THE EFFECT OF LOW-CARBOHYDRATE DIET ON HYPERTENSIVE PATIENTS WITH OBESITY

Abstract

Objective: Non-pharmacological treatment such as a healthy diet, is important for hypertensive patients as it has a effect of lowering blood pressure (BP). We aimed to evaluate the effect of low-carbohydrate diet (LCD) on hypertensive patients with obesity. Design and method: Four electronic databases (KoreaMed, Embase, Medline, and the Cochrane Library) were searched from their inception to June 2021. Randomized clinical trials evaluating LCD (<130 g/day or <26% of the 2000 kcal/day diet) and very low-carbohydrate diet (VLCD) (<20-50 g/day or <10% of the 2000 kcal/day) for at least 8 weeks in adults with hypertension were eligible. Studies in which more than 50% of patients taking antihypertensive drugs, or systolic blood pressure (SBP) of 140 mmHg or more or diastolic blood pressure (DBP) of 90 mmHg or more were included. Primary outcomes were change of SBP and DBP. The comparative diets were diets with calorie restriction equivalent to those of the intervention diets, and most were included in a calorie-restricted diet and a low fat diet. Results: From 18, 151 studies identified in the initial search results, 6 randomized studies were included in the final analysis. Compared to the control diet, decreased SBP (mean difference: -3.25; 95% CI -7.28, 0.77) is observed in LCD for a period of six months or less, with no statistically significant difference in more than six months to one year or less and more than one year (36-52weeks: mean difference -1.30; 95% CI -76.04, 3.44, and > 1year: mean difference -4.51, 95% CI -15.38, 6.37) (Figure). LCD did not effect on DBP compared to control diet. VLCD marginally decreased SBP compared with the control diet, but not lead to a significant difference in DBP. Conclusions: For obese adults with hypertension, LCD had no additional benefit in reducing BP and weight compared to calorie-restricted or low fat diets when maintained for one year or longer. There is insufficient evidence to support the beneficial effect of a LCD in adults with hypertension, and further studies are needed to evaluate the effect of LCD in hypertensive patients.