INDIVIDUAL VARIATION IN PLASMA-CHOLESTEROL RESPONSE TO DIETARY SATURATED FAT

Objective-To determine the extent to which plasma lipid concentrations of individuals are consistently sensitive to changes in saturated fat s; to examine whether groups that consistently have large or small res ponses can be defined; and to identify factors which predict response of lipids to dietary change. Design-A double crossover design in which two diets (S, providing 21% energy from saturated fat, and P, providi ng 10%) were followed for periods of six weeks in the sequence SPSP or PSPS. Setting-67 free living subjects, total cholesterol 5.5-7.9 mmol /l. Main outcome measures-Relation of cholesterol responses to repeate d dietary changes and of potential predictors and cholesterol response . Results Similar average changes in cholesterol mask a wide range of individual responses. Response was not related to compliance. In all p articipants the change in cholesterol observed when the nature of diet ary fat was changed on the two crossovers was correlated (r=0.31, P=0. 01); the degree of correlation between the two sets of responses was g reater in the 46 consistent responders than in the 21 variable respond ers (r=0.71 v r=0.21). Mean differences in cholesterol between diet S and diet P during the two crossovers were 1.16 (SD 0.35) mmo/l and 0.9 5 (0.26) mmol/l for consistent hyperresponders and 0.18 (0.26) mmol/l and 0.18 (0.25) mmol/l for consistent minimal responders. in consisten t responders, changes in total cholesterol in response to increasing s aturated fats correlated with baseline cholesteryl ester transfer acti vity (r=0.32, P=0.03); total cholesterol (r=0 37, P=0.01); triglycerid es (r=0.30, P=0.04); and apolipoprotein B (r=0.54, P=0.01). Conclusion s-There is a degree of consistency in cholesterol response to instruct ions to change dietary fat which is not explained by dietary complianc e, and there are groups of consistent hyperresponders and minimal resp onders within population of hypercholesterolaemic individuals. Several factors predicting response have been identified. These results have relevance to dietary approaches aimed at reducing the Lipoprotein medi ated risk of coronary heart disease.