Plant Foods and Brain Aging: A Critical Appraisal

Abstract

In the 21st century, human aging will be one of the biggest challenges for most societies throughout the world. The decline in human fitness is a typical hallmark of the aging process. Aside from the cardiovascular system, the brain most often suffers significantly from the life-long impact of stressors, such as reactive oxygen and nitrogen species. Oxytosis, i.e. oxidative stress-induced cell death, has been identified to play a major role in the development and onset of chronic diseases. Foods, especially of plant origin, are rich in antioxidants and numerous in vivo data suggest that a diet rich in fruits and vegetables supports the maintenance of animal and human health. These beneficial effects also extend to the central nervous system, which, due to the presence of the blood-brain barrier, tightly controls the influx of metabolites and nutrients. In earlier studies the impact of antioxidant vitamins, such as alpha-tocopherol and ascorbic acid, on brain health has been of interest. Recently, the focus moved to assessing the potential of unsaturated fatty acids and secondary plant metabolites, particularly of polyphenols, to act as neuroprotectants. Considerable experimental evidence suggests that polyphenols and other plant-derived bioactivities affect animal and human brain function not only by directly lowering oxidative stress load but also by modulating various signal transduction pathways.

Natural polyphenol disposition via coupled metabolic pathways

“…Polyphenols have gained increasing interest in scientific research and in public media. Some polyphenols, especially flavonoids that are abundant present in vegetables, fruit, tea, flowers, wine, and soybean, have been associated with numerous beneficial biological effects including free-radical scavenging, enhancement of detoxifying enzymatic activities, and inhibition of cellular proliferation [16][17][18][19][20][21]. However, the development of polyphenols into successful chemopreventive agents is highly dependent on both their respective intakes and their bioavailability, which varied widely among polyphenols and between subjects.…”

“…1A and 1B) such as flavonoids [11], isoflavonoids [13], resveratrol [14], curcumin [15] and tea polyphenols [16] have gathered significant interests in scientific research and public media. The aura associated with this class of compounds is that they are supposed to be non-toxic and that they have significant chemopreventive effects ranging from antiageing to cancer prevention [11,[16][17][18][19][20][21], many if not all of these problems or diseases lack conventional pharmaceutical products. For example, isoflavones such as genistein and daidzein found in soy have significant effects on bone health among postmenopausal women, together with some weak hormonal effects.…”

Bioactive Compounds in small Fruits and their Influence on Human Health

“…The antimicrobial activity of berry extracts is evidently a synergistic effect of various phenolic compounds, many of which are still unidentifi ed. Also other bioactive compounds in plant extracts, alone or in combination with phenols, might be responsible for antimicrobial effects (44,45,60,78).…”

Metabolomic approach to identifying bioactive compounds in berries: Advances toward fruit nutritional enhancement

“…With regard to the small Mwt, soluble components the health benefits are believed to be attributable to are vitamin C (Vit. C) [12,13], soluble fibre [14,15] and the chemically diverse polyphenols [16][17][18][19].…”