Plant Foods Rich in Antioxidants and Human Cognition: A Systematic Review

Abstract

Oxidative stress can compromise central nervous system integrity, thereby affecting cognitive ability. Consumption of plant foods rich in antioxidants could thereby protect cognition. We systematically reviewed the literature exploring the effects of antioxidant-rich plant foods on cognition. Thirty-one studies were included: 21 intervention, 4 cross-sectional (one with a cohort in prospective observation as well), and 6 prospective studies. Subjects belonged to various age classes (young, adult, and elderly). Some subjects examined were healthy, some had mild cognitive impairment (MCI), and some others were demented. Despite the different plant foods and the cognitive assessments used, the results can be summarized as follows: 7 studies reported a significant improvement in all cognitive domains examined; 19 found significant improvements only in some cognitive areas, or only for some food subsets; and 5 showed no significant improvement or no effectiveness. The impact of dietary plant antioxidants on cognition appears promising: most of the examined studies showed associations with significant beneficial effects on cognitive functions—in some cases global or only in some specific domains. There was typically an acute, preventive, or therapeutic effect in young, adult, and elderly people, whether they were healthy, demented, or affected by MCI. Their effects, however, are not attributable only to anti-oxidation.

Bioactive Foods Decrease Liver and Brain Alterations Induced by a High-Fat-Sucrose Diet through Restoration of Gut Microbiota and Antioxidant Enzymes

“…Studies in individuals and animals have demonstrated that consumption of a high fat and sugar diet causes inflammation which spread into the brain, affecting key components of cognition [ 1 ]. Several factors have been involved in the development of cognitive dysfunction, including dysbiosis in the gut microbiota [ 2 ], increase in oxidative stress in the central nervous system [ 3 ], and possibly other metabolic abnormalities in other organs of the body, particularly in the liver. In obesity, which is often associated with consumption of a high fat and sugar diet, an imbalance in the gut microbiota was found to be associated with impaired gut barrier function and translocation of lipopolysaccharide (LPS) and inflammation in various tissues, such as liver, adipose, and brain tissue [ 4 , 5 , 6 ].…”

“…Furthermore, a crosstalk between adipose tissue and the brain was suggested to contribute to cognitive deficits [ 6 ]. Several dietary guidelines have focused on the consumption of antioxidant-rich plant foods, which may be effective in maintaining cognitive health [ 3 ]. Thus, the purpose of the present work was to develop a combination of functional foods that included nopal, soy protein, turmeric, and chia seed oil (bioactive foods) to modulate gut microbiota and enhance antioxidant activity to improve cognitive function.…”

Effect of Nutrition on Age-Related Metabolic Markers and the Gut Microbiota in Cats

“…Oat groats were added to the test food to serve as a source of beta-glucan that could reach the colon and be fermented by saccharolytic microbes. The fiber blend of broccoli and tomato pomace was to serve as a source of natural antioxidant polyphenols known to have a protective effect against age-associated cognitive decline [17,18]. Both foods were supplemented with vitamins, minerals, and palatability enhancers.…”

Differential Effects of Polyphenols on Insulin Proteolysis by the Insulin-Degrading Enzyme

“…An attractive alternative to the development of small-molecule inhibitors of IDE is a nutritional strategy that implicates polyphenols. Polyphenols are naturally occurring compounds that possess antioxidant [ 18 , 19 , 20 ], anti-inflammatory [ 19 , 20 , 21 ], and anti-amyloidogenic [ 22 ] properties. As such, polyphenols have been hypothesized to prevent T2D [ 23 ] and AD [ 24 ].…”