Gender differences in lipoprotein responses to diet.

Gender and dietary saturated fat remain two strong predictors of coronary heart disease susceptibility. In a retrospective meta-analysis of five studies, we analyzed the impact of gender and diet composition on lipoprotein change, or 'response' (delta) in 63 normolipidemic subjects fed two contrasting, metabolically controlled diets. One diet had a low polyunsaturated to saturated fatty acid ratio (low P:S) and the second, a high P:S ratio in a crossover design. Lipid profile 'responsiveness' was calculated as the adjusted difference (mg/dl) following each diet period. Multivariate analysis of variance revealed that triglyceride (delta TG), very low density (delta VLDL-C), and high density lipoprotein cholesterol responses (delta HDL-C) were the only statistically significant, gender-specific lipid responders. Difference in low density lipoprotein (LDL-C) response to diet was similar between the sexes. Multiple regression analysis identified the independent predictors of delta HDL-C for males and females. In females, the HDL-C lowering was predicted by the percentage increase in polyunsaturated fatty acids, baseline HDL-C levels and, inversely by delta TG. The male predictor of delta HDL-C was diet alone (replacement of saturated fat by dietary polyunsaturated fatty acids). Results showed that while normolipidemic males and females show similar reductions in LDL-C following dietary change, delta HDL-C is gender-specific, with females showing a greater fall in the potentially 'beneficial' HDL-C than males. We conclude that a diet crossover may be of less benefit to normolipidemic females than to males, due to HDL-C lowering. Gender and diet may both become pivotal considerations in achieving plasma lipid goals.