An extended study of the effect of Iranian village and urban flatbreads on the mineral balances of two men before and after supplementation with vitamin D†

The Role of Sunlight in the Cutaneous Production of Vitamin D3

“…Their diet is low in fortified foodstuffs but high in fiber [which may increase the rate of turnover of 25-0H-D (4)] and phytic acid [which decreases the bioavailability of dietary calcium (92,94)]. Exposure to UV radiation is low because of the move to higher latitudes (101) and for social and religious reasons; furthermore the absorption of UVB radiation by melanin pigmentation exacerbates this and reduces cutaneous synthesis of vitamin D3 (13).…”

From absorption and excretion of minerals...to the importance of bioavailability and adaptation

“…Significant amounts of Ca can be absorbed in the colon, and the fact that phytic acid has no effect on colonic absorption (Sandstrom et al 1990) supports the suggestion that the microflora are involved in the breakdown of phytate-mineral complexes. A more recent human study reported no reduction in losses of Ca when high-phytate breads were fed to adults for a period of 98 d (Reinhold et al 1981), which does not lend support to the adaptation theory. Studies with rats show mat high and low levels of Ca intake affect the utilization of 14 C-labelled phytate differently (Nahapetian & Young, 1980), which might partly explain the inconsistent results.…”

Exacerbation of rickets and osteomalacia by maize: A study of bone histomorphometry and composition in young baboons

“…There appears to be a multiple etiology to the disease pattern, with both the consumption of high-extraction cereals as staple diets and a deficiency of vitamin D being contributary factors [1][2][3][4]. Although Mellanby showed several years ago that cereals can exacerbate rickets in vitamin D-deficient puppies [5], little is really known as to the detailed effects of such diets that might be expected in children.…”