Longitudinal association between dairy consumption and changes of body weight and waist circumference: the Framingham Heart Study.

BACKGROUND: Dairy foods are nutrient dense and may be protective against long-term weight gain. OBJECTIVE: We aimed to examine the longitudinal association between dairy consumption and annualized changes in weight and waist circumference (WC) in adults. METHODS: Members of the Framingham Heart Study Offspring Cohort who participated in the fifth through eighth study examinations (1991-2008) were included in these analyses (3440 participants with 11 683 observations). At each exam, dietary intake was assessed by a validated food frequency questionnaire, and weight and WC were assessed following standardized procedures. Repeated measures models were used for the longitudinal analyses of annualized weight and waist circumference changes, adjusting for time-varying or invariant covariates. RESULTS: On average, participants gained weight and WC during follow-up. Dairy intake increased across exams. After adjusting for demographic and lifestyle factors (including diet quality), participants who consumed ≥3 servings per day of total dairy had 0.10 kg (±0.04) smaller annualized increment of weight (P(trend)=0.04) than those consuming <1 serving per day. Higher total dairy intake was also marginally associated with less WC gain (P(trend)=0.05). Similarly, participants who consumed ≥3 servings per week of yogurt had a 0.10 kg (±0.04) and 0.13 cm (±0.05) smaller annualized increment of weight (P(trend)=0.03) and WC (P(trend)=0.008) than those consuming <1 serving per week, respectively. Skim/low-fat milk, cheese, total high-fat or total low-fat dairy intake were not associated with long-term change in weight or WC. CONCLUSION: Further longitudinal and interventional studies are warranted to confirm the beneficial role of increasing total dairy and yogurt intake, as part of a healthy and calorie-balanced dietary pattern, in the long-term prevention of gain in weight and WC.

Lipoprotein receptor-related protein 1 variants and dietary fatty acids: meta-analysis of European origin and African American studies.

OBJECTIVE: Low-density lipoprotein-related receptor protein 1 (LRP1) is a multi-functional endocytic receptor and signaling molecule that is expressed in adipose and the hypothalamus. Evidence for a role of LRP1 in adiposity is accumulating from animal and in vitro models, but data from human studies are limited. The study objectives were to evaluate (i) relationships between LRP1 genotype and anthropometric traits, and (ii) whether these relationships were modified by dietary fatty acids. DESIGN AND METHODS: We conducted race/ethnic-specific meta-analyses using data from 14 studies of US and European whites and 4 of African Americans to evaluate associations of dietary fatty acids and LRP1 genotypes with body mass index (BMI), waist circumference and hip circumference, as well as interactions between dietary fatty acids and LRP1 genotypes. Seven single-nucleotide polymorphisms (SNPs) of LRP1 were evaluated in whites (N up to 42 000) and twelve SNPs in African Americans (N up to 5800). RESULTS: After adjustment for age, sex and population substructure if relevant, for each one unit greater intake of percentage of energy from saturated fat (SFA), BMI was 0.104 kg m(-2) greater, waist was 0.305 cm larger and hip was 0.168 cm larger (all P<0.0001). Other fatty acids were not associated with outcomes. The association of SFA with outcomes varied by genotype at rs2306692 (genotyped in four studies of whites), where the magnitude of the association of SFA intake with each outcome was greater per additional copy of the T allele: 0.107 kg m(-2) greater for BMI (interaction P=0.0001), 0.267 cm for waist (interaction P=0.001) and 0.21 cm for hip (interaction P=0.001). No other significant interactions were observed. CONCLUSION: Dietary SFA and LRP1 genotype may interactively influence anthropometric traits. Further exploration of this, and other diet x genotype interactions, may improve understanding of interindividual variability in the relationships of dietary factors with anthropometric traits.

Use of biological markers to validate self-reported dietary intake in a random sample of the European Prospective Investigation into Cancer United Kingdom Norfolk cohort.

BACKGROUND: The validity of dietary assessment methods should be established before diet-disease associations are reported. OBJECTIVE: Our objective was to validate a 7-d food diary and a food-frequency questionnaire (FFQ) against independent biomarkers of intake in urine (nitrogen, potassium, and sodium) and blood (plasma ascorbic acid). DESIGN: A total of 146 healthy middle-aged men and women were recruited from the European Prospective Investigation into Cancer UK Norfolk cohort, a free-living cohort of approximately 25000 persons. Over a 9-mo period, urinary nitrogen, potassium, and sodium were estimated from 2-6 complete 24-h urine collections in 134 subjects and plasma ascorbic acid was estimated from 2-3 fasting blood samples in 118 subjects. Subjects completed 2 FFQs and two 7-d food diaries. RESULTS: In men and women combined, correlations between 24-h urinary nitrogen excretion and dietary intake from the 7-d food diary were high (r = 0.57-0.67) compared with those for the FFQ (r = 0.21-0.29). Similarly, correlations between urinary potassium and dietary potassium were higher for the 7-d food diary (r = 0.51-0.55) than for the FFQ (r = 0.32-0.34). There was no overall difference in correlations between plasma ascorbic acid and dietary vitamin C between the 7-d food diary (r = 0.40-0.52) and the FFQ (r = 0.44-0.45). CONCLUSIONS: These data indicate that, despite increased subject burden, the 7-d food diary provided a better estimate of nitrogen and potassium intakes than did the FFQ in this study population. However, with respect to plasma ascorbic acid, both the FFQ and 7-d food diary provided a similar ranking of subjects according to vitamin C intake.

Effects of a hydrogenated form of vitamin K on bone formation and resorption.

BACKGROUND: Hydrogenation of vegetable oils affects blood lipid and lipoprotein concentrations. However, little is known about the effects of hydrogenation on other components, such as vitamin K. Low phylloquinone (vitamin K1) intake is a potential risk factor for bone fracture, although the mechanisms of this are unknown. OBJECTIVE: The objective was to compare the biological effects of phylloquinone and its hydrogenated form, dihydrophylloquinone, on vitamin K status and markers of bone formation and resorption. DESIGN: In a randomized crossover study in a metabolic unit, 15 young adults were fed a phylloquinone-restricted diet (10 microg/d) for 15 d followed by 10 d of repletion (200 microg/d) with either phylloquinone or dihydrophylloquinone. RESULTS: There was an increase and subsequent decrease in measures of bone formation (P = 0.002) and resorption (P = 0.08) after dietary phylloquinone restriction and repletion, respectively. In comparison with phylloquinone, dihydrophylloquinone was less absorbed and had no measurable biological effect on measures of bone formation and resorption. CONCLUSION: Hydrogenation of plant oils appears to decrease the absorption and biological effect of vitamin K in bone.

Whole grain intake and risk of ischemic stroke in women.

In a recent prospective study, whole grain intake was associated with a reduced risk of ischemic stroke. Refined grain, however, did not elicit such protection. Given the potential health benefits associated with whole grain diets, further exploration on the effects of whole grains on health and risk of chronic disease is warranted.

Predicted 25-hydroxyvitamin D score and change in fasting plasma glucose in the Framingham offspring study.

Data on the association between vitamin D status and actual change in glycemic measures are limited. We examined the prospective association between a predicted 25-hydroxyvitamin D (25(OH)D) score and change in fasting plasma glucose concentration over a mean follow-up of 7 years, in 2571 men and women (mean age 54 years) without diabetes in the Framingham Offspring Study cohort. After adjustment for age, sex, body mass index and fasting plasma glucose at baseline, higher predicted 25(OH)D score at baseline was associated with a smaller 7-year increase in fasting plasma glucose concentrations (0.23 mmol/l versus 0.35 mmol/l for highest versus lowest tertile of 25(OH)D score, respectively, P-trend=0.002). Vitamin D status may be an important determinant for change in fasting plasma glucose concentration among middle-aged and older adults without diabetes.

Relationships between dietary intakes and fasting plasma concentrations of fat-soluble vitamins in humans.

Dietary intakes of retinol equivalents, alpha-tocopherol equivalents, vitamin D and phylloquinone were estimated from three sets of 4-d weighed diet records and compared to three corresponding fasting plasma concentrations of retinol, 25-hydroxyvitamin D, alpha-tocopherol, and phylloquinone measured in 34 healthy adults over 20 wk. The magnitude of the correlation between dietary vitamin intake and its corresponding biochemical measure is in part determined by the reproducibility of each of the measures, so within-to-between subject variance ratios were calculated for both dietary intakes and plasma concentrations. Phylloquinone was the only fat-soluble vitamin with a significant correlation between dietary intake and fasting plasma concentration (r = 0.51, P = 0.004). This correlation improved with an increase in both the number of independent diet records and independent plasma measures. Of the dietary intake measures, all the fat-soluble vitamins had greater within than between subject variance, with the highest measured for phylloquinone (6.86:1). Of the plasma measures, only phylloquinone had a within-to-between subject variance ratio greater than one (5.36:1). Comparisons across age and sex for dietary intake and plasma concentrations differed in pattern among the fat-soluble vitamins.