Malabsorption of essential amino acids in tropical sprue.

The absorption of seven amino acids from an equimolar mixture containing each of the eight essential amino acids in a concentration of 20 mM was evaluated using a marker perfusion technique in 9 patients with untreated tropical sprue and in 6 healthy Puerto Rican control subjects. The rate of absorption of from two to six of the amino acids tested was lower in 7 of the patients than in the control subjects. The absorption of isoleucine, leucine, valine, and threonine was significantly lower in the group of sprue patients than in the control subjects. Treatment of 4 patients with oral tetracycline for 2 weeks was associated with return of amino acid absorption to normal in the 3 persons who had improved intestinal function, as tested by other parameters. More prolonged treatment was required for normalization of amino acid absorption in the 4th patient. These observations indicate that the absorption of certain essential amino acids is reduced in some patients with untreated tropical sprue.