Dietary polyphenols have been the focus of major interest for their potential benefits on human health. Several preclinical studies have been conducted to provide a rationale for their potential use as therapeutic agents in preventing or ameliorating cognitive decline. However, results from human studies are scarce and poorly documented. The aim of this review was to discuss the potential mechanisms involved in age-related cognitive decline or early stage cognitive impairment and current evidence from clinical human studies conducted on polyphenols and the aforementioned outcomes. The evidence published so far is encouraging but contrasting findings are to be taken into account. Most studies on anthocyanins showed a consistent positive effect on various cognitive aspects related to aging or early stages of cognitive impairment. Studies on cocoa flavanols, resveratrol, and isoflavones provided substantial contrasting results and further research is needed to clarify the therapeutic potential of these compounds. Results from other studies on quercetin, green tea flavanols, hydroxycinnamic acids (such as chlorogenic acid), curcumin, and olive oil tyrosol and derivatives are rather promising but still too few to provide any real conclusions. Future translational studies are needed to address issues related to dosage, optimal formulations to improve bioavailability, as well as better control for the overall diet, and correct target population.

膳食多酚因其对人类健康的潜在益处而成为人们关注的焦点。已经进行了几项临床前研究，为它们作为预防或改善认知衰退的治疗剂的潜在用途提供了基本原理。然而，人类研究的结果很少且记录不充分。本综述的目的是讨论与年龄相关的认知衰退或早期认知障碍的潜在机制，以及对多酚进行的临床人体研究的现有证据和上述结果。迄今为止公布的证据令人鼓舞，但需要考虑对比结果。大多数关于花青素的研究表明，对与衰老或认知障碍早期阶段相关的各种认知方面都有一致的积极影响。对可可黄烷醇、白藜芦醇和异黄酮的研究提供了大量对比结果，需要进一步研究来阐明这些化合物的治疗潜力。其他关于槲皮素、绿茶黄烷醇、羟基肉桂酸（如绿原酸）、姜黄素和橄榄油酪醇及其衍生物的研究结果相当有希望，但仍然太少，无法提供任何真正的结论。未来的转化研究需要解决与剂量、优化配方以提高生物利用度以及更好地控制整体饮食和正确目标人群相关的问题。羟基肉桂酸（如绿原酸）、姜黄素和橄榄油酪醇及其衍生物相当有前景，但仍然太少，无法提供任何真正的结论。未来的转化研究需要解决与剂量、优化配方以提高生物利用度以及更好地控制整体饮食和正确目标人群相关的问题。羟基肉桂酸（如绿原酸）、姜黄素和橄榄油酪醇及其衍生物相当有前景，但仍然太少，无法提供任何真正的结论。未来的转化研究需要解决与剂量、优化配方以提高生物利用度以及更好地控制整体饮食和正确目标人群相关的问题。