Changes in atherogenic dyslipidemia induced by carbohydrate restriction in men are dependent on dietary protein source

Abstract

Previous studies have shown that multiple features of atherogenic dyslipidemia are improved by replacement of dietary carbohydrate with mixed sources of protein and that these lipid and lipoprotein changes are independent of dietary saturated fat content. Because epidemiological evidence suggests that red meat intake may adversely affect cardiovascular disease risk, we tested the effects of replacing dietary carbohydrate with beef protein in the context of high- vs. low-saturated fat intake in 40 healthy men. After a 3-wk baseline diet [50% daily energy (E) as carbohydrate, 13% E as protein, 15% E as saturated fat], participants consumed for 3 wk each in a randomized crossover design two high-beef diets in which protein replaced carbohydrate (31% E as carbohydrate, 31% E as protein, with 10% E as beef protein). The high-beef diets differed in saturated fat content (8% E vs. 15% E with exchange of saturated for monounsaturated fat). Two-week washout periods were included following the baseline diet period and between the randomized diets periods. Plasma TG concentrations were reduced after the 2 lower carbohydrate dietary periods relative to after the baseline diet period and these reductions were independent of saturated fat intake. Plasma total, LDL, and non-HDL cholesterol as well as apoB concentrations were lower after the low-carbohydrate, low-saturated fat diet period than after the low-carbohydrate, high-saturated fat diet period. Given our previous observations with mixed protein diets, the present findings raise the possibility that dietary protein source may modify the effects of saturated fat on atherogenic lipoproteins.

Trial registration: ClinicalTrials.gov NCT00852267.

Conflict of interest statement

Author disclosures: L. Mangravite, S. Chiu, K. Wojnoonski, R. Rawlings, N. Bergeron, and R. Krauss, no conflicts of interest.

Figures

FIGURE 1

Associations between differences in plasma concentrations of small LDL particles and total VLDL particles in men following intake of two LC diets that differed in saturated fat content, n = 40. LC, lower carbohydrate.

FIGURE 2

Changes in plasma TG (A) and apoB48 (B) in men following administration of an oral fat tolerance test after diet periods that differed in carbohydrate and saturated fat content. Values are presented as the ratio of postprandial:fasting concentrations to adjust for differences in fasting measurements. Values are mean ± SEM, n = 40. Labeled means at a time without a common letter differ, P < 0.05. LCLSF, lower carbohydrate, low-saturated fat; LCHSF, lower carbohydrate, high-saturated fat.