The Effects of Low-Carbohydrate Diets on Cardiovascular Risk Factors: A Meta-Analysis

PLoS One. 2020 Jan 14;15(1):e0225348. doi: 10.1371/journal.pone.0225348. eCollection 2020.

Abstract

Background: Low-carbohydrate diets are associated with cardiovascular risk factors; however, the results of different studies are inconsistent.

Purpose: The aim of this meta-analysis was to assess the relationship between low-carbohydrate diets and cardiovascular risk factors.

Method: Four electronic databases (PubMed, Embase, Medline, and the Cochrane Library) were searched from their inception to November 2018. We collected data from 12 randomized trials on low-carbohydrate diets including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, and blood pressure levels, as well as weight as the endpoints. The average difference (MD) was used as the index to measure the effect of a low-carbohydrate diet on cardiovascular risk factors with a fixed-effects model or random-effects model. The analysis was further stratified by factors that might affect the results of the intervention.

Results: From 1292 studies identified in the initial search results, 12 randomized studies were included in the final analysis, which showed that a low-carbohydrate diet was associated with a decrease in triglyceride levels of -0.15mmol/l (95% confidence interval -0.23 to -0.07). Low-carbohydrate diet interventions lasting less than 6 months were associated with a decrease of -0.23mmol/l (95% confidence interval -0.32 to -0.15), while those lasting 12-23 months were associated with a decrease of -0.17mmol/l (95% confidence interval -0.32 to -0.01). The change in the body weight in the observation groups was -1.58kg (95% confidence interval -1.58 to -0.75); with for less than 6 months of intervention,this change was -1.14 kg (95% confidence interval -1.65 to -0.63),and with for 6-11 months of intervention, this change was -1.73kg (95% confidence interval -2.7 to -0.76). The change in the systolic blood pressure of the observation group was -1.41mmHg (95% confidence interval-2.26 to -0.56); the change in diastolic blood pressure was -1.71mmHg (95% confidence interval-2.36 to -1.06); the change in plasma HDL-C levels was 0.1mmHg (95% confidence interval 0.08 to 0.12); and the change in serum total cholesterol was 0.13mmol/l (95% confidence interval 0.08 to 0.19). The plasma LDL-C level increased by 0.11mmol/l (95% confidence interval 0.02 to 0.19), and the fasting blood glucose level changed 0.03mmol/l (95% confidence interval -0.05 to 0.12),which was not significant.

Conclusions: This meta-analysis confirms that low-carbohydrate diets have a beneficial effect on cardiovascular risk factors but that the long-term effects on cardiovascular risk factors require further research.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Pressure
  • Body Weight
  • Cardiovascular Diseases / blood
  • Cardiovascular Diseases / diet therapy*
  • Cardiovascular Diseases / epidemiology
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Diet, Carbohydrate-Restricted*
  • Diet, Fat-Restricted*
  • Energy Intake*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Randomized Controlled Trials as Topic
  • Risk Factors
  • Triglycerides / blood

Substances

  • Cholesterol, HDL
  • Cholesterol, LDL
  • Triglycerides

Grant support

The work was supported by the Department of Science and Technology of Sichuan Province-Luzhou city-Luzhou Medical College joint fund (14JC0175).