Disease (OmniHeart) trial is a randomized cross‐over feeding study which tested three dietary patterns with varied macronutrient content (carbohydrate‐rich; protein‐rich with about half from plant sources; and unsaturated fat‐rich). In 156 adults, differences in log‐transformed plasma metabolite levels at the end of the protein‐ and carbohydrate‐rich diet periods using paired t‐tests is examined. Partial least‐squares discriminant analysis is used to identify a set of metabolites which are influential in discriminating between the protein‐rich versus carbohydrate‐rich dietary patterns. Of 839 known metabolites, 102 metabolites differ significantly between the protein‐rich and the carbohydrate‐rich dietary patterns after Bonferroni correction, the majority of which are lipids (n = 35), amino acids (n = 27), and xenobiotics (n = 24). Metabolites which are the most influential in discriminating between the protein‐rich and the carbohydrate‐rich dietary patterns represent plant protein intake, food or beverage intake, and preparation methods.

Conclusions

The study identifies many plasma metabolites associated with the protein‐rich dietary pattern. If replicated, these metabolites may be used to assess level of adherence to a similar dietary pattern.

Characterizing patterns of dietary exposure using metabolomic profiles of human biospecimens: a systematic review

CONTEXT

Establishing diet-disease associations requires reliable assessment of dietary intake. With the rapid advancement of metabolomics, its use in identifying objective biomarkers of dietary exposure has substantially increased.

OBJECTIVE

The aim of our review was to systematically combine all observational studies linking dietary intake patterns with metabolomic profiles of human biospecimens.

DATA SOURCES

Five databases were searched - MEDLINE, Embase, Scopus, Web of Science, and Cochrane CENTRAL - to March 2020.

DATA EXTRACTION

Of the 14 328 studies initially screened, 35 observational studies that met the specified inclusion criteria were included.

DATA ANALYSIS

All reviewed studies indicated that metabolomic measures were significantly correlated with dietary patterns, demonstrating the potential for using objective metabolomic measures to characterize individuals' dietary intake. However, similar dietary patterns did not always result in similar metabolomic profiles across different study populations.

CONCLUSION

Metabolomic profiles reflect a multitude of factors, including diet, genetic, phenotypic, and environmental influences, thereby providing a more comprehensive picture of the impact of diet on metabolism and health outcomes. Further exploration of dietary patterns and metabolomic profiles across different population groups is warranted.

Detection of transdermal biomarkers using gradient-based colorimetric array sensor

Accurate assessment of dietary macronutrients intake is critical for the effective management of multiple diseases, such as obesity, diabetes, cardiovascular disease, metabolic disease, and cancer. Conventional self-reporting method is burdensome, inaccurate, and often biased. Though blood analysis and breath analysis can provide evidence-based information, they are either invasive or subject to human errors. Here we reported a wearable transdermal volatile biomarkers detection system based on novel colorimetric sensing technology for dietary macronutrients intake assessment. This technique quantifies the emission rates of transdermal volatile biomarkers via a gradient-based colorimetric array sensor (GCAS). The optical system of the GCAS device tracks the localized color development associated with the chemical reaction between the volatile biomarkers and the porous sensing probes, and determines the biomarkers emission rates through image processing algorithms. The localized chemical reaction and the image-based signal processing also make the GCAS capable for multiplexed detection of multiple analytes simultaneously. The GCAS sensor has been applied for transdermal acetone detection on 5 subjects in a keto diet intervention. The study indicates that the transdermal acetone increases after the subjects consuming keto diets and it decreases to basal level after intaking carb-rich diets. The transdermal acetone response from the GCAS sensor correlates well with breath acetone concentration in the range between 0 and 40 ppm and the correlation factor (R²) is as high as 0.8877. This method provides a noninvasive, low-cost, and wearable tool for assessing dietary macronutrients intake outside of lab or hospital settings. It could be widely applied in disease management, weight control, and nutrition management.

Development and Validation of a Lifestyle Behavior Tool in Overweight and Obese Women through Qualitative and Quantitative Approaches

There is a paucity of effective intervention tools for overweight/obese women to assess, guide and monitor their eating behavior. This study aimed to develop a lifestyle intervention tool, assess its acceptability and usefulness, and verify its construct validity in overweight/obese women. The 6P tool (Portion, Proportion, Pleasure, Phase, Physicality, Psychology) was developed and 15 women with a body mass index (BMI) ≥ 25 kg/m2 were interviewed to assess its perceived acceptability and usefulness. Subsequently, the revised 6P tool was tested in 46 women with a BMI ≥ 25 kg/m2. The Three-Factor Eating Questionnaire (TFEQ), International Physical Activity Questionnaire-Short (IPAQ), and weight were measured at baseline and one-month. Most participants were satisfied with the presentation of the 6P tool (86.8%), and agreed it was useful in guiding healthy eating (81.6%) and raising awareness of eating behavior (97.4%). There were significant improvements in cognitive restraint (p = 0.010) and disinhibition (p = 0.030) (TFEQ), portion size (P1), pleasure behaviors (P3), and total composite 6P score (p < 0.001). However, there was no significant reduction in weight or increase in physical activity. The 6P tool is acceptable and presents with good validity for assessing lifestyle behaviors.

Effects of vitamin D and high dairy protein intake on bone mineralization and linear growth in 6- to 8-year-old children: the D-pro randomized trial

BACKGROUND

Vitamin D and dairy protein may stimulate bone mineralization and linear growth in children, but previous studies show inconsistent results and have not examined their combined effects.

OBJECTIVES

To investigate combined and separate effects of vitamin D supplementation and high-protein (HP) compared with normal-protein (NP) yogurt intake on children's bone mineralization and linear growth.

METHODS

In a 2 × 2-factorial trial, 200 healthy, 6- to 8-year-old, Danish, children with light skin (55°N) were randomized to 20 µg/d vitamin D3 or placebo and to substitute 260 g/d dairy with HP (10 g protein/100 g) or NP (3.5 g protein/100 g) yogurt for 24 weeks during an extended winter. Outcomes were total body less head (TBLH) and lumbar spine bone mineral density (BMD), bone mineral content (BMC), and bone area (BA) by dual-energy X-ray absorptiometry, height, and biomarkers of bone turnover and growth. The primary outcome was TBLH BMD.

RESULTS

In total, 184 children (92%) completed the study. The baseline serum 25-hydroxyvitamin D was 80.8 ± 17.2 nmol/L, which increased by 7.2 ± 14.1 nmol/L and decreased by 32.3 ± 17.5 nmol/L with vitamin D and placebo, respectively. The baseline protein intake was 15.4 ± 2.4 energy percentage (E%), which increased to 18.3 ± 3.4 E% with HP. There were no vitamin D-yogurt interactions and no main effects of either intervention on TBLH BMD. However, vitamin D supplementation increased lumbar spine BMD and TBLH BMC compared to placebo, whereas HP groups showed lower increments in lumbar spine BMD, TBLH BMC and BA, and plasma osteocalcin compared to NP groups. Height, growth factors, and parathyroid hormone levels were unaffected.

CONCLUSIONS

Although there were no effects on whole-body BMD, vitamin D increased bone mass and spinal BMD, whereas high compared with normal dairy protein intake had smaller incremental effects on these outcomes. This supports a recommended vitamin D intake of around 20 µg/d during winter but not use of HP dairy products for improved bone mineralization among healthy, well-nourished children. This trial was registered at clinicaltrials.gov as NCT03956732.

Assessing the social validity of a brief dietary survey for Sri Lankan adults with a focus on gender: a qualitative study

BACKGROUND

As the World Health Organization urges countries to strengthen their noncommunicable disease monitoring and surveillance activities, setting-specific innovations are emerging. Diet - a key, modifiable risk factor for chronic diseases - is particularly challenging to capture reliably. By socially validating self-report dietary survey tools, we may be able to increase the accuracy and representativeness of data for improved population health outcomes. The purpose of this study was to explore the factors that impact Sri Lankan Brief Dietary Survey (a newly developed tool) and 24-h Dietary Recall participation, engagement, and social validity among Sri Lankan adults.

METHODS

We conducted semi-structured interviews with 93 participants (61 women and 32 men) in three Sri Lankan districts (Colombo, Kalutara, and Trincomalee). Interview data were analysed thematically and are presented as non-hierarchical thematic networks.

RESULTS

Participants identified a number of factors that influenced their survey participation and engagement. These included the time of day interviews occur, recall ease, level of commitment required, perceived survey value, emotional response to surveys, and interviewer positionality. Many of these factors were gendered, however, both female and male participants expressed a preference for engaging with socially valid research that they felt justified their personal investment in data collection. When explicitly asked to share ideas about how to improve the surveys, many participants opted not to provide suggestions as they felt they lacked the appropriate expertise.

CONCLUSIONS

Our findings have implications for the accuracy and equity of dietary surveillance activities, and ultimately the appropriateness and effectiveness of programmes and policies informed by these data. Only through understanding how and why the target population engages with dietary research can we develop socially valid methods that assess and address the dietary risks of individuals and groups that are underrepresented by current conventions.

A Single-Carbon Stable Isotope Ratio Model Prediction Equation Can Estimate Self-Reported Added Sugars Intake in an Adult Population Living in Southwest Virginia

The δ13C value of blood is a novel proposed biomarker of added sugars (AS) intake. AS prediction equations using either a single- (δ13C) or dual-isotope model (δ13C and δ15N) were previously developed in an adult population with high AS intake living in southwest Virginia (reference group). The purpose of this investigation was to test the δ13C single- and δ13C and δ15N dual-isotope prediction equations for AS intake in adults with a lower mean AS intake and different demographic characteristics (test group). The blood samples for the reference (n = 257 for single-isotope, n = 115 for dual-isotope) and test groups (n = 56) were analyzed for δ13C and δ15N values using natural abundance stable isotope mass spectrometry and were compared to reported dietary AS intake. When the δ13C single-isotope equation was applied to the test group, predicted AS intake was not significantly different from reported AS intake (mean difference ± standard error = -3.6 ± 5.5 g, Z = -0.55, p = 0.51). When testing the dual-isotope equation, predicted AS was different from reported AS intake (mean difference ± SEM = 13.0 ± 5.4 g, Z = -2.95, p = 0.003). δ13C value was able to predict AS intake using a blood sample within this population subset. The single-isotope prediction equation may be an alternative method to assess AS intake and is more objective, cost-feasible, and efficient than traditional dietary assessment methods. However, more research is needed to assess this biomarker with rigorous study designs such as controlled feeding.

Nature of the evidence base and frameworks underpinning dietary recommendations for prevention of non-communicable diseases: a position paper from the Academy of Nutrition Sciences

This Position Paper from the Academy of Nutrition Sciences is the first in a series which describe the nature of the scientific evidence and frameworks that underpin nutrition recommendations for health. This first paper focuses on evidence which underpins dietary recommendations for prevention of non-communicable diseases. It considers methodological advances made in nutritional epidemiology and frameworks used by expert groups to support objective, rigorous and transparent translation of the evidence into dietary recommendations. The flexibility of these processes allows updating of recommendations as new evidence becomes available. For CVD and some cancers, the paper has highlighted the long-term consistency of a number of recommendations. The innate challenges in this complex area of science include those relating to dietary assessment, misreporting and the confounding of dietary associations due to changes in exposures over time. A large body of experimental data is available that has the potential to support epidemiological findings, but many of the studies have not been designed to allow their extrapolation to dietary recommendations for humans. Systematic criteria that would allow objective selection of these data based on rigour and relevance to human nutrition would significantly add to the translational value of this area of nutrition science. The Academy makes three recommendations: (i) the development of methodologies and criteria for selection of relevant experimental data, (ii) further development of innovative approaches for measuring human dietary intake and reducing confounding in long-term cohort studies and (iii) retention of national nutrition surveillance programmes needed for extrapolating global research findings to UK populations.

The potential of salivary biomarkers of nutritional status and dietary intake: A Systematic Review

OBJECTIVES

To explore whether nutritional salivary biomarkers could be used to aid nutritional status assessment and/or support traditional dietary assessment methods for patients.

DATA AND SOURCES

Searches were performed using four electronic databases; MEDLINE, EMBASE, Scopus and Web of Science. Trial registers (i.e. Cochrane), grey literature and reference lists were searched.

STUDY SELECTION

Studies which measured nutritional salivary biomarkers related to nutritional status and/or dietary intake outcome were included. No restrictions on participants' age, study design, publication date, setting or health status. Animal studies, non-English language studies, commentaries, and conference abstracts were excluded.

RESULTS

Study titles and abstracts were screened (n = 7982), full-texts assessed (n = 176) and 85 studies were included in a narrative synthesis. The most promising salivary biomarkers for nutritional status included: glucose, where saliva and serum levels were positively correlated in those with type 2 diabetes (T2D), higher salivary calcium levels in post-menopausal women in general and specifically those with lower bone mineral density (BMD), and salivary vitamin D to assess vitamin D status in healthy volunteers. Higher salivary total antioxidant capacity (TAC), nitrate/nitrite and fluoride were observed with increased antioxidant, nitrate/nitrite and fluoride dietary intake, respectively. A meta-analysis found significantly higher mean salivary glucose (n = 12) in T2D compared with healthy controls, but there was substantial heterogeneity (I²=94%) and evidence of publication bias.

CONCLUSIONS

The most promising salivary biomarkers identified in this systematic review were, glucose, vitamin D, calcium, TAC, nitrate/nitrite and fluoride. However, this was based on a small number of studies of varying quality, with many lacking a salivary assay performance assessment.

CLINICAL SIGNIFICANCE

At present, nutritional salivary biomarkers cannot be used alone to assess nutritional status or dietary intake. Further research into the most promising nutritional salivary biomarkers is required.

Saturated fats and cardiovascular health: Current evidence and controversies

A diet high in saturated fatty acids (SFA) is a suspected contributor to atherosclerotic cardiovascular disease (ASCVD) risk, in large part because of an effect to raise the low-density lipoprotein cholesterol (LDL-C) concentration. Most dietary guidance from health authorities advocates limiting intake of SFA, particularly for people with clinical ASCVD, dyslipidemia, or diabetes mellitus. However, recent reviews have highlighted controversies regarding SFA intake and cardiovascular health. This brief editorial commentary includes a discussion of the evidence regarding SFA intake and cardiovascular health, outlines gaps in the available evidence, and proposes tentative conclusions based on what is known today about SFA consumption and ASCVD risk. Results from observational studies demonstrate that dietary patterns with lower average intakes of SFA are associated with favorable cardiovascular outcomes. Additionally, although the number of randomized controlled trials testing the effects of reducing SFA intake on ASCVD outcomes is limited, the available evidence supports the view that replacing SFA with unsaturated fatty acids, particularly polyunsaturated fatty acids, may reduce ASCVD risk. Beyond raising LDL-C and atherogenic lipoprotein particle concentrations, higher intakes of SFA may influence pathways affecting inflammation, cardiac rhythm, hemostasis, apolipoprotein CIII production, and high-density lipoprotein function. However, the impacts of these effects on ASCVD risk remain uncertain. In the authors' view, the totality of the evidence supports the current recommendation to limit SFA intake to <10% of total daily energy for the general healthy population and further (e.g., to 5-6% of total daily energy) for patients with hypercholesterolemia.

Correlation between the Macronutrient Content of Dental Calculus and the FFQ-Based Nutritional Intake of Obese and Normal-Weight Individuals

The growing epidemic of chronic diseases afflicting both developed and developing countries is related to diet and lifestyle. The current dietary assessment still has many constraints, particularly related to the objectivity of data gathering. Dental calculus, which is usually considered as medical waste in dental treatment, turns out to be a provider of abundant oral information. The objective of this study is to obtain the correlation between the macronutrient content of dental calculus and nutritional intake based on FFQ. This research is an analytic observational study with a case-control study design. Samples consisting of 35 obese individuals and 21 normal-weight individuals were taken using purposive sampling. The nutritional intake data were obtained using FFQ. The macronutrient content of dental calculus was checked using a colorimetric assay. The comparison between obese individuals and normal-weight individuals was tested using the Mann–Whitney test and T-test. The correlation between the macronutrient content of dental calculus and nutritional intake based on FFQ was measured using Spearman's rank-order correlation. The results showed there was a correlation between the macronutrient content of dental calculus and macronutrient intake based on FFQ. However, strong correlation was found only between fat intake with the total lipid content of dental calculus with rs = 0.521 and between carbohydrate intake with the total carbohydrate content of dental calculus with rs = 0.519. It was concluded that carbohydrate, protein, and lipid intake can be assessed using dental calculus. Dental calculus can be an alternative source of noninvasive, inexpensive, and specific dietary biomarkers.

Urinary Tartaric Acid, a Biomarker of Wine Intake, Correlates with Lower Total and LDL Cholesterol

Postmenopausal women are at higher risk of developing cardiovascular diseases due to changes in lipid profile and body fat, among others. The aim of this study was to evaluate the association of urinary tartaric acid, a biomarker of wine consumption, with anthropometric (weight, waist circumference, body mass index (BMI), and waist-to-height ratio), blood pressure, and biochemical variables (blood glucose and lipid profile) that may be affected during the menopausal transition. This sub-study of the PREDIMED (Prevención con Dieta Mediterránea) trial included a sample of 230 women aged 60-80 years with high cardiovascular risk at baseline. Urine samples were diluted and filtered, and tartaric acid was analyzed by liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Correlations between tartaric acid and the study variables were adjusted for age, education level, smoking status, physical activity, BMI, cholesterol-lowering, antihypertensive, and insulin treatment, total energy intake, and consumption of fruits, vegetables, and raisins. A strong association was observed between wine consumption and urinary tartaric acid (0.01 μg/mg (95% confidence interval (CI): 0.01, 0.01), p-value < 0.001). Total and low-density lipoprotein (LDL) cholesterol were inversely correlated with urinary tartaric acid (-3.13 μg/mg (-5.54, -0.71), p-value = 0.016 and -3.03 μg/mg (-5.62, -0.42), p-value = 0.027, respectively), whereas other biochemical and anthropometric variables were unrelated. The results suggest that wine consumption may have a positive effect on cardiovascular health in postmenopausal women, underpinning its nutraceutical properties.

The Effectiveness of Randomized Controlled Trials to Improve Dietary Intake in the Context of Cardiovascular Disease Prevention and Management in Rural Communities: A Systematic Review

BACKGROUND

Dietary intake is an important modifiable risk factor for cardiovascular disease. However, to our knowledge, there are no systematic reviews of nutrition interventions in the context of cardiovascular disease prevention and management within rural communities. This is important to investigate, given the unique geographic, social, and contextual factors associated with rurality.

OBJECTIVE

Our primary objective was to systematically assess evidence on the effectiveness of randomized controlled trials to improve dietary intake in the context of cardiovascular disease prevention and management in rural communities.

METHODS

Nine electronic databases were searched from inception to June 2020, including MEDLINE, The Cochrane Library, Embase, Emcare, PsycINFO, Scopus, Rural and Remote Health, CINAHL, and AMED. Randomized controlled trials that reported results of interventions with adult, rural populations and measured change in dietary intake compared to usual care, alternative intervention, or no intervention controls were included. Included randomized controlled trials were also assessed according to the TIDieR (Template for Intervention Description and Reporting) checklist and RE-AIM (reach, effectiveness, adoption, implementation, maintenance) framework.

RESULTS

Thirteen articles reporting results of randomized controlled trials were identified. Included articles reported a range of nutrition interventions and measured 18 dietary intake outcomes. Most studies (n = 10) demonstrated effectiveness in altering at least 1 dietary intake outcome, including fruit and/or vegetable (n = 9), fiber (n = 2), Dietary Risk Assessment score (n = 2), energy, dairy, carotene, vitamin C and sodium (all n = 1). However, there was wide variation in the reporting of intervention components (according to the TIDieR checklist) and impact (according to RE-AIM framework), resulting in difficulty interpreting the "real-world" implications of these results.

CONCLUSIONS

Through this systematic review, we found limited evidence of improvement in dietary intakes due to nutrition interventions in the context of cardiovascular disease prevention and management in rural communities. Fruit and/or vegetable intakes were the most frequently reported dietary intake outcomes, and most likely to be improved across the included studies. Included studies were generally not well reported, which may hinder replication by clinicians and consolidation of the evidence base by other researchers. Given the substantial burden of cardiovascular disease experienced by those living in rural areas of developed countries, additional high-quality nutrition research that acknowledges the complexities of rural health is required.

Common Limitations and Challenges of Dietary Clinical Trials for Translation into Clinical Practices

The progressive development of clinical and public health nutrition has long relied on dietary clinical trials (DCTs), investigating the causal relationship between diet and multiple risk factors of non-communicable and chronic diseases. DCTs are also hallmarks for establishing dietary requirements and promoting overall nutritional health among the population. Despite their critical importance in translation into public health strategies and practices, DCTs have several limitations and challenges for study design, implementation and finding interpretation. The complex nature of nutrition interventions, collinearity between diet components, multi-target effects of the interventions, diverse dietary behaviors, and food culture are the most challenging issues. Furthermore, baseline exposure and dietary status, appropriate control groups, blinding, randomization, and poor adherence undermine the effectiveness of DCTs in translation into practices. Disruptive factors will be minimized if researchers are committed to following good clinical practice (GCP) standards available for common designs of clinical trials. Planning DCTs, however, needs careful considerations for hypothesis generation, study design development, the definition of primary and secondary outcome measures, and target population.

24 h urinary creatinine excretion during pregnancy and its application in appropriate estimation of 24 h urinary iodine excretion

BACKGROUND

Urinary creatinine can be used to adjust urinary iodine to evaluate iodine nutritional status during pregnancy. However, the reference intervals and impact factors of urinary creatinine are unknown.

METHODS

24 h urine creatinine concentration (24 hUCr) and spot UCr at four different time periods of the day of pregnant women from Part 1 (n = 743) were measured. Linear regression analysis was performed to identify the impact factors of 24 h urinary creatinine excretion (24 hUCrE) and obtain the estimated 24 h urinary creatinine excretion (24 hUCrE_est). Then measured urinary iodine concentration (UIC) of 24 h and at fasting of pregnant women from Part 2 (n = 325), used spot urinary iodine to creatinine concentration ratio (UIC/UCr) and 24 hUCrE_est to calculate the estimated 24 h urinary iodine excretion (24 hUIE_est), finally checked the consistency and correlation of 24 hUIE_est and 24 h urinary iodine excretion (24 hUIE).

RESULTS

In Part 1, the median 24 hUCrE was 1.24(IQR0.98-1.76)g, and the reference interval was 0.61-2.93 g. The median 24 hUCr was 0.76 (IQR0.57-1.01)g/L, and the reference interval was 0.36-1.88 g/L. Multiple linear regression results showed that pregnancy weight was an influencing factor to 24 hUCrE after adjusting by gestational weeks, age, pre-pregnancy BMI, and percentage of body fat (F = 45.029, p＜0.001). In Part 2, there was no statistically significant difference between 24 hUIE_est and 24 hUIE (Z =-0.767, p = 0.443). Using 24hUIE as the gold standard, the relative average difference in 24hUIE_est was 4.2 %, the relative average differences for UIC and UIC/UCr were 32.4 % and 37.2 %. The reference interval of 24 hUIE and 24 hUIE_est were 88.43-585.90 μg and 50.97-700.39 μg, respectively.

CONCLUSIONS

The reference intervals of 24 hUCrE, spot UCr, 24 hUIE, and 24 hUIE_est during pregnancy were established. 24 hUCrE has important application value in iodine nutrition evaluation to gain more lead time for pregnant women with iodine nutrition-related diseases.

Plasma Metabolomic Signatures of Healthy Dietary Patterns in the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

In individuals with chronic kidney disease (CKD), healthy dietary patterns are inversely associated with CKD progression. Metabolomics, an approach that measures many small molecules in biofluids, can identify biomarkers of healthy dietary patterns.

OBJECTIVES

We aimed to identify known metabolites associated with greater adherence to 4 healthy dietary patterns in CKD patients.

METHODS

We examined associations between 486 known plasma metabolites and Healthy Eating Index (HEI)-2015, Alternative Healthy Eating Index (AHEI)-2010, the Dietary Approaches to Stop Hypertension (DASH) diet, and alternate Mediterranean diet (aMED) in 1056 participants (aged 21-74 y at baseline) in the Chronic Renal Insufficiency Cohort (CRIC) Study. Usual dietary intake was assessed using a semiquantitative FFQ. We conducted multivariable linear regression models to study associations between healthy dietary patterns and individual plasma metabolites, adjusting for sociodemographic characteristics, health behaviors, and clinical factors. We used principal component analysis to identify groups of metabolites associated with individual food components within healthy dietary patterns.

RESULTS

After Bonferroni correction, we identified 266 statistically significant diet-metabolite associations (HEI: n = 60; AHEI: n = 78; DASH: n = 77; aMED: n = 51); 78 metabolites were associated with >1 dietary pattern. Lipids with a longer acyl chain length and double bonds (unsaturated) were positively associated with all 4 dietary patterns. A metabolite pattern low in saturated diacylglycerols and triacylglycerols, and a pattern high in unsaturated triacylglycerols was positively associated with intake of healthy food components. Plasmalogens were negatively associated with the consumption of nuts and legumes and healthy fat, and positively associated with the intake of red and processed meat.

CONCLUSIONS

We identified many metabolites associated with healthy dietary patterns, indicative of food consumption. If replicated, these metabolites may be considered biomarkers of healthy dietary patterns in patients with CKD.

Dietary patterns related to zinc and polyunsaturated fatty acids intake are associated with serum linoleic/dihomo-γ-linolenic ratio in NHANES males and females

Identifying dietary patterns that contribute to zinc (Zn) and fatty acids intake and their biomarkers that may have an impact on health of males and females. The present study was designed to (a) extract dietary patterns with foods that explain the variation of Zn and PUFAs intake in adult men and women; and (b) evaluate the association between the extracted dietary patterns with circulating levels of serum dihomo-γ-linolenic fatty acid (DGLA) or serum linoleic/dihomo-γ-linolenic (LA/DGLA) ratio in males and females. We used reduced rank regression (RRR) to extract the dietary patterns separated by sex in the NHANES 2011-2012 data. A dietary pattern with foods rich in Zn (1st quintile = 8.67 mg/day; 5th quintile = 11.11 mg/day) and poor in PUFAs (5th quintile = 15.28 g/day; 1st quintile = 18.03 g/day) was found in females (S-FDP2) and the same pattern, with foods poor in PUFAs (5th quintile = 17.6 g/day; 1st quintile = 20.7 g/day) and rich in Zn (1st quintile = 10.4 mg/day; 5th quintile = 12.9 mg/day) (S-MDP2), was found in males. The dietary patterns with foods rich in Zn and poor in PUFAs were negatively associated with serum LA/DGLA ratio. This is the first study to associate the LA/DGLA ratio with Zn and PUFAs related dietary patterns in males and females.

A Systematic Review and Meta-Analysis of Validation Studies Performed on Dietary Record Apps

Mobile dietary record apps have been increasingly validated by studies with various study designs. This review aims to evaluate the overall accuracy of dietary record apps in measuring the intake of energy, macro- and micronutrients, and food groups in real-life settings and the designs of validation studies. We systematically searched mobile dietary record validation studies published during the period from 2013 to 2019. We identified 14 studies for the systematic review, of which 11 studies were suitable for meta-analyses on energy intake and 8 studies on macronutrient intake. Mean differences and SDs of nutrient estimations between the app and the reference method from studies were pooled using a random-effects model. All apps underestimated energy intake when compared with their reference methods, with a pooled effect of -202 kcal/d (95% CI: -319, -85 kcal/d); the heterogeneity of studies was 72%. After stratification, studies that used the same food-composition table for both the app and the reference method had a lower level of heterogeneity (0%) and a pooled effect of -57 kcal/d (95% CI: -116, 2 kcal/d). The heterogeneity of studies in the differences in carbohydrate, fat, and protein intake was 54%, 73%, and 80%, with the pooled effect of -18.8 g/d, -12.7 g/d, and -12.2 g/d, respectively, after excluding outliers. The intakes of micronutrients and food groups were statistically nonsignificantly underestimated by the apps in most cases. In conclusion, dietary record apps underestimated food consumption compared with traditional dietary assessment methods. Moreover, varying study designs have been found across studies. Recommended practices for conducting validation studies were formulated including considering biomarkers as the reference, testing in a larger and more representative study population for a longer period, avoiding the learning effect of each method, and comparing food group or food item consumption in addition to comparing energy and nutrient intakes.

Reliability and Concurrent and Construct Validity of a Food Frequency Questionnaire for Pregnant Women at High Risk to Develop Fetal Growth Restriction

Accuracy of dietary assessment instruments such as food frequency questionnaire (FFQ) is crucial in the evaluation of diet–disease relationships. Test–retest reliability and concurrent and construct validity of a FFQ were evaluated in 150 pregnant women at high risk to develop fetal growth restriction randomly selected from those included in the improving mothers for better prenatal care trial Barcelona (IMPACT BCN). The FFQ and dietary records were performed at baseline and 34–36 weeks of gestation. Test–retest reliability of the FFQ for 12 food groups and 17 nutrients was moderate (ICC = 0.55) and good (ICC = 0.60), respectively. Concurrent validity between food, nutrients and a composite Mediterranean diet score (MedDiet score) and food records was fair for foods and nutrients (ρ average = 0.38 and 0.32, respectively) and moderate (r = 0.46) for the MedDiet score. Validation with biological markers ranged from poor (r = 0.07) for olives to moderate (r = 0.41) for nuts. A fair concordance between methods were found for nutrients (weighted κ = 0.22) and foods (weighted κ = 0.27). The FFQ-derived MedDiet score correlated in anticipated directions with intakes of nutrients and foods derived by food records. The FFQ showed a moderate test–retest reliability and reasonable validity to rank women according to their food and nutrient consumption and adherence to the Mediterranean diet.

n-3 Fatty Acid Biomarkers and Incident Type 2 Diabetes: An Individual Participant-Level Pooling Project of 20 Prospective Cohort Studies

OBJECTIVE

Prospective associations between n-3 fatty acid biomarkers and type 2 diabetes (T2D) risk are not consistent in individual studies. We aimed to summarize the prospective associations of biomarkers of α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) with T2D risk through an individual participant-level pooled analysis.

RESEARCH DESIGN AND METHODS

For our analysis we incorporated data from a global consortium of 20 prospective studies from 14 countries. We included 65,147 participants who had blood measurements of ALA, EPA, DPA, or DHA and were free of diabetes at baseline. De novo harmonized analyses were performed in each cohort following a prespecified protocol, and cohort-specific associations were pooled using inverse variance-weighted meta-analysis.

RESULTS

A total of 16,693 incident T2D cases were identified during follow-up (median follow-up ranging from 2.5 to 21.2 years). In pooled multivariable analysis, per interquintile range (difference between the 90th and 10th percentiles for each fatty acid), EPA, DPA, DHA, and their sum were associated with lower T2D incidence, with hazard ratios (HRs) and 95% CIs of 0.92 (0.87, 0.96), 0.79 (0.73, 0.85), 0.82 (0.76, 0.89), and 0.81 (0.75, 0.88), respectively (all P < 0.001). ALA was not associated with T2D (HR 0.97 [95% CI 0.92, 1.02]) per interquintile range. Associations were robust across prespecified subgroups as well as in sensitivity analyses.

CONCLUSIONS

Higher circulating biomarkers of seafood-derived n-3 fatty acids, including EPA, DPA, DHA, and their sum, were associated with lower risk of T2D in a global consortium of prospective studies. The biomarker of plant-derived ALA was not significantly associated with T2D risk.

The relationship between urinary polyphenol metabolites and dietary polyphenol intakes in young adults

Spot urinary polyphenols have potential as a biomarker of polyphenol-rich food intakes. The aim of this study is to explore the relationship between spot urinary polyphenols and polyphenol intakes from polyphenol-rich food sources. Young adults (18-24 years old) were recruited into a sub-study of an online intervention aimed at improving diet quality. Participants' intake of polyphenols and polyphenol-rich foods was assessed at baseline and 3 months using repeated 24-h recalls. A spot urine sample was collected at each session, with samples analysed for polyphenol metabolites using LC-MS. To assess the strength of the relationship between urinary polyphenols and dietary polyphenols, Spearman correlations were used. Linear mixed models further evaluated the relationship between polyphenol intakes and urinary excretion. Total urinary polyphenols and hippuric acid (HA) demonstrated moderate correlation with total polyphenol intakes (rs = 0·29-0·47). HA and caffeic acid were moderately correlated with polyphenols from tea/coffee (rs = 0·26-0·46). Using linear mixed models, increases in intakes of total polyphenols or polyphenols from tea/coffee or oil resulted in a greater excretion of HA, whereas a negative relationship was observed between soya polyphenols and HA, suggesting that participants with higher intakes of soya polyphenols had a lower excretion of HA. Findings suggest that total urinary polyphenols may be a promising biomarker of total polyphenol intakes foods and drinks and that HA may be a biomarker of total polyphenol intakes and polyphenols from tea/coffee. Caffeic acid warrants further investigation as a potential biomarker of polyphenols from tea/coffee.

Metabolomic Markers of Southern Dietary Patterns in the Jackson Heart Study

SCOPE

New biomarkers are needed that are representative of dietary intake.

METHODS AND RESULTS

We assess metabolites associated with Southern dietary patterns in 1401 Jackson Heart Study participants. Three dietary patterns are empirically derived using principal component analysis: meat and fast food, fish and vegetables, and starchy foods. We randomly select two subsets of the study population: two-third sample for discovery (n = 934) and one-third sample for replication (n = 467). Among the 327 metabolites analyzed, 14 are significantly associated with the meat and fast food dietary pattern, four are significantly associated with the fish and vegetables dietary pattern, and none are associated with the starchy foods dietary pattern in the discovery sample. In the replication sample, nine remain associated with the meat and fast food dietary pattern [indole-3-propanoic acid, C24:0 lysophosphatidylcholine (LPC), N-methyl proline, proline betaine, C34:2 phosphatidylethanolamine (PE) plasmalogen, C36:5 PE plasmalogen, C38:5 PE plasmalogen, cotinine, hydroxyproline] and three remain associated with the fish and vegetables dietary pattern [1,7-dimethyluric acid, C22:6 lysophosphatidylethanolamine, docosahexaenoic acid (DHA)].

CONCLUSION

Twelve metabolites are discovered and replicated in association with dietary patterns detected in a Southern U.S. African-American population, which could be useful as biomarkers of Southern dietary patterns.