Association of a Low-carbohydrate High-fat (Ketogenic) Diet With Plasma Lipid Levels and Cardiovascular Risk in a Population-based Cohort

Presented at the ACC.23 by: Iulia Iatan, MD, PhD - Vancouver, Canada

Introduction and methods

Low-carbohydrate high-fat (LCHF) diets (also called “ketogenic diets”) are increasingly popular due to their purported health benefits for a variety of conditions, including obesity and DM. These diets can lead to hypercholesterolemia in some people. However, data on the effect of LCHF diets on the overall lipid profile and the risk of ASCVD are limited.

In a prospective population-based cohort study, the association between consumption of a LCHF diet and serum lipids as well as incident MACE was assessed. For this purpose, data on serum lipids, amongst others, from participants aged 40–69 years were collected in the UK Biobank. Upon enrolment in the biobank, dietary patterns of the participants were assessed using a self-reported 24-hour dietary intake questionnaire. This identified 305 individuals (73% female) whose diet met the definition of an LCHF diet (i.e., daily carbohydrate consumption <100 g (<25% of total daily energy) and >45% of total daily energy from fat). Each individual on a LCHF diet was age- and sex-matched to individuals on a standard diet (i.e., a diet that did not meet LCHF diet criteria; n=1220) in a 1:4 ratio.

Incident MACE was defined as a composite outcome of angina, MI, coronary artery disease, ischemic stroke, peripheral artery disease, and coronary and carotid revascularization.

Main results

• Participants in the LCHF-diet group had higher mean levels of total cholesterol (6.08 mmol/L [1.2] vs. 5.85 mmol/L [1.1]), LDL-c (3.80 mmol/L [SD 0.9] vs. 3.64 mmol/L [0.8]), non–HDL-c (4.46 mmol/L [1.2] vs. 4.29 mmol/L [1.0], and apoB (1.09 g/L [0.25] vs. 1.04 g/L [0.23] compared with participants on a standard diet (all P≤0.03).
• After a mean follow-up time of 11.8 years, the incident MACE rate was greater in the LCHF-diet group than in the standard-diet group (9.8% vs. 4.3%; adjusted HR: 2.18; 95%CI: 1.39–3.43; P<0.001).
• Subgroup analyses showed the increased MACE risk was most prominent in participants on a LCHF diet who had LDL-c ≥5 mmol/L compared with participants on a standard diet and LDL <3.5 mmol/L (reference group) (HR : 6.68: 95%CI: 2.62–17.09; P<0.001). Those on a standard diet with LDL ≥5 mmol/L had an HR of 1.90 (0.64-5.69) for MACE (participants on a standard diet and LDL <3.5 mmol/L as the reference group).

Conclusion

In this population-based cohort (of British descent), self-reported consumption of a LCHF diet was associated with higher LDL-c and apoB levels and an increased risk of incident MACE compared with a standard diet.

- Our reporting is based on the information provided at the ACC.23 -

Watch a video by Liam Brunham on this study