Biomarker and dietary validation of a Canadian food frequency questionnaire to measure eicosapentaenoic and docosahexaenoic acid intakes from whole food, functional food, and nutraceutical sources

Lipidomic and Fatty Acid Biomarkers in Whole Blood Can Predict the Dietary Intake of Eicosapentaenoic and Docosahexaenoic Acids in a Danish Population

BACKGROUND

The intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been associated with health benefits. Blood levels of these fatty acids, measured by gas chromatography (GC), are associated with their dietary intake, but the relationships with lipidomic measurements are not well defined.

OBJECTIVES

This study aimed to determine the lipidomic biomarkers in whole blood that predict intakes of EPA + DHA and examine the relationship between lipidomic and GC-based n-3 polyunsaturated fatty acid (n-3 PUFA) biomarkers.

METHODS

Lipidomic and fatty acid analyses were completed on 120 whole blood samples collected from Danish participants. Dietary intakes were completed using a web-based 7-d food diary. Stepwise multiple linear regression was used to identify the fatty acid and lipidomic variables that predict intakes of EPA + DHA and to determine lipidomic species that predict commonly used fatty acid biomarkers.

RESULTS

Stepwise regression selected lipidomic variables with an R2 = 0.52 for predicting EPA + DHA intake compared to R2 = 0.40 for the selected fatty acid GC-based variables. More predictive models were generated when the lipidomic variables were selected for females only (R2 = 0.62, n = 68) and males only (R2 = 0.72, n = 52). Phosphatidylethanolamine plasmalogen species containing EPA or DHA tended to be the most predictive lipidomic variables. Stepwise regression also indicated that selected lipidomic variables can predict commonly used fatty acid GC-based n-3 PUFA biomarkers as the R2 values ranged from 0.84 to 0.91.

CONCLUSIONS

Both fatty acid and lipidomic data can be used to predict EPA + DHA intakes, and fatty acid GC-based biomarkers can be emulated by lipidomic species. Lipidomic-based biomarkers appear to be influenced by sex differences, probably in n-3 PUFA and lipoprotein metabolism. These results improve our ability to understand the relationship between novel lipidomic data and GC fatty acid data and will increase our ability to apply lipidomic methods to fatty acid and lipid nutritional research.

Development and Validation of Vitamin D- Food Frequency Questionnaire for Moroccan Women of Reproductive Age: Use of the Sun Exposure Score and the Method of Triad's Model

This cross-sectional study aimed to develop and validate a vitamin D food frequency questionnaire (VitD-FFQ) to assess vitamin D intake in Moroccan women of reproductive age. Using the method of triads, the VitD-FFQ was validated against seven-day dietary records (7d-FR) and 25-hydroxyvitamin D (25(OH)D) as a biomarker of vitamin D status in 152 women (aged 18-45 years). Participants' sun exposure scores (SES) were assessed using a specific questionnaire (SEQ). Predictors of vitamin D status were identified via linear regression models. Several statistical tests were applied to evaluate the criterion validity of the FFQ against two references methods (7d-FR and the biomarker-serum 25(OH)D). Median (Interquartile range) intakes were 7.10 ± 6.95 µg /day and 6.33 ± 5.02 µg/ day, respectively, for VitD-FFQ and 7d-FR. Vitamin D status was mainly determined by SES (R = 0.47) and vitamin D absolute food intakes derived by the VitD-FFQ (R = 0.56), which demonstrated a more significant prediction ability compared to 7d-FR (R = 0.36). An agreement was observed between the VitD-FFQ and 7d-FR (BA index of 3.29%) with no proportional bias (R² = 0.002, p = 0.54). <10% of participants were incorrectly classified, and weighted kappa statistics showed that VitD-FFQ had an acceptable ranking ability compared to the 7d-FR and the biomarker. The validity coefficient for the VitD-FFQ was high: ρQR = 0.90 (95%CI: 0.89-0.92), and a range from 0.46 to 0.90. Adjustment for the participants' SES and BMI (body mass index) improved the biomarker's validity coefficient (ρRB 0.63 (95% CI 0.39-0.82). Our results indicate that the VitD-FFQ is valid for estimating absolute vitamin D intake in Moroccan women of reproductive age.

Relative Validity and Reproducibility of Dietary Measurements Assessed by a Semiquantitative Food Frequency Questionnaire among Chinese Healthy Adults

This study aimed to evaluate the relative validity and reproducibility of a semiquantitative food frequency questionnaire (SFFQ) in adult populations in China. Among the 49 recruited healthy participants (age range: 20-60 years), the relative validity of a 79-item SFFQ was assessed in two ways: (1) by comparing its dietary intake estimates with those from the average measurements of three inconsecutive 24 h dietary records (24-HDRs); and (2) by comparing its estimates of dietary fatty acids with the measured plasma levels of fatty acids. The reproducibility of the SFFQ was evaluated by a comparison of two SFFQ measurements from the same participants collected one year apart. In the relative validity study, the average Spearman correlation coefficient (r) was 0.27 among 18 prespecified food group intakes estimated from the SFFQ and the 24-HDRs; nevertheless, that of five food group intakes (e.g., red meat and seafood) was higher (all r_s > 0.40, p < 0.05). In addition, a moderate correlation between the SFFQ estimate of polyunsaturated fatty acid intakes (energy-adjusted percentage of total fatty acids) and its plasma level was observed (r = 0.42, p < 0.05). Regarding the one-year reproducibility of the SFFQ-assessed intakes, the average rank intraclass correlation coefficient (ICC) was 0.35 for the 18 food group estimates. In particular, moderately reproducible estimates of seven food group intakes (e.g., refined grains and red meat, all ICCs ≥ 0.40, p < 0.05) were observed. In conclusion, the SFFQ provides valid and reproducible estimates of dietary intakes for various food groups in general and performs well as a potential tool for estimating habitual dietary intakes of some unsaturated fatty acids.

Diet and Disease Activity in Patients with Axial Spondyloarthritis: SpondyloArthritis and NUTrition Study (SANUT)

Axial Spondyloarthritis (axSpA) patients with inflamed intestines have higher SpA activity. Diets that modulate microbiota may influence inflammation and SpA activity. Today, data concerning the impact of diet on SpA activity are scarce. SANUT was a single-center, noninterventional, cohort study that assessed dietetic profiles associated with SpA activity in axSpA. Demographic, clinical, SpA-related, quality of life (QoL), fatigue, physical activity, and dietary data were collected. SpA activity was assessed by Ankylosing Spondylitis Disease Activity Score (ASDAS) and by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). We assessed whether high SpA activity was associated with nutriment consumption. Between 12 February 2018 and 12 February 2020, 278 patients participated. High SpA activity, as measured by ASDAS and BASDAI, was significantly associated with higher body mass index and waist circumference, negative HLA-B27, lower QoL, higher fatigue, and higher digestive-symptom scores. Furthermore, high SpA activity, as measured by BASDAI, was associated with female sex, smoking status, patients who were not actively employed, reduced physical activity, and high intake of ultra-transformed foods, while high SpA activity, as measured by ASDAS, was associated with low intake of omega-3 PUFAs and fiber. Therefore, low intakes of omega-3 PUFAs and fiber, and high intake of ultra-transformed foods, are associated with high SpA activity.

Validity and reproducibility of a FFQ for assessing dietary intake among residents of northeast China: northeast cohort study of China

The study was to evaluate the reproducibility and validity of the FFQ for residents of northeast China. A total of 131 participants completed two FFQ (FFQ1 and FFQ2) within a 3-month period, 125 participants completed 8-d weighed diet records (WDR) and 112 participants completed blood biomarker testing. Reproducibility was measured by comparing nutrient and food intake between FFQ1 and FFQ2. The validity of the FFQ was assessed by WDR and the triad method. The Spearman correlation coefficients (SCC) and intraclass correlation coefficients (ICC) for reproducibility ranged from 0·41 to 0·69 (median = 0·53) and from 0·18 to 0·68 (median = 0·53) for energy and nutrients and from 0·37 to 0·73 (median = 0·59) and from 0·33 to 0·86 (median = 0·60) for food groups, respectively. The classifications of same or adjacent quartiles ranged from 73·64 to 93·80 % for both FFQ. The crude SCC between the FFQ and WDR ranged from 0·27 to 0·55 (median = 0·46) for the energy and nutrients and from 0·26 to 0·70 (median = 0·52) for food groups, and classifications of the same or adjacent quartiles ranged from 65·32 to 86·29 %. The triad method indicated that validation coefficients for the FFQ were above 0·3 for most nutrients, which indicated a moderate or high level of validity. The FFQ that was developed for residents of northeast China for the Northeast Cohort Study of China is reliable and valid for assessing the intake of most foods and nutrients.

Functional and Oxidative Quality Characterization of Spray-Dried Omega-3-Enriched Milk Powder

In the present study, fish oil (FO) and wall material were supplemented to milk to produce spray-dried powder (SDP). Furthermore, the mandate of the study was to enlighten the effect of spray-drying (SD) operating conditions on functional and oxidative quality of produced SDP samples. Purposefully, the cow milk was supplemented with 3% FO as omega-enriched source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for development of milk and FO blends (MFOBs). The lecithin was used as an emulsifier and maltodextrin was supplemented as the wall material (WM) in the MFOBs. Initially, the FO, milk fat (MF), and MFOB samples were characterized for EPA, DHA, and peroxide value (PV) before the SD. The SD of MFOB samples was carried out to produce SDP samples by using a mini spray dryer. Central composite design (CCD) with face-centered rotation was used to optimize SD independent conditions such as inlet air temperature (IAT), pump speed (PS), maltodextrin percentage (MD), and needle speed (NS) in the ranges of 160–200°C, 3–9 mL/min, 10–30%, and 5–9 s, respectively. The encapsulation efficiency (EE) ranged between 89.30 and 81.57%. The EPA and DHA retentions were in the ranges of 2.19–1.87 g/100 g and 3.20–2.75 g/100 g, respectively. The highest results for responses were observed on the following conditions: IAT was 160°C, PS was 9 mL/min, MD was 30%, and NS was 9 s, respectively; the minimum values of response factors were obtained on the following conditions: IAT was 200°C, PS was 3 mL/min, MD was 10%, and NS was 5 s, respectively. The percent losses of EPA and DHA were noted in the range of 2–18%. The IAT was observed as main factor for FA reduction in SDP samples. The SDP samples were stable, and low rate of peroxide values was noted. Overall, spray drying can be potentially used to incorporate the essential fatty acids in milk to produce stable SDP for food applications.

Role of n-3 long-chain polyunsaturated fatty acids in human nutrition and health: review of recent studies and recommendations

Long-chain (LC) n-3 polyunsaturated fatty acids (n-3 PUFAs), in particular docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are nutrients involved in many metabolic and physiological processes, and are referred to as n-3 LCPUFA. They have been extensively studied for their effects in human nutrition and health. This paper provides an overview on metabolism, sources, dietary intake, and status of n-3 LCPUFA. A summary of the dietary recommendations for n-3 LCPUFAs for different age groups as well as specific physiological conditions is provided. Evidence for n-3 LCPUFA in cardiovascular diseases, including new studies, is reviewed. Expert recommendations generally support a beneficial effect of n-3 LCPUFA on cardiovascular health and recommend a daily intake of 500 mg as DHA and EPA, or 1-2 servings of fish per week. The role of n-3 LCPUFA on brain health, in particular neurodegenerative disorders and depression, is reviewed. The evidence for beneficial effects of n-3 LCPUFA on neurodegenerative disorders is non-conclusive despite mechanistic support and observational data. Hence, no definite n-3 LCPUFA expert recommendations are made. Data for the beneficial effect of n-3 LCPUFA on depression are generally compelling. Expert recommendations have been established: 200-300 mg/day for depression; up to 1-2 g/day for major depressive disorder. Recent studies support a beneficial role of n-3 LCPUFAs in reducing the risk for premature birth, with a daily intake of 600-800 mg of DHA during pregnancy. Finally, international experts recently reviewed the scientific evidence on DHA and arachidonic acid (ARA) in infant nutrition and concluded that the totality of data support that infant and follow-on formulas should provide both DHA and ARA at levels similar to those in breast milk. In conclusion, the available scientific data support that dietary recommendations for n-3 LCPUFA should be established for the general population and for subjects with specific physiological conditions.

Biomarker-based validity of a food frequency questionnaire estimating intake in Brazilian children and adolescents

This study evaluated the validity of nutrient and food group intakes estimated by an FFQ against biomarkers. A 71-item semiquantitative FFQ was administered to 210 Brazilian children and adolescents aged 9-13 years. Intakes were correlated with biomarkers in plasma and red blood cells. Correlations between nutrients and their biomarkers were presented for animal protein, myristic acid (C14:0), EPA, DHA, β-carotene, folate, and vitamins B3, B5 and B6. Food groups and biomarkers were correlated as follows: fish products with EPA and DHA; milk and dairy with C14:0, pyridoxal 5'-phosphate and vitamin B12; total vegetables and dark green and orange vegetables with β-carotene; 5-methyltetrahydrofolate with green vegetables; and flour products with para-aminobenzoylglutamic acid. This FFQ is a valid tool for ranking Brazilian children and adolescents according to their intake of several nutrients and food groups.

Biomarkers of meat and seafood intake: an extensive literature review

Meat, including fish and shellfish, represents a valuable constituent of most balanced diets. Consumption of different types of meat and fish has been associated with both beneficial and adverse health effects. While white meats and fish are generally associated with positive health outcomes, red and especially processed meats have been associated with colorectal cancer and other diseases. The contribution of these foods to the development or prevention of chronic diseases is still not fully elucidated. One of the main problems is the difficulty in properly evaluating meat intake, as the existing self-reporting tools for dietary assessment may be imprecise and therefore affected by systematic and random errors. Dietary biomarkers measured in biological fluids have been proposed as possible objective measurements of the actual intake of specific foods and as a support for classical assessment methods. Good biomarkers for meat intake should reflect total dietary intake of meat, independent of source or processing and should be able to differentiate meat consumption from that of other protein-rich foods; alternatively, meat intake biomarkers should be specific to each of the different meat sources (e.g., red vs. white; fish, bird, or mammal) and/or cooking methods. In this paper, we present a systematic investigation of the scientific literature while providing a comprehensive overview of the possible biomarker(s) for the intake of different types of meat, including fish and shellfish, and processed and heated meats according to published guidelines for biomarker reviews (BFIrev). The most promising biomarkers are further validated for their usefulness for dietary assessment by published validation criteria.

The Development, Validation, and User Evaluation of Foodbook24: A Web-Based Dietary Assessment Tool Developed for the Irish Adult Population

BACKGROUND

The application of technology in the area of dietary assessment has resulted in the development of an array of tools, which are often specifically designed for a particular country or region.

OBJECTIVE

The aim of this study was to describe the development, validation, and user evaluation of a Web-based dietary assessment tool "Foodbook24."

METHODS

Foodbook24 is a Web-based, dietary assessment tool consisting of a 24-hour dietary recall (24HDR) and food frequency questionnaire (FFQ) alongside supplementary questionnaires. Validity of the 24HDR component was assessed by 40 participants, who completed 3 nonconsecutive, self-administered 24HDR using Foodbook24 and a 4-day semi-weighed food diary at separate time points. Participants also provided fasted blood samples and 24-hour urine collections for the identification of biomarkers of nutrient and food group intake during each recording period. Statistical analyses on the nutrient and food group intake data derived from each method were performed in SPSS version 20.0 (SPSS Inc). Mean nutrient intakes (and standard deviations) recorded using each method of dietary assessment were calculated. Spearman and Pearson correlations, Wilcoxon Signed Rank and Paired t test were used to investigate the agreement and differences between the nutritional output from Foodbook24 (test method) and the 4-day semi-weighed food diary (reference method). Urinary and plasma biomarkers of nutrient intake were used as an objective validation of Foodbook24. To investigate the user acceptability of Foodbook24, participants from different studies involved with Foodbook24 were asked to complete an evaluation questionnaire.

RESULTS

For nutrient intake, correlations between the dietary assessment methods were acceptable to very good in strength and statistically significant (range r=.32 to .75). There were some significant differences between reported mean intakes of micronutrients recorded by both methods; however, with the exception of protein (P=.03), there were no significant differences in the reporting of energy or macronutrient intake. Of the 19 food groups investigated in this analysis, there were significant differences between 6 food groups reported by both methods. Spearman correlations for biomarkers of nutrient and food group intake and reported intake were similar for both methods. A total of 118 participants evaluated the acceptability of Foodbook24. The tool was well-received and the majority, 67.8% (80/118), opted for Foodbook24 as the preferred method for future dietary intake assessment when compared against a traditional interviewer led recall and semi-weighed food diary.

CONCLUSIONS

The results of this study demonstrate the validity and user acceptability of Foodbook24. The results also highlight the potential of Foodbook24, a Web-based dietary assessment method, and present a viable alternative to nutritional surveillance in Ireland.

Evaluating Changes in Omega-3 Fatty Acid Intake after Receiving Personal FADS1 Genetic Information: A Randomized Nutrigenetic Intervention

Nutrigenetics research is anticipated to lay the foundation for personalized dietary recommendations; however, it remains unclear if providing individuals with their personal genetic information changes dietary behaviors. Our objective was to evaluate if providing information for a common variant in the fatty acid desaturase 1 (FADS1) gene changed omega-3 fatty acid (FA) intake and blood levels in young female adults (18–25 years). Participants were randomized into Genetic (intervention) and Non-Genetic (control) groups, with measurements taken at Baseline and Final (12 weeks). Dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was assessed using an omega-3 food frequency questionnaire. Red blood cell (RBC) FA content was quantified by gas chromatography. Implications of participation in a nutrigenetics study and awareness of omega-3 FAs were assessed with online questionnaires. Upon completion of the study, EPA and DHA intake increased significantly (p = 1.0 × 10⁻⁴) in all participants. This change was reflected by small increases in RBC %EPA. Participants in the Genetic group showed increased awareness of omega-3 terminology by the end of the study, reported that the dietary recommendations were more useful, and rated cost as a barrier to omega-3 consumption less often than those in the Non-Genetic group. Providing participants FADS1 genetic information did not appear to influence omega-3 intake during the 12 weeks, but did change perceptions and behaviors related to omega-3 FAs in this timeframe.

A review of the design and validation of web- and computer-based 24-h dietary recall tools

Technology-based dietary assessment offers solutions to many of the limitations of traditional dietary assessment methodologies including cost, participation rates and the accuracy of data collected. The 24-h dietary recall (24HDR) method is currently the most utilised method for the collection of dietary intake data at a national level. Recently there have been many developments using web-based platforms to collect food intake data using the principles of the 24HDR method. This review identifies web- and computer-based 24HDR tools that have been developed for both children and adult population groups, and examines common design features and the methods used to investigate the performance and validity of these tools. Overall, there is generally good to strong agreement between web-based 24HDR and respective reference measures for intakes of macro- and micronutrients.

Comparison of fatty acid intakes assessed by a cardiovascular-specific food frequency questionnaire with red blood cell membrane fatty acids in hyperlipidaemic Australian adults: a validation study

BACKGROUND/OBJECTIVES

Limited dietary intake tools have been validated specifically for hyperlipidaemic adults. The Australian Eating Survey (AES) Food Frequency Questionnaire (FFQ) was adapted to include foods with cardio-protective properties (CVD-AES). The aims were to estimate dietary fatty acid (FA) intakes derived from the CVD-AES and AES and compare them with red blood cell (RBC) membrane FA content.

SUBJECTS/METHODS

Dietary intake was measured using the semi-quantitative 120-item AES and 177-item CVD-AES. Nutrient intakes were calculated using AUSNUT 2011-2013. Fasting RBC membrane FAs were assessed using gas chromatography. Extent of agreement between intakes estimated by AES or CVD-AES and RBC membrane composition (% of total FAs) for linoleic acid (LA), alpha-linolenic acid (ALA), eicosapentanoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) were assessed using Spearman's correlation coefficients, adjusted linear regressions and Kappa statistics.

RESULTS

Data from 39 participants (72% female, 59.3±11.1 years) indicate stronger positive correlations between RBC membrane FAs and CVD-AES dietary estimates compared with the AES. Significant (P<0.05) moderate-strong correlations were found between CVD-AES FAs and FA proportions in RBC membranes for EPA (r=0.62), DHA (r=0.53) and DPA (r=0.42), with a moderate correlation for LA (r=0.39) and no correlation with ALA. Significant moderate correlations were found with the AES for DHA (r=0.39), but not for LA, ALA, EPA or DPA.

CONCLUSIONS

The CVD-AES provides a more accurate estimate of long chain FA intakes in hyperlipidaemic adults, compared with AES estimates. This indicates that a CVD-specific FFQ should be used when evaluating FA intakes in this population.

Global survey of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid in the blood stream of healthy adults

Studies reporting blood levels of the omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were systematically identified in order to create a global map identifying countries and regions with different blood levels. Included studies were those of healthy adults, published in 1980 or later. A total of 298 studies met all inclusion criteria. Studies reported fatty acids in various blood fractions including plasma total lipids (33%), plasma phospholipid (32%), erythrocytes (32%) and whole blood (3.0%). Fatty acid data from each blood fraction were converted to relative weight percentages (wt.%) and then assigned to one of four discrete ranges (high, moderate, low, very low) corresponding to wt.% EPA+DHA in erythrocyte equivalents. Regions with high EPA+DHA blood levels (>8%) included the Sea of Japan, Scandinavia, and areas with indigenous populations or populations not fully adapted to Westernized food habits. Very low blood levels (≤4%) were observed in North America, Central and South America, Europe, the Middle East, Southeast Asia, and Africa. The present review reveals considerable variability in blood levels of EPA+DHA and the very low to low range of blood EPA+DHA for most of the world may increase global risk for chronic disease.

A Correlation Study of DHA Dietary Intake and Plasma, Erythrocyte and Breast Milk DHA Concentrations in Lactating Women from Coastland, Lakeland, and Inland Areas of China

We aimed to assess the correlation between docosahexaenoic acid (DHA) dietary intake and the plasma, erythrocyte and breast milk DHA concentrations in lactating women residing in the coastland, lakeland and inland areas of China. A total of 408 healthy lactating women (42 ± 7 days postpartum) were recruited from four hospitals located in Weihai (coastland), Yueyang (lakeland) and Baotou (inland) city. The categories of food containing DHA, the average amount consumed per time and the frequency of consumption in the past month were assessed by a tailored DHA food frequency questionnaire, the DHA Intake Evaluation Tool (DIET). DHA dietary intake (mg/day) was calculated according to the Chinese Food Composition Table (Version 2009). In addition, fasting venous blood (5 mL) and breast milk (10 mL) were collected from lactating women. DHA concentrations in plasma, erythrocyte and breast milk were measured using capillary gas chromatography, and were reported as absolute concentration (μg/mL) and relative concentration (weight percent of total fatty acids, wt. %). Spearman correlation coefficients were used to assess the correlation between intakes of DHA and its concentrations in biological specimens. The study showed that the breast milk, plasma and erythrocyte DHA concentrations were positively correlated with DHA dietary intake; corresponding correlation coefficients were 0.36, 0.36 and 0.24 for relative concentration and 0.33, 0.32, and 0.18 for absolute concentration (p < 0.05). The median DHA dietary intake varied significantly across areas (p < 0.05), which was highest in the coastland (24.32 mg/day), followed by lakeland (13.69 mg/day), and lowest in the inland (8.84 mg/day). The overall relative and absolute DHA concentrations in breast milk were 0.36% ± 0.23% and 141.49 ± 107.41 μg/mL; the concentrations were significantly lower in inland women than those from coastland and lakeland. We conclude that DHA dietary intake is positively correlated with DHA concentrations in blood and breast milk in Chinese lactating women, suggesting that the tailored DHA food frequency questionnaire, DIET, is a valid tool for the assessment of DHA dietary intake.

The relationship between omega-3 and smoking habit: a cross-sectional study

Background

Omega3 polyunsaturated fatty acids (PUFAs) are related to several diseases, including smoking. The aim of this study was to evaluate the relationship between omega-3 intake and tobacco smoking, taking into account the qualitative differences in dietary intake between smokers and non-smokers, the amount of the ingested PUFA and their red blood (RBC) contents. We also looked for an association between omega-3 RBC content and smoking, and also between omega3 intake and the level of nicotine dependence.

Methods

Using a cross-sectional study, we included 50 current smokers (group I) and 50 lifetime non-smokers (group II), aged 18–75 years. We screened them at the Toronto Western Hospital and the Centre for Addiction and Mental Health (Toronto, Canada). The subjects completed a questionnaire with demographic data, lifestyle habits and details of food intake. The PUFAs measured in the RBC membranes were alphalinolenic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid and docosahexaenoic acid (DHA). In order to perform an adjusted comparison between smokers and non-smokers we used the ANCOVA model.

Results

After adjusting for confounding factors, non-smokers showed higher consumption of PUFAs, especially salmon: 800 g (0–7.740) than smokers 430 g (0–2.150) P < 0.001. They also had higher DHA levels compared to smokers: 4.81 % (2.79–10.21) and 4.13 % (2.33–7.73), respectively, p < 0.05. The other PUFAs showed no significant differences between the two groups.

Conclusions

Smokers ate less fish rich in omega3 fatty acids than non-smokers, showing and inverse and significant relationship between omega3 intake and smoking. Smokers had lower levels of DHA and EPA, a not previously reported finding. Considering that PUFAs probably interfere in smoking habit, the increase in omega-3 consumption may become a perspective in prevention or treatment of smoking. However, this inference must be evaluated through specific studies.

The stability of blood fatty acids during storage and potential mechanisms of degradation: A review

Fatty acids in blood samples, particularly polyunsaturated fatty acids (PUFAs), are susceptible to degradation through peroxidation reactions during long-term storage. Storage of blood samples is necessary in almost all studies and is crucial for larger clinical studies and in field research settings where it is not plausible for analytical infrastructure. Despite this, PUFA stability during blood storage is often overlooked. This review introduces and discusses lipid peroxidation and popular strategies employed to prevent or minimize peroxidation reactions during fatty acid analysis. Further, an in-depth examination of fatty acid stability during storage of blood is discussed in detail for all blood fractions including plasma/serum, erythrocytes and whole blood stored both in cryovials and on chromatography paper before discussing the associated mechanisms of degradation during storage. To our knowledge this is the first review of its kind and will provide researchers with the necessary information to confidently store blood samples for fatty acid analysis.

Omega-3 polyunsaturated fatty acid blood biomarkers increase linearly in men and women after tightly controlled intakes of 0.25, 0.5, and 1 g/d of EPA + DHA

Blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been related to coronary heart disease risk. Understanding the response of EPA + DHA in blood to dietary intake of EPA + DHA would facilitate the use of blood measures as markers of adherence and enable the development of dietary recommendations. The objective of this study is examine the blood response to intakes of EPA + DHA ≤1 g/d with an intervention designed for dietary adherence. It was hypothesized this relationship would be linear and that intakes of EPA + DHA <1 g/d would result in blood levels below those associated with the highest level of protection for cardiovascular events. Background EPA + DHA intake of men and women (n = 20) was determined by food frequency questionnaire and adherence was monitored by weekly fingertip blood sampling for fatty acid determinations. Participants consumed nutraceuticals to achieve intakes of 0.25 g/d and 0.5 g/d EPA + DHA for successive four-week periods. A subgroup (n = 5) had intakes of 1.0 g/d EPA + DHA for an additional 4 weeks. Fatty acid composition of whole blood, erythrocytes, and plasma phospholipids were determined at each time point. Blood levels of EPA and DHA increased linearly in these pools. A comprehensive review of the literature was used to verify the blood-intake relationship. Blood levels of long chain omega-3 polyunsaturated fatty acids reached blood levels associated with the highest levels of primary cardiac arrest reduction and sudden cardiac death risk only with intakes of 1.0 g/d of EPA + DHA. The blood biomarker response to intakes of EPA + DHA ≤1 g/d is linear in a small but highly adherent study sample and this information can assist in determining adherence in clinical studies and help identify dietary intake targets from associations between blood and disease.

Accuracy of self-reported intake of signature foods in a school meal intervention study: comparison between control and intervention period

Bias in self-reported dietary intake is important when evaluating the effect of dietary interventions, particularly for intervention foods. However, few have investigated this in children, and none have investigated the reporting accuracy of fish intake in children using biomarkers. In a Danish school meal study, 8- to 11-year-old children (n 834) were served the New Nordic Diet (NND) for lunch. The present study examined the accuracy of self-reported intake of signature foods (berries, cabbage, root vegetables, legumes, herbs, potatoes, wild plants, mushrooms, nuts and fish) characterising the NND. Children, assisted by parents, self-reported their diet in a Web-based Dietary Assessment Software for Children during the intervention and control (packed lunch) periods. The reported fish intake by children was compared with their ranking according to fasting whole-blood EPA and DHA concentration and weight percentage using the Spearman correlations and cross-classification. Direct observation of school lunch intake (n 193) was used to score the accuracy of food-reporting as matches, intrusions, omissions and faults. The reporting of all lunch foods had higher percentage of matches compared with the reporting of signature foods in both periods, and the accuracy was higher during the control period compared with the intervention period. Both Spearman's rank correlations and linear mixed models demonstrated positive associations between EPA+DHA and reported fish intake. The direct observations showed that both reported and real intake of signature foods did increase during the intervention period. In conclusion, the self-reported data represented a true increase in the intake of signature foods and can be used to examine dietary intervention effects.

Docosahexaenoic acid supplementation in lactating women increases breast milk and plasma docosahexaenoic acid concentrations and alters infant omega 6:3 fatty acid ratio

This study investigated the effects of docosahexaenoic acid (DHA) supplementation on the fatty acid composition of breast milk and plasma concentrations in lactating women and their infants. Eighty-nine lactating women 4-6 weeks post-partum received placebo, 200 mg or 400 mg DHA for 6 weeks with usual diets. Breast milk fatty acids and maternal plasma fatty acids were measured at the beginning and end of the study and infant plasma at the end of the study. Breast milk and maternal plasma DHA were significantly greater with 200 mg and 400 mg DHA compared with placebo (50% and 123% breast milk p<0.05; 71% and 101% plasma, p<0.0001), respectively. Infant plasma omega 6:3 and arachidonic acid (AA):DHA were significantly greater in the placebo group compared to both supplement groups (67% and 106%; 71% and 116%, respectively, p<0.05). DHA supplementation impacts infant fatty acids important for brain development and breast milk fatty acid composition.

Women who take n-3 long-chain polyunsaturated fatty acid supplements during pregnancy and lactation meet the recommended intake

The aim of the current study was to estimate total intake and dietary sources of eicosapentaenoic acid (EPA), docosapentanoic (DPA), and docosahexaenoic acid (DHA) and compare DHA intakes with the recommended intakes in a cohort of pregnant and lactating women. Twenty-four-hour dietary recalls and supplement intake questionnaires were collected from 600 women in the Alberta Pregnancy Outcomes and Nutrition (APrON) cohort at each trimester of pregnancy and 3 months postpartum. Dietary intake was estimated in 2 ways: by using a commercial software program and by using a database created for APrON. Only 27% of women during pregnancy and 25% at 3 months postpartum met the current European Union (EU) consensus recommendation for DHA. Seafood, fish, and seaweed products contributed to 79% of overall n-3 long-chain polyunsaturated fatty acids intake from foods, with the majority from salmon. The estimated intake of DHA and EPA was similar between databases, but the estimated DPA intake was 20%-30% higher using the comprehensive database built for this study. Women who took a supplement containing DHA were 10.6 and 11.1 times more likely to meet the current EU consensus recommendation for pregnancy (95% confidence interval (CI): 6.952-16.07; P<0.001) and postpartum (95% CI: 6.803-18.14; P<0.001), respectively. Our results suggest that the majority of women in the cohort were not meeting the EU recommendation for DHA during pregnancy and lactation, but taking a supplement significantly improved the likelihood that they would meet recommendations.

Cryopreservation prevents iron-initiated highly unsaturated fatty acid loss during storage of human blood on chromatography paper at -20°C

BACKGROUND

Fingertip prick whole blood collection on chromatography paper is amenable to high-throughput fatty acid (FA) profiling for large clinical and field studies. However, sample storage is problematic because highly unsaturated FAs (HUFAs) in erythrocytes rapidly degrade in samples stored at -20°C.

OBJECTIVE

The aim of the current study was to determine the mechanism of HUFA degradation and to develop prevention protocols.

METHODS

Free fatty acid (FFA) standards and whole blood reference material from a single participant were used to examine sample storage at -20°C for up to 90 d in triplicate. Iron chelation with deferoxamine (0-5000 μg), antioxidant protection with butylated hydroxytoluene (50 μg), cryopreservation with glycerol, and blood drying were examined using whole blood on chromatography strips. Biological replicate blood samples from additional participants (n = 6) with a range of ω-3 (n-3) HUFA concentrations were similarly assessed.

RESULTS

FFAs were relatively stable when stored on chromatography strips at -20°C. Glycerol treatment prevented HUFA degradation in whole blood reference material for 30 d (45 ± 0.4 to 46.8 ± 0.1, means ± SDs) compared to untreated saline controls (45.9 ± 1.0 to 6.8 ± 0.2). Pretreatment of paper for blood spots with deferoxamine and drying blood before storage slowed, but not entirely prevented, HUFA degradation over 30 d to 22% and 19% below baseline, respectively, compared to 86-92% in the controls. Protection against HUFA degradation with blood drying and glycerol treatment was confirmed in the biological replicate study and confirmed by prevention of cell lysis.

CONCLUSIONS

HUFA degradation during storage at -20°C appears to be due to hemolysis and subsequent iron-initiated peroxidation. This degradation may be prevented by glycerol, iron chelation, and/or dried blood spotting. A more thorough understanding of methods to prevent degradation during storage is critical with increasing use of FA profiling in large clinical studies.

Development and validation of an electronic FFQ to assess food intake in the Slovene population

OBJECTIVE

To develop and validate an electronic FFQ that estimates the food and nutrient intakes, especially fat intake, in a healthy, adult population from the coastal (Mediterranean) part of Slovenia.

DESIGN

A new electronic FFQ was developed for a survey entitled 'A multidisciplinary approach in the treatment of obesity', conducted at the University of Primorska, and validated against a 3 d weighed food record (FR).

SETTING

Coastal region of Slovenia.

SUBJECTS

Our study population included eighty-five healthy adults aged 25-49 years, recruited from the local coastal region of Slovenia. Intakes of food groups, macronutrients and energy, estimated by the FR and the FFQ, were compared using correlation coefficients, cross-classification and Bland-Altman plots.

RESULTS

The mean value of most nutrient intakes tended to be higher in the FFQ compared with the FR, except for carbohydrate, fibre and energy. Regression analysis demonstrated an acceptable agreement between the FFQ and FR. The FFQ was moderately correlated with the FR (0·30-0·54), and most of the correlations increased after energy adjustment and after de-attenuation. Relatively high (more than 70 %) proportions of participants were correctly classified into the same or an adjacent quartile. Bland-Altman analysis confirmed an acceptable level of agreement between the two methods.

CONCLUSIONS

The electronic FFQ, developed for a healthy adult Slovene population from the coastal region, was shown to be a valid tool to assess food group and nutrient intakes, especially fat intakes, and to rank individuals by their intakes within gene-nutrient studies.

Validity and reproducibility of an interviewer-administered food frequency questionnaire in Austrian adults at risk of or with overt diabetes mellitus

Food frequency questionnaires (FFQs) provide an inexpensive tool for dietary assessment. Given the scarcity of data on their validity for nutritional analysis in persons with overt diabetes mellitus or with increased risk of diabetes (relatives of patients with diabetes), this study tests the hypothesis that an FFQ, adapted to local dietary habits, yields a reliable estimate of nutrient intake when compared with 7-day food record (7DR) in healthy, prediabetes, and diabetes cohorts. One hundred three volunteers (50 persons with overt diabetes mellitus, 24 relatives of patients with diabetes, and 29 nondiabetic individuals without a family history of diabetes) completed both FFQ and 7DR. A second FFQ was completed by 100 of these volunteers after 3 months to evaluate its reproducibility. Data were compared by correlation and Bland-Altman analyses. Across the entire group, estimates for gram intakes of nutrients and total energy were associated with wide limits of agreement between FFQ and 7DR (correlation coefficients, 0.23-0.72; P < .02). Compared with 7DR, the FFQ overestimated intakes of saturated fat in the entire group (+6.6 ± 14 g; P < .001) and in persons with overt diabetes mellitus (+7.6 ± 15 g; P < .001) but underestimated protein intake in relatives of patients with diabetes (-16.36 ± 31 g; P = .01). The repeated FFQ revealed variable agreement (correlation coefficients, 0.34-0.72; P < .001) and underestimated (P < .01) macronutrient and total energy intakes, with slightly better performance in persons with overt diabetes mellitus and relatives of patients with diabetes than in nondiabetic individuals without a family history of diabetes. Hence, the FFQ allows measuring intakes of total energy and macronutrients in prediabetes and diabetes cohorts but reveals limitations when assessing dietary composition.

The percentage of DHA in erythrocytes can detect non-adherence to advice to increase EPA and DHA intakes

Characterisation of long-term adherence to EPA and DHA intakes through biomarkers and dietary assessments has implications for interpreting the findings of long-term intervention studies. Adherence to dietary advice targeting an EPA+DHA intake of 1 g/d was examined over 1 year. Men and women (n 45) received dietary advice to increase EPA and DHA intakes from seafood, nutraceutical (fish oil) or functional food sources, while a fourth group received combined advice. Blood biomarkers and dietary intakes of EPA and DHA were evaluated at baseline and post-intervention at weeks 4, 8, 12, 24 and 52. Assessment by 3 d diet records indicated that EPA+DHA intakes increased relative to baseline in weeks 4–52 following the seafood, nutraceutical and combined advice (advice group × time effect, P= 0·03). The percentage of DHA in plasma and whole blood and the percentage of EPA in erythrocytes, plasma and whole blood were higher in weeks 4–52 when compared with the corresponding baseline measurement. In contrast, the percentage of DHA in erythrocytes increased to a maximum at week 12 and returned to baseline levels in weeks 24 and 52 (time effect, P< 0·01). Measurement of the percentage of DHA in erythrocytes indicates that adherence was sustained during the first 12 weeks following the dietary advice, while other blood measurements of the percentage of EPA and DHA and dietary assessment suggest short-term increases in EPA+DHA intakes immediately before weeks 24 and 52. The percentage of DHA in erythrocytes characterises adherence to EPA and DHA intakes in long-term interventions.

EPA and DHA--protein, not fat is "where it's at"?

Guidelines and recommendations for the dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are topics of debate. Recently, EPA and DHA intakes have been demonstrated to be associated with dietary protein intakes and not dietary fat intakes that are distinct from α-linolenic acid. We presently confirm these observations in a secondary analysis of baseline dietary intake data for the validation of a food frequency questionnaire (n=99). DHA intakes measured by both 3 d dietary record and food frequency questionnaire and EPA intakes measured by food frequency questionnaire were positively correlated with protein intakes. EPA and DHA were not associated with fat intakes in either assessment, while ?-linolenic acid was positively correlated with fat intakes. Future recommendations regarding the intake of omega-3 polyunsaturated fatty acids, and EPA and DHA specifically, should consider these associations that provide insight on dietary sources of EPA and DHA in the food supply.