Branched‐chain ketoacids reduce muscle protein degradation in duchenne muscular dystrophy

In order to determine whether branched‐chain ketoacids can reduce the excessive rate of muscle protein degradation that characterizes Duchenne muscular dystrophy, nine boys affected with the disease were studied in a metabolic ward while receiving meat‐free diets. After a three‐day equilibration period, excretion rates of 3‐methylhistidine and creatinine were measured in two consecutive four‐day periods. In the second period, a supplement containing a mixture of ornithine α‐ketoisocaproate, α‐ketoisovalerate, and α‐keto‐β‐methylvalerate in a proportion of 4 : 1 : 1 was administered orally at a dosage of 0.45 gm/kg/day. During treatment with the ketoacids, 3‐methylhistidine excretion fell by a small (mean: 14%) but highly significant (P < 0.01) extent, whether expressed in absolute terms or in relation to creatinine excretion. No adverse effects were noted. We conclude that this mixture of ketoacids acutely reduces muscle protein degradation in patients with Duchenne muscular dystrophy.