Effect of Carbohydrate and Fat in the Diet on Uric Acid Excretion

Apart from an early observation by Umeda (1) of a single case in which a diet high in fat and low in carbohydrate led to a diminution of uric acid output, little attention was devoted to this phase of the uric acid problem prior to the introduction of the ketogenic diet in the treatment of epilepsy. This stimulated the study of the uric acid elimination during fasting in epileptic children, normal persons being used as controls. All observers (2-6) reported that fasting resulted in decreased uric acid elimination in the urine. Leopold, Bernhard, and Jacobi (4) further showed that a high fat diet results in a marked decrease in the uric acid output. Their diet, used in children, was unusually low in carbohydrate, containing, ‘daily, only 15 gm. of carbohydrate, 12 gm. of protein, and 110 gm. of fat. They also noted that a high carbohydrate, almost purine-free diet does not result in greater uric acid elimination than that observed on a diet with an equally low purine content, and moderate amounts of carbohydrate. Lennox (5), in a very comprehensive paper, showed that the feeding of a high fat diet does not relieve the uric acid retention resulting from prolonged fasting, but that the feeding of carbohydrate results in a prompt rise in uric acid excretion. A state of acidosis and ketosis may be induced by a high fat, extremely low carbohydrate diet, as well as by prolonged fasting. The first may be considered an “exogenous” high fat diet, whereas the effect of fasting is essentially equivalent to an “endogenous” high fat diet. The diminished excretion of uric acid under both these conditions may therefore have been due to acidosis or ketosis. In fact, Lennox (5) demonstrated a fairly reciprocal relationship