Abstract:
Effect of diets varying in amount of cholesterol and
polyunsaturated to saturated fatty acid ratio (P/S) on plasma lipid
levels and lecithin:cholesterol acyltransferase (LCAT) activity was
determined in fourteen young adult male subjects during a 13-week
experimental period in a crossover design.
Control diet was fed for two weeks prior to 11-week experimental
period. Two experimental diets were sequentially fed to each group
during the 11-week experimental period switching the diet at the
midpoint. The blood was drawn five times and LCAT activity and plasma
lipid levels were measured. The effect of fat modifications in the
diets on fractional LCAT activity showed a systematic change in LCAT
activity independent of diet. Plasma total cholesterol levels were
significantly (p < 0.05) elevated by diets containing high saturated
fat with either high (22%) or low (7%) cholesterol while diets high in
polyunsaturated fat with either high or low cholesterol levels lowered
the total cholesterol in Groups I and II but increased it in Groups
III and IV. Trend of changes in plasma triglyceride was similar to
that of plasma LCAT in Groups I and IV. However, there was
inconsistency in the relationship between the LCAT activity and plasma
lipid levels. LCAT enzyme was purified by 436-fold from plasma with
14% yield.
