Damage to the vascular endothelium resulting in endothelial dysfunction has been implicated as an important mechanism in the development of cardiovascular disease (CVD). Curcumin extracts from turmeric (Curcuma longa, Zingiberaceae) rhizome have cardioprotective, antioxidant, and anti-inflammatory properties. Ex vivo, curcumin has been shown to reverse endothelial dysfunction, and one small (n = 32), randomized, controlled trial found curcumin supplementation for 8 weeks was comparable to exercise in improving endothelial function in postmenopausal women. According to the authors, there are no studies evaluating the effect of curcumin supplementation on endothelial function in healthy people. The purpose of this 8-week, randomized, placebo-controlled, double-blind study was to evaluate the effect of high and low doses of a proprietary curcumin supplement on endothelial function in healthy, young adults.
Healthy, nonsmoking men and women (n = 59, aged 19-29 years) participated in this study conducted in Fort Worth, Texas [study dates not reported]. Included subjects had no musculoskeletal, medical, or metabolic contraindications to exercise and did at least 150 min/week of moderate aerobic activity or 75 min/week of vigorous aerobic activity for the 3 months prior to enrollment. Excluded subjects were pregnant or lactating, participated in another clinical trial or consumed the investigational product within the previous 30 days, were regularly treated with anti-inflammatory/analgesic/antioxidant drugs in the previous month, or used any ergogenic aid during the 9 weeks prior to the study.
In this 3-arm trial, subjects received either placebo (corn [Zea mays, Poaceae] starch), 50 mg/day of curcumin (71.5% curcumin, 19.4% desmethoxycurcumin, and 9.1% bisdemethoxycurcumin), or 200 mg/day of curcumin for 8 weeks. The curcumin treatments (CurcuWIN®; OmniActive Health Technologies Ltd.; Mumbai, India) were formulated with a hydrophilic carrier to improve absorption.
Subjects were told to abstain from eating foods that contain curcumin. At baseline and study end, fasting blood was drawn to assess safety, maximal aerobic capacity (treadmill test) was performed to control for the effect of exercise, and flow-mediated dilation (FMD) was assessed with sonography. FMD is a measure of endothelial function. A 1% increase in FMD was considered clinically relevant a priori.
The results of the blood analyses (complete blood count and metabolic panel) were within the normal range, and no adverse events were reported. The maximal aerobic capacity test verified that subjects’ normal exercise routine did not affect endothelial function. The 200 mg/day dose significantly increased FMD (3%) compared to placebo (P < 0.032) and the increase was considered clinically meaningful (˃1%). Inference statistics also indicated that for the 200 mg/day dose, clinical benefit was likely with a benefit-to-harm ratio of 546:1.
The authors conclude that 200 mg/day of CurcuWIN for 8 weeks clinically and significantly increased FMD in healthy, young adults. As FMD is inversely associated with future cardiovascular events in healthy subjects, the authors suggest that curcumin may be “a simple lifestyle strategy for decreasing the risk of cardiovascular diseases in individuals who are apparently healthy.” Further studies are needed to confirm whether the antioxidant and anti-inflammatory actions of curcumin are the mechanisms by which curcumin improves FMD. Limitations of this study include the small sample size, short study duration, and minimal reporting. Markers of inflammation and oxidative stress were not measured, and other CVD risk factors were not assessed or controlled for as variables in the statistical analyses. These results must be confirmed in a larger, longer-duration study using more rigorous methodology. The study was financially supported by OmniActive Health Technologies, the manufacturer of CurcuWIN.
Oliver JM, Stoner L, Rowlands DS, et al. Novel form of curcumin improves endothelial function in young, healthy individuals: A double-blind placebo controlled study. J Nutr Metab. 2016;2016:1089653. doi: 10.1155/2016/1089653.