The effects of low-carbohydrate diets on cardiovascular risk factors: A meta-analysis.
Study Goal
The researchers aimed to assess the relationship between low-carbohydrate diets and cardiovascular risk factors through a meta-analysis of randomized trials.
Results Summary
The study found that low-carbohydrate diets were associated with beneficial effects on cardiovascular risk factors, including reduced triglyceride levels, body weight, and blood pressure, as well as increased HDL-C, though LDL-C levels slightly increased. The long-term effects require further research.
Population
Participants in 12 randomized trials (specific demographics not detailed in the abstract).
Effective Dosage
Not specified
Duration
Interventions ranged from less than 6 months to 12-23 months.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low-carbohydrate diet | decrease | triglyceride levels | - | -0.15mmol/l (95% confidence interval -0.23 to -0.07) | was associated with a decrease | #1 |
low-carbohydrate diet interventions lasting less than 6 months | decrease | triglyceride levels | - | -0.23mmol/l (95% confidence interval -0.32 to -0.15) | were associated with a decrease | #2 |
low-carbohydrate diet interventions lasting 12-23 months | decrease | triglyceride levels | - | -0.17mmol/l (95% confidence interval -0.32 to -0.01) | were associated with a decrease | #3 |
low-carbohydrate diet | decrease | body weight | observation groups | -1.58kg (95% confidence interval -1.58 to -0.75) | change in the body weight | #4 |
low-carbohydrate diet interventions lasting less than 6 months | decrease | body weight | - | -1.14 kg (95% confidence interval -1.65 to -0.63) | change in the body weight | #5 |
low-carbohydrate diet interventions lasting 6-11 months | decrease | body weight | - | -1.73kg (95% confidence interval -2.7 to -0.76) | change in the body weight | #6 |
low-carbohydrate diet | decrease | systolic blood pressure | observation group | -1.41mmHg (95% confidence interval-2.26 to -0.56) | change in the systolic blood pressure | #7 |
low-carbohydrate diet | decrease | diastolic blood pressure | observation group | -1.71mmHg (95% confidence interval-2.36 to -1.06) | change in diastolic blood pressure | #8 |
low-carbohydrate diet | increase | plasma HDL-C levels | - | 0.1mmHg (95% confidence interval 0.08 to 0.12) | change in plasma HDL-C levels | #9 |
low-carbohydrate diet | increase | serum total cholesterol | - | 0.13mmol/l (95% confidence interval 0.08 to 0.19) | change in serum total cholesterol | #10 |
low-carbohydrate diet | increase | plasma LDL-C level | - | 0.11mmol/l (95% confidence interval 0.02 to 0.19) | increased | #11 |
low-carbohydrate diet | no change | fasting blood glucose level | - | 0.03mmol/l (95% confidence interval -0.05 to 0.12), which was not significant | changed | #12 |
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.