Associations of Changes in Blood Lipid Concentrations with Changes in Dietary Cholesterol Intake in the Context of a Healthy Low-Carbohydrate Weight Loss Diet: A Secondary Analysis of the DIETFITS Trial.

Monica Vergara,Cynthia W Shih,Christopher D Gardner,Priya Fielding-Singh,Lucia Aronica,Michelle E Hauser,Joseph Rigdon

doi:10.3390/nu13061935

Abstract

In 2015, the Dietary Guidelines for Americans (DGA) eliminated the historical upper limit of 300 mg of dietary cholesterol/day and shifted to a more general recommendation that cholesterol intake should be limited. The primary aim of this secondary analysis of the Diet Intervention Examining the Factors Interacting With Treatment Success (DIETFITS) weight loss diet trial was to evaluate the associations between 12-month changes in dietary cholesterol intake (mg/day) and changes in plasma lipids, particularly low-density lipoprotein (LDL) cholesterol for those following a healthy low-carbohydrate (HLC) diet. Secondary aims included examining high-density lipoprotein (HDL) cholesterol and triglycerides and changes in refined grains and added sugars. The DIETFITS trial randomized 609 healthy adults aged 18–50 years with body mass indices of 28–40 kg/m2 to an HLC or healthy low-fat (HLF) diet for 12 months. Linear regressions examined the association between 12-month change in dietary cholesterol intake and plasma lipids in 208 HLC participants with complete diet and lipid data, adjusting for potential confounding variables. Baseline dietary cholesterol intake was 322 ± 173 (mean ± SD). At 12 months, participants consumed an average of 460 ± 227 mg/day of dietary cholesterol; 76% consumed over the previously recommended limit of 300 mg/day. Twelve-month changes in cholesterol intake were not significantly associated with 12-month changes in LDL-C, HDL-C, or triglycerides. Diet recall data suggested participants’ increase in dietary cholesterol was partly due to replacing refined grains and sugars with eggs. An increase in daily dietary cholesterol intake to levels substantially above the previous 300 mg upper limit was not associated with a negative impact on lipid profiles in the setting of a healthy, low-carbohydrate weight loss diet.

Highlights

Poor diet is a key risk factor for cardiovascular disease (CVD), the leading cause of death in the United States [1]
Discrepancies between different studies’ findings were examined and highlighted the importance of considering two important features: (1) confounding with saturated fat, which is found in most foods high in cholesterol, and (2) overall diet quality and food patterns, which may modify the effect of cholesterol on low-density lipoprotein (LDL)-C and CVD risk [14]
There were no significant differences between the healthy low-carbohydrate (HLC) subjects included in the analysis (n = 208) and those excluded (n = 96) with regard to sex, race, education, or baseline diet, but those with missing data were younger (38 ± 6.9 years vs. 40 ± 6.6 years, mean ± standard deviation (SD), heavier (99 ± 15 kg vs. 95 ± 16 kg), and had lower mean LDL cholesterol (LDL-C) level (109 ± 25 month change in plasma LDL-C (mg/dL) vs. 116 ± 26 mg/dL) (Table A1)

Summary

Introduction

Poor diet is a key risk factor for cardiovascular disease (CVD), the leading cause of death in the United States [1]. A “heart-healthy diet” included a recommendation to limit dietary cholesterol to no more than 300 mg/day [2,3,4,5]. This recommendation was based on a body of evidence that included both interventional studies and observational epidemiology studies suggesting links between dietary cholesterol and blood concentrations of LDL cholesterol (LDL-C), a major risk factor for CVD [6,7,8]. There is a paucity of data on the effects of a high-cholesterol diet or a diet high in egg consumption where this intake occurs in the context of an overall high-quality diet

Methods

Results

Conclusion