Quantitative relations between dietary fat and cholesterol and plasma lipid concentrations have been the subject of much study and controversy during the past 40 years. Previous meta-analyses have focused on the most tightly controlled, highest-quality experiments.
To test whether the findings of these investigations are generalizable to broader experimental settings and to the design of practical dietary education investigations, data from 224 published studies on 8143 subjects in 366 independent groups including 878 diet-blood lipid comparisons were subjected to weighed multiple-regression analysis.
Inclusion criteria specified intervention studies published in English between 1966 and 1994 reporting quantitative data on charges in dietary cholesterol and fat and corresponding changes in serum cholesterol, triacylglycerol, and lipoprotein cholesterol concentrations.
Regression models are reported for serum total cholesterol, triacyglycerol, and low-density-high-density, and very-low-density-lipoprotein cholesterol, with multiple correlations of 0.74, 0.65, 0.41, 0.14, and 0.34, respectively. Interactions of dietary factors, initial dietary intakes and serum concentrations, and study and subject characteristics had little effect on these models.
Predictions indicated that compliance with current dietary recommendations (30% of energy of fat, <10% from saturated fat, and <300 mg cholesterol/d) will reduce plasma total and low-density-lipoprotein-cholesterol concentrations by = 5% compared with amounts associated with the average American diet.
Plasma lipid and lipoprotein responses to dietary fat and cholesterol: a meta-analysis. Howell WH, McNamara DJ, Tosca MA et al. (1997) American Journal of Clinical Nutrition 65(6):1747-64