Clinical Nutrition Research Centre, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, Australia.
Division of Research and Innovation, University of Southern Queensland, Raceview, Australia.
Adv Nutr. 2018 Mar 1;9(2):105-113. doi: 10.1093/advances/nmx013.
The rate of cognitive decline in the elderly is highly variable. One potential factor contributing to accelerated cognitive decline is chronic systemic inflammation, because it has been linked to cognitive impairment and increased dementia risk. Certain lifestyle factors, such as excess body weight and sedentary behavior, can exacerbate a proinflammatory state in older adults, resulting in chronic low-grade inflammation. Supplementing the diet with curcumin, an anti-inflammatory polyphenolic compound from the curry spice turmeric, is a potential approach to prevent accelerated cognitive decline by counteracting chronic inflammatory processes. Although the anti-inflammatory effects of curcumin are well established, the potential cognitive benefits of curcumin were discovered more recently. Several animal and epidemiologic studies on the effect of curcumin supplementation on cognition showed promising results; however, randomized controlled trials in humans are limited. In this review, we identified 5 randomized controlled trials, of which only 2 observed a beneficial effect of curcumin supplementation on cognition by improving working memory. By critically examining the methodologies of those studies, we identified some limitations, one of which is that none of the studies explored the possibility that anti-inflammatory mechanisms were mediating cognitive benefits (i.e., no study tested participants with low-grade inflammation or measured inflammatory biomarkers). Other factors influencing the likelihood of conclusive outcomes include choice of study population (cognitively unimpaired compared with impaired), study duration, curcumin dose and its bioavailability, and neurocognitive test battery. On the basis of these findings, we offer recommendations for future studies to examine the potential cognitive benefits of curcumin in humans, which include evaluating its effects on cerebral endothelial vasodilator function and boosting its cognitive effects by combining it with long-chain omega-3 (n-3) fatty acids.
老年人认知能力下降的速度差异很大。导致认知能力加速下降的一个潜在因素是慢性系统性炎症，因为它与认知障碍和痴呆风险增加有关。某些生活方式因素，如超重和久坐不动的行为，会使老年人的促炎状态恶化，导致慢性低度炎症。在饮食中补充姜黄素，一种来自咖喱香料姜黄的抗炎多酚化合物，是一种通过对抗慢性炎症过程来预防认知能力加速下降的潜在方法。尽管姜黄素的抗炎作用已得到充分证实，但最近才发现姜黄素对认知可能有好处。一些关于姜黄素补充对认知影响的动物和流行病学研究显示出有希望的结果；然而，人类的随机对照试验是有限的。在这篇综述中，我们确定了 5 项随机对照试验，其中只有 2 项观察到姜黄素补充通过改善工作记忆对认知有有益的影响。通过批判性地检查这些研究的方法学，我们发现了一些局限性，其中之一是没有一项研究探索抗炎机制是否介导认知益处（即，没有研究测试有低度炎症的参与者或测量炎症生物标志物）。其他影响得出明确结论的可能性的因素包括研究人群的选择（与认知受损者相比，认知未受损者）、研究持续时间、姜黄素剂量及其生物利用度，以及神经认知测试组合。基于这些发现，我们为未来的研究提供了建议，以检查姜黄素对人类认知的潜在益处，其中包括评估其对大脑内皮血管舒张功能的影响，并通过将其与长链 omega-3（n-3）脂肪酸结合来增强其认知作用。
