Safety of Vitamin D Food Fortification and Supplementation: Evidence from Randomized Controlled Trials and Observational Studies.

The safety considerations of food-based solutions for vitamin D deficiency prevention, such as fortification and supplementation, are critical. On the basis of collective data from 20 randomized controlled trials (RCTs) and 20 national healthy surveys, as well as prospective cohort studies (PCSs) across the ODIN project ("Food-based solutions for optimal vitamin D nutrition and health through the life cycle", FP7-613977), we analyzed the potential safety issues arising from vitamin D intakes and/or supplementation. These adverse consequences included high serum 25-hydroxyvitamin D (S-25(OH)D) concentrations (>125 nmol/L), high serum calcium concentrations, and vitamin D intakes in excess of the tolerable upper intake levels (ULs). In the RCTs (n = 3353, with vitamin D doses from 5-175 µg/day), there were no reported adverse effects. The prevalence of high S-25(OH)D was <10% when vitamin D supplements were administered, and <0.1% for fortified foods. Elevated serum calcium was observed among <0.5% in both administration types. No ODIN RCT participants exceeded the age-specific ULs. In observational studies (n = 61,082), the prevalence of high 25(OH)D among children/adolescents, adults, and older adults was <0.3%, with no evidence of adverse effects. In conclusion, high S-25(OH)D concentrations >125 nmol/L were rare in the RCTs and PCSs, and no associated adverse effects were observed.

Differences in the dietary requirement for vitamin D among Caucasian and East African women at Northern latitude.

CONTEXT: Current vitamin D recommendations have been established based on an assumption that there are no differences between Caucasian and other ethnic/racial groups in terms of vitamin D requirements. This assumption, largely made due to the absence of data, is a key knowledge gap identified by a number of authorities. OBJECTIVE: To test whether the distribution of dietary requirements for maintaining winter serum 25-hydroxyvitamin D [25(OH)D] concentrations ≥ 30 nmol/L (a priority threshold linked to vitamin D deficiency prevention) differ between Caucasian and Somali women living at northerly latitude. METHODS: We used data from a 5-month, winter-based, vitamin D3 dose-related randomized, placebo-controlled trial in Somali (n 47) and Causcian women (n 69), aged 21-64-year old, living in Southern Finland (60°N), to model the vitamin D intake-serum 25(OH)D dose-response relationship. Regression analyses were used to predict the vitamin D intake required to maintain 97.5% (as well as 50, 90, and 95%) of women in both ethnic groups above serum 25(OH)D thresholds of 30, 40 and 50 nmol/L. RESULTS: Using a model which adjusted for baseline 25(OH)D, age, and BMI, the estimated vitamin D intake that maintained serum 25(OH)D ≥ 30 nmol/L in 97.5% of Caucasian and Somali women was 8 and 18 µg/day, respectively. Ethnic differences were also evident at 40 and 50 nmol/L serum 25(OH)D thresholds. CONCLUSION: The present study adds further evidence that ethnic differences in the dietary requirement for vitamin D do exist and that dose-response vitamin D intervention studies are required in at-risk target populations specified by ethnicity.

Vitamin D intake, serum 25-hydroxyvitamin D status and response to moderate vitamin D3 supplementation: a randomised controlled trial in East African and Finnish women.

Insufficient vitamin D status (serum 25-hydroxyvitamin D (S-25(OH)D)0·05 for differences between ethnic groups). In conclusion, high prevalence of vitamin D insufficiency existed among East African women living in Finland, despite higher vitamin D intake than their Finnish peers. Moderate vitamin D3 supplementation was effective in increasing S-25(OH)D in both groups of women, and no ethnic differences existed in the response to supplementation.