Objectives To review and synthesize the literature in the following areas: the association of specific circulating 25(OH)D concentrations with bone health outcomes in children, women of reproductive age, postmenopausal women and elderly men; the effect of dietary intakes (foods fortified with vitamin D and/or vitamin D supplementation) and sun exposure on serum 25(OH)D; the effect of vitamin D on bone mineral density (BMD) and fracture or fall risk; and the identification of potential harms of vitamin D above current reference intakes. Data sources MEDLINE(R) (1966-June Week 3 2006); Embase (2002-2006 Week 25); CINAHL (1982-June Week 4, 2006); AMED (1985 to June 2006); Biological Abstracts (1990-February 2005); and the Cochrane Central Register of Controlled Trials (2nd Quarter 2006). Review methods Two independent reviewers completed a multi-level process of screening the literature to identify eligible studies (title and abstract, followed by full text review, and categorization of study design per key question). To minimize bias, study design was limited to randomized controlled trials (RCTs) wherever possible. Study criteria for question one were broadened to include observational studies due to a paucity of available RCTs, and question four was restricted to systematic reviews to limit scope. Data were abstracted in duplicate and study quality assessed. Differences in opinion were resolved through consensus or adjudication. If clinically relevant and statistically feasible, meta-analyses of RCTs on vitamin D supplementation and bone health outcomes were conducted, with exploration of heterogeneity. When meta-analysis was not feasible, a qualitative systematic review of eligible studies was conducted. Results 167 studies met our eligibility criteria (112 RCTs, 19 prospective cohorts, 30 case-controls and six before-after studies). The largest body of evidence on vitamin D status and bone health was in older adults with a lack of studies in premenopausal women and infants, children and adolescents. The quality of RCTs was highest in the vitamin D efficacy trials for prevention of falls and/or fractures in older adults. There was fair evidence of an association between low circulating 25(OH)D concentrations and established rickets. However, the specific 25(OH)D concentrations associated with rickets is uncertain, given the lack of studies in populations with dietary calcium intakes similar to North American diets and the different methods used to determine 25(OH)D concentrations. There was inconsistent evidence of an association of circulating 25(OH)D with bone mineral content in infants, and fair evidence that serum 25(OH)D is inversely associated with serum PTH. In adolescents, there was fair evidence for an association between 25(OH)D levels and changes in BMD. There were very few studies in pregnant and lactating women, and insufficient evidence for an association between serum 25(OH)D and changes in BMD during lactation, and fair evidence of an inverse correlation with PTH. In older adults, there was fair evidence that serum 25(OH)D is inversely associated with falls, fair evidence for a positive association with BMD, and inconsistent evidence for an association with fractures. The imprecision of 25(OH)D assays may have contributed to the variable thresholds of 25(OH)D below which the risk of fractures, falls or bone loss was increased. There was good evidence that intakes from vitamin D-fortified foods (11 RCTs) consistently increased serum 25(OH)D in both young and older adults. Eight randomized trials of ultraviolet (UV)-B radiation (artificial and solar exposure) were small and heterogeneous with respect to determination of the exact UV-B dose and 25(OH)D assay but there was a positive effect on serum 25(OH)D concentrations. It was not possible to determine how 25(OH)D levels varied by ethnicity, sunscreen use or latitude. Seventy-four trials examined the effect of vitamin D(3) or D(2) on 25(OH)D concentrations. Most trials used vitamin D(3), and the majority enrolled older adults. In three trials, there was a greater response of serum 25(OH)D concentrations to vitamin D(3) compared to vitamin D(2), which may have been due to more rapid clearance of vitamin D(2) in addition to other mechanisms. Meta-analysis of 16 trials of vitamin D(3) was consistent with a dose-response effect on serum 25(OH)D when comparing daily doses of /= 400 IU. An exploratory analysis of the heterogeneity demonstrated a significant positive association comparable to an increase of 1 - 2 nmol/L in serum 25(OH)D for every 100 additional units of vitamin D although heterogeneity remained after adjusting for dose. Vitamin D(3) in combination with calcium results in small increases in BMD compared to placebo in older adults although quantitative synthesis was limited due to variable treatment durations and BMD sites. The evidence for fracture reduction with vitamin D supplementation was inconsistent across 15 trials. The combined results of trials using vitamin D(3) (700 - 800 IU daily) with calcium (500 - 1,200 mg) was consistent with a benefit on fractures although in a subgroup analysis by setting, benefit was primarily in elderly institutionalized women (fair evidence from two trials). There was inconsistent evidence across 14 RCTs of a benefit on fall risk. However, a subgroup analysis showed a benefit of vitamin D in postmenopausal women, and in trials that used vitamin D(3) plus calcium. In addition, there was a reduction in fall risk with vitamin D when six trials that adequately ascertained falls were combined. Limitations of the fall and fracture trials included poor compliance with vitamin D supplementation, incomplete assessment of vitamin D status and large losses to follow-up. We did not find any systematic reviews that addressed the question on the level of sunlight exposure that is sufficient to maintain serum 25(OH)D concentrations but minimizes risk of melanoma and non-melanoma skin cancer. There is little evidence from existing trials that vitamin D above current reference intakes is harmful. In most trials, reports of hypercalcemia and hypercalciuria were not associated with clinically relevant events. The Women's Health Initiative study did report a small increase in kidney stones in postmenopausal women aged 50 to 79 years whose daily vitamin D(3) intake was 400 IU (the reference intake for 50 to 70 years, and below the reference intake for > 70 years) combined with 1000 mg calcium. The increase in renal stones corresponded to 5.7 events per 10,000 person-years of exposure. The women in this trial had higher calcium intakes than is seen in most post-menopausal women. Conclusions The results highlight the need for additional high quality studies in infants, children, premenopausal women, and diverse racial or ethnic groups. There was fair evidence from studies of an association between circulating 25(OH)D concentrations with some bone health outcomes (established rickets, PTH, falls, BMD). However, the evidence for an association was inconsistent for other outcomes (e.g., BMC in infants and fractures in adults). It was difficult to define specific thresholds of circulating 25(OH)D for optimal bone health due to the imprecision of different 25(OH)D assays. Standard reference preparations are needed so that serum 25(OH)D can be accurately and reliably measured, and validated. In most trials, the effects of vitamin D and calcium could not be separated. Vitamin D(3) (>700 IU/day) with calcium supplementation compared to placebo has a small beneficial effect on BMD, and reduces the risk of fractures and falls although benefit may be confined to specific subgroups. Vitamin D intake above current dietary reference intakes was not reported to be associated with an increased risk of adverse events. However, most trials of higher doses of vitamin D were not adequately designed to assess long-term harms.

http://www.reboundhealth.com/cms/images/pdf/MedicalAbstract/effectiveness%20and%20safety%20of%20vitamin%20d%20in%20relation%20to%20bone%20health%20id%2016060.pdf

Effectiveness and safety of vitamin D in relation to bone health.

Maternal vitamin d intake during pregnancy and early childhood wheezing

Ranking and/or classifying foods based on their nutrient composition is known as nutrient profiling. Nutrition quality indices need to be tested and validated against quality of the total diet. A family of nutrient-rich foods (NRF) indices were validated against the Healthy Eating Index (HEI), an accepted measure of diet quality. All foods consumed by participants in NHANES 1999-2002 studies were scored using NRFn.3 (where n = 6-15) indices based on unweighted sums, means, and ratios of percent daily values (DV) for nutrients to encourage (n) and for nutrients to limit (LIM) (3). Individual food scores were calculated based on 100 kcal (418 kJ) and FDA serving sizes [reference amounts customarily consumed (RACC)]. Energy-weighted food-based scores per person were then regressed against HEI, adjusting for gender, age, and ethnicity. The measure of index performance was the percentage of variation in HEI (R2) explained by each NRF score. NRF indices based on both nutrients to encourage and LIM performed better than indices based on LIM only. Maximum variance in HEI was explained using 6 or 9 nutrients to encourage; index performance actually declined with the inclusion of additional vitamins and minerals. NRF indices based on 100 kcal (418 kJ) performed similarly to indices based on RACC. Algorithms based on sums or means of nutrient DV performed better than ratio-based scores. The NRF9.3 index, based on 9 nutrients to encourage and 3 LIM per RACC and per 100 kcal, explained the highest percentage of variation from HEI and could be readily expected to rank foods based on nutrient density.

Development and Validation of the Nutrient-Rich Foods Index: A Tool to Measure Nutritional Quality of Foods

Dietary composition has been shown to influence metabolism and to impact on the prevalence and risk for certain diseases, but hitherto, there have been no systematic studies on the effects of dietary modulation of human metabolic phenotype (metabotype). Here, we have applied 1 H NMR spectroscopy in combination with multivariate statistical analysis to characterize the effects of three diets: “vegetarian”, “low meat”, and “high meat” on the metabotype signature of human participants. Twelve healthy male participants (age range of 25-74 years) consumed each of these diets, in a randomized order, for continuous 15-day-periods with an intervening washout period between each diet of 7 days duration. Each participant provided three consecutive 24-hour urine collections on days 13, 14, and 15 of each dietary period, and 1 H NMR spectra were acquired on all samples. Pattern recognition analysis allowed differentiation of the characteristic metabolic signatures of the diets with creatine, carnitine, acetylcarnitine, and trimethylamine-N-oxide (TMAO) being elevated in the high-meat consumption period. Application of orthogonal projection to latent structure discriminant analysis (O-PLS-DA) allowed the low-meat diet and vegetarian diet signatures to be characterized, and p-hydroxyphenylacetate (a microbial mammalian cometabolite) was higher in the vegetarian than meat diet samples, signaling an alteration of the bacterial composition or metabolism in response to diet. This work shows the potential for the routine use of metabonomics in nutritional and epidemiological studies, in characterizing and predicting the metabolic effects and the influence of diet on human metabotypes.

Susceptibility of human metabolic phenotypes to dietary modulation.

Vitamin D and cancer.

Objective To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR). Design Subjects completed the Scottish Collaborative Group FFQ and carried out a 4-day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients, the percentages of subjects classified into the same and opposite thirds of intake, and Cohen's weighted kappa. Subjects Forty-one men, mean age 36 (range 21-56) years, and 40 women, mean age 33 (range 19-58) years, recruited from different locations in Aberdeen, Scotland. Results Spearman correlation coefficients tended to be lower than Pearson correlation coefficients, and were above 0.5 for 10 of the 27 nutrients in men and 17 of the 27 nutrients in women. For nutrients with Spearman correlation coefficients above 0.5, the percentage of subjects correctly classified into thirds ranged from 39 to 78%, and weighted kappa values ranged from 0.23 to 0.66. Conclusions Both Spearman correlation coefficients and weighted kappa values are useful in assessing the relative validity of estimates of nutrient intake by FFQs. Spearman correlation coefficients above 0.5, more than 50% of subjects correctly classified and less than 10% of subjects grossly misclassified into thirds, and weighted kappa values above 0.4 are recommended for nutrients of interest in epidemiological studies.

/pdf/statistical-approaches-for-assessing-the-relative-validity-4gzxlksfi7.pdf

Statistical approaches for assessing the relative validity of a food-frequency questionnaire: use of correlation coefficients and the kappa statistic

Serum ferritin, serum vitamin B12, erythrocyte folate, plasma vitamin C and plasma 25-hydroxycholecalciferol levels were measured in 208 men and 197 women, >75 years old and living in the community, in order to assess micronutrient status. Anthropometric measurements (height, weight, demispan and mid-upper arm circumference) were made and a 114-item questionnaire covering a wide range of health and diet-related topics was administered by an interviewer. Only 4 % of subjects had a BMI <20, but the prevalence of marginal deficiency of the micronutrients ranged from 7 % for Fe to 47 % for vitamin D. There was no association between low micronutrient status (defined as being in the lowest third of the distribution of micronutrient status) and having BMI or mid-upper arm circumference in the lowest third of the distribution for any of the nutrients. Leaving food on the plate was strongly associated with both low Fe status and low vitamin D status. Having breakfast cereal less than once per week was strongly associated with low folate status, while having fresh fruit juice less than once per week, having had less than two portions of fruits and vegetables the previous day and believing that food is not important for health were strongly associated with low vitamin C status. Low vitamin D status was strongly associated with a wide range of general health and disability measures. Having a weekly household income of less than pound 150 was associated with low status of Fe, folate, vitamin C and vitamin D.

/pdf/predictors-of-micronutrient-status-in-men-and-women-over-75-4icdj4wx1v.pdf

Predictors of micronutrient status in men and women over 75 years old living in the community.

Letter to the Editor. Beware the fatty acid-free sausage!

BACKGROUND: Prevention policies do not have an upper age limit, and as the overwhelming majority of older people continue to reside in the community there is a growing role for community dietetics and primary care team members in the promotion of healthy eating. METHOD: The multi-method project ascertained the dietary beliefs and practices of older people residing in high-income, low-income and rural localities of Scotland. One hundred and fifty-two people aged 75 years and over were interviewed using a semistructured interview schedule and 24-h food recall questionnaire. RESULTS: An analysis of the food recall questionnaire demonstrated that the diets of the elderly appear to differ little from the Scottish population as a whole. In all groups there was an under consumption of fruits and vegetables reported. Findings from the interviews demonstrated that dietary beliefs were found to be firmly rooted in childhood and lifetime experiences. Participants defined healthy eating as 'proper meals', 'proper foods', and a variety of foods eaten in moderation. These definitions were based upon the consumption of fresh foods which would be considered healthy. Changing and conflicting advice on health and nutrition was contrasted with personal experiences. Few knew of the role of the dietitian or community dietitian. CONCLUSIONS: This study demonstrates a contrast between stated beliefs and actual consumption patterns. Access to food, and the cost and quality of foods impacted upon food practices. The role of the community dietitian should be promoted. Advice on healthy eating must work with contemporary practices and beliefs building upon positive aspects of diet and eating and involving the food industry, retail sector and health services.

The food consumption patterns and perceptions of dietary advice of older people.

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Statistical approaches for assessing the relative validity of a food-frequency questionnaire: use of correlation coefficients and the kappa statistic

Predictors of micronutrient status in men and women over 75 years old living in the community.

Letter to the Editor. Beware the fatty acid-free sausage!

The food consumption patterns and perceptions of dietary advice of older people.