Controlled human intervention trials are required to confirm the hypothesis that dietary fat quality may influence insulin action. The aim was to develop a food-exchange model, suitable for use in free-living volunteers, to investigate the effects of four experimental diets distinct in fat quantity and quality: high SFA (HSFA); high MUFA (HMUFA) and two low-fat (LF) diets, one supplemented with 1·24 g EPA and DHA/d (LFn-3). A theoretical food-exchange model was developed. The average quantity of exchangeable fat was calculated as the sum of fat provided by added fats (spreads and oils), milk, cheese, biscuits, cakes, buns and pastries using data from the National Diet and Nutrition Survey of UK adults. Most of the exchangeable fat was replaced by specifically designed study foods. Also critical to the model was the use of carbohydrate exchanges to ensure the diets were isoenergetic. Volunteers from eight centres across Europe completed the dietary intervention. Results indicated that compositional targets were largely achieved with significant differences in fat quantity between the high-fat diets (39·9 (sem 0·6) and 38·9 (sem 0·51) percentage energy (%E) from fat for the HSFA and HMUFA diets respectively) and the low-fat diets (29·6 (sem 0·6) and 29·1 (sem 0·5) %E from fat for the LF and LFn-3 diets respectively) and fat quality (17·5 (sem 0·3) and 10·4 (sem 0·2) %E from SFA and 12·7 (sem 0·3) and 18·7 (sem 0·4) %E MUFA for the HSFA and HMUFA diets respectively). In conclusion, a robust, flexible food-exchange model was developed and implemented successfully in the LIPGENE dietary intervention trial.

The food industry is playing an increasing role in the development and marketing of new products although little is known regarding the bioavailability of the phytochemicals they contain. Our aim was to assess the effect of the presence of absorption modifiers (milk and iron) on the in vitro bioaccessibility and the serum response in vivo of carotenoids and α-tocopherol from fruit juices. Thirty-two young women participated in a three-period (21 d each) supplementation study with a 2-week wash-out in between. Subjects consumed consecutively 2 × 250 ml/d vitamin C-fortified juices supplied as fruit juice, fruit juice containing milk and fruit juice containing milk and iron. Fasting blood samples were collected before and after each supplementation period. In vitro bioaccessibility of carotenoids and α-tocopherol was assessed by a static digestion model. Vitamin E and carotenoids from both studies were determined by HPLC. In vitro, xanthophyll ester hydrolysis and transference of free xanthophylls and α-tocopherol into the micellar phase were higher in the presence of absorption modifiers. In vivo, consumption of the fruit juices provoked significant increments (within-subject) of α-tocopherol and some carotenoids in serum. Dose-adjusted increments in serum of some carotenoids were higher when subjects consumed juices with milk and milk plus iron, although differences did not reach statistical significance. In conclusion, the presence of milk and milk plus iron do not influence the bioavailability of carotenoids and α-tocopherol from fruit juices in vivo. Our results support the use of in vitro models to assess food-related factors affecting bioavailability of carotenoids and tocopherols from foods.

The distribution of the four macronutrients is associated with energy intake and body fatness according to short-term interventions. The present study involves macronutrient distribution in relation to energy intake and body fatness over a period of 23 years in individuals who have ad libitum access to food. Eight follow-up measurements have been performed in 168 men and 182 women who participate in the Amsterdam Growth and Health Longitudinal Study. From the age of 13 years onwards, dietary intake, physical activity and the thickness of four skinfolds have been assessed. Body fatness was assessed using dual-energy X-ray absorptiometry at the age of 36 years. Generalised estimating equation regression analyses showed that energy percentages (En%) from protein and (in men) carbohydrates were inversely related to energy intake, while the En% from fat was positively related with energy intake. The men and women with high body fatness at the age of 36 years had a 1 En% higher protein intake, and the women with high body fatness had a 2 En% lower alcohol intake at the age of 32 and 36 years. The apparent inconsistent relationships between protein and energy intake and protein and body fatness can in women be explained by reverse causation and underreporting, as in women, low energy intake could not be explained by low physical activity. In conclusion, high intake of protein and (in men) carbohydrate, and low intake of fat are inversely related to total energy intake. High body fatness at the age of 36 years is related to a higher protein intake and, in women, to a lower alcohol intake.

The aim of the study was to examine the effect of the introduction of a new food-support benefit ‘Healthy Start’ (HS) on dietary intakes and eating patterns of low-income, Caucasian, pregnant and postpartum women living in Sheffield (UK). A before-and-after study comparing nutritional behaviour of participants, who were beneficiaries or eligible for the Welfare Food Scheme (WFS) (phase 1) or HS (phase 2), was conducted. Dietary intakes and eating patterns were assessed using a validated semi-quantified FFQ. In phase 1, 176 WFS subjects (ninety pregnant and eighty-six postpartum) were recruited and in phase 2, there were 160 HS subjects (ninety-six pregnant and sixty-four postpartum). The results suggested that pregnant and postpartum HS women significantly increased their daily intakes of energy, Fe, Ca, folate and vitamin C compared with the WFS women. Observed differences remained significant after controlling for potential confounding effects of known factors, i.e. education and age. HS women were more likely to meet the recommended nutrient intakes for Fe, folate, Ca and vitamin C. HS women ate significantly more mean portions of fruit and vegetables per d (P = 0·004 and P = 0·023) respectively. None of the HS recipients was receiving HS vitamin supplements. The present study showed that pregnant and postpartum HS women increased their food consumption, and a higher proportion of them than the earlier WFS scheme met the recommended intakes for Ca, folate, Fe and vitamin C.

The objectives of the study were to investigate whether the health conditions of mothers with short stature differed from those with normal stature, and to establish if these aspects were associated with the health of the offspring. Data relating to health and socio-economic, demographic and anthropometric conditions were collected from a probabilistic sample population consisting of 1180 mothers and 1511 children ( < 10 years) living in the semi-arid region of the State of Alagoas, Brazil. Mothers were categorised according to stature, with those in the 1st quartile being defined as of short stature and those in the 4th quartile being defined as of normal stature and serving as a reference for the comparison of variables of interest. Following verification that maternal stature fulfilled parametric assumptions, its associations with the other variables were determined by calculating Pearson correlation coefficients. After excluding strongly self-correlated variables (r ≥ 0·70), the remaining variables were analysed by multiple linear regression. The results showed that low maternal stature was independently associated with obesity (percentage body fat ≥ 30; P = 0·045), abdominal adiposity (waist:hip ratio ≥ 0·85; P = 0·007) and high systolic blood pressure ( ≥ 140 mmHg; P = 0·006). Short maternal stature was associated with low birth weight ( < 3000 g; P = 0·01) and stunting (height-for-age Z score < − 2; P = 0·019) in the offspring. Thus, in the semi-arid region of Alagoas, women of short stature presented a higher prevalence of chronic degenerative diseases and produced less healthy children than women of normal stature.

Diabetic retinopathy increases with duration of diabetes and may be associated with carotenoid status. Carotenoids alter the pro-oxidation/antioxidation balance, and circulating levels depend largely on dietary intake. Lower levels have been reported in diabetes and age-related macular degeneration; however, little is known of the relationship between carotenoids and diabetic complications. Consequently, the purpose of the present study was to evaluate the relationship between plasma carotenoids and diabetic retinopathy. We assessed the carotenoid–retinopathy relationship in 111 individuals with type 2 diabetes in a community-based, cross-sectional study. We photodocumented retinal status and used HPLC to measure plasma carotenoid concentrations. Data for clinical and demographic variables and risk factors for diabetic retinopathy were obtained from 24 h urine and fasting blood samples, and an interviewer-assisted lifestyle questionnaire. We found that the combined lycopene and lutein/zeaxanthin (non-pro-vitamin A (non-PVA) carotenoid) concentration when compared with the pro-vitamin A (PVA) carotenoids (α-carotene, β-carotene and β-cryptoxanthin) was significantly lower in the retinopathy than non-retinopathy group (OR 1·2 (95 % CI 1·0, 1·4) v. 1·6 (95 % CI 1·4, 1·7), respectively; P = 0·009). A higher non-PVA:PVA ratio also predicted a lower risk of diabetic retinopathy, after adjustment for potential confounders (OR 0·33 (95 % CI 0·12, 0·95); P = 0·039). Finally, a higher concentration of PVA carotenoids was associated with greater odds of diabetic retinopathy, after adjustment for risk factors (P = 0·049). We suggest synergies between carotenoids are implicated in diabetic retinopathy, independent of established risk factors. Importantly, our observations indicate dietary modulation of retinopathy risk may be possible by increasing intakes of lutein- and lycopene-rich foods.

The role of nutrition in onset, progression and treatment of periodontitis has not been thoroughly evaluated. In the present prospective clinical study, we investigated the influence of a nutritional intervention on changes in clinical, microbiological and immunological periodontal variables during a period of 12 months in patients with the metabolic syndrome and chronic periodontitis. Twenty female subjects with the metabolic syndrome and mild to moderate chronic periodontitis participated in a guided nutritional intervention programme. Examinations were assessed before, and at 2 weeks, 3, 6 and 12 months after intervention. Clinical measurements included probing depth, Löe and Silness gingival index and Quigley–Hein plaque index. In gingival crevicular fluid, periodontopathogens, levels of IL-1β and IL-6 as well as the activity of granulocyte elastase were determined. In stimulated saliva, antioxidative and oxidative variables were measured. After 12 months the following significant changes could be observed: reduction of clinical probing depth (2·40 v. 2·20 mm; P < 0·001), reduction of gingival inflammation (gingival index 1·13 v. 0·9; P < 0·001), reduced concentrations of IL-1β (4·63 v. 1·10 pg/ml per site; P < 0·001) as well as IL-6 (1·85 v. 0·34 pg/ml per site; P = 0·022) in gingival crevicular fluid. Bacterial counts in gingival crevicular fluid as well as oxidative and antioxidative variables in saliva showed no significant changes. Only salivary catalase showed a tendency to lower values. These findings indicate that in patients with the metabolic syndrome wholesome nutrition might reduce inflammatory variables of periodontal disease and promote periodontal health.

With the exception of iodine and Fe, there is still very limited information on the effect of micronutrients on cognitive function, especially among school-age children. The present analysis evaluates the relationship between dietary Fe, Zn and B vitamins (B12, B6, folate and riboflavin) and gains in cognitive test scores among school children in rural Kenya. Data for the present study were obtained from The Child Nutrition Kenya Project, a 2-year longitudinal, randomised controlled feeding intervention study using animal source foods. Dietary nutrient values were based on monthly and bimonthly 24 h recall data collected during the study period. In longitudinal regression analyses, available Fe, available Zn, vitamin B12 and riboflavin showed significant relationships with improved cognitive test scores, after controlling for confounders such as energy intake, school, socio-economic status and morbidity. Available Fe intake was associated with significantly higher gains in Raven's Coloured Progressive Matrices test scores over time. Available Zn intake was associated with significantly higher gains in digit span-total test scores over time, while vitamin B12 and riboflavin intakes were each associated with significantly higher gains in digit span-forward test scores over time. This analysis demonstrates the influence of improved dietary micronutrient status on school children's cognitive function.

Few studies have examined the association between Japanese diet and mortality outcomes. We analysed the relationship between a healthy Japanese diet and all-cause and cause-specific mortality using the database from the National Integrated Project for Prospective Observation of Non-Communicable Diseases and its Trends in the Aged, 1980. At baseline in 1980, data were collected on study participants aged ≧30 years from randomly selected areas in Japan. We defined a measure of a healthy reduced-salt Japanese diet based on seven components from FFQ. The total score ranged from 0 to 7, with 0 being least healthy and 7 being most healthy. Participants were divided into approximate tertiles of dietary scores (0–2, 3 and 4–7 scores). After excluding participants with co-morbidities, we followed 9086 participants (44 % men) for 19 years. There were 1823 all-cause and 654 cardiovascular deaths during the follow-up. With the dietary score group 0–2 serving as a reference, the Cox multivariate-adjusted hazard ratios for groups with scores 3 and 4–7 were 0·92 (95 % CI 0·83, 1·04) and 0·78 (95 % CI 0·70, 0·88) for all-cause mortality (trend P < 0·0001), and 0·91 (95 % CI 0·75, 1·10) and 0·80 (95 % CI 0·66, 0·97) for cardiovascular mortality (trend P = 0·022). Adherence to a healthy reduced-salt Japanese diet was associated with an approximate 20 % lower rate of all-cause and cardiovascular mortality.

Zinc deficiency is common among the elderly and has been associated with oxidative stress, immune dysfunction and CVD. We examined whether low zinc concentrations are associated with total, cardiovascular and non-cardiovascular mortality. Serum zinc concentrations were measured in 3316 patients from the Ludwigshafen Risk and Cardiovascular Health study, who were routinely referred to coronary angiography at a single tertiary care centre in Southwest Germany. After a median follow-up period of 7·75 years, 769 patients had died, including 484 deaths due to cardiovascular and 261 due to non-cardiovascular causes. After adjustments for cardiovascular risk factors and other possible confounders, the hazard ratios in the first when compared with the fourth zinc quartile, and per quartile decrease were 1·44 (95 % CI 1·13, 1·83; P = 0·001) and 1·15 (95 % CI 1·07, 1·24; P < 0·001) for total mortality, 2·20 (95 % CI 1·42, 3·42; P < 0·001) and 1·32 (95 % CI 1·16, 1·50; P < 0·001) for non-cardiovascular mortality and 1·24 (95 % CI 0·92, 1·66; P = 0·162) and 1·10 (95 % CI 1·01, 1·21; P = 0·038) for cardiovascular mortality. Furthermore, serum zinc concentrations correlated negatively with age and markers of inflammation and positively with antioxidants. The present results suggest that zinc deficiency may contribute to a reduced life expectancy in patients scheduled for coronary angiography.

The long-chain PUFA (LCPUFA) content of an infant's diet might affect early weight gain. In early trials on supplementation of formula feeding n-3 LCPUFA affected weight gain adversely. n-6 LCPUFA are thought to promote adipose tissue development and might be associated with higher weight gain. We studied the association between the natural n-3 and n-6 LCPUFA content of breast milk of Dutch women and weight and BMI gain of their breast-fed infants in the first year of life. The children in this study were enrolled in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort study and were born in 1996–1997 in the Netherlands. Parents reported their child's weight and length in a questionnaire. Of a subgroup of the total population breast-milk samples were collected (n 244). The fatty acid composition of breast milk was determined by GLC and expressed as weight percentages. Linear regression was used for data analysis. Mean gain in weight, length and BMI per week from birth to 1 year of age was 119·5 (sd 16·1) g, 0·48 (sd 0·05) cm and 0·06 (sd 0·03) kg/m2, respectively. The associations between n-6 and n-3 LCPUFA in breast milk, and infant weight, length and BMI gain were weak and inconsistent. The n-3 and n-6 LCPUFA content in breast milk did not affect weight or BMI gain in the first year of life in breast-fed term infants.

The aim of the present study was to assess the impact of fortified food (FF) consumption on overall dietary quality in Irish adults. Data for this analysis was based on the North/South Ireland Food Consumption Survey w7/15/2008hich used a 7 d food diary to collect food and beverage intake data in a representative sample of 1379 Irish adults (662 men and 717 women) aged 18–64 years. Foods contained in the database that are fortified were identified from the presence of vitamins and/or minerals in the ingredient list on the label. The results showed that an increased level of FF consumption was associated with lower intakes (percentage food energy) of total fat and saturated fat (women only) and higher intakes of total carbohydrate, total sugars (but not added sugars) and starch. Increased consumption was associated with a more micronutrient-dense diet and a reduced prevalence of dietary inadequacies of Ca, Fe, riboflavin and folate, particularly in women. Higher FF consumption was associated with higher intakes of fruit, lower intakes of alcohol and a lower likelihood of smoking in men and women. Thus it appears that FF consumption is a marker of both better dietary quality and healthy lifestyle behaviours.

The present study was undertaken to assess the beneficial effects of a daily consumption of 8 % freeze-dried red-pigmented leafy lettuce (Lactuca sativa) on CVD. C57BL/6J mice were fed a high-fat high-cholesterol diet supplemented with or without red-pigmented leafy lettuce for 4 weeks. The present results showed that the red-pigmented leafy lettuce-supplemented diet significantly decreased the level of total and LDL-cholesterol and TAG in the plasma of the mice. The atherosclerotic index was calculated to be 46 % lower in the mice fed with the lettuce diet compared with the control diet. Lipid peroxidation measured by 2-thiobarbituric acid-reactive substances was markedly reduced in the plasma, liver, heart and kidney of the mice fed the lettuce diet. The content of antioxidants (total glutathione and β-carotene) was significantly increased by lettuce supplementation. The antioxidant defence system by antioxidant enzymes including glutathione S-transferase, glutathione peroxidase, glutathione reductase, superoxide dismutase and paraoxanase in blood or liver tissues was also increased, and showed the improved oxidative stress in the mice fed the lettuce diet. The measurement of tail DNA (%), tail extent moment and olive tail moment indicated that the lettuce diet increased the resistance of hepatocyte and lymphocyte DNA to oxidative damage. The present study showed that the supplementation of a high-cholesterol high-fat diet with 8 % red-pigmented leafy lettuce resulted in an improvement of plasma cholesterol and lipid levels, prevention of lipid peroxidation and an increase of the antioxidant defence system and, therefore, could contribute to reduce the risk factors of CVD.

Recent studies suggest a benefit of seafood and n-3 fatty acid intake on fetal growth and infant development. The objective was to study the association between fatty acid intake and fetal growth in pregnant French women. Pregnant women included in the EDEN mother–child cohort study completed FFQ on their usual diet: (1) in the year before pregnancy and (2) during the last 3 months of pregnancy (n 1439). Conversion into nutrient intakes was performed using data on portion size and a French food composition table. Associations between maternal fatty acid intakes and several neonatal anthropometric measurements were studied using linear regressions adjusted for centre, mother's age, smoking habits, height, parity, gestational age and newborn's sex. Due to significant interaction, analyses were stratified according to maternal pre-pregnancy overweight status. Neither total lipid nor SFA, MUFA or PUFA intake was significantly associated with newborn size. In overweight women only (n 366), a high pre-pregnancy n-3 fatty acid intake (% PUFA) was positively associated with the newborn's birth weight (P = 0·01), head, arm and wrist circumferences and sum of skinfolds (P < 0·04). A substitution of 1 % of n-3 fatty acids per d before pregnancy by other PUFA was related to an average decrease in birth weight of 60 g (P = 0·01). Relationships with n-3 fatty acid intake at the end of pregnancy were weaker and not significant. We concluded that a high pre-pregnancy n-3 fatty acid:PUFA ratio may sustain fetal growth in overweight women. Follow-up of the children may help determine whether this has beneficial consequences for the child's health and development.

Several recent reports have found a high prevalence of vitamin D deficiency in the adult British population. The present paper investigates the associations of low income/material deprivation and other predictors of serum 25-hydroxyvitamin D (25(OH)D) status in two surveys: The National Diet and Nutrition Survey (NDNS) of the population aged 19–64 years in mainland Britain and the Low Income Diet and Nutrition Survey (LIDNS) of adults aged ≥ 19 years in all regions of the UK who were screened to identify low-income/materially deprived households. A valid serum 25(OH)D sample was obtained in 1297 and 792 participants from the NDNS and LDNS respectively. The NDNS participants who were not receiving benefits (n 1054) had a mean 25(OH)D of 50·1 nmol/l, which was higher than among NDNS participants receiving benefits (n 243) with a mean 25(OH)D of 43·0 nmol/l (P < 0·001) and the LIDNS sample (46·5 nmol/l; P < 0·05). For all three samples, the season of drawing blood, skin colour, dietary intake of vitamin D, and intake of dietary supplements were significant predictors (P < 0·05) of serum 25(OH)D status in mutually adjusted regression models. National prevention and treatments strategies of poor vitamin D status need to be targeted to include the adult population, particularly deprived populations, in addition to the elderly and ethnic minorities.

The aim of the study was to investigate how soft drink and fruit juice consumption in teenagers is associated with life-style, other food choices, eating behaviour and maternal characteristics. A cross-sectional study of 16-year-old girls (n 275) and boys (n 199) and their mothers was undertaken. Questionnaires were used to assess habitual dietary intake, eating behaviour, physical activity, smoking and educational level. Weight and height were measured. It was found that eating breakfast less than five times per week was independently associated with a high soft drink consumption in both girls and boys. A low intake of cooked meals and milk and a high intake of salty snacks were associated with soft drinks in boys only, and a low intake of fruits in girls only. A high maternal juice intake, low milk and high fruit consumption were independent correlates of fruit juice intake in both girls and boys. In girls, being a smoker, having a smoking mother, a high soft drink intake, scoring low on emotional eating and high on cognitive restraint were also associated with fruit juice intake. A low intake of soft drinks and cooked meals was associated with fruit juice intake in boys only. Neither soft drinks nor fruit juice was associated with BMI. In conclusion, a high intake of both fruit juice and soft drinks were associated with a lower intake of foods such as milk and cooked meals. It might be possible to influence fruit juice intake among teenagers by aiming at their mothers, whereas the adolescents themselves should be targeted when the aim is to reduce soft drink consumption.

Animal evidence indicates that green tea may modulate insulin sensitivity, with epigallocatechin-3-gallate (EGCG) proposed as a likely health-promoting component. The purpose of this study was to investigate the effect of dietary supplementation with EGCG on insulin resistance and associated metabolic risk factors in man. Overweight or obese male subjects, aged 40–65 years, were randomly assigned to take 400 mg capsules of EGCG (n 46) or the placebo lactose (n 42), twice daily for 8 weeks. Oral glucose tolerance testing and measurement of metabolic risk factors (BMI, waist circumference, percentage body fat, blood pressure, total cholesterol, LDL-cholesterol, HDL-cholesterol, TAG) was conducted pre- and post-intervention. Mood was evaluated weekly using the University of Wales Institute of Science and Technology mood adjective checklist. EGCG treatment had no effect on insulin sensitivity, insulin secretion or glucose tolerance but did reduce diastolic blood pressure (mean change: placebo − 0·058 (se 0·75) mmHg; EGCG − 2·68 (se 0·72) mmHg; P = 0·014). No significant change in the other metabolic risk factors was observed. The EGCG group also reported feeling in a more positive mood than the placebo group across the intervention period (mean score for hedonic tone: EGCG, 29·11 (se 0·44); placebo, 27·84 (se 0·46); P = 0·048). In conclusion, regular intake of EGCG had no effect on insulin resistance but did result in a modest reduction in diastolic blood pressure. This antihypertensive effect may contribute to some of the cardiovascular benefits associated with habitual green tea consumption. EGCG treatment also had a positive effect on mood. Further studies are needed to confirm the findings and investigate their mechanistic basis.

Data on the vitamin A equivalency of β-carotene in food are inconsistent. We quantified the vitamin A equivalency (μg) of β-carotene in two diets using the dual-isotope dilution technique and the oral–faecal balance technique. A diet-controlled, cross-over intervention study was conducted in twenty-four healthy adults. Each subject followed two diets for 3 weeks each: a diet containing vegetables low in β-carotene with supplemental β-carotene in salad dressing oil (‘oil diet’) and a diet containing vegetables and fruits high in β-carotene (‘mixed diet’). During all 6 weeks, each subject daily consumed a mean of 55 (sd 0·5) μg [13C10]β-carotene and 55 (sd 0·5) μg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of β-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum and from apparent absorption by oral–faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]β-carotene in oil of 3·4 μg (95 % CI 2·8, 3·9), thus the bio-efficacy of the β-carotene in oil was 28 % in the presence of both diets. However, data from oral–faecal balance estimated vitamin A equivalency as 6:1 μg (95 % CI 4, 7) for β-carotene in the ‘oil diet’. β-Carotene in the ‘oil diet’ had 2·9-fold higher vitamin A equivalency than β-carotene in the ‘mixed diet’. In conclusion, this extrinsic labelling technique cannot measure effects of mixed vegetables and fruits matrices, but can measure precisely the vitamin A equivalency of the β-carotene in oil capsules.

Serum banks from large, decades-old epidemiological studies provide a valuable opportunity to explore the contributions of in utero vitamin D exposure to fetal origins of adult diseases. We compared 25-hydroxyvitamin D (25(OH)D) by race and season (two powerful predictors of vitamin D status) in sera frozen for ≥  40 years with sera frozen for ≤  2 years to determine whether 25(OH)D is stable enough to test vitamin D-related hypotheses. Data and sera came from seventy-nine pregnant women at 29–32 weeks' gestation in the Boston Collaborative Perinatal Project (CPP; 1959–66) and 124 women at 20–36 weeks' gestation in a 2003–2006 Pittsburgh cohort study. Multivariable linear regression models were used to test main and joint effects of race and season after confounder adjustment. In both cohorts, serum 25(OH)D levels were lower among black than white women (CPP 33·3 v. 46·7 nmol/l, P < 0·01; Pittsburgh 47·1 v. 89·6 nmol/l; P < 0·0001) and in winter than summer (CPP 32·7 v. 47·6 nmol/l, P < 0·0001; Pittsburgh 66·7 v. 89·8 nmol/l, P < 0·001), with no evidence of a race × season interaction in either cohort. Differences remained significant after confounder adjustment. When CPP and Pittsburgh results were compared, there was no significant difference in the race or season effects. The similarity in the relative change in 25(OH)D in these cohorts by two powerful predictors of vitamin D status suggests that, even if 25(OH)D deteriorated somewhat, it did so similarly across samples. Therefore, trends could be obtained from the decades-old serum data that would be relevant in exploring vitamin D-related hypotheses in future studies.

Probiotics and long-chain PUFA (LC-PUFA) may be beneficial supplements for infants who are not breast-fed. The aim of the present study is to evaluate the safety of an infant formula containing the LC-PUFA DHA and arachidonic acid (AA) and the probiotic Bifidobacterium lactis by comparing the growth rate of infants fed the supplemented and unsupplemented formulas. One hundred and forty-two healthy, term infants were enrolled in a single-centre, randomised, double-blind, controlled, parallel-group trial, and allocated to receive either standard or probiotic and LC-PUFA-containing experimental formulas. The infants were fed with their assigned formulas for 7 months. The primary outcome (weight gain) and the secondary outcomes (length, head circumference and formula tolerance) were measured throughout the study. LC-PUFA status was assessed at 4 months of age and immune response to childhood vaccines was measured at 7 months of age. There was no significant difference in growth between the two groups. The 90 % CI for the difference in mean weight gain was − 0·08, 3·1 g in the intention-to-treat population and 0·1–3·8 g in the per protocol population, which lay within the predefined boundaries of equivalence, − 3·9–3·9. There were no significant differences in mean length and head circumference. DHA and AA concentrations were higher in infants in the experimental formula group compared with the control formula group. No influence of the supplements on the response to vaccines was observed. Growth characteristics of term infants fed the starter formula containing a probiotic and LC-PUFA were similar to standard formula-fed infants.