Assessing Dietary Outcomes in Intervention Studies: Pitfalls, Strategies, and Research Needs

The Carbon Isotope Ratio as an Objective Biomarker of Added Sugar Intake: A Scoping Review of Current Evidence in Human Nutrition

Objective biomarkers of dietary intake are needed to advance nutrition research. The carbon isotope ratio (C13/C12; CIR) holds promise as an objective biomarker of added sugar (AS) and sugar-sweetened beverage (SSB) intake. This systematic scoping review presents the current evidence on CIRs from human studies. Search results (through April 12, 2024) yielded 6297 studies and 24 final articles. Studies were observational (n = 12), controlled feeding (n = 10), or dietary interventions (n = 2). CIRs were sampled from blood (n = 23), hair (n = 5), breath (n = 2), and/or adipose tissue (n = 1). Most (n = 17) conducted whole tissue (that is, bulk) analysis, 8 used compound specific isotope analysis (CSIA), and/or 2 studies used methods appropriate for analyzing breath. Studies were conducted in 3 concentrated geographic regions of the United States (n = 7 Virginia; n = 5 Arizona; n = 4 Alaska), with only 2 studies conducted in other countries. Studies that used CSIA to examine the CIR from the amino acid alanine (CIR-Ala; n = 4) and CIR analyzed from breath (n = 2) provided the most robust evidence for CIR as an objective biomarker of AS and SSBs (R2 range 0.36-0.91). Studies using bulk analysis of hair or blood showed positive, but modest and more variable associations with AS and SSBs (R2 range 0.05-0.48). Few studies showed no association, particularly in non-United States populations and those with low AS and SSB intakes. Two studies provided evidence for CIR to detect changes in SSB intake in response to dietary interventions. Overall, the most compelling evidence supports CIR-Ala as an objective indicator of AS intake and breath CIR as an indicator of short-term AS intake. Considering how to adjust for underlying dietary patterns remains an important area of future work and emerging methods using breath and CSIA warrant additional investigation. More evidence is needed to refine the utility and specificity of CIRs to measure AS and SSB intake.

Identifying the Leading Sources of Saturated Fat and Added Sugar in U.S. Adults

The 2020-2025 Dietary Guidelines for Americans recommend limiting intakes of saturated fat and added sugars (SF/AS) to <10% total energy. Data-driven approaches to identify sources of SF/AS are needed to meet these goals. We propose using a population-based approach to identify the leading food and beverage sources of SF/AS consumed by US adults. Foods and beverages reported as consumed were assessed from two, 24 h dietary recalls (24HRDR) from 36,378 adults aged 19 years and older from the 2005-2018 National Health and Nutrition Examination Survey. Intakes of SF/AS were aggregated across both 24HRDR to identify What We Eat in America food categories accounting for ≥90% of SF/AS, respectively, by the total population and within population subgroups. Data were weighted to estimate a nationally representative sample. Ninety-five discrete food categories accounted for ≥90% of the total SF/AS intakes for >88% of the representative sample of U.S. adults. The top sources of SF were cheese, pizza, ice cream, and eggs. The leading sources of AS were soft drinks, tea, fruit drinks, and cakes and pies. This analysis reflects a parsimonious approach to reliably identify foods and beverages that contribute to SF/AS intakes in U.S. adults.

Maternal Iron and Vitamin D Status during the Second Trimester Is Associated with Third Trimester Depression Symptoms among Pregnant Participants in the APrON Cohort

BACKGROUND

The maternal status of multiple micronutrients during pregnancy and postpartum and their potential associations with maternal health outcomes are largely undescribed.

OBJECTIVES

This study aimed to examine associations between maternal iron and vitamin D status, individually and in combination, on depression symptoms in pregnant individuals.

METHODS

The Alberta Pregnancy Outcomes and Nutrition cohort study included pregnant participants and their children from Calgary and Edmonton, Canada. Iron biomarkers (serum ferritin [SF], soluble transferrin receptor, and hepcidin) were measured via immunoassays and vitamin D [25-hydroxyvitamin D3 (25(OH)D3) and 3-epi-25-hydoxyvitamin D3 (3-epi-25(OH)D3)] metabolites were quantifed using liquid chromatography with tandem mass spectroscopy. Four categories of maternal iron and vitamin D status during the second trimester were conceptualized using concentrations of SF and total 25-hydoxyvitamin D [25(OH)D], respectively. Maternal Edinburgh Postnatal Depression Scale (EPDS) scores during the third trimester (n = 1920) and 3 mo postpartum (n = 1822) were obtained.

RESULTS

Concentrations of maternal 25(OH)D3, 3-epi-25(OH)D3, and the ratio of both metabolites were significantly higher during the second trimester compared with their status at 3 mo postpartum. Higher second trimester maternal concentrations of SF (β: -0.8; 95% confidence interval [CI]: -1.5, -0.01), hepcidin (β: -0.5; 95% CI: -0.9, -0.2), and 25(OH)D3 (β: -0.01; 95% CI: -0.02, -0.004) predicted lower maternal EPDS scores during the third trimester. Pregnant individuals with a low iron (SF <15 μg/L) and replete vitamin D (25(OH)D ≥75 nmol/L) (β: 1.1; 95% CI: 0.03, 2.1) or low iron (SF <15 μg/L) and vitamin D (25(OH)D <75 nmol/L) (β: 2.2; 95% CI: 0.3, 4.2) status during midpregnancy had higher third trimester EPDS scores compared with those that were replete in both micronutrients.

CONCLUSIONS

A higher midpregnancy maternal iron and vitamin D status, independently or in combination, predicted fewer maternal depression symptoms in the third trimester. Concentrations of maternal 25(OH)D3 and 3-epi-25(OH)D3 may be lower in the postpartum period compared with midpregnancy.

Perceptions of self-monitoring dietary intake according to a plate-based approach: A qualitative study

Dietary self-monitoring is a behaviour change technique used to help elicit and sustain dietary changes over time. Current dietary self-monitoring tools focus primarily on itemizing foods and counting calories, which can be complex, time-intensive, and dependent on health literacy. Further, there are no dietary self-monitoring tools that conform to the plate-based approach of the 2019 Canada Food Guide (CFG), wherein the recommended proportions of three food groups are visually represented on a plate without specifying daily servings or portion sizes. This paper explored the perceptions of end-users (i.e., general public) and Registered Dietitians of iCANPlateTM-a dietary self-monitoring mobile application resembling the CFG. Qualitative data were collected through virtual focus groups. Focus group questions were based on the Capability, Opportunity, Motivation-Behaviour (COM-B) theoretical framework to explore perceptions of using the CFG and currently available dietary self-monitoring tools. The prototype iCANPlateTM (version 0.1) was presented to gain feedback on perceived barriers and facilitators of its use. Focus group discussions were audio recorded and verbatim transcribed. Trained researchers used thematic analysis to code and analyze the transcripts independently. Seven focus groups were conducted with Registered Dietitians (n = 44) and nine focus groups with members from the general public (n = 52). During the focus groups, participants mainly discussed the capabilities and opportunities required to use the current iteration of iCANPlateTM. Participants liked the simplicity of the application and its capacity to foster self-awareness of dietary behaviours rather than weight control or calorie counting. However, concerns were raised regarding iCANPlateTM's potential to improve adherence to dietary self-monitoring due to specific characteristics (i.e., insufficient classifications, difficulty in conceptualizing proportions, and lack of inclusivity). Overall, participants liked the simplicity of iCANPlateTM and its ability to promote self-awareness of dietary intakes, primarily through visual representation of foods on a plate as opposed to reliance on numerical values or serving sizes, were benefits of using the app. Findings from this study will be used to further develop the app with the goal of increasing adherence to plate-based dietary approaches.

Examining Potential Modifiers of Human Skin and Plasma Carotenoid Responses in a Randomized Trial of a Carotenoid-Containing Juice Intervention

BACKGROUND

Skin carotenoid measurements are emerging as a valid and reliable indicator of fruit and vegetable intake and carotenoid intake. However, little is known about the extent to which skin carotenoid responsivity to dietary changes differs based on demographic and physiologic characteristics.

OBJECTIVES

This study examined potential effect modifiers of skin carotenoid and plasma carotenoid responses to a carotenoid-rich juice intervention.

METHODS

We leveraged data from 2 arms of a 3-site randomized controlled trial of a carotenoid-containing juice intervention (moderate dose = 6 ounces juice, 4 mg total carotenoids/d, high dose = 12 ounces juice, 8 mg total carotenoids/d) (n = 106) to examine effect modification by age, self-categorized race/ethnicity, biological sex, baseline body fat, body mass index, skin melanin, skin hemoglobin, skin hemoglobin saturation, skin coloration, sun exposure, and baseline intake of carotenoids from foods. Skin carotenoid concentrations were assessed using pressure-mediated reflection spectroscopy (Veggie Meter), and plasma carotenoid concentrations were measured using high-performance liquid chromatography.

RESULTS

In bivariate analyses, among the high-dose group (8 mg/d), those of older age had lower skin carotenoid responsiveness than their younger counterparts, and those with greater hemoglobin saturation and lighter skin had higher skin carotenoid score responsiveness. In the moderate-dose group (4 mg/d), participants from one site had greater plasma carotenoid responsiveness than those from other sites. In multivariate analyses, participants with higher baseline skin carotenoids had smaller skin carotenoid responses to both moderate and high doses.

CONCLUSIONS

Changes in skin carotenoid scores in response to interventions to increase fruit and vegetable intake should be interpreted in the context of baseline skin carotenoid scores, but other variables (e.g., self-categorized race/ethnicity, biological sex, baseline body fat, body mass index, skin melanin, and sun exposure) do not significantly modify the effect of carotenoid intake on changes in skin carotenoid scores. This trial was registered at clinicaltrials.gov as NCT04056624.

Associations between food and beverage purchases and skin carotenoids among diverse small food retail store customers

OBJECTIVE

To determine if customer purchases at small food stores are associated with healthfulness of the diet as approximated by skin carotenoids.

DESIGN

This is a cross-sectional survey of customers in small food stores regarding demographics and food purchases. Food and beverage purchases were classified as 'healthy' or 'non-healthy' and 'carotenoid' v. 'non-carotenoid' using a systematic classification scheme. Fruit and vegetable intake was objectively assessed using a non-invasive device to measure skin carotenoids. Associations between variables of interest were examined using Pearson's correlation coefficients, t tests and multiple linear regression analyses.

SETTING

Twenty-two small food retail stores in rural (n 7 stores) and urban (n 15) areas of North Carolina.

PARTICIPANTS

Customers of small food stores.

RESULTS

Of study participants (n 1086), 55·1 % were male, 60·0 % were African American/Black and 4·2 % were Hispanic, with a mean age of 43·5 years. Overall, 36 % purchased at least one healthy item, and 7·6 % of participants purchased a carotenoid-containing food/beverage. Healthy foods and beverages purchased included produce, lean meats, 100 % juices, plain popcorn, plain nuts, milk and yogurt. Unhealthy items included non-100 % juices, crackers, chips, candy, cakes and donuts. Purchase of a healthy or carotenoid-containing item was positively associated with skin carotenoid scores (P = 0·002 and 0·006, respectively).

CONCLUSIONS

A relatively small proportion of customers purchased any healthy or carotenoid-containing foods and beverages, and those who did purchase healthy options had higher skin carotenoid scores. Future research should confirm these findings in different populations.

Estimation of food portion sizes in women of childbearing age and young children in Ouagadougou (Burkina Faso) using a food photography atlas and salted replicas: Comparison with weighed records

Quantitative assessment of foods consumed when using 24-hour dietary recall requires accurate tools to estimate portion sizes. Therefore, we developed a food portion photography atlas with age-appropriate portion sizes for 11 foods frequently consumed by young children (sizes for 6-11-month- and for 12-23-month-old children) and women of childbearing age in Ouagadougou, Burkina Faso capital. We then compared the accuracy and precision of portion estimation with this atlas and with salted replicas relative to weighed records (the reference). After weighing, we randomly assigned food portions to 67 women and their children. The next day, women estimated the served portions and leftovers by recall using the atlas and then salted replicas (n = 1156 measurements, ranging from 19 to 113 for each food). For most food types, the portions estimated with the atlas and salted replicas were positively correlated and showed good concordance with the weighed records. However, accuracy and precision varied in function of the estimation method, food type, and age group. The mean crude differences ranged from -28 to +12g (with errors in absolute values from 24 to 69%) for children, and from -32 to +44g (errors from 17 to 56%) for women. The atlas-based method showed the lowest Lin's concordances (coefficients of 0.1 to 0.2) for the leafy vegetable dish, meat, and fish in 12-23-month-old children. Bland-Altman plots indicated that the salted replicas allowed estimating the consumed portions with fewer errors than the photographic atlas (56 to 91% vs 46 to 79% between the limits of ±50%). Our study highlights that mothers have difficulties in perceiving the quantities of food consumed by their children. Our findings also indicate that the food atlas could be used in food consumption surveys when salted replicas are not available for all food types.

A Systematic Literature Review of Nutrition Interventions Implemented to Address Food Insecurity as a Social Determinant of Health

BACKGROUND

Policy initiatives have provided funding for non-acute nutrition interventions to address food insecurity as a social determinant of health, but more research is needed to understand the outcomes of these initiatives in order to determine the areas of highest impact. Therefore, the purpose of this systematic review was to evaluate the outcomes that were assessed in three nutrition interventions (produce prescription programs, medically tailored meals, and community supported agriculture) that aim to address food insecurity as a social determinant of health, and this was undertaken in order to identify future areas of study that can heighten impact.

METHODS

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria. A list of search terms and keywords were compiled by the research team. A Boolean search was conducted from 1 January 2000 to 1 January 2023 in the PubMed advanced search database.

RESULTS

A total of 1015 articles were initially pulled from the PubMed database, and, after a screening process, 21 articles were included in our review. Nineteen of the articles focused on adult populations or families and two focused on children. The main outcomes assessed were changes in self-reported dietary intake, while a few of the articles addressed feasibility and cost-related outcomes.

CONCLUSIONS

More research is needed to assess whether nutritional interventions to address food insecurity as a social determinant of health are feasible and more cost effective in the long term. Additionally, more work should be conducted in pediatric populations, which could have a robust return on investment in terms of both healthcare utilization and healthcare expenditure.

Can Anthocyanins Reduce Delayed Onset Muscle Soreness or Are We Barking Up the Wrong Tree?

Exercise-induced muscular overload can trigger delayed onset muscle soreness (DOMS). DOMS is related to the indiscriminate use of analgesics and nonsteroidal anti-inflammatory drugs without proper guidance, decreased physical exercise adherence and degenerating sports performance, increased risk of injury, and reduced muscle strength and function. Dietary anthocyanins have been extensively studied as potential natural treatments for DOMS, but the indication, dosage, and form of use remain highly variable. Therefore, this review aims to synergize and present evidence relating to the effect of anthocyanins on DOMS in clinical studies. Notably, the results of anthocyanin supplementation for DOMS were found to be inconclusive. The use of protocols with lower anthocyanin doses yielded better results than those with high-dose supplements, suggesting that anthocyanin-rich foods are more accessible as therapeutic tools, leading to the conclusion that these foods could be used to prevent and treat DOMS. However, consumption protocols for this purpose are not yet well established, and the answer is dependent on the methodological quality of future studies.

Optimizing Maternal Nutrition: The Importance of a Tailored Approach

Improving nutritional status during pregnancy is a global interest. Frequently, women either fail to meet or exceed nutrient recommendations. Current strategies to improve maternal nutrition focus on a "one-size-fits-all" approach and fail to consider individual factors that affect the mother's overall nutritional status. The objectives of this review were to determine the importance of key nutrients for optimal maternal and fetal health, to explore to what extent current recommendations consider individual factors, and to explore novel strategies to close the gap between current guidelines and real-world challenges through more personalized approaches. This review intercalated different nutritional guidelines and recent scientific publications and research initiatives related to maternal nutrition. Based on that, an overview of current recommendations, challenges related to present approaches, and perspectives for future directions are described. Current guidelines are not optimally supporting adequate nutrient intake and health of expectant mothers and their offspring. Existing recommendations are not consistent and do not sufficiently take into account how interindividual variation leads to differences in nutrient status. Personalized nutrition offers women the opportunity to improve their health by using strategies that are tailored to their unique nutritional needs. Such strategies can include personalized supplementation, holistic lifestyle interventions, digital and application-based technologies, and dietary assessment through blood biomarker and genetic analysis. However, these approaches warrant further investigation and optimization. More personalized approaches have the potential to optimize mothers' and their offspring's health outcomes more appropriately to their nutritional needs before, during, and after pregnancy. Moving away from a generalized "one-size-fits-all" approach can be achieved through a variety of means. Future aims should be to provide supporting evidence to create customized subpopulation-based or individualized recommendations, improve nutrition education, and develop novel approaches to improve adherence to dietary and lifestyle interventions.

Comparisons of Three Measures of Maternal Engagement Activities in the Neonatal Intensive Care Unit

BACKGROUND

Mothers' engagement with their hospitalized preterm infant(s) is recognized as an important aspect of treatment in neonatal intensive care units (NICUs). However, no gold standard exists for measuring maternal engagement, and the various methods used to measure mothers' time have documented limitations.

OBJECTIVES

This study sought to compare three measurement methods of maternal engagement (a five-item maternal cross-sectional survey, time use diaries, and electronic health records [EHRs]) to identify whether these methods capture consistent data and patterns in detected differences in measures of engagement.

METHODS

Maternal engagement was defined as time spent visiting the infant in the NICU (presence), holding (blanket holding in the mother's arms or by kangaroo care [KC]), and caregiving (e.g., bathing and changing diapers). The survey estimating daily maternal engagement was administered in two Level III NICUs and one Level IV NICU at study enrollment, at least 2 weeks after admission. Mothers then completed the daily time use diaries until infant discharge. Data were also collected from participants' EHRs, charted by nursing staff. Wilcoxon signed-rank tests were used for pairwise analysis of the three measures for maternal engagement activities.

RESULTS

A total of 146 participants had data across all three measurement types and were included in the analysis. In the Level III NICUs (n = 101), EHR data showed significantly more time spent with all engagement activities than the diary data. In the Level IV data, only differences in time holding were significant when comparing EHR data with survey data, with mothers reporting more time doing KC and less time blanket holding. Comparison of EHR data with diary data showed more time in all activities except KC.

DISCUSSION

In most cases, time spent in engagement activities measured in the EHR was higher than in the surveys or time use diaries. Accuracy of measurements could not be determined because of limitations in data collection, and there is no gold standard for comparison. Nevertheless, findings contribute to ongoing efforts to develop the most valuable and accurate strategies for measuring maternal engagement-a significant predictor of maternal and infant health.

PUFA-Induced Metabolic Enteritis as a Fuel for Crohn's Disease

BACKGROUND & AIMS

Crohn's disease (CD) globally emerges with Westernization of lifestyle and nutritional habits. However, a specific dietary constituent that comprehensively evokes gut inflammation in human inflammatory bowel diseases remains elusive. We aimed to delineate how increased intake of polyunsaturated fatty acids (PUFAs) in a Western diet, known to impart risk for developing CD, affects gut inflammation and disease course. We hypothesized that the unfolded protein response and antioxidative activity of glutathione peroxidase 4 (GPX4), which are compromised in human CD epithelium, compensates for metabolic perturbation evoked by dietary PUFAs.

METHODS

We phenotyped and mechanistically dissected enteritis evoked by a PUFA-enriched Western diet in 2 mouse models exhibiting endoplasmic reticulum (ER) stress consequent to intestinal epithelial cell (IEC)-specific deletion of X-box binding protein 1 (Xbp1) or Gpx4. We translated the findings to human CD epithelial organoids and correlated PUFA intake, as estimated by a dietary questionnaire or stool metabolomics, with clinical disease course in 2 independent CD cohorts.

RESULTS

PUFA excess in a Western diet potently induced ER stress, driving enteritis in Xbp1-/-IEC and Gpx4+/-IEC mice. ω-3 and ω-6 PUFAs activated the epithelial endoplasmic reticulum sensor inositol-requiring enzyme 1α (IRE1α) by toll-like receptor 2 (TLR2) sensing of oxidation-specific epitopes. TLR2-controlled IRE1α activity governed PUFA-induced chemokine production and enteritis. In active human CD, ω-3 and ω-6 PUFAs instigated epithelial chemokine expression, and patients displayed a compatible inflammatory stress signature in the serum. Estimated PUFA intake correlated with clinical and biochemical disease activity in a cohort of 160 CD patients, which was similarly demonstrable in an independent metabolomic stool analysis from 199 CD patients.

CONCLUSIONS

We provide evidence for the concept of PUFA-induced metabolic gut inflammation which may worsen the course of human CD. Our findings provide a basis for targeted nutritional therapy.

Pressure-Mediated Reflection Spectroscopy Criterion Validity as a Biomarker of Fruit and Vegetable Intake: A 2-Site Cross-Sectional Study of 4 Racial or Ethnic Groups

BACKGROUND

Valid biomarkers of fruit and vegetable (FV) intake are needed for field-based nutrition research.

OBJECTIVES

To examine criterion-related validity of pressure-mediated reflection spectroscopy as a proxy measure of FV intake, using plasma carotenoids and self-reported FV and carotenoid intake as primary and secondary criterion measures, respectively.

METHODS

Healthy adults 18-65 y of age, self-identifying as African American/black (n = 61), Asian (n = 53), white (n = 70), or Hispanic (n = 29), in North Carolina and Minnesota were recruited. Skin carotenoids were assessed via pressure-mediated reflection spectroscopy (Veggie Meter), skin melanin via spectrophotometer, and total plasma carotenoid concentration by HPLC-photodiode array detection. Self-reported carotenoid and FV intake was assessed using a semiquantitative FFQ. Relations between skin carotenoids, plasma carotenoids, FV, and carotenoid intake, with differences by race or ethnicity, age, sex, weight status, cholesterol, and melanin index, were examined by bivariate correlations and adjusted multivariate linear regressions.

RESULTS

The overall unadjusted correlation between skin and total plasma carotenoids was r = 0.71 and ranged from 0.64 (non-Hispanic black) to 0.80 (Hispanic). Correlations between skin carotenoids and self-reported FV intake ranged from 0.24 (non-Hispanic black) to 0.53 (non-Hispanic white), with an overall correlation of r = 0.35. In models adjusted for age, sex, racial or ethnic group, and BMI, skin carotenoids were associated with plasma carotenoids (R2 = 0.55), FV (R2 = 0.17), and carotenoid intake (R2 = 0.20). For both plasma carotenoid and FV measures, associations with skin carotenoids did not vary by race, but these relations did differ by skin melanin-those with lower melanin had a lower correlation between skin and plasma carotenoids.

CONCLUSIONS

Reflection spectroscopy-assessed skin carotenoids may be a reasonable alternative to measurement of plasma carotenoids, a biomarker used to approximate FV intake.

Physical activity and healthy eating behavior changes among rural women: an exploratory mediation analysis of a randomized multilevel intervention trial

Rural women experience disproportionately higher levels of obesity in comparison to their non-rural counterparts. The present exploratory mediation analysis sought to identify mechanisms that might have contributed to rural women's physical activity and diet changes after participating in a 6-month multilevel community-randomized trial: Strong Hearts, Healthy Communities (SHHC). SHHC was conducted in 16 rural towns in Montana and New York, between 2015 and 2016; 194 overweight, sedentary midlife, and older women (mean age 59; 26.8% overweight; 73.2% obese) participated. Participants in eight towns received the SHHC intervention (n = 101), which focused on healthy behavior change at the individual level as well as creating supportive social and built environments for physical activity and healthy eating. Participants in the other eight towns received an education-only control intervention (n = 93). We investigated the direct and indirect effects of the SHHC intervention through changes to self-efficacy, social support, and built environment perception, on changes in participants' physical activity and diet. Compared to the controls, SHHC intervention participants increased their social support from friends for physical activity (p = 0.009) and healthy eating (p = 0.032). Participants' improved social support from friends marginally mediated the intervention effects for walking metabolic equivalent minutes per week, explaining 40.5% of the total effect (indirect effect = +45.24, 95% CI: -1.51, +91.99; p = 0.059). Increasing social support from friends appears to be helpful in encouraging rural women to become more active. Further investigations are needed to better understand how multilevel interventions work in rural communities.

Does Personalized Nutrition Advice Improve Dietary Intake in Healthy Adults? A Systematic Review of Randomized Controlled Trials

Personalized nutrition (PN) behavior-change interventions are being used increasingly in attempts to improve dietary intake; however, the impact of PN advice on improvements in dietary intake has not been reviewed systematically. The aim of this systematic review was to evaluate the effect of PN advice on changes in dietary intake compared with generalized advice in healthy adults. Three databases (EMBASE, PubMed, and CINAHL) were searched between 2009 and 2020 for randomized controlled trials (RCTs) that tested the effect of PN and tailored advice based on diet, phenotype, or genetic information. The Evidence Analysis Library Quality Criteria checklist was used to conduct a risk-of-bias assessment. Information on intervention design and changes in nutrients, foods, and dietary patterns was extracted from the 11 studies meeting the inclusion criteria. Studies were conducted in the United States, Canada, or Europe; reported outcomes on 57 to 1488 participants; and varied in follow-up duration from 1 to 12 mo. Five studies incorporated behavior-change techniques. The risk of bias for included studies was low. Overall, the available evidence suggests that dietary intake is improved to a greater extent in participants randomly assigned to receive PN advice compared with generalized dietary advice. Additional well-designed PN RCTs are needed that incorporate behavior-change techniques, a broader range of dietary outcomes, and comparisons between personalization based on dietary, biological, and/or lifestyle information.

Using the Veggie Meter in Elementary Schools to Objectively Measure Fruit and Vegetable Intake: A Pilot Study

Self-reported fruit and vegetable (FV) consumption in children has limitations that could be overcome with objective measures that are easy to implement. The Veggie Meter (VM) is a non-invasive portable device that measures skin carotenoid levels, a concentration biomarker of usual FV intake. While VM has been used to measure FV consumption in adults, few studies have explored its use in elementary school settings. Designing research studies using the VM with elementary school-age children requires an understanding of how well this device can be used in a school setting and of the distribution of VM scores in this population. We used VM to measure skin carotenoids in a diverse sample of 143 elementary school children who also answered commonly asked questions about consumption frequency of FV the previous day. Multivariable regression was used to assess the independent association of demographic variables with VM scores. VM scores were also compared with student-reported FV intake. There was a weak but statistically significant correlation between reported frequency of total vegetable consumption the previous day and observed VM scores (r = 0.174, p = 0.042). This study provides an example of the successful use of the VM in a school setting to collect an objective measure of FV intake and provides important description of data that can inform future studies.

A meta-analysis of studies examining associations between resonance Raman spectroscopy-assessed skin carotenoids and plasma carotenoids among adults and children

CONTEXT

No meta-analyses appeared to have been conducted to examine overall correlations between resonance Raman spectroscopy (RRS)-assessed skin carotenoids and plasma/serum carotenoids.

OBJECTIVE

To review the available literature and quantify the association between RRS-assessed skin carotenoids and plasma/serum carotenoids via a meta-analysis of observational studies.

DATA SOURCES

To identify relevant publications, we searched the PubMed, Embase, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, ProQuest, and Scopus databases in April 2020 for items combining 3 concepts: Raman spectroscopy, skin, and plasma or serum.

DATA EXTRACTION

Criteria for inclusion were publication in a peer-reviewed journal between 1990 and 2020, available in English language, and results reported as a baseline Pearson correlation coefficient. In teams of 2, the researchers independently reviewed titles and abstracts of 2212 nonduplicate papers with initial screening yielding 62 papers for full-text review, of which 15 were deemed eligible for inclusion.

DATA ANALYSIS

A random-effects model in R (version 4.0.0) "meta" package was used to analyze the correlation between RRS-assessed skin and plasma/serum carotenoids. A subgroup analysis was conducted for studies involving adults and children, respectively.

CONCLUSIONS

The 15 studies included 1155 individuals: 963 adults and 192 children. One study included children and adults. The random-effects model yielded an overall correlation of 0.68 (95%CI, 0.61-0.74; I2 = 74%; P < 0.01). The results were similar when grouped by adults and children. Among 963 adults, the correlation in the random-effects model was 0.69 (95%CI, 0.61-0.75; I2 = 78%; P < 0.01). Among 192 children, the correlation in the random-effects model was 0.66 (95%CI, 0.52- 0.77; I2 = 55%; P = 0.06). Overall, there was a positive, statistically significant correlation between RRS-assessed skin carotenoids and plasma/serum carotenoids in a pooled meta-analysis of 15 studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (record number 178835).

Skin Carotenoid Status Over Time and Differences by Age and Sex Among Head Start Children (3-5 Years)

OBJECTIVE

Examine differences in skin carotenoid status (SCS) based on time, age, and sex of preschool-aged children enrolled in Head Start (HS) in North Carolina.

DESIGN

Data were collected using surveys from participating families. preschool-aged children's SCS were measured 3 times over a 6-month period.

SETTING

Three HS centers in North Carolina.

PARTICIPANTS

One hundred twelve children aged 3-5 years, enrolled in HS.

MAIN OUTCOME MEASURE(S)

Differences in SCS assessed using the Veggie Meter (Longevity Link, Salt Lake City, UT) based on time, sex, and age.

ANALYSIS

One-way ANOVA to assess SCS at time 1 between sex and age (n = 112). Repeated measures ANOVA with a Greenhouse-Geisser correction for assessment of SCS over time (n = 45) using Bonferroni correction.

RESULTS

On average, children were aged 4 years, African American (81.3%), male (57%), and had a mean SCS of 266 (SD = 82.9). Skin carotenoid status (Veggie Meter units) were significantly different over time (P < 0.001). Significant differences were observed between ages (P = 0.01) and sex (P < 0.01).

CONCLUSIONS AND IMPLICATIONS

The Veggie Meter is a promising tool to assess fruit and vegetable intake but needs to be validated in preschool-aged children as it has been in adults. Sex and age are potential confounders which should be assessed in future studies using the Veggie Meter.

Characterizing Measurement Error in Dietary Sodium in Longitudinal Intervention Studies

Background: Previous measurement error work that investigates the relationship between a nutritional biomarker and self-reported intake levels has typically been at a single time point, in a single treatment group, or with respect to basic patient demographics. Few studies have examined the measurement error structure in longitudinal randomized trials, and whether the error varies across time or group. This structure is crucial to understand, however, in order to correct for measurement error in self-reported outcomes and properly interpret the longitudinal effects of dietary interventions. Methods: Using two longitudinal randomized controlled trials with internal longitudinal validation data (urinary biomarkers and self-reported values), we examine the relationship between urinary sodium and self-reported sodium and whether this relationship changes as a function of time and/or treatment condition. We do this by building a mixed effects regression model, allowing for a flexible error variance-covariance structure, and testing all possible interactions between time, treatment condition, and self-reported intake. Results: Using a backward selection approach, we arrived at the same final model for both validation data sets. We found no evidence that measurement error changes as a function of self-reported sodium. However, we did find evidence that urinary sodium can differ by time or treatment condition even when conditioning on self-reported values. Conclusion: In longitudinal nutritional intervention trials it is possible that measurement error differs across time and treatment groups. It is important for researchers to consider this possibility and not just assume non-differential measurement error. Future studies should consider data collection strategies to account for the potential dynamic nature of measurement error, such as collecting internal validation data across time and treatment groups when possible.

Weight Management Efforts, But Not Weight Perceptions, Are Associated with Dietary Quality among Youth and Young Adults in Canada

BACKGROUND

Efforts to lose, gain, or maintain weight are prevalent among youth and young adults, but little is known about the relationship between weight management efforts and dietary quality. Attempts to manage weight are typically driven by weight perceptions, which may also uniquely affect overall diet.

OBJECTIVE

The objective was to explore sex-stratified associations between weight management efforts and perceptions with dietary quality among youth and young adults.

DESIGN

Cross-sectional online survey data were drawn from Wave 1 (2016) of the Canada Food Study.

PARTICIPANTS/SETTING

Youth and young adults (n = 3,000), aged 16 to 30 years, were recruited from community settings in five Canadian cities and completed the online survey. The analytic sample consisted of 2,040 participants.

MAIN OUTCOME MEASURES

The Healthy Eating Index-2015 (HEI-2015) was used to characterize dietary quality among participants who completed a 24-hour recall. Respondents reported their weight change efforts over the past year and their weight perception.

STATISTICAL ANALYSES PERFORMED

Sex-stratified multiple linear regression analyses were conducted to investigate relationships between each of weight management efforts and perceptions, separately, and dietary quality, controlling for known covariates.

RESULTS

The HEI-2015 mean score was 52 of 100 possible points. Nearly one quarter of male and female respondents reported not trying to do anything about their weight, whereas 16% reported trying to maintain, 28% and 5% trying to gain, and 33% and 55% trying to lose weight, respectively. Most respondents (63% of males and 66% of females) perceived their weight as just about right. Among males, trying to gain or maintain weight were each significantly associated with higher HEI-2015 mean scores compared with not trying to manage weight (P < .01 and <.001, respectively), whereas this relationship existed only for weight maintenance among female respondents (P < .01). Weight perceptions and HEI-2015 mean scores were not significantly related.

CONCLUSIONS

Efforts to manage weight, which are commonplace among youth and young adults, are associated with dietary quality. Future behavioral research may provide insights into strategies used by youth to manage weight, guiding interventions that recognize links among weight-related behaviors, dietary quality, and other determinants of health.

Impact on Dietary Intake of Two Levels of Technology-Assisted Personalized Nutrition: A Randomized Trial

Advances in web and mobile technologies have created efficiencies relating to collection, analysis and interpretation of dietary intake data. This study compared the impact of two levels of nutrition support: (1) low personalization, comprising a web-based personalized nutrition feedback report generated using the Australian Eating Survey® (AES) food frequency questionnaire data; and (2) high personalization, involving structured video calls with a dietitian using the AES report plus dietary self-monitoring with text message feedback. Intake was measured at baseline and 12 weeks using the AES and diet quality using the Australian Recommended Food Score (ARFS). Fifty participants (aged 39.2 ± 12.5 years; Body Mass Index 26.4 ± 6.0 kg/m2; 86.0% female) completed baseline measures. Significant (p < 0.05) between-group differences in dietary changes favored the high personalization group for total ARFS (5.6 points (95% CI 1.3 to 10.0)) and ARFS sub-scales of meat (0.9 points (0.4 to 1.6)), vegetarian alternatives (0.8 points (0.1 to 1.4)), and dairy (1.3 points (0.3 to 2.3)). Additional significant changes in favor of the high personalization group occurred for proportion of energy intake derived from energy-dense, nutrient-poor foods (-7.2% (-13.8% to -0.5%)) and takeaway foods sub-group (-3.4% (-6.5% to 0.3%). Significant within-group changes were observed for 12 dietary variables in the high personalization group vs one variable for low personalization. A higher level of personalized support combining the AES report with one-on-one dietitian video calls and dietary self-monitoring resulted in greater dietary change compared to the AES report alone. These findings suggest nutrition-related web and mobile technologies in combination with personalized dietitian delivered advice have a greater impact compared to when used alone.

The Carbon Isotope Ratios of Serum Amino Acids in Combination with Participant Characteristics can be Used to Estimate Added Sugar Intake in a Controlled Feeding Study of US Postmenopausal Women

BACKGROUND

The carbon isotope ratio (CIR) is a proposed biomarker for added sugar (AS) intake in the United States; however, because the CIR is also associated with meat intake in most populations the need for specificity remains. The CIR of amino acids (AAs) has the potential to differentiate sugars from meat intakes, because essential AAs must derive from dietary protein whereas certain nonessential AAs can be synthesized from sugars.

OBJECTIVES

We tested whether serum CIR-AAs in combination with participant characteristics could meet a prespecified biomarker criterion for AS intake in the Nutrition and Physical Activity Assessment Study Feeding Study (NPAAS-FS) of the Women's Health Initiative, a population in which the whole-serum CIR was not associated with AS intake.

METHODS

Postmenopausal women (n = 145) from Seattle, WA, were provided with individualized diets that approximated their habitual food intakes for 2 wk. Dietary intakes from consumed foods were characterized over the feeding period using the Nutrition Data System for Research. The CIR of 7 AAs-Ala, Gly, Val, Leu, Ile, Pro, and Phe-were measured in fasting serum collected at the end of the 2-wk feeding period, using gas chromatography-combustion isotope ratio mass spectrometry. Biomarker models were evaluated using regression R2 ≥ 0.36 as a major biomarker criterion, based on the benchmark R2 values of well-established recovery biomarkers in the NPAAS-FS.

RESULTS

AS intake was associated with CIR-Ala (ρ = 0.32; P < 0.0001). A model of AS intake based on CIR-Ala, CIR-Gly, CIR-Ile, smoking, leisure physical activity, and body weight met the biomarker criterion (R2 = 0.37). Biomarker-estimated AS intake was not associated with meat or animal protein intake.

CONCLUSIONS

Results support serum CIR-AAs in combination with participant characteristics as potential biomarkers of AS intake in US populations, including those with low AS intake.The Women's Health Initiative is registered at clinicaltrials.gov (NCT00000611).

Effects of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Beverages on Cardiometabolic Risk Factors, Body Composition, and Sweet Taste Preference: A Randomized Controlled Trial

Background

A 2018 American Heart Association science advisory indicated that, pending further research, artificially sweetened beverages (ASBs) may be an appropriate initial replacement for sugar‐sweetened beverages (SSBs) during transition to unsweetened beverages (USBs).

Methods and Results

We randomly assigned 203 adults (121 males, 82 females; 91.6% retention), who habitually consumed SSBs, to 3 groups and delivered free SSBs, ASBs, or USBs to their homes for 12 months. Outcomes included serum triglyceride to high‐density lipoprotein cholesterol ratio (primary), body weight, and sweet taste preference (experimental assessment, 0%–18% sucrose solutions). Change in serum triglyceride to high‐density lipoprotein cholesterol ratio was not different between groups. Although overall change in weight also was not different between groups, we found effect modification (P=0.006) by central adiposity. Among participants in the highest tertile of baseline trunk fat but not other tertiles, weight gain was greater (P=0.002) for the SSB (4.4±1.0 kg, estimate±SE) compared with ASB (0.5±0.9 kg) or USB (−0.2±0.9 kg) group. Both sweetness threshold (–1.0±0.2% m/v; P=0.005) and favorite concentration (–2.3±0.4% m/v; P<0.0001) decreased in the USB group; neither changed in the SSB group. In the ASB group, sweetness threshold did not change, and favorite concentration decreased (–1.1±0.5% m/v; P=0.02). Pairwise comparison between the ASB and USB groups indicated a difference in sweetness threshold (P=0.015).

Conclusions

Replacing SSBs with noncaloric beverages for 12 months did not affect serum triglyceride to high‐density lipoprotein cholesterol ratio. Among individuals with central adiposity, replacing SSBs with either ASBs or USBs lowered body weight. However, USBs may have the most favorable effect on sweet taste preference.

Registration

URL: https://www.clinicaltrials.gov; unique identifier: NCT01295671.

The Application of an Evidence Framework for Obesity Prevention at the Population-Level

PURPOSE OF REVIEW

To review existing frameworks for assessing the evidence of effectiveness of obesity prevention interventions, and discuss the application of a custom-developed evidence framework to inform an obesity prevention priority-setting study in Australia.

RECENT FINDINGS

There are a wide range of frameworks for grading evidence. However, most frameworks are not well suited to assess the effectiveness of obesity prevention interventions because they do not include processes to synthesise evidence from multiple study designs and outcome measures. The key features of the Obesity Prevention Evidence Assessment (OPEA) Framework are: [1] separately assessed weight-, diet- and physical activity-related outcomes; [2] consideration of the balance of evidence from multiple study types; and [3] a summary indication of the degree of certainty of intervention effectiveness. Evidence frameworks that recognise the complexities of obesity prevention research can support decision-makers in prioritising actions to address obesity alongside broader priority-setting considerations.

Reducing cardiometabolic risk in adults with a low socioeconomic position: protocol of the Supreme Nudge parallel cluster-randomised controlled supermarket trial

Background

Unhealthy lifestyle behaviours such as unhealthy dietary intake and insufficient physical activity (PA) tend to cluster in adults with a low socioeconomic position (SEP), putting them at high cardiometabolic disease risk. Educational approaches aiming to improve lifestyle behaviours show limited effect in this population. Using environmental and context-specific interventions may create opportunities for sustainable behaviour change. In this study protocol, we describe the design of a real-life supermarket trial combining nudging, pricing and a mobile PA app with the aim to improve lifestyle behaviours and lower cardiometabolic disease risk in adults with a low SEP.

Methods

The Supreme Nudge trial includes nudging and pricing strategies cluster-randomised on the supermarket level, with: i) control group receiving no intervention; ii) group 1 receiving healthy food nudges (e.g., product placement or promotion); iii) group 2 receiving nudges and pricing strategies (taxing of unhealthy foods and subsidizing healthy foods). In collaboration with a Dutch supermarket chain we will select nine stores located in low SEP neighbourhoods, with the nearest competitor store at > 1 km distance and managed by a committed store manager. Across the clusters, a personalized mobile coaching app targeting walking behaviour will be randomised at the individual level, with: i) control group; ii) a group receiving the mobile PA app. All participants (target n = 1485) should be Dutch-speaking, aged 45–75 years with a low SEP and purchase more than half of their household grocery shopping at the selected supermarkets. Participants will be recruited via advertisements and mail-invitations followed by community-outreach methods. Primary outcomes are changes in systolic blood pressure, LDL-cholesterol, HbA1c and dietary intake after 12 months follow-up. Secondary outcomes are changes in diastolic blood pressure, blood lipid markers, waist circumference, steps per day, and behavioural factors including healthy food purchasing, food decision style, social cognitive factors related to nudges and to walking behaviours and customer satisfaction after 12 months follow-up. The trial will be reflexively monitored to support current and future implementation.

Discussion

The findings can guide future research and public health policies on reducing lifestyle-related health inequalities, and contribute to a supermarket-based health promotion intervention implementation roadmap.

Trial registration

Dutch Trial Register ID NL7064, 30th of May, 2018

Use of the Veggie Meter® as a tool to objectively approximate fruit and vegetable intake among youth for evaluation of preschool and school-based interventions

BACKGROUND

Reflection spectroscopy is an emerging, non-invasive objective measure used to approximate fruit and vegetable intake. The present study aimed to use a reflection spectroscopy device (the Veggie Meter®, Longevity Link Corporation, Salt Lake City, UT, USA) to assess skin carotenoid status in preschool, middle- and high-school students and to examine associations between skin carotenoids and self-reported dietary intake.

METHODS

In Autumn 2018, we used the Veggie Meter® to assess skin carotenoids and age-appropriate validated dietary assessment measures to approximate fruit and vegetable (FV) intake. Preschool participants completed a previously validated pictorial liking tool using an iPad (Apple Inc., Cupertino, CA, USA). Middle-school participants completed selected questions from the validated School Physical Activity and Nutrition (SPAN) (Michael & Susan Dell Center for Healthy Living, University of Texas, Austin, TX, USA) questionnaire regarding frequency of their FV and beverage intake on the previous day, with additional questions about physical activity. High-school participants' FV intake was assessed using the Fruit and Vegetable Screener (National Cancer Institute, Bethesda, MD, USA). Spearman correlation coefficients were used to determine bivariate associations between measures of dietary intake and Veggie Meter®-assessed skin carotenoid levels.

RESULTS

Mean (SD) Veggie Meter® readings were 266 (82.9), 219 (68.1) and 216 (67.2) among preschool, middle- and high-school students. There was an inverse association between soda intake and Veggie Meter® readings (r = -0.22, P = 0.03) among middle-school students; and a positive association between daily fruit intake and Veggie Meter® readings (r = 0.25, P = 0.06) among high-school students.

CONCLUSIONS

The Veggie Meter® comprises a promising evaluation tool for preschool and school-based nutrition interventions.

Evaluation of plasma and erythrocyte fatty acids C15:0, t-C16:1n-7 and C17:0 as biomarkers of dairy fat consumption in adolescents

INTRODUCTION

Pentadecanoic (C15:0), heptadecanoic (C17:0) and trans-palmitoleic (t-C16:1n-7) fatty acids (FAs) are often used as biomarkers for dairy fat in adults. This study aimed to investigate the relationship between dairy product intake and these FAs in adolescents.

MATERIAL AND METHODS

Healthy adolescents were randomized to one of three groups (Group 1: control; Group 2: consume 3 dairy servings/day; and Group 3: consume ≥ 4 servings/d). C15:0, C17:0 and t-C16:1n-7 were quantified using gas chromatography. Dietary intakes were assessed by 24 h diet recalls.

RESULTS

No difference was observed in FAs at baseline or 6 months (mo), however, at 12 mo, erythrocyte C15:0 increased in group 3 (+0.37 µg/ml, p = 0.01). Dairy intake increased in both intervention groups (Group 2: +1.4 servings/d; Group 3: +2.4 servings/d, p < 0.0001) and positively correlated with erythrocyte C15:0 at 12 mo.

CONCLUSION

Erythrocyte FAs appear to be associated with increasing dairy intakes during adolescence.

Personalised nutrition - phenotypic and genetic variation in response to dietary intervention

Personalised nutrition allows individual differences in dietary, lifestyle, anthropometry, phenotype and/or genomic profile to be used to direct specific dietary advice. For personalised nutrition advice to be effective both sides need to be considered; firstly, that factors influencing variation in response to dietary intervention are identified and appropriate advice can be derived and secondly; that these are then used effectively in the provision of nutrition advice, resulting in a positive dietary and/or lifestyle behaviour change. There is considerable evidence demonstrating genetic and phenotypic influence on the biological response to the consumption of nutrients and bioactives. However, findings are often mixed, with studies often investigating at the level of a single nutrient/bioactive and/or a single genetic/phenotypic variation, meaning the derivation of specific advice at a dietary level in an individual/group of individuals can be complex. Similarly, the impact of using this information to derive personalised advice is also mixed, with some studies demonstrating no effectiveness and others showing a significant impact. The present paper will outline examples of phenotypic and genetic variation influencing response to nutritional interventions, and will consider how they could be used in the provision of personalised nutrition.

Issues in Measuring and Interpreting Diet and Its Contribution to Obesity

PURPOSE OF REVIEW

This review summarises the issues related to the measurement and interpretation of dietary intake in individuals with overweight and obesity, as well as identifies future research priorities.

RECENT FINDINGS

Some aspects of the assessment of dietary intake have improved through the application of technology-based methods and the use of dietary biomarkers. In populations with overweight and obesity, misreporting bias related to social desirability is a prominent issue. Future efforts should focus on combining technology-based dietary methods with the use of dietary biomarkers to help reduce and account for the impact of these biases. Future research will be important in terms of strengthening methods used in the assessment and interpretation of dietary intake data in the context of overweight and obesity.

Rationale and design of the frequency of eating and Satiety Hormones (FRESH) study: A randomized cross-over clinical trial

Background

The goal of the Frequency of Eating and Satiety Hormones (FRESH) Study is to understand the relationship between eating frequency (EF) and biomarkers of appetite and disease risk. This report gives the study rationale and design.

Methods

The FRESH study was conducted in n = 50 overweight and obese, but otherwise healthy, male and female adults aged 18–50 years. The protocol included four in-person clinic visits for protocol instruction, blood draws, anthropometry, and meal testing; all other activities were done at home. Participants completed two 21-day phases in random order with a two-week washout between phases. One phase was high EF (6 eating occasions/day) and the other was low EF (3 eating occasions/day). Each phase specified time of day for each eating occasion. Participants prepared their own meals throughout the study using study-provided individualized, structured meal plans ensuring that calories, macronutrients and micronutrients were identical during both study phases. Fasting blood was collected before and after each phase to test intervention effects on the biomarkers. At the end of each phase participants also completed extended appetite testing with meals prepared by the study clinic.

Results

Participants were recruited using print, radio, and digital ads. 60 participants consented to enroll; 10 dropped out due to work or school scheduling conflicts and 50 (target sample size) completed the study. Compliance was assessed by completion of daily on-line meal plan checklists.

Conclusions

The FRESH study will provide data on whether higher vs. lower daily EF in the context of constant energy and nutrient intake may be harmful or beneficial based on intervention effects on biomarkers of health and disease risk.

Reducing waste in nutritional epidemiology: review and perspectives

We discuss efforts in improving the value of nutrition research. We organised the paper in five research stages: Stage 1: research priority setting; Stage 2: research design, conduct and analysis; Stage 3: research regulation and management; Stage 4: research accessibility and Stage 5: research reporting and publishing. Along the stages of the research cycle, varied initiatives exist to improve the quality and added value of nutrition research. However, efforts are focused on single stages of the research cycle without vision of the research system as a whole. Although research on nutrition research has been limited, it has potential to improve the quality of nutrition research and develop new tools and instruments for this purpose. A comprehensive assessment of the magnitude of research waste in nutrition and consensus on priority actions is needed. The nutrition research community at large needs to have open discussions on the usefulness of these tools and lead suitable efforts to enhance nutrition research across the stages of the research cycle. Capacity building is essential and considerations of nutrition research quality are vital to be integrated in training efforts of nutrition researchers.