Vitamin D Supplementation and Blood Pressure in Children and Adolescents: A Systematic Review and Meta-Analysis.

Suboptimal vitamin D status is associated with elevated blood pressure (BP) in children and adolescents. Whether vitamin D supplementation reduces BP remains unclear. To systematically review whether vitamin D supplementation reduces BP in children and adolescents, we conducted a literature review according to the PRISMA statement. We included vitamin-D supplementation human interventions studies that reported on BP as an outcome. We searched PUBMED, MEDLINE, CINAHL, EMBASE, the Cochrane Library, and the clinical trials website. We also hand searched the references of the included articles and previous reviews of vitamin D therapy. No language or time restrictions were applied. We extracted data on population characteristics, baseline and endline vitamin D and BP values, and assessed the risk of bias of the included studies. We performed a narrative review of the findings, conducted a meta-analysis when possible, and performed sensitivity analyses to test the robustness of our results. We assessed the overall quality of the evidence produced in the meta-analysis. We included eight studies in our review and five studies in the meta-analysis, none of which included hypertensive only participants. The risk of bias was variable. In non-randomized studies, no effect of vitamin D supplementation was seen on systolic BP (SBP) (mean difference: 0.39 (95% confidence interval (CI): -0.9; 1.68) mmHg; p = 0.55; I2 = 0%). Only a significant decrease in diastolic BP (DBP) (mean difference: -1.87 (95% CI: -3.02; -0.72) mmHg; p = 0.001; I2 = 0%) was noted. Both analyses had a low quality of evidence. In randomized controlled trials (RCTs), no effect was noted on SBP (mean difference: -2.04 (95% CI: -5.12; 1.04) mmHg; p = 0.19; I2 = 71%) nor DBP (mean difference: 0.01 (95% CI: -1.09; 1.12) mmHg; p = 0.98; I2 = 0%). The final quality of evidence ranged between low and moderate. Sensitivity analyses did not affect the results. Vitamin D supplementation was found to be ineffective in lowering SBP and DBP in children and adolescents.

Nutritional supplement use among Slovenian adolescents.

OBJECTIVE: Little is known about the prevalence of nutritional supplement use in European adolescents. We conducted the present study to analyse the prevalence of nutritional supplement use and factors associated with this use among Slovenian adolescents. DESIGN: The nutritional supplementation practices of 818 adolescents were studied using an anonymous questionnaire. Information was sought on the type of supplements used, frequency of use and sources of information. SETTING: The region of north-west Slovenia. SUBJECTS: Schoolchildren from twenty primary schools and twelve secondary schools. RESULTS: Some 19·3% of all adolescents reported using at least one nutritional supplement and the prevalence of use was significantly higher in adolescents who were members of sports clubs. Multivitamins were the most common nutritional supplement. Older adolescents were significantly more likely to be supplementing with iron, protein and minerals. Less than 16% of supplement users in our study sought information from health-care professionals. Nearly 62% obtained information from parents and coaches, and many adolescents appear to decide on nutritional supplementation themselves, without advice. Older adolescents were significantly more likely to combine supplements than younger adolescents. CONCLUSIONS: One-fifth of Slovenian adolescents use nutritional supplements. There are clear differences in supplement use between younger (age 12 years) and older (age 17 years) adolescents. Multiple use of supplements, coupled with self-managed supplementation in older adolescents, is concerning. Hence, there is an urgent need to provide accurate information regarding nutritional supplements, which will help adolescents, their parents and coaches to make informed choices about their use.

Food intake in Slovenian adolescents and adherence to the Optimized Mixed Diet: a nationally representative study.

OBJECTIVES: To investigate the food intake of Slovenian adolescents and to compare it with food-based dietary guidelines developed for children and adolescents, named the Optimized Mixed Diet (OMD). The OMD is a useful tool for the evaluation of food intake of adolescents. DESIGN: All adolescents completed an FFQ at a regional health centre; a subgroup also completed a 3 d weighed dietary protocol at home. SETTING: This study is a part of the first national representative study on the dietary habits of Slovenian adolescents. SUBJECTS: This cross-sectional study included a representative sample of 2813 Slovenian adolescents entering high school, aged 14-17 years, from all ten geographical regions of Slovenia. RESULTS: The greatest deviations from the recommended intakes of the main food groups in the OMD were significantly lower intakes of (P < 0·001, mean): vegetables (179 and 163 g/d in boys and girls, respectively), bread/cereals (271 and 226 g/d), potatoes/rice/pasta (212 and 163 g/d); in boys also a significantly lower intake of fruits (mean: 321 g/d, P < 0·001) and a significantly higher intake of meat/meat products (mean: 126 g/d, P < 0·001). Additionally, the results show too high intake of sugar-sweetened beverages and too low intakes of fish and plant oils in both genders. CONCLUSIONS: The food intake pattern of Slovenian adolescents deviates markedly from a healthy eating pattern. Nutrition education and interventions are needed for Slovenian adolescents.

The selection and prevalence of natural and fortified calcium food sources in the diets of adolescent girls.

OBJECTIVE: To assess the impact of calcium-fortified food and dairy food on selected nutrient intakes in the diets of adolescent girls. DESIGN: Randomized controlled trial, secondary analysis. SETTING AND PARTICIPANTS: Adolescent girls (n = 149) from a midwestern metropolitan area participated in randomized controlled trials of bone physiology from 1997 to 2008. INTERVENTION: Subjects randomly assigned to a high-calcium (HC) diet supplying 1,500 mg calcium/d, or their usual diet (UC). MAIN OUTCOME MEASURES: Dietary intake was assessed from 3-day food records and calcium intakes categorized by food source. Food group composites, representing calcium-fortified and dairy food categories, were examined for their relative nutrient contributions. Student t tests were used to evaluate differences in selected nutrient intakes between the 2 study groups. RESULTS: Dairy food contributed 68% of the total mean 1,494 mg calcium/d in the HC group, and calcium-fortified food contributed 304 mg calcium. In the UC group, dairy food contributed 69% of the total mean 765 mg calcium/d and calcium-fortified food contributed 50 mg calcium. Nutrient profiles of the dairy composites differed significantly from the calcium-fortified composites (P < .05). CONCLUSIONS AND IMPLICATIONS: Dairy food was the primary source of calcium selected by these adolescent girls; calcium-fortified food augmented calcium intakes.

Position of the American Dietetic Association: child and adolescent nutrition assistance programs.

t is the position of the American Dietetic Association that children and adolescents should have access to an adequate supply of healthful and safe foods that promote optimal physical, cognitive, and social growth and development. Nutrition assistance programs, such as food assistance and meal service programs and nutrition education initiatives, play a vital role in meeting this critical need. Nutrition assistance programs create a safety net that ensures that children and adolescents at risk for poor nutritional intakes have access to a safe, adequate, and nutritious food supply. Federally funded nutrition assistance programs help ensure that children and adolescents receive meals that provide adequate energy and nutrients to meet their growth and development needs; children and adolescents have access to adequate food supplies; and women, infants, and children who have nutritional or medical risk factors, such as iron-deficiency anemia or overweight, receive supplemental nutritious foods as well as nutrition education. In addition, federally funded nutrition assistance programs serve as a means to combat hunger and food insecurity and as a vehicle for nutrition education and promotion of physical activity designed to prevent or reduce obesity and chronic disease. It is important that continued funding be provided for these programs that have been consistently shown to have a positive influence on child and adolescent well-being. Registered dietitians and dietetic technicians, registered, are uniquely qualified to design, implement, and evaluate nutrition assistance programs for children and adolescents. Registered dietitians and dietetic technicians, registered, are the only food and nutrition practitioners with adequate training in food science, nutrition, and food systems to implement research and surveillance programs to monitor, evaluate, and improve the nutritional status of children and adolescents.

Nutritional habits of Flemish adolescent sprint athletes.

PURPOSE AND METHODS: To investigate dietary habits of Flemish adolescent track and field athletes using a 7-d weighed-food record. Besides adequacy for growth, development, and physical performance, dietary health aspects were considered. RESULTS: Twenty-nine girls and 31 boys, with minimum 2 yr of track and field training practice, were recruited. All participants had daily breakfast (girls 22.5% +/- 5.5% of total energy intake [TEI]; boys 19.8% +/- 7.3%). Fruit in girls and juices and sports drinks in boys were consumed mostly between meals (girls 21.3% +/- 8.1% of TEI; boys 24.3% +/- 10.1%). Soft drinks contributed considerably to energy intake between meals in both sexes. Protein intake (1.5 +/- 0.3 g . kg-1 . d-1 for both sexes) was within the recommended daily intake (RDI) for strength athletes. Mean daily carbohydrate intake in girls was lower than in boys (girls 5.1 +/- 1.1 g/kg; boys 6.0 +/- 0.9 g/kg), with mono- and disaccharides contributing 26% to TEI in both sexes. Total fat intake was above 30% of TEI in more than half the participants, and only 10 participants had a saturated-fat intake below 10% of TEI. Fiber intake (girls 23.7 +/- 7.9 g; boys 29.1 +/- 11.2 g) was far below the Belgian RDI. Intake of vitamins and minerals were generally low, despite micronutrient supplementation in 37.5% of the participants. CONCLUSION: Few athletes reached all nutrient RDIs. Unhealthy food habits with regard to refined sugars, fat, and micronutrients were observed. These adolescent sprinters should be encouraged to consume more nonsweetened beverages, fruits, and vegetables.

25-Hydroxyvitamin D and functional outcomes in adolescents.

Vitamin D is essential for bone growth and development in children and adolescents. Adolescence is a crucial phase in bone development. Cross-sectional studies have shown a relation between vitamin D status and bone mineral density in adolescents. Long-term supplementation studies have supported the importance of vitamin D for bone health in adolescence. However, we need more studies on the optimal serum 25-hydroxyvitamin D concentration and the optimal vitamin D dosage for bone health in this age group. In addition, we need to evaluate the best way to increase vitamin D status in the general public from a public health point of view.

Effectiveness of weekly supplementation of iron to control anaemia among adolescent girls of Nashik, Maharashtra, India.

A national nutritional anaemia-control programme in India, focusing on supplementation of iron to pregnant women after the first trimester of pregnancy, failed to make an impact. It is prudent to recommend the correction of iron stores before the woman becomes pregnant. 'Efficacy' of weekly supplementation of iron has been proved to improve iron stores in adolescence in many studies abroad and in India. The objective was to study the 'effectiveness' of a weekly iron-supplementation regimen among urban-slum, rural, and tribal girls of Nashik district, Maharashtra, India. A baseline and the mid-term assessments were done using the cluster-sampling techniques. In each stratum, 30 clusters were identified. Twelve and 10 adolescent girls from each cluster were identified in the baseline and mid-term surveys respectively. The haemoglobin estimation was done using the HemoCue system. Data were analyzed using the Epi Info software (version 6.04). The overall prevalence of anaemia came down significantly to 54.3% from 65.3%. The decline was statistically significant (p<0.001) in tribal girls (48.6% from 68.9%) and among rural girls (51.6% from 62.8%). But the decline was not statistically significant among urban slum girls. Similarly, a significant rise in the mean haemoglobin levels was seen among tribal and rural girls. However, it did not increase significantly among urban slum girls. The programme had performed poorly in urban-slum areas, as the mean number of tablets consumed in urban-slum areas was only 5.6+/-3.3, as against 6.7+/-2.6 tablets in tribal girls and 7.2+/-2.2 tablets in rural girls. Considering the biological and operational feasibility and the effectiveness of the intervention, weekly supplementation of iron to adolescent girls should be universally started to correct the iron stores of a woman before she becomes pregnant.

The role of nutrition on optimizing peak bone mass.

The growth years provide an important window of opportunity for building peak bone mass. More than one-fourth of adult bone mass is acquired between the ages of 12 to 14 years in girls and 13 to 15 years in boys. Although genetics determine 60-80% of peak bone mass, lifestyle choices including diet and physical activity are also predictors of bone accrual during growth. Calcium and vitamin D are two nutrients that are most likely to be deficient. Dietary calcium predicts 10-15% of skeletal calcium retention during adolescence with race and sexual maturity in the models. Boys retain more calcium than girls and black girls retain more calcium than whites girls. The role of Vitamin D status on peak bone mass is not well understood. Results of randomized, controlled trials are mixed and the effects of vitamin D supplementation on calcium absorption in children has not been studied. Dietary salt increases urinary calcium excretion. Exercise can enhance the effect of dietary calcium through enhanced bone geometry.

Fatty acid status and behavioural symptoms of attention deficit hyperactivity disorder in adolescents: a case-control study.

BACKGROUND: Most studies of Attention-deficit hyperactivity disorder (ADHD) have focused on either young children or older adults. The current study compared 11 ADHD adolescents with 12 age-matched controls. The purpose was to examine differences in dietary intake, particularly of essential fatty acids, and determine whether this could explain the typical abnormalities in red blood cell fatty acids observed in previous studies of young children. A secondary purpose was to determine if there were relationships between circulating concentrations of essential fatty acids and specific ADHD behaviours as measured by the Conners' Parent Rating Scale (CPRS-L). METHODS: Eleven ADHD adolescents and twelve age-matched controls were recruited through newspaper ads, posters and a university website. ADHD diagnosis was confirmed by medical practitioners according to DSM-IV criteria. Blood, dietary intake information as well as behavioural assessments were completed. RESULTS: Results showed that ADHD adolescents consumed more energy and fat than controls but had similar anthropometry. ADHD children consumed equivalent amounts of omega-3 and omega-6 fatty acids to controls, however they had significantly lower levels of docosahexaenoic acid (DHA, 22:6n-3) and total omega-3 fatty acids, higher omega-6 fatty acids and a lower ratio of n-3:n-6 fatty acids than control subjects. In addition, low omega-3 status correlated with higher scores on several Conners' behavioural scales. CONCLUSION: These data suggest that adolescents with ADHD continue to display abnormal essential fatty acid profiles that are often observed in younger children and distinctly different from normal controls of similar age. Further these red blood cell fatty acid differences are not explained by differences in intake. This suggests that there are metabolic differences in fatty acid handling between ADHD adolescents and normal controls. The value of omega-3 supplements to improve fatty acid profiles and possibly behaviours associated with ADHD, need to be examined.

Treatment of obesity in children and adolescents. How nutrition can work?

Overweight appears when persistent positive energy imbalances occur for long periods of time. Knowledge of dietary risk factors during childhood and adolescence is needed in order to design preventive measures against the increase in the prevalence of obesity and its consequences but is, however, largely missing. Longitudinal studies in children have not found clear causal associations between energy intake or diet composition and overweight development. Research has been ongoing to develop effective intervention studies for obese children but it is not clear which intervention is the most effective in assisting overweight/obese children to improve body composition without affecting growth rates. The objective of this article is to review the available knowledge on dietary risk factors for the development of childhood obesity, to discuss different dietary treatment strategies, and to propose an evidence-based approach to treat obese adolescents.

The efficacy of micronutrient supplementation in reducing the prevalence of anaemia and deficiencies of zinc and iron among adolescents in Sri Lanka.

OBJECTIVE: To determine the effectiveness of combined iron and zinc over the iron or zinc-only supplementation in correcting deficiency and possible interactive effects in a group of adolescent school children. SUBJECTS AND METHODS: Schoolchildren (n=821) of 12-16 years of age were randomized into four groups and supplemented with iron (50 mg/day), zinc (14 mg/day), iron+zinc or placebo capsules 5 days per week for 24 weeks. Anthropometry, and haemoglobin (Hb), serum zinc (SZn) and serum ferritin (SF) concentrations were determined before and after the intervention. RESULTS: There were no significant effects between-groups in their weight, height and Hb concentrations with the intervention when compared with the placebo group. Iron-only and combination-supplemented groups had reached mean SF concentrations of 55.1 microg/l with no difference between them (P=0.99). The zinc-only group had a mean change of 4.3 micromol//l whereas the combine-supplemented group had a mean change of 4.0 micromol/l (P=0.82). The prevalence of anaemia was found to be 70.3% in the iron group at baseline; this was reduced to 14.5% after the supplementation. In the combine-supplemented group anaemia, prevalence was reduced from 64.8 to 19.3%. CONCLUSIONS: Zinc alone or in combination with iron has not shown a significant improvement in growth in adolescence. Severe and moderate forms of anaemia were successfully treated in children who received iron supplementation. Initial high prevalence of low SZn and iron stores was significantly improved with micronutrient supplementation.

The lack of effect of isoflavones on high-density lipoprotein cholesterol concentrations in adolescent boys: a 6-week randomised trial.

BACKGROUND: A substantial fall in high-density lipoprotein cholesterol (HDL-C) during puberty in boys, but not girls, has been reported in Western populations. The fall in boys is believed to be due to hormonal changes--androgens have been shown to be associated with lower HDL-C, whereas oestrogens are associated with higher HDL-C. The fall in HDL-C during puberty was not observed, however, in a study of Moslem boys in Israel, nor in a group of Japanese boys. A diet high in phyto-oestrogens may account for the lack of a fall in HDL-C in these populations. OBJECTIVE: To examine the effect of dietary supplementation with phyto-oestrogens on the HDL-C concentration of adolescent boys from a Western population. We hypothesised that dietary supplementation of 50 mg of the isoflavones daidzein and genistein would produce a 12% higher HDL-C concentration than in controls at the end of a 6-week intervention period. DESIGN: A randomised controlled trial. SETTING: Hellyer College in Burnie (Tasmania, Australia). SUBJECTS: Adolescent boys (aged 16-18 years) were recruited through a letter sent to parents. A total of 132 eligible participants enrolled and five subjects withdrew from the trial. RESULTS: No significant increase in HDL-C was observed in the treatment group (-0.02 mmol l(-1), standard error (SE)=0.03, P = 0.53) or the placebo group (0.05 mmol l(-1), SE = 0.03, P = 0.11). CONCLUSIONS: Factors other than isolated dietary isoflavones may be responsible for the lack of fall in HDL-C during puberty in Japanese and Moslem boys.

Iodine intake of Slovenian adolescents.

BACKGROUND: Slovenia is classified as being iodine-deficient. We recently found that Slovenian adolescents are iodine-sufficient (median urinary iodine concentration of the population 140 microg/l) and the prevalence of goiter is low (0.9%). The objective of this study was to evaluate iodine intake, the prevalence of marginal, low and excessive intake (<50, 50-100 and >or=300 microg/day), as well as the main sources of iodine in the diet of Slovenian adolescents. METHODS: A cross-sectional study included 2,581 adolescents (1,415 girls, 1,166 boys, mean age +/- SD 15.6 +/- 0.5 years) representing 10% of 15-year-old Slovenian adolescents. Iodine intake was determined using a food frequency questionnaire (FFQ) in the whole population studied (n = 2,485) and weighted 3-day dietary protocols (3DPs) in a subgroup of participants (n = 191). RESULTS: Median iodine intake determined from FFQ was 155.8 microg/day. There was no significant difference between genders. Marginal, low and excessive iodine intake was observed in 3.3, 20.3 and 11.3% of the adolescents, respectively. The major food sources of dietary iodine included table salt (39 % of the mean daily iodine intake), beverages (22%) and milk/milk products (19%). CONCLUSIONS: Dietary iodine intake in Slovenian adolescents is adequate, illustrating the effective salt iodization program.

Importance of seafood as nutrient source in the diet of Belgian adolescents.

BACKGROUND: Regular seafood consumption is recommended in dietary guidelines. The aim of this study was to investigate the importance of seafood as a nutrient source in adolescents' diet and the extent to which seafood consumption can increase the intake of omega-3 polyunsaturated fatty acids and vitamin D. METHODS: Consumption data recorded during seven consecutive days for 341 adolescents selected in Ghent (Belgium) were used to estimate the intake of vitamin D, linoleic (LA), alpha-linolenic (LNA), arachidonic (AA), eicosapentaenoic (EPA), docosapentaenoic (DPA) and docosahexaenoic (DHA) acid. RESULTS: The adolescents consumed on average 3.21 microg/day vitamin D, 11.7 g/day LA and 1.4 g/day LNA. The mean intakes of AA, EPA, DPA and DHA were 83.2, 55.9, 18.4 and 111.4 mg/day respectively. The major source of vitamin D was fortified margarine. Fats and oils were the main sources for LA and LNA. The intake of AA was mainly contributed by meat, poultry and eggs. Fish and seafood contributed for 84.1%, 59.3% and 64.4% respectively for EPA, DPA and DHA. CONCLUSION: Flemish adolescents would benefit from increased seafood consumption, as this would lead to a higher intake of EPA and DHA as well as of vitamin D. Moreover, replacement of foods rich in saturated fat (SFA) by seafood products can help to reduce SFA intake.

Evaluation of energy, nutrient and dietary fiber intakes of adolescent males.

OBJECTIVE: The minimal data available on the current energy, nutrient and dietary fiber intakes of adolescent males challenges the development of effective nutrition education programs. There is a need for research into the current intakes of adolescent males and in particular their relation to the current Dietary Reference Intakes (DRIs). The primary objective of this study was to assess the diet of adolescent males and relate energy, nutrient and dietary fiber intakes to the DRIs. Secondary objectives were to relate energy, macronutrient and dietary fiber intakes to body mass index (BMI)-for-age percentile categories as well as to explore vitamin/mineral supplement use and soft drink consumption. METHODS: Three-day food records were completed by 180 healthy adolescent males for analysis of energy, nutrient and dietary fiber intakes from food and supplements. Following adjustment for intra-individual variability, nutrient intake percentile distributions were related to the DRIs. Energy, macronutrient and dietary fiber intakes were compared among BMI-for-age percentile categories and diets were evaluated for vitamin/mineral supplement use and soft drink consumption. RESULTS: Median intakes for percent energy from carbohydrate, fat and protein were within the Accepted Macronutrient Distribution Ranges. Intakes of micronutrients with Estimated Average Requirement values indicated that greater than 50% of subjects consumed inadequate amounts of vitamin A and vitamin B6, and greater than 75% of subjects consumed inadequate amounts of magnesium, phosphorus and zinc. Subjects classified as overweight had significantly lower energy and carbohydrate intakes compared with subjects classified as having an acceptable body weight. The prevalence of vitamin/mineral supplement use was 16.1% and 67% of subjects reported daily consumption of soft drinks. CONCLUSION: Results of this study reveal that adolescent males are consuming the recommended amounts of macronutrients but may be at risk for consuming inadequate levels of specific micronutrients. Nutrition education programs should consider targeting select micronutrients to improve nutritional intakes of adolescent males.

Vitamin intakes from supplements and fortified food in German children and adolescents: results from the DONALD study.

Frequent consumption of supplements is a common behavior in adults, as well as children and adolescents. We report on vitamin intake from consuming supplements, taking into account the vitamin intake from fortified and usual foods. A total of 5990 3-d weighed dietary records from 931 German subjects (452 males, 479 females, 2-18 y of age) between 1986 and 2003 from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study were evaluated. We identified 133 different vitamin-containing supplements in 451 records (7.5%). Slightly more males (8.0%) than females (7.1%) consumed supplements, with highest frequencies found between ages 15 and 18 y. For the majority (10 of 13) of vitamins (vitamin A, vitamin E, vitamin K, thiamin, riboflavin, vitamin B-6, vitamin B-12, niacin, biotin, and vitamin C), intake from usual and fortified food already reached or exceeded 80% of the recommended dietary allowances in all age groups. In the case of folate and pantothenic acid, intake from supplements was necessary to achieve at least 80% of recommended dietary allowances for half of the age groups, especially in females. Supplements with vitamin D considerably helped increase vitamin intake but failed to achieve 80% of references in almost all age groups. Intakes of vitamin A and folic acid exceeded the tolerable upper level most frequently in many age groups and were most pronounced in up to 32% and 13% of children aged 2-3 y. Intake of vitamin D, vitamin E, and vitamin C exceeded the tolerable upper level in single age groups only (<7% of subjects). For the other vitamins, no exceeded limits were identified. The ubiquitous availability of supplements might indicate that even healthy children and adolescents profit by taking them. However, it is difficult to evaluate whether consumers receive more benefits or risks from the unrestricted consumption of supplements as they are marketed today.

Improvement of nutrition stimulates bone mineral gain in Japanese school children and adolescents.

Calcium supplementation could accelerate bone mineral accrual, but the effect of other dietary factors in children is unclear. The aim of this study was to determine associations of changes in diet with bone accrual in Japanese children. All female (n=262) and male (n=286) school children aged 10-15 years living in a small town were recruited. We measured bone status at the os calcis using quantitative ultrasound (QUS) and assessed diet and other lifestyle factors using questionnaires annually for 5 years. The greatest increase in QUS values was observed between ages 11-13 years in boys and girls and peak bone status was attained typically by age 14-15 years (approximately 2 years since menarche) in girls and 1-2 years later in boys. Initial bone status adjusted by height and weight in 10-year-old or 11-year-old children was associated positively with intake of small fish and dairy products, and negatively with age of menarche in girls, and negatively with preference for meat in boys. Annual increase in QUS bone status in girls age 10 years or 11 years was associated positively with increased intake of fish, fruit, vegetables, soybeans, and intake of milk products and negatively with preference for meat. Annual increase in QUS bone status in boys was associated positively with increased height and weight, increased intake of small fish and vegetables, intake of dairy products, and awareness of bone measurement. Thus, a dietary change incorporating an increased intake of fish, fruit, vegetables, and soy products could lead to higher bone QUS values in children.

Nutrition influences skeletal development from childhood to adulthood: a study of hip, spine, and forearm in adolescent females.

This study evaluated the long-term efficacy of supplemental calcium and dairy products on bone mineral areal density of the hip and spine and on the bone geometry and volumetric bone mineral density of the forearm in young females during late adolescence. The study was conducted among participants of a randomized double-blinded, placebo-controlled clinical trial with calcium supplements and among participants of an observational study with higher consumption of dairy products. Hip and spine measurements by dual-energy X-ray absorptiometry were done every 6 mo (dairy group every 12 mo) during last 3 y of the follow-up while peripheral quantitative computerized tomography of the forearm was done at the last visit. The results of the study show a positive influence of calcium supplementation and dairy products on bone mineral density of the hip and the forearm. Dairy products were also associated with a higher bone mineral density of the spine while calcium supplementation did not have an effect. Calcium exerts its action on bone accretion during growth primarily by influencing volumetric bone mineral density while milk may have an additional impact on bone growth and periosteal bone expansion.

Zinc and vitamin A intake and status in a national sample of British young people aged 4-18 y.

OBJECTIVE: To examine zinc and vitamin A intake and status and associated dietary, socio-demographic, lifestyle and physiological factors in British young people. DESIGN: National Diet and Nutrition Survey of young people aged 4-18 y. SETTING: Great Britain, 1997. SUBJECTS: Complete 7-day weighed dietary records were provided by 1520 participants, while 1193 provided blood samples. RESULTS: A total of 13 and 11% of participants respectively reported low dietary intakes of zinc and vitamin A (retinol equivalents), relative to the UK lower reference nutrient intake. These percentages were not altered significantly by including contributions to intake from supplements, mainly containing vitamin A (as retinol). Likelihood of low zinc and/or vitamin A intake was more often associated with age, sex and likely under-reporting of food consumption than with other socio-demographic and lifestyle factors. Low zinc and vitamin A intakes were generally less likely in those with higher consumption of dairy foods (mainly milk). Zinc and vitamin A status (assessed by plasma zinc and retinol concentrations) were adequate in almost all participants. Plasma zinc concentration was not significantly associated with zinc intake. Plasma retinol concentration was correlated with vitamin A intake (overall r=0.17, P<0.001; adjusted for age and plasma alpha(1)-antichymotrypsin concentration) and increased significantly with age (P<0.001) in both sexes. A significant association was found between plasma zinc and retinol concentrations in boys only (r=0.17, P=0.001). CONCLUSION: Zinc and vitamin A intakes and status were generally adequate in this national sample of British young people.