The British journal of nutrition
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Secondary hyperparathyroidism (SHPT) is one of the outcomes of vitamin D deficiency that negatively affects bone metabolism. We studied the ethnic differences in vitamin D status in Finland and its effect on serum intact parathyroid hormone (S-iPTH) concentration and bone traits. The study was done in the Helsinki area (60°N) during January-February 2008. ⋯ Ethnicity and S-25OHD together explained 30 % of the variation in S-iPTH. The total bone mass at all sites of the forearm, fracture load and stress-strain index was higher (P < 0·001) in Bangladeshi and Finnish women than in Somali women. The high prevalence of hypovitaminosis D, SHPT and low bone status in Somali women indicates a higher risk of osteoporosis.
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The natural source of vitamin B₁₂ in human diets comes from animal products. For example, one glass (250 ml) of milk provides approximately 50 % of the RDA (2·4 μg/d). It was hypothesised that the provision of vitamin B₁₂ from milk is more efficiently absorbed than the synthetic form used in vitamin supplements. ⋯ The cumulative PDV fluxes during the 24 h following ingestion of meals complemented with milk varied from 5·5 to 6·8 μg. These values correspond to an efficiency of intestinal absorption of vitamin B₁₂ from milk varying between 8 and 10 %. Therefore, vitamin B₁₂, which is abundant in cows' milk, is also substantially more available than the most commonly used synthetic form of this vitamin.