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Vitamin D status indicators in indigenous populations in East Africa
European Journal of Nutrition, 08/21/2012
Luxwolda MF et al. – This ancient 25(OH)D amounted to about 115 nmol/L and sunlight exposure, rather than fish intake, was the principal determinant. The fetoplacental unit was exposed to high 25(OH)D, possibly by maternal vitamin D mobilization from adipose tissue, reduced insulin sensitivity, trapping by vitamin D–binding protein, diminished deactivation, or some combination.
Methods- Authors studied serum 25(OH)D [defined as 25(OH)D2 + 25(OH)D3] and its determinants in 5 East African ethnical groups across the life cycle: Maasai (MA) and Hadzabe (HA) with traditional life styles and low fish intakes, and people from Same (SA; intermediate fish), Sengerema (SE; high fish), and Ukerewe (UK; high fish).
- Samples derived from non–pregnant adults (MA, HA, SE), pregnant women (MA, SA, SE), mother–infant couples at delivery (UK), infants at delivery and their lactating mothers at 3 days (MA, SA, SE), and lactating mothers at 3 months postpartum (SA, SE).
- Erythrocyte docosahexaenoic acid (RBC–DHA) was determined as a proxy for fish intake.
- The mean ± SD 25(OH)D of non–pregnant adults and cord serum were 106.8 ± 28.4 and 79.9 ± 26.4 nmol/L, respectively.
- Pregnancy, delivery, ethnicity (which authros used as a proxy for sunlight exposure), RBC–DHA, and age were the determinants of 25(OH)D. 25(OH)D increased slightly with age.
- RBC–DHA was positively related to 25(OH)D, notably 25(OH)D2.
- Pregnant MA (147.7 vs. 118.3) and SE (141.9 vs. 89.0) had higher 25(OH)D than non–pregnant counterparts (MA, SE).
- Infant 25(OH)D at delivery in Ukerewe was about 65 % of maternal 25(OH)D.