Studies on plasma amino acids in East African adults in relation to endomyocardial fibrosis.

I. An examination has been made of the plasma amino acids of adult Uganda Africans at risk to endomyocardial fibrosis compared with people from areas where the disorder is rare. The amino acid profile, both free and in the protein of the main staples, has also been examined. 2. Plasma tryptophan was found to be low in adults at risk and intermediate in Africans receiving a higher protein intake, as compared with Europeans whose protein intake might include more than 40 % as animal products. 3. Leucine and valine were also low in the plasma of adult Africans at risk. 4. The non-essential amino acids alanine and glycine were increased in the adult Africans at risk. 5. The similarity of these changes with the changes seen in kwashiorkor by other workers suggests that adherence to limited vegetable diets may introduce a chronic stress with regard to certain essential amino acids. 6 . Studies on the vegetable staples used by Africans established that they are particularly poor in tryptophan and such Africans are probably dependent on other sources for their tryptophan. None of the staples was a rich source of leucine. Plantain contained relatively large amounts of histidine, and cassava of arginine. 7. A comparative study of muscle protein suggests that the composition is similar regardless of diet and species. Leucine is quantitatively one of the most important amino acids in the muscle profile. 8. The above findings are discussed in the context of the requirements for heart muscle and the high incidence of cardiomyopathies within such African communities.