Lipoprotein lipase activity in skeletal muscle and adipose tissue of marathon runners after simple and complex carbohydrate-rich diets

Abstract

A comparison of the influence of simple and complex carbohydrate (CHO) consumption on adipose tissue- and skeletal muscle-lipoprotein lipase activity (AT-LPLA, SM-LPLA) was examined. Twenty male marathon runners were divided into two equal dietary groups: simple-CHO and complex-CHO. Half of the subjects in each group consumed either a low-CHO (15% energy [E] intake), or a mixed diet (50% CHO) for 3 days. Immediately following this dietary period, the subjects consumed a CHO-rich diet (70% E intake) predominant in simple-CHO or in complex-CHO for an additional 3 days. Thereafter, all subjects returned to a normal mixed diet. Skeletal muscle biopsies, adipose tissue aspirations, and venous blood samples were obtained prior to dietary manipulation (PRE), upon completion of the 6 day diet (POST I), and 2 weeks after returning to a normal diet (POST II). The samples were analysed for AT-LPLA, SM-LPLA, serum insulin, and free fatty acids (FFA), and blood glucose, and lactate. SM-LPLA fell 71% from PRE values of 0.39±0.30 μ mol · g⁻¹ · h⁻¹ to POST I values of 0.11 ±0.09 μ mol · g⁻¹ · h⁻¹ (means±SD) (ppp−1) but were unchanged after a complex-CHO diet. Blood glucose and lactate, and serum insulin were not altered following a CHO-rich diet.