Increased low-density lipoprotein cholesterol on a low-carbohydrate diet in adults with normal but not high body weight: A meta-analysis.
Study Goal
The researchers aimed to evaluate LDL cholesterol changes in response to low-carbohydrate diets (LCDs), focusing on the role of baseline BMI.
Results Summary
The study found that LDL cholesterol changes on LCDs varied significantly by baseline BMI: individuals with BMI <25 experienced a 41 mg/dL increase, those with BMI 25-<35 saw no change, and those with BMI ≥35 had a 7 mg/dL decrease. The relationship between BMI and LDL cholesterol change was not observed with higher-carbohydrate diets.
Population
Adults consuming <130 g/d carbohydrate, with varying baseline BMIs.
Effective Dosage
<130 g/d carbohydrate
Duration
Mean intervention duration of 19.4 weeks
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low-carbohydrate diet (LCD) | decrease | LDL cholesterol change | participants in randomized controlled trials | β = -2.5 mg/dL/BMI unit | had a strong inverse association with | #1 |
saturated fat amount | no change | LDL cholesterol change | participants in randomized controlled trials | null | was not significantly associated with | #2 |
low-carbohydrate diet (LCD) | increase | LDL cholesterol | trials with mean baseline BMI <25 | 41 mg/dL | increased | #3 |
low-carbohydrate diet (LCD) | no change | LDL cholesterol | trials with a mean of BMI 25-<35 | null | did not change | #4 |
low-carbohydrate diet (LCD) | decrease | LDL cholesterol | trials with a mean BMI ≥35 | 7 mg/dL | decreased | #5 |
higher-carbohydrate diets | no change | LDL cholesterol change | individual participants | null | relationship was not observed on | #6 |
BACKGROUND: Low-density lipoprotein (LDL) cholesterol change with consumption of a low-carbohydrate diet (LCD) is highly variable. Identifying the source of this heterogeneity could guide clinical decision-making. OBJECTIVES: To evaluate LDL cholesterol change in randomized controlled trials involving LCDs, with a focus on body mass index (BMI) in kg/m2. METHODS: Three electronic indexes (Pubmed, EBSCO, and Scielo) were searched for studies between 1 January, 2003 and 20 December, 2022. Two independent reviewers identified randomized controlled trials involving adults consuming <130 g/d carbohydrate and reporting BMI and LDL cholesterol change or equivalent data. Two investigators extracted relevant data, which were validated by other investigators. Data were analyzed using a random-effects model and contrasted with results of pooled individual participant data. RESULTS: Forty-one trials with 1379 participants and a mean intervention duration of 19.4 wk were included. In a meta-regression accounting for 51.4% of the observed variability on LCDs, mean baseline BMI had a strong inverse association with LDL cholesterol change [β = -2.5 mg/dL/BMI unit, 95% confidence interval (CI): -3.7, -1.4], whereas saturated fat amount was not significantly associated with LDL cholesterol change. For trials with mean baseline BMI <25, LDL cholesterol increased by 41 mg/dL (95% CI: 19.6, 63.3) on the LCD. By contrast, for trials with a mean of BMI 25-<35, LDL cholesterol did not change, and for trials with a mean BMI ≥35, LDL cholesterol decreased by 7 mg/dL (95% CI: -12.1, -1.3). Using individual participant data, the relationship between BMI and LDL cholesterol change was not observed on higher-carbohydrate diets. CONCLUSIONS: A substantial increase in LDL cholesterol is likely for individuals with low but not high BMI with consumption of an LCD, findings that may help guide individualized nutritional management of cardiovascular disease risk. As carbohydrate restriction tends to improve other lipid and nonlipid risk factors, the clinical significance of isolated LDL cholesterol elevation in this context warrants investigation. This trial was registered at PROSPERO as CRD42022299278.