Inflammation Modifies the Effects of a Reduced-Fat Low-Cholesterol Diet on Lipids

Abstract

Background-Inflammatory mediators regulate key aspects of lipid metabolism. We hypothesized that inflammation could diminish the cholesterol-lowering effect of a reduced-fat/low-cholesterol diet. Methods and Results-After a 2-week run-in period on a control diet (37% total fat, 16% saturated fat), 100 participants were randomized to the control or DASH diet (27% total fat, 6% saturated fat) for 12 weeks. Median C-reactive protein (CRP) at baseline was 2.37 mg/L (interquartile range, 1.20, 3.79). The DASH diet, net of control, had no effect on CRP. Overall, there were significant net reductions in total (Ϫ0.34 mmol/L), LDL (Ϫ0.29 mmol/L), and HDL (Ϫ0.12 mmol/L) cholesterol from the DASH diet (each, PϽ0.001) and little change in triglycerides (ϩ0.05 mmol/L, Pϭ0.21). Baseline CRP was strongly associated with lipid responsiveness to the DASH diet. Total and LDL cholesterol were reduced to a greater degree in those with a "low" (below median) compared with a "high" (above median) baseline CRP (total, Ϫ9.8% versus Ϫ3%; P for interactionϭ0.006; LDL cholesterol, Ϫ11.8% versus Ϫ3%; P for interactionϭ0.009). Reductions in HDL cholesterol (Ϫ8.8%) were similar in persons with low versus high CRP. Triglycerides were increased in those with a high CRP but not in those with a low CRP (19.8% versus ϩ0%; P for interactionϭ0.019). Conclusions-In this study, the presence of increased CRP was associated with less total and LDL cholesterol reduction and a greater increase in triglycerides from a reduced-fat/low-cholesterol diet. These findings document an additional mechanism by which inflammation might increase cardiovascular disease risk.

Comparison of a dietary portfolio diet of cholesterol-lowering foods and a statin on LDL particle size phenotype in hypercholesterolaemic participants

“…Hilpert et al 31 have recently shown that subjects with low CRP exhibited significant reductions in LDL-cholesterol levels with a low-fat diet, whereas subjects with high CRP showed increased LDL-cholesterol concentrations. Subanalyses of the DASH diet study also indicated that LDL-cholesterol levels were significantly reduced only in subjects with baseline CRP below the median (, 2·37 mg/l) 30 . Furthermore, we have recently shown that plasma total and VLDL-TAG levels were significantly increased in subjects with high baseline CRP levels after a low-fat diet, but remained unchanged in the subgroup with low CRP concentration at baseline 29 .…”

Inflammation, Metabolic Syndrome, and Diet Responsiveness

“…It makes use of high intakes of fruits and vegetables (total of about 9 servings per day), low-fat dairy products, and other reduced-fat foods. The diet used in the study by Erlinger et al 12 provided about 27% of total energy as fat, 6% of energy from saturated fatty acids, and 151 mg/d of cholesterol. Besides lowering blood pressure, the DASH diet previously has been shown to reduce plasma lipids.…”

“…In the study of Erlinger et al, 12 the DASH diet was compared with a diet that contained 37% of energy from total fat and 16% from saturated fat. A majority of subjects were African-American women who were either overweight or obese.…”

“…The major finding from Erlinger et al 12 was that persons with higher levels of CRP failed to respond favorably in plasma lipid levels to the DASH diet when compared with those with lower CRP levels. Total cholesterol and LDL cholesterol concentrations fell on the DASH diet when CRP levels were low but not did not fall much-if at all-when CRP levels were high.…”

“…There has been a long history to the investigation of factors that influence variation in responsiveness of plasma lipids to dietary change. These factors have been reviewed in detail by Denke et al 15,16 12 naturally raise the question of mechanism. What are the reasons for a relationship between CRP concentrations and dietary responsiveness?…”