Validation of a food-frequency questionnaire assessment of carotenoid and vitamin E intake using weighed food records and plasma biomarkers: the method of triads model

BACKGROUND: Reliability or validity studies are important for the evaluation of measurement error in dietary assessment methods. An approach to validation known as the method of triads uses triangulation techniques to calculate the validity coefficient of a food-frequency questionnaire (FFQ). OBJECTIVE: To assess the validity of an FFQ estimates of carotenoid and vitamin E intake against serum biomarker measurements and weighed food records (WFRs), by applying the method of triads. DESIGN: The study population was a sub-sample of adult participants in a randomised controlled trial of beta-carotene and sunscreen in the prevention of skin cancer. Dietary intake was assessed by a self-administered FFQ and a WFR. Nonfasting blood samples were collected and plasma analysed for five carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene) and vitamin E. Correlation coefficients were calculated between each of the dietary methods and the validity coefficient was calculated using the method of triads. The 95% confidence intervals for the validity coefficients were estimated using bootstrap sampling. RESULTS: The validity coefficients of the FFQ were highest for alpha-carotene (0.85) and lycopene (0.62), followed by beta-carotene (0.55) and total carotenoids (0.55), while the lowest validity coefficient was for lutein (0.19). The method of triads could not be used for beta-cryptoxanthin and vitamin E, as one of the three underlying correlations was negative. CONCLUSIONS: Results were similar to other studies of validity using biomarkers and the method of triads. For many dietary factors, the upper limit of the validity coefficients was less than 0.5 and therefore only strong relationships between dietary exposure and disease will be detected.     

Dietary total antioxidant capacity is negatively associated with some metabolic syndrome features in healthy young adults

ObjectiveOxidative stress has been related to the development of obesity and other features accompanying chronic diseases. Furthermore, dietary antioxidant intake has been suggested to protect against oxidative damage and related clinical complications. Therefore, the aim of this study was to assess the potential associations among dietary total antioxidant capacity (TAC) and several early metabolic syndrome manifestations in healthy young adults.MethodsAnthropometric variables and blood pressure from 153 healthy subjects (20.8 ± 2.7 y old) were measured. Dietary intake was assessed by a validated food-frequency questionnaire and a 3-d record, which were also used to calculate TAC and to adjust by daily energy intake. Fasting blood samples were collected for measuring biochemical markers.ResultsDietary TAC showed positive and significant associations with fiber, folic acid, vitamin A and C, magnesium, selenium, and zinc intakes, after adjusting by sex and daily energy intake. Interestingly, systolic blood pressure, serum glucose, and free fatty acids were also found to be negatively associated with dietary TAC independently of sex and daily energy intake. Also, a relevant relation was found between body mass index and TAC values. Interestingly, after adjusting by sex and daily energy intake, complement factor-3 circulating levels appeared to be negatively and significantly associated with dietary TAC, whereas blood plasminogen activator inhibitor-1 and homocysteine concentrations showed an inverse marginally statistical trend.ConclusionsThese data suggest that dietary TAC may be also a potential early estimate of the risk to develop metabolic syndrome features and that dietary TAC could be a useful research tool in assessing antioxidant intake.     

Validation of the assessment of folate and vitamin B12 intake in women of reproductive age: the method of triads

OBJECTIVE: To validate the folate and vitamin B12 intakes estimated by a food-frequency questionnaire (FFQ) designed to be used in a case-control study on the association between maternal dietary intake and the risk of having a child with a congenital heart defect. DESIGN AND SUBJECTS: The FFQ was filled out by 53 women of reproductive age. Immediately thereafter, blood samples were taken to determine serum folate, red blood cell (RBC) folate and serum vitamin B12 concentrations. Subsequently, three dietary 24-h recalls (24HR) were completed during a period of three successive weeks and used as a reference method. The recalls comprised two weekdays and one weekend day. Using the method of triads, validity coefficients were calculated by comparing nutrient intakes derived from the FFQ and 24HR with the corresponding nutritional biomarkers in blood. The validity coefficient is the correlation between the dietary intake reported by the FFQ and the unknown 'true' dietary intake. RESULTS: The comparison of B-vitamin intakes reported by the FFQ and the mean of the 24HR revealed deattenuated correlation coefficients of 0.98 for folate and 0.66 for vitamin B12. The correlation coefficients between the B-vitamin intakes estimated by the FFQ and concentrations of serum folate, RBC folate and serum vitamin B12 were 0.20, 0.28 and 0.21, respectively. The validity coefficients for serum folate, RBC folate and serum vitamin B12 were 0.94, 0.75 and 1.00, respectively. The estimated folate and vitamin B12 intakes were comparable with the results of the most recent Dutch food consumption survey. CONCLUSIONS: The adapted FFQ is a reliable tool to estimate the dietary intake of energy, macronutrients, folate and vitamin B12 in women of reproductive age. Therefore, this FFQ is suitable for the investigation of nutrient-disease associations in future. SPONSORSHIP: Funding was provided by the Netherlands Heart Foundation (Grant 2002.B027).     

Application of the method of triads to evaluate the performance of food frequency questionnaires and biomarkers as indicators of long-term dietary intake.

Little is documented about the performance of the food frequency questionnaire (FFQ) in US minority groups and in populations in developing countries. The authors applied a novel technique, the method of triads, to assess the validity and reproducibility of the FFQ among Hispanics. The subjects were men (n = 78) and women (n = 42) living in Costa Rica. Seven 24-hour dietary recalls and two FFQ interviews (12 months apart) were conducted between 1995 and 1998 to estimate dietary intake during the past year. Plasma and adipose tissue samples were collected from all subjects. Validity coefficients, which measure the correlation between observed and "true" dietary intake, were also estimated. The median validity coefficients for tocopherols and carotenoids estimated by dietary recall, the average of the two FFQs, and plasma were 0.71, 0.60, and 0.52, respectively. Compared with adipose tissue, plasma was a superior biomarker for carotenoids and tocopherols. Adipose tissue was a poor biomarker for saturated and monounsaturated fatty acids but performed well for polyunsaturated fatty acids (validity coefficients, 0.45-1.01) and lycopene (validity coefficient, 0.51). This study also showed that biomarkers did not perform better than the FFQ and that they should be used to complement the FFQ rather than substitute for it.     

Dietary glycemic index is inversely associated with the risk of Parkinson's disease: A case–control study in Japan

ObjectiveHigh glycemic index (GI) or glycemic load (GL) carbohydrates might be expected to decrease the risk of Parkinson's disease (PD) by an insulin-induced increase in brain dopamine. We conducted a hospital-based case–control study in Japan to examine associations between dietary GI and GL and other dietary carbohydrate variables, including intake of available carbohydrate and dietary fiber, and PD.MethodsPatients with PD diagnosed using the U.K. Parkinson's Disease Society Brain Bank criteria (n = 249) and controls without neurodegenerative diseases (n = 368) were recruited. Dietary intake during the preceding month was assessed at the time of study recruitment using a validated, self-administered, semiquantitative, comprehensive diet history questionnaire.ResultsAfter adjustment for potential dietary and non-dietary confounding factors, dietary GI was significantly inversely associated with the risk of PD. Multivariate odds ratios (95% confidence intervals) for PD in the first, second, third, and fourth quartiles of dietary GI were 1.00 (reference), 1.03 (0.64–1.66), 0.68 (0.41–1.15), and 0.61 (0.34–1.09), respectively (P for trend = 0.04). Conversely, no significant association was observed for other dietary carbohydrates, including dietary GL (P for trend = 0.77), available carbohydrate intake (P for trend = 0.28), or dietary fiber intake (P for trend = 0.73).ConclusionThis preliminary case–control study based on current dietary habits found an independent inverse relation between dietary GI and PD. Considering the plausibility of the putative mechanism, further investigation using a case–control design with accurate assessment of past dietary habits or a prospective design is warranted.     

Calibration of a semi-quantitative food frequency questionnaire in early pregnancy

PURPOSE: We assessed the validity of a semi-quantitative food frequency questionnaire (FFQ) among pregnant women. METHODS: We enrolled 72 African American and 132 Caucasian pregnant women in a calibration study of an existing FFQ. For eight categories of intake of fatty acids, carotenoids, and gamma- tocopherol estimated by the FFQ (energy-adjusted deciles 1, 2, 3, 4+5, 6+7, 8, 9, 10) we compared measurements of the corresponding nutrient level measured in pooled blood specimens from all participants in each category. RESULTS: For alpha-carotene, plasma levels were 1.9 (p=0.10) and 2.9 (p=0.0007) microg/L higher for every 100 microg increase in dietary intake among African American and Caucasian women, respectively. A high percent increase in plasma levels was apparent between extreme dietary deciles of alpha-carotene (275% for African American and 152% for Caucasian women). Increases across deciles were evident for lycopene, lutein, and gamma-tocopherol, ranging from 12% to 64%. We also observed relationships between dietary intake and their erythrocyte concentrations of long-chain n-3 fatty acids and trans-fatty acids, but not alpha-linolenic acid. CONCLUSION: The observed differences in biomarkers across varying levels of dietary intake suggest that this FFQ is an appropriate epidemiologic tool for assessing intake of at least several important nutrients during early pregnancy in both African American and Caucasian women.     

Evaluation of the Validity of a Food Frequency Questionnaire and 24-Hour Dietary Recall to Assess Dietary Iron Intake in Children and Adolescents from the South American Youth/Child Cardiovascular and Environmental Study

BackgroundA food frequency questionnaire (FFQ) for South American children and adolescents was developed, but its validity for assessing dietary iron intake has not been evaluated.ObjectiveTo evaluate the validity of the FFQ and 24-hour dietary recalls (24h-DR) for assessing dietary iron intake in children and adolescents.DesignThe South American Youth/Child Cardiovascular and Environmental study is a multicenter observational study, conducted in five South American cities: Buenos Aires (Argentina), Lima (Peru), Medellin (Colombia), Sao Paulo, and Teresina (Brazil). The FFQ assessed dietary intake over the previous 3 months, and the 24h-DR was completed three times (2 weekdays and 1 weekend day) with a minimum 5-day interval between recalls. Blood samples were collected to assess serum iron, ferritin, and hemoglobin levels.Participants and settingData of 99 children (aged 3 to 10 years) and 50 adolescents (aged 11 to 17 years) from public and private schools were collected during 2015 to 2017.Main outcome measuresDietary iron intake calculated from the FFQ (using the sum of daily iron intake in all food/food groups) and 24h-DR (mean of 3 days using the multiple source method).Statistical analyses performedDietary iron intake in relation to blood biomarkers were assessed using Spearman rank correlations adjusted for sex, age, and total energy intake, and the quadratic weighted κ coefficients for agreement.ResultsSpearman correlations showed very good coefficients (range = 0.78 to 0.85) for the FFQ in both age groups; for the 24h-DR, the coefficients were weak in children and adolescents (range = 0.23 to 0.28). The agreement ranged from 59.9% to 72.9% for the FFQ and from 63.9% to 81.9% for the 24h-DR.ConclusionThe South American Youth/Child Cardiovascular and Environmental study FFQ exhibited good validity to rank total dietary iron intake in children and adolescents, and as well as the 24h-DR, presented good strength of agreements when compared with serum iron and ferritin levels.     

Higher dietary intake of alpha-linolenic acid is associated with lower insulin resistance in middle-aged Japanese

ObjectiveTo investigate the associations between dietary intake of n-3 polyunsaturated fatty acids (plant-derived alpha-linolenic acid: ALA, and marine-derived eicosapentaenoic and docosahexaenoic acid: EPA + DHA) and insulin resistance (IR) in a lean population with high n-3 PUFA intake.MethodWe cross-sectionally studied 3383 Japanese local government workers aged 35–66 in 2002. IR was defined as the highest quartile of homeostasis model assessment, and nutrient intake was estimated from a diet history questionnaire. The odds ratios (ORs) of IR taking the lowest quartile of ALA or EPA + DHA intake as the reference were calculated by logistic regression analysis.ResultsMean age, body mass index (BMI), and dietary ALA, and median of dietary EPA + DHA were 47.9 years, 22.9 kg/m², and 1.90 g/day (0.88%E) and 0.77 g/day (0.36%E), respectively. The ORs of IR decreased across the quartiles of ALA intake (multivariate-adjusted OR for Q4 versus Q1 = 0.74, P for trend = 0.01) and the association was observed only in subjects with a BMI of < 25 kg/m² (P for interaction = 0.033). However EPA + DHA showed no such associations consistently.ConclusionHigher ALA intake was significantly associated with a lower prevalence of IR in normal weight individuals of middle-aged Japanese men and women.     

Construction of an N-nitroso database for assessing dietary intake

Dietary N-nitroso compounds are carcinogens synthesized during food processing from two main classes of precursors, oxides of nitrogen and amines or amides. Quantification of the dietary intake of N-nitroso compounds is significant to human cancers, including those of the stomach and upper gastro-intestinal tract, colon, and brain. Previous studies investigating these cancers primarily used proxy estimates of N-nitroso intake and not a full and complete database. In this report, we describe the development of a database to be used in conjunction with a food frequency questionnaire (FFQ) or 24 h dietary records. Published analytical data for N-nitroso compounds were compiled and evaluated for inclusion in the database. The final database consisted of 23 different N-nitroso compounds for 500 foods from 39 different food subgroups. Next, database foods were matched to foods in a standard FFQ by imputation, or calculated value, or assumed zero. Using the FFQ modified with N-nitroso values, we evaluated the ability to compute N-nitroso intakes for a sample of healthy control subjects of cancer epidemiological studies. N-nitroso content of food items ranged from <0.01 μg/100 g to 142 μg/100 g and the richest sources were sausage, smoked meats, bacon, and luncheon meats. The database is useful to quantify N-nitroso intake for observational and epidemiological studies.     

A 51-item calcium-focused food frequency questionnaire is a reliable tool to assess dietary calcium intake in postmenopausal women

Given the lack in a valid biomarker to assess dietary calcium intake (dCa_i), reproducible estimation of usual dCa_i is crucial for better understanding of its interaction with health outcomes in specific populations. This study tested the hypothesis that a calcium-focused food frequency questionnaire (FFQ) may be used to estimate dCa_i of women ≥50 years residing in a multicultural environment (Montreal, Canada). One hundred and eight women (age, 63.1 ± 7.7 years; 98% postmenopausal) completed the FFQ twice and 4 nonconsecutive 24-hour recalls (24HRs) over 1 month. Medians of dCa_i were compared by Wilcoxon signed rank test. Reproducibility and relative validity of the FFQ were assessed by Spearman correlation (r_s) and Cohen's weighted kappa (κw). Agreement was further assessed by cross-classification by quartiles, Bland-Altman plot, and sensitivity and specificity analyses. The median (interquartile range) dCa_i estimated by the FFQ and 24HRs were 723 (524-1033) mg/d and 854 (666-1068) mg/d, respectively (P < .001). The FFQs had a strong correlation (r_s = 0.72, P < .001) and moderate agreement (κw = 0.55). The FFQ and 24HRs were moderately correlated (r_s = 0.65, P < .001). Cross-classification showed moderate agreement (κw = 0.42), with 85% of the participants classified into identical or contiguous quartiles and 2.8% into extreme opposite quartiles. According to the Bland-Altman plot, the FFQ underestimated dCa_i with a bias of 99 mg/d (95% limits of agreement, −677 to +480 mg/d). Sensitivity and specificity of identifying intakes <1000 mg/d were 90% and 57%, respectively. This FFQ is a useful tool to discriminate dCa_i <600 and ≥1000 mg/d in postmenopausal women and to rank dCa_i in epidemiological studies.     

Estimated intakes of brominated flame retardants via diet and dust compared to internal concentrations in a Swedish mother–toddler cohort

Tri-decabrominated diphenyl ethers (tri-decaBDEs), isomer-specific hexabromocyclododecanes (HBCDs) and 14 emerging brominated flame retardants (EBFRs) were determined in Swedish market basket samples, two pooled breast milk samples and house dust collected in homes of first-time mothers. Daily dietary and dust intakes were estimated for the mothers and their toddlers and compared to previously reported levels in serum of both the mothers and toddlers and in feces of the toddlers (n = 20). Diet was the main contributor for intake of ΣpentaBDE and α-tetrabromoethylcyclohexane (DBE-DBCH) for both mothers and toddlers. For ΣoctaBDE, ΣHBCD and pentabromobenzene (PBBz), dietary intake was more important for mothers while house dust ingestion was more important for toddlers. House dust was the main exposure route for ΣdecaBDE, decabromodiphenyl ethane (DBDPE), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP), bis(2,4,6-tribromophenoxy) ethane (BTBPE) and pentabromotoluene (PBT) for both mothers and toddlers. Significant correlations (Spearmans, α < 0.05) were found between the mothers’ BDE serum concentrations and their consumption of meat and fish while no correlations were found between BFR dietary intake and serum or feces concentrations in toddlers. Octa-decaBDE congener concentrations in serum and feces of toddlers were significantly correlated to those in house dust. BDE-207 and -208 concentrations in serum of mothers were significantly correlated with the nonaBDEs in house dust. The correlations between house dust and internal concentrations and comparison of the house dust and dietary contributions to the estimated daily intakes suggest that dust exposure plays a larger role for the octa-decaBDE body burden in toddlers than in their mothers.     

Dietary intakes of essential nutrients among Arab and Berber ethnic groups on rural Tunisian island

ObjectiveThe dietary intake was investigated and food sources were identified among Tunisian ethnic groups from Jerba Island in the south of Tunisia.MethodsNinety-four subjects of moderate socioeconomic status (47 Berbers and 47 Arabs) aged 32 to 64 y completed a 1-mo qualitative food-frequency questionnaire and a single 24-h dietary recall, and dietary intakes and demographic status were observed from 2006 to 2007.ResultsThe prevalence of overweight and obesity was not significantly associated with Arab men compared with Berber men. Therefore, obesity was significantly associated with Berber women (P < 0.001). Height was significantly different between Arab and Berber women (P < 0.001). There were no significant differences in energy intake between men and women. Protein intake was not significantly different between ethnic groups. Milk and dairy products in the Berber group were significantly different from the Arab group. Intakes of calcium, zinc, iron, and folate were below recommended nutrient intakes in men and women in the two ethnic groups. Vitamin E intake was greater in Berbers than in Arabs (P < 0.01).ConclusionEthnicity was significantly associated with dietary intakes in the two ethnic groups of Jerba Island.     

Development and validation of a food frequency questionnaire to estimate the intake of genistein in Malaysia

Abstract

Objective: To develop and validate a food frequency questionnaire (FFQ) to estimate the genistein intake in a Malaysian population of pregnant women. Method: A single 24-h dietary recall was obtained from 40 male and female volunteers. A FFQ of commonly consumed genistein-rich foods was developed from these recalls, and a database of the genistein content of foods found in Malaysia was set up. The FFQ was validated against 7-d food diary (FD) kept by 46 pregnant women and against non-fasting serum samples obtained from 64 pregnant women. Reproducibility was assessed by comparing the responses on two FFQs administered approximately 1 month apart. Results: The Pearson correlation coefficient between FFQ1 and FD was 0.724 and that between FFQ2 and FD was 0.807. Classification into the same or adjacent quintiles was 78% for FFQ1 versus FD and 88% for FFQ2 versus FD. A significant dose -- response relation was found between FFQ-estimated genistein intake and serum levels. Conclusion: The FFQ developed is a reliable, valid tool for categorising people by level of genistein intake.     

Fructo-oligosaccharides enhance the mineral absorption and counteract the adverse effects of phytic acid in mice

ObjectiveWe explored the effects of fructo-oligosaccharides (FOS) and phytic acid (PA) on the absorption of minerals and their interaction.MethodsA 3 × 2 factorial experiment was designed to evaluate the effects of FOS (in the presence or absence of PA) on the apparent absorption rate of minerals and the mineral status (plasma, hepatic, and bone) in mice. Sixty Kun-Ming mice were randomized into six groups: basal diet group; basal diet + 1% PA group (PA); basal diet + 0.8 g/kg of body weight FOS group (FOS1); FOS1 + 1% PA group (FOS1 + PA); basal diet + 2.5 g/kg of body weight group (FOS2); and FOS2 + 1% PA group (FOS2 + PA). The mice received FOS by gavage for consecutive 4 wk, and the PA was added in the diet. The mice were housed individually in the last week. The food intake was recorded and the feces were collected for calculation of the apparent absorption rate. Then the mice were sacrificed, the ceca were removed and weighed, and the cecum contents were used for the detection of pH and short-chain fatty acids. The blood, liver, and the left femur were collected for the measurement of the minerals.ResultsFOS supplementation resulted in the enlargement of the cecum and increased cecal acidification (P < 0.01). In addition, FOS effectively boosted the apparent absorption rate of calcium (FOS1, +7%; FOS2, +9%, P < 0.05), magnesium (FOS1, +26%; FOS2, +19%, P < 0.05), and iron (FOS1, +17%; FOS2, +22%, P < 0.05), and restored the PA-impaired magnesium and iron apparent absorption rates (P < 0.01). In addition, FOS significantly increased hepatic zinc levels (P < 0.01) and femoral magnesium levels (P < 0.01).ConclusionThese data indicate that FOS effectively enhances the mineral apparent absorption rate and counteracts the deleterious effects of PA.     

Using the method of triads in the validation of a food frequency questionnaire to assess the consumption of fatty acids in adults

Background

It is of great value to develop valid instruments to estimate food consumption; for this purpose, the triads method has been applied in validation studies of dietary intake to evaluate the correlation between three measurements [food frequency questionnaire (FFQ), reference method and biomarker]. The main aim of the present study was to validate a FFQ for Brazilian adults by means of the method of triads by estimating the ingestion of total fatty acids based on the level of saturation.

Methods

The present study enrolled 152 Brazilian adults of both sexes, who were residents in the city of Viçosa, Brazil. The ingestion of total saturated, monounsaturated, polyunsaturated, trans, linoleic and linolenic fatty acids was assessed by means of a FFQ, two food records, and biomarkers, which were detected by gas chromatography. The validation coefficients were calculated using the method of triads and concordance was determined by Kappa statistics.

Results

The FFQ was considered an adequate dietary method, because, based on the validation coefficients, it estimates the intake of total fat (0.84), as well as linolenic (0.90) and linoleic acids (0.31). A high concordance rate was confirmed for all nutrients assessed by the FFQ and food records. Regarding the biomarkers, linolenic acid and linoleic acid presented greater concordance.

Conclusions

According to the validation coefficients, the FFQ precisely estimated total fat, linolenic acid and linoleic acid contents.     

The Theory of Planned Behaviour and dietary patterns: A systematic review and meta-analysis

ObjectivePromoting adherence to healthy dietary patterns is a critical public health issue. Models of behaviour, such as the Theory of Planned Behaviour (TPB) allow programme designers to identify antecedents of dietary patterns and design effective interventions. The primary aim of this study was to examine the association between TPB variables and dietary patterns.MethodsA systematic literature search was conducted to identify relevant studies. Random-effects meta-analysis was used to calculate average correlations. Meta-regression was used to test the impact of moderator variables.ResultsIn total, 22 reports met the inclusion criteria. Attitudes had the strongest association with intention (r+ = 0.61) followed by perceived behavioural control (PBC, r+ = 0.46) and subjective norm (r+ = 0.35). The association between intention and behaviour was r+ = 0.47, and between PBC and behaviour r+ = 0.32. Moderator analyses revealed that younger participants had stronger PBC–behaviour associations than older participants had, and studies recording participants' perceptions of behaviour reported significantly higher intention–behaviour associations than did those using less subjective measures.ConclusionsTPB variables were found to have medium to large associations with both intention and behaviour that were robust to the influence of key moderators. Recommendations for future research include further examination of the moderation of TPB variables by age and gender and the use of more valid measures of eating behaviour.     

No difference in the 24-hour interstitial fluid glucose profile with modulations to the glycemic index of the diet

ObjectiveReducing the glycemic index (GI) of the diet may decrease metabolic risk, primarily through reduction and stabilization of blood glucose. The objective of this research was to investigate whether incorporation of lower or higher GI foods into mixed meals had different effects on daylong glucose profiles, measured in interstitial fluid by a continuous glucose-monitoring system.MethodsThe study was a randomized, balanced, two-way crossover intervention of 2 × 1-wk periods of lower and higher GI diets. Participants were 12 overweight healthy adult women (mean body mass index ± standard deviation 27.5 ± 2.3 kg/m²). Changes in GI were achieved through substitution of key staple carbohydrate-rich foods. After a 4-d run-in on each dietary regimen, participants wore the continuous glucose-monitoring system over 2 d of identical controlled feeding in the laboratory, separated by 1 d of ad libitum consumption at home.ResultsOn controlled days, diets differed in GI by 15 U and provided equal energy, macronutrients, and fiber. On ad libitum days, diet diaries revealed a difference in GI of 14 ± 1 U (mean ± standard error), with no detectable difference in energy, macronutrient, or fiber intake. No differences were observed in glucose profiles between higher and lower GI interventions in the controlled or ad libitum setting. There was significant agreement in area under the glucose curve on repeated controlled feeding days (intraclass correlation 0.75).ConclusionThis study indicates that a difference in dietary GI of 14–15 U is insufficient to alter daylong glycemia as measured in interstitial fluid by the continuous glucose-monitoring system.     

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

BackgroundCanadian dietary sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) include marine and non-marine whole foods, functional foods, and nutraceuticals.Objective/designIn the present study, these sources were incorporated into a nutrient-specific, semi-quantitative food frequency questionnaire (FFQ) and the ability to measure the EPA and DHA intakes of Canadian adults was assessed. Specifically, the EPA and DHA intakes estimated by FFQ of 78 men and women, 20 to 60 years of age, were compared with EPA and DHA measurements from 3-day food records and measures of EPA and DHA in fasting whole blood.ResultsMean (±standard deviation) and median intakes of EPA+DHA were 0.34±0.34 and 0.21 g/day by FFQ and 0.47±0.71 and 0.13 g/day by food record, with no significant differences between mean intakes (P=0.93). The FFQ provided higher estimates than the food record at low intakes of EPA and DHA and lower estimates at high intakes based on Bland-Altman plots. The FFQ was moderately correlated with food record (r=0.31 to 0.49) and with blood biomarker measures of EPA and DHA (r=0.31 to 0.51). Agreement analysis revealed that 42% of participants were classified in the same and 77% into same or adjacent quartile when EPA and DHA intake was assessed by food record and by FFQ. Similar quartile agreement was found for EPA and DHA intakes by FFQ with blood biomarker EPA and DHA. The range of the validity coefficients, calculated using the method of triads, was 0.43 to 0.71 for FFQ measurement of EPA+DHA.ConclusionsThe FFQ is an adequate tool for estimating usual EPA and DHA intakes and ranking Canadian adults by their intakes.     

Dietary folate and vitamin B12 intake before diagnosis decreases gastric cancer mortality risk among susceptible MTHFR 677TT carriers

ObjectiveTo assess gastric cancer survival in relation to dietary intake of methyl donors and the methylenetetrahydrofolate reductase 677C > T (MTHFR 677C > T) polymorphism.MethodsA prospective cohort of 257 incidental, histologically confirmed gastric cancer cases was assembled in January 2004 and followed until June 2006. Patients were recruited from the main oncology and/or gastroenterology units in Mexico City and were queried regarding their sociodemographic information, clinical history, and dietary habits 3 y before the onset of their symptoms. The intake of methyl donors was estimated with a food-frequency questionnaire and the MTHFR 677C > T polymorphisms were determined by polymerase chain reaction/restriction fragment length polymorphism analysis. Cox's multivariate regression models were used to estimate the mortality risk of gastric cancer.ResultsMTHFR 677TT carriers with low folate and vitamin B12 intakes had the lowest survival rate in cases of gastric cancer. High intakes of folate and vitamin B12 before diagnosis was associated with decreased gastric cancer mortality risk in susceptible MTHFR 677TT carriers (mortality risk for folate 0.14, 95% confidence interval 0.04–0.46, P for trend = 0.001; mortality risk for vitamin B12 0.23, 95% confidence interval 0.08–0.66, P for trend = 0.008).ConclusionFolate and related B vitamins may be used as an intervention strategy to improve the survival outcome of gastric cancer.     

Tracking of children's body-mass index, television viewing and dietary intake over five-years

ObjectiveTo examine the tracking of children's body mass index, television viewing, and dietary intake over five-years.MethodsIn 2002/3 (T1) parents of children aged 5–6 years (n = 175) and 10–12 years (n = 121), from Victoria, Australia, completed measures assessing their child's frequency of fruit, vegetable, and energy-dense sweet and savory snack consumption, and their child's television (TV) viewing. Children's height and weight were measured by researchers and sex–age adjusted body mass index (BMI) calculated. All measures were repeated in 2006 (T2) and 2008 (T3). Generalized estimating equations (GEE) (standardized stability coefficients, β) were used to assess tracking and were interpreted as: β < 0.3 = low, 0.3–0.6 = moderate, and > 0.6 = high.ResultsHigh standardized stability coefficients were found for BMI (β = 0.74–0.92), TV viewing (β = 0.65–0.73), and frequency of fruit consumption (β = 0.73–0.89) among younger and older children. Moderate-to-high standardized stability coefficients were found for frequency of vegetable (β = 0.52–0.86), energy-dense sweet (β = 0.41–0.65), and savory snack consumption (0.40–0.67) among younger and older children.ConclusionsBMI, TV viewing and dietary intake patterns are moderate-highly stable throughout childhood and into adolescence. Further research that identifies and targets high risk groups to prevent increased BMI, reduce TV viewing and promote healthy dietary behaviors may be justified.