Effects of a dietary magnesium deficiency and excess vitamin D3 on swine coronary arteries.

The effect of a moderate magnesium (Mg) deficiency on coronary arteries of 61 swine, fed various levels of vitamin D3, was studied by light and electron microscopy. The effect of subnormal Mg intake on vitamin D3-induced intimal lesions of the arteries showed a trend towards increased damage. The degree of cell degeneration and intimal thickening, which was induced by high vitamin D intakes, was as great in swine whose diet was low in Mg and moderately high in vitamin D as it was in those on twice as much vitamin D. Also, the degree of arterial calcification was intensified by inadequate Mg intake at the two higher vitamin D intakes. Present findings indicate that suboptimal dietary Mg, in combination with an excess of vitamin D, has an additive effect in the initiation of ultrastructural changes in the coronary arteries. Extension of the study is indicated to ascertain the extent to which further reduction of Mg intake can potentiate vitamin-D-induced coronary lesions.