Background: Due to the widespread unorthodox use of nuts to improve cardiovascular health, this clinical trial was carried out to evaluate the efficacy of walnut as an adjuvant statin in hypertensive subjects.
Method: A single-blind placebo-controlled randomized clinical trial that lasted for 3 months. Forty-five screened hypertensive subjects on treatment, aged 45-65 years, were randomized into intervention and placebo groups according to their blood pressure defined by the American Heart Association criteria. Fifteen (15) normotensive subjects were also recruited for this study. The participants in the intervention group included daily 7 g of boiled walnut taken as snacks. The study was not controlled for type of diet and frequency of meals in a day. Low-density lipoprotein cholesterol (LDLc) was the primary endpoint for this study.
Results: The mean LDLc levels of the intervention groups (84.6 mg/dl and 79.7 mg/dl, respectively) were significantly (p < .005) lower than the placebo (137.6 mg/dl). The high-density lipoprotein cholesterol (HDLc) levels of the intervention groups were significantly higher than the placebo. The mean total cholesterol levels of the intervention groups were significantly lower than the placebo group. The intervention groups recorded a significantly lower systolic and diastolic blood pressure compared to the placebo. The supplementation of walnut significantly decreased the apolipoprotein E (APOE), proprotein convertase subtilisin kexin 9 (PCSK9), and cholesteryl ester transfer protein (CETP) activities relative to the placebo.
Conclusion: The use of walnut as a statin adjuvant during hypertension treatment reduced LDLc levels within 42.1% and improved HDL levels by 33.6%, and the LDLc decrease related to reduced PCSK9 and APOE activities while the HDLc increase related to reduced CETP activities.
Keywords: Statins; blood pressure; cholesterol; hypertension; walnut.