Plasma homocysteine concentrations in a population with a low coronary heart disease prevalence.

To evaluate hyperhomocysteinemia as a possible coronary heart disease risk factor, the South African black population as example of a population with a low coronary heart disease prevalence was investigated and compared with a population prone to coronary heart disease (South African Whites). In traditionally living adult black men, plasma homocysteine concentrations were significantly lower compared with Whites. The plasma homocysteine frequency distribution in Whites was positively skewed; individuals with high plasma homocysteine concentrations probably acquire these during or after young adulthood, because the plasma homocysteine frequency distribution in children was normal. Compared with Blacks, young adult Whites showed methionine intolerance expressed as high plasma homocysteine concentrations after an oral methionine load test. The results indicate that Blacks generally have lower circulating plasma homocysteine concentrations and more effective homocysteine metabolism after oral methionine loading, which may partially explain their relative resistance against coronary heart disease.