Journal of Nutrition Nutritional Epidemiology

Body Mass Index Is an Important Determinant of Methylation Biomarkers in Women of Reproductive Ages [Nutritional Epidemiology]

Fri, 20 Nov 2009 10:01:59 PST

B vitamin deficiencies lead to moderate hyperhomocysteinemia, which has been associated with health and disease. However, concomitant derangements in cellular methylation, reflected by altered plasma S-adenosylmethionine (SAM) or S-adenosylhomocysteine (SAH) concentrations, may be the primary cause. Therefore, we identified determinants of homocysteine, SAM, and SAH concentrations in 336 women, aged 20–48 y, as part of a large study focusing on risk factors for reproductive disorders. Blood was obtained to determine plasma SAM, SAH, and total homocysteine (tHcy), serum vitamin B-12 and folate, RBC folate concentrations, and the related single nucleotide polymorphisms 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C > T and 1298A > C, methionine synthase reductase (MTRR) 66A > G, and nicotinamide N-methyltransferase IVS1–151G > A. Questionnaires provided information on demographics, lifestyles, and nutrient intakes. Correlation coefficients were calculated and multivariable associations were assessed with a general linear model. Serum folate was positively correlated with SAM concentrations (r = 0.159; P = 0.004). Folate and vitamin B-12 were not correlated with SAH concentrations or the SAM:SAH ratio but were inversely correlated with tHcy concentrations (serum folate r = –0.324; RBC folate r = –0.294; vitamin B-12 r = –0.307; P < 0.01). From the multivariable analysis, BMI was the strongest determinant of SAM (standardized β = 19.145; P < 0.001) and SAH concentrations (standardized β = 3.241; P = 0.010). MTHFR 677TT (standardized β = 0.195; P = 0.001), B vitamin supplement use (standardized β = –0.156; P < 0.001) and dietary protein intake (standardized β = –0.011; P < 0.001) were the strongest determinants of tHcy concentrations. Thus, the determinants of SAM and SAH differ from those of tHcy concentrations. Given that BMI was a strong determinant of SAM concentrations, it should be included in future studies on cellular methylation.

Dietary Patterns are Linked to Cardiovascular Risk Factors but Not to Inflammatory Markers in Alaska Eskimos [Nutritional Epidemiology]

Fri, 20 Nov 2009 10:01:59 PST

Despite the tradition of a diet high in fish oils and abundant physical activity, coronary artery disease is increasing among Alaska Eskimos. Explanations for this observation include lifestyle changes. In this cross-sectional analysis, we evaluated dietary patterns of Alaska Eskimos and investigated the relations between these dietary patterns and known cardiovascular risk factors, including inflammatory markers. We used a principal component analysis with data from FFQ collected in 2000–2004 to determine dietary patterns of Alaska Eskimos. Four dietary patterns were identified: a traditional pattern, plus 3 patterns based on purchased food, one of which reflected healthy food choices. The traditional dietary pattern was associated with lower triglycerides (P < 0.001) and blood pressure (P = 0.04) and slightly higher LDL cholesterol (LDL-C) (P = 0.05). Whereas the healthy purchased diet was associated with a trend toward lower LDL-C (P = 0.09), the beverages and sweets diet was positively associated with LDL-C (P = 0.02). Diet pattern was not associated with inflammatory markers or pathogen burden. Our data show that the traditional diet is related to a better profile of cardiovascular disease risk factors and should be encouraged. Programs are needed to encourage the availability of healthy food choices for those not able to obtain traditional foods.

Intakes of (n-3) Fatty Acids and Fatty Fish Are Not Associated with Cognitive Performance and 6-Year Cognitive Change in Men Participating in the Veterans Affairs Normative Aging Study [Nutritional Epidemiology]

Fri, 20 Nov 2009 10:01:59 PST

High intake of fish and (n-3) PUFA may protect against age-related cognitive decline. However, results are inconsistent and limited data exist regarding changes in multiple cognitive functions over a longer period of time. In this study, we assessed the association between fatty fish intake as well as (n-3) PUFA intake with cognitive performance and cognitive change over 6 y in 1025 elderly men. Participants were from the Veterans Affairs Normative Aging Study. Cognitive function was assessed with a battery of cognitive tests focusing on factors representing memory/language, speed, and visuospatial/attention. Dietary intakes were assessed with a validated FFQ. We used general linear models to assess cross-sectional associations and mixed models to assess the associations over time. Models were adjusted for age, education, BMI, smoking, diabetes, and intake of alcohol, saturated fat, vitamin C, and vitamin E. The mean age of participating men was 68 y at baseline. Median fish consumption ranged from 0.2 to 4.2 servings/wk across quartiles. Cross-sectional analyses showed no association between fatty fish or (n-3) PUFA intake and cognitive performance. Longitudinal analyses, over 6 y of follow-up, also did not show any significant associations between fatty fish or (n-3) PUFA intake and cognitive change. In this population of elderly men, intake of neither fatty fish nor (n-3) PUFA was associated with cognitive performance.

Past and Current Body Size Affect Validity of Reported Energy Intake among Middle-Aged Danish Men [Nutritional Epidemiology]

Fri, 20 Nov 2009 10:01:59 PST

Our objectives were to estimate the degree of misreporting energy intake (EI) and analyze associations with previous BMI, current BMI, or both. The study was part of the Adiposity and Genetics Study follow-up study including 309 Danish men (age 40–65 y) originally sampled from the obligatory draft board examination. Height and weight were measured at the mean ages of 20 (draft board), 33, 44, and 49 y (current age). Obesity was categorized as BMI ≥ 31 kg/m². Dietary intake for 7 d and physical activity (PA) level (PAL) were self-reported. Resting metabolic rate (RMR) was measured in a ventilated hood system. By comparing EI with energy expenditure and assuming energy balance, reporting accuracy (RA) was estimated as EI/(RMR·PAL). A plausibility interval was calculated to encompass specific variation components of EI, RMR, and PAL; the specific 95% plausibility interval was 1.00 ± 0.35. Participants were categorized as underreporters (RA ≤ 0.65), plausible reporters (0.65 < RA ≤ 1.35), or overreporters (RA > 1.35) of EI. The relation between RA and BMI was studied through linear regression analysis. Overall, the RA was (mean ± SE) 0.76 ± 0.01. Of 309 participants, 35% underreported and 7% overreported. Whether stratified for current BMI or draft board BMI, the obese men were more likely to underreport than those who were not obese. Among those currently not obese, underreporting was more prevalent among those who were obese at the draft board examination (44%) than among those who were not (21%). Regression analysis showed that both previous and current BMI and their combination were significantly associated with RA. Thus, underreporting of dietary intake seems to be associated with not only current BMI but also with current BMI in combination with previous BMI.

Dietary Arachidonic Acid to EPA and DHA Balance Is Increased among Canadian Pregnant Women with Low Fish Intake [Nutritional Epidemiology]

Friesen, R. W., Innis, S. M. — Fri, 20 Nov 2009 10:01:59 PST

Arachidonic [ARA, 20:4(n-6)], eicosapentaenoic [EPA, 20:5(n-3)], and docosahexaenoic acids [DHA, 22:6(n-3)] occur in the diet in animal tissue lipids, play important roles in human development and health, but have interactive and opposing functions. Meat and poultry have higher ARA and fish are richer in EPA and DHA. National databases were recently revised to include complete data on ARA in foods. We used a validated FFQ and the revised nutrient databases to quantify the distribution of ARA, EPA, and DHA intakes and balance for 204 healthy Canadian pregnant women. We focused on intake distributions because risk of adverse health effects increases at lower nutrient intakes. RBC fatty acids were analyzed concurrenly with dietary assessment. The distribution of ARA, EPA, and DHA intakes were skewed (P < 0.001), with a median (5–95th percentile) of 107 (41–225), 65 (10–228), and 105 (10–430) mg/d ARA, EPA, and DHA, respectively. Fish provided 66 and 76% of EPA and DHA, respectively, whereas eggs, poultry, and meats provided 81% of ARA. Women consuming <101 g fish/wk consumed less EPA and DHA and had markedly elevated median dietary ARA:EPA and ARA:DHA ratios and RBC lipid ARA:EPA + DHA ratios compared with women consuming ≥101 g fish/wk (P < 0.001). Relatively small increases in fish intake of 1–2 servings (25–50 g)/wk corrected the distorted dietary (n-6):(n-3) fatty acid balance among women consuming meats, but not fish. Median fish and DHA intakes below the recommended 1–2 servings/wk fish for pregnant women suggest major changes in the availability, cost, or acceptance of fish are needed.

Regular Consumption from Fast Food Establishments Relative to Other Restaurants Is Differentially Associated with Metabolic Outcomes in Young Adults [Nutritional Epidemiology]

Duffey, K. J., Gordon-Larsen, P., Steffen, L. M., Jacobs, D. R., Popkin, B. M. — Tue, 20 Oct 2009 10:01:51 PDT

Although away-from-home eating is adversely associated with weight, other comorbidities have not been examined; therefore, we sought to determine the associations of fast food (e.g. Wendy's, McDonalds) and restaurant (sit-down style) consumption (times per week) with weight and multiple metabolic outcomes, including homeostatic model assessment insulin resistance (HOMA-IR), waist circumference, and plasma triglycerides (TG), LDL cholesterol, and HDL cholesterol (HDL-C). We used 3 waves of data (exam y 7, 10, and 20) from the Coronary Artery Risk Development in Young Adults Study, a prospective cohort study of black and white young adults [aged 25–42 y in 1992–93, n = 3643 (men, 1659; women, 1984)]. Individuals in the highest (vs. lowest) quartile of baseline (defined as the mean of y 7 and 10) fast food consumption had higher y 20 weight [adjusted mean (95% CI): 5.6 kg (CI, 2.1, 9.2); P = 0.002], HOMA-IR [0.9 (CI, 0.4, 1.3); P < 0.001], waist circumference [5.3 cm (CI, 2.8, 7.9); P < 0.000], TG concentrations [0.25 mmol/L (CI, 0.10, 0.40), 22.7 mg/dL (CI, 9.1, 36.3); P = 0.001], and lower HDL-C concentrations [–0.014 mmol/L (CI, –0.215, –0.067), 5.4 mg/dL (CI, –8.3, –2.6); P < 0.000]. Baseline restaurant consumption was unrelated to y 20 outcomes. Adjusted change in weekly restaurant (P < 0.05) and fast food intake (P < 0.001) was associated with 13-y changes in body weight [0.09 kg (CI, 0.02, 0.17) and 0.15 kg (CI, 0.06, 0.24), respectively] and waist circumference [0.08 cm (CI, 0.02, 0.14) and 0.12 cm (CI, 0.04, 0.20), respectively]. Fast food consumption may be an important target for the prevention of adverse metabolic health outcomes.

Increases in Plasma Holotranscobalamin Can Be Used to Assess Vitamin B-12 Absorption in Individuals with Low Plasma Vitamin B-12 [Nutritional Epidemiology]

Tue, 20 Oct 2009 10:01:51 PDT

Low plasma concentrations of vitamin B-12 are common in Indians, possibly due to low dietary intakes of animal-source foods. Whether malabsorption of the vitamin contributes to this has not been investigated. A rise in the plasma holotranscobalamin (holo-TC) concentration after a standard dose of oral vitamin B-12 has been proposed as a measure of gastrointestinal absorption in people with normal plasma vitamin B-12 concentrations. We studied 313 individuals (children and parents, 109 families) in the Pune Maternal Nutrition Study. They received 3 doses of 10 µg (n = 191) or 2 µg (n = 122) of cyanocobalamin at 6-h intervals. A rise in plasma holo-TC of ≥15% and >15 pmol/L above baseline was considered normal vitamin B-12 absorption. The baseline plasma vitamin B-12 concentration was <150 pmol/L in 48% of participants; holo-TC was <35 pmol/L in 98% and total homocysteine was high in 50% of participants (>10 µmol/L in children and >15 µmol/L in adults). In the 10 µg group, the plasma holo-TC concentration increased by 4.8-fold from (mean ± SD) 9.3 ± 7.0 pmol/L to 53.8 ± 25.9 pmol/L and in the 2 µg group by 2.2-fold from 11.1 ± 8.5 pmol/L to 35.7 ± 19.3 pmol/L. Only 10% of the participants, mostly fathers, had an increase less than the suggested cut-points. Our results suggest that an increase in plasma holo-TC may be used to assess vitamin B-12 absorption in individuals with low vitamin B-12 status. Because malabsorption is unlikely to be a major reason for the low plasma vitamin B-12 concentrations in this population, increasing dietary vitamin B-12 should improve their status.

Dietary Patterns Are Associated with Metabolic Syndrome in Adult Samoans [Nutritional Epidemiology]

Fri, 18 Sep 2009 10:01:30 PDT

The prevalence of metabolic syndrome has reached epidemic levels in the Samoan Islands. In this cross-sectional study conducted in 2002–2003, dietary patterns were described among American Samoan (n = 723) and Samoan (n = 785) adults (≥18 y) to identify neo-traditional and modern eating patterns and to relate these patterns to the presence of metabolic syndrome using Adult Treatment Panel III criteria. The neo-traditional dietary pattern, similar across both polities, was characterized by high intake of local foods, including crab/lobster, coconut products, and taro, and low intake of processed foods, including potato chips and soda. The modern pattern, also similar across both polities, was characterized by high intake of processed foods such as rice, potato chips, cake, and pancakes and low intake of local foods. The neo-traditional dietary pattern was associated with significantly higher serum HDL-cholesterol in American Samoa (P-trend = 0.05) and a decrease in abdominal circumference in American Samoa and Samoa (P-trend = 0.004 and 0.01, respectively). An inverse association was found with metabolic syndrome, although it did not reach significance (P = 0.23 in American Samoa; P = 0.13 in Samoa). The modern pattern was significantly positively associated with metabolic syndrome in Samoa (prevalence ratio = 1.21 for the fifth compared with first quintile; 95% CI: 0.93.1.57; P-trend = 0.05) and with increased serum triglyceride levels in both polities (P < 0.05). Reduced intake of processed foods high in refined grains and adherence to a neo-traditional eating pattern characterized by plant-based fiber, seafood, and coconut products may help to prevent growth in the prevalence of metabolic syndrome in the Samoan islands.

Diet Quality Is Associated with Better Cognitive Test Performance among Aging Men and Women [Nutritional Epidemiology]

Wengreen, H. J., Neilson, C., Munger, R., Corcoran, C. — Fri, 18 Sep 2009 10:01:30 PDT

Most studies of association between diet and cognition among the elderly focus on the role of single nutrients or foods and ignore the complexity of dietary patterns and total diet quality. We prospectively examined associations between an index of diet quality and cognitive function and decline among elderly men and women of the Cache County Study on Memory and Aging in Utah. In 1995, 3634 resident men and women ≥65 y of age completed a baseline survey that included a 142-item FFQ. Cognition was assessed using an adapted version of the Modified Mini-Mental State Examination (3MS) at baseline and 3 subsequent interviews spanning ~11 y. A recommended food score (RFS) and non-RFS were computed by summing the number of recommended foods (n = 57) and nonrecommended foods (n = 23) regularly consumed. Multivariable-mixed models were used to estimate associations between the RFS and non-RFS and average 3MS score over time. Those in the highest quartile of RFS scored 1.80 points higher on the baseline 3MS test than did those in the lowest quartile of RFS (P < 0.001). This effect was strengthened over 11 y of follow-up. Those with the highest RFS declined by 3.41 points over 11 y compared with the 5.2-point decline experienced by those with the lowest RFS (P = 0.0013). The non-RFS was not associated with cognitive scores. Consuming a diverse diet that includes a variety of recommended foods may help to attenuate age-related cognitive decline among the elderly.

Whole-Grain Intake and Cereal Fiber Are Associated with Lower Abdominal Adiposity in Older Adults [Nutritional Epidemiology]

Fri, 18 Sep 2009 10:01:30 PDT

Foods high in dietary fiber may play an important role in regulating body weight. Few observational studies have examined the relationship between dietary fiber from different sources and body fat in older adults. Our objectives were to examine the associations among grain intake (whole and refined), dietary fiber and fiber sources, and body fat among older adults. We used data from 434 free-living adults (177 men and 257 women) aged between 60 and 80 y. Dietary intake was estimated from a 126-item semiquantitative FFQ. Percent body fat and percent trunk fat mass were measured by whole-body dual-energy X-ray absorptiometry. After adjustment for covariates, whole-grain intake was inversely associated with BMI [26.8 kg/m² (25.7–28.1) vs. 25.8 kg/m² (24.6–27.1), (95% CI); P-trend = 0.08], percent body fat [34.5% (32.7–36.3) vs. 32.1% (30.1–34.1); P-trend = 0.02], and percent trunk fat mass [43.0% (40.4–45.5) vs. 39.4% (36.7–42.1); P-trend = 0.02] in the lowest compared with the highest quartile category of whole-grain intake. Refined grain intake was not associated with any measure of body fat distribution. Cereal fiber was inversely associated with BMI [27.3 kg/m² (26.1–28.6) vs. 25.4 kg/m² (24.3–26.7); P-trend = 0.012], percent body fat [34.7% (32.8–36.6) vs. 31.5% (29.4–33.5); P-trend = 0.004], and percent trunk fat mass [42.8% (40.2–45.4) vs. 37.8% (35.0–40.6); P-trend = 0.001]. No significant association was observed between intakes of total fiber, vegetable or fruit fiber, and body composition measurements. Higher intakes of cereal fiber, particularly from whole-grain sources, are associated with lower total percent body fat and percent trunk fat mass in older adults.

Women's Dietary Patterns Change Little from Before to During Pregnancy [Nutritional Epidemiology]

Crozier, S. R., Robinson, S. M., Godfrey, K. M., Cooper, C., Inskip, H. M. — Fri, 18 Sep 2009 10:01:30 PDT

Principal component analysis (PCA) is a popular method of dietary patterns analysis, but our understanding of its use to describe changes in dietary patterns over time is limited. Using a FFQ, we assessed the diets of 12,572 nonpregnant women aged 20–34 y from Southampton, UK, of whom 2270 and 2649 became pregnant and provided complete dietary data in early and late pregnancy, respectively. Intakes of white bread, breakfast cereals, cakes and biscuits, processed meat, crisps, fruit and fruit juices, sweet spreads, confectionery, hot chocolate drinks, puddings, cream, milk, cheese, full-fat spread, cooking fats and salad oils, red meat, and soft drinks increased in pregnancy. Intakes of rice and pasta, liver and kidney, vegetables, nuts, diet cola, tea and coffee, boiled potatoes, and crackers decreased in pregnancy. PCA at each time point produced 2 consistent dietary patterns, labeled prudent and high-energy. At each time point in pregnancy, and for both the prudent and high-energy patterns, we derived 2 dietary pattern scores for each woman: a natural score, based on the pattern defined at that time point, and an applied score, based on the pattern defined before pregnancy. Applied scores are preferred to natural scores to characterize changes in dietary patterns over time because the scale of measurement remains constant. Using applied scores, there was a very small mean decrease in prudent diet score in pregnancy and a very small mean increase in high-energy diet score in late pregnancy, indicating little overall change in dietary patterns in pregnancy.

Total Antioxidant Performance Is Associated with Diet and Serum Antioxidants in Participants of the Diet and Physical Activity Substudy of the Jackson Heart Study [Nutritional Epidemiology]

Fri, 18 Sep 2009 10:01:30 PDT

Total antioxidant performance (TAP) measures antioxidant capacities in both hydrophilic and lipophilic compartments of serum and interactions known to exist between them. Our objective was to assess TAP levels in a subset of Jackson Heart Study (JHS) participants and to examine associations with dietary and total (diet + supplement) intakes of -tocopherol, -tocopherol (diet only), β-carotene, vitamin C, fruit, vegetables, and nuts, and serum concentrations of -tocopherol, -tocopherol, and β-carotene. We conducted a cross-sectional analysis of 420 (mean age 61 y; 254 women) African American men and women participating in the Diet and Physical Activity Sub-Study of the JHS in Jackson, Mississippi. In multivariate-adjusted models, we observed positive associations between total -tocopherol, total and dietary β-carotene, and total vitamin C intakes and TAP levels (P-trend < 0.05). Positive associations were also observed for vegetable, fruit, and total fruit and vegetable intakes (P-trend < 0.05). For serum antioxidant nutrients, -tocopherol but not β-carotene was associated with serum TAP levels. There were inverse associations for serum -tocopherol and TAP levels. Associations for -tocopherol were seen at intake levels much higher than the current Recommended Dietary Allowance. It may, therefore, be prudent to focus on increasing consumption of fruit, vegetables, nuts, and seeds to increase total antioxidant capacity.

Adherence to the Mediterranean Diet Is Associated with Lower Abdominal Adiposity in European Men and Women [Nutritional Epidemiology]

Thu, 20 Aug 2009 10:02:30 PDT

Given the lack of consistent evidence of the relationship between Mediterranean dietary patterns and body fat, we assessed the cross-sectional association between adherence to a modified Mediterranean diet, BMI, and waist circumference (WC). A total of 497,308 individuals (70.7% women) aged 25–70 y from 10 European countries participated in this study. Diet was assessed at baseline using detailed validated country-specific questionnaires, and anthropometrical measurements were collected using standardized procedures. The association between the degree of adherence to the modified-Mediterranean Diet Score (mMDS) (including high consumption of vegetables, legumes, fruits and nuts, cereals, fish and seafood, and unsaturated:saturated fatty acids ratio; moderate alcohol intake; and low consumption of meat and meat products and dairy products) and BMI (kg·m^–2) or WC (cm) was modeled through mixed-effects linear regression, controlling for potential confounders. Overall, the mMDS was not significantly associated with BMI. Higher adherence to the Mediterranean diet was significantly associated with lower WC, for a given BMI, in both men (–0.09; 95% CI –0.14 to –0.04) and women (–0.06; 95% CI –0.10 to –0.01). The association was stronger in men (–0.20; 95% CI –0.23 to –0.17) and women (–0.17; 95% CI –0.21 to –0.13) from Northern European countries. Despite the observed heterogeneity among regions, results of this study suggest that adherence to a modified Mediterranean diet, high in foods of vegetable origin and unsaturated fatty acids, is associated with lower abdominal adiposity measured by WC in European men and women.