Effect of high carbohydrate diet on serum lactate dehydrogenase isozyme pattern in Japanese young men

Changes in the activity of serum lactate dehydrogenase (LDH) and the serum LDH isozyme pattern in healthy young men given a high carbohydrate diet (480-636 g/day, 80% of the total energy) for 21 days were examined. Serum total LDH activity showed no significant change in four healthy young volunteers who received high carbohydrate diet for 21 days. However, the percentage of LDH-4 increased significantly (P less than 0.01) from 8.5 +/- 2.4 to 10.9 +/- 1.9% after 21 days, as did also the percentage of LDH-5 (P less than 0.01) from 5.1 +/- 1.9 to 10.7 +/- 2.9%. The percentage of M-type LDH activity increased 30% during the experiment (P less than 0.05). It is concluded from the results that the high carbohydrate intake affects the percentage of LDH-4 and LDH-5, but not the total serum LDH activity.