Polyphenols and Fatty Acids May Benefit the Brain

Like other antioxidants, polyphenols eliminate free-radicals. Free-radicals are charged ions that are unstable, and therefore seek stability by adding or shedding electrons which oxidizes other molecules. Polyphenols neutralize free-radicals in the body, potentially reducing the effects of oxidation on biological systems. That is likely how they benefit health in general, and is surely the source of the benefit seen in a new study that found that a diet rich in polyphenols and polyunsaturated fatty acids (such as omega-3 fats) delayed the onset of Alzheimer's Disease in mice.

In the study, Spanish researchers fed mice either a standard diet or a food paste consisting of dried fruits, nuts, coconut, vegetable oils and a soluble fiber-rich flour that was high in polyphenols and fatty acids for 40 days. According to the researchers, 40 days in a mouse lifespan is equivalent to approximately 5 years in human lifespans.

The researchers used several biochemical and molecular analysis techniques to determine growth of new neurons or decline in neurons. The researchers said that "the analyses carried out in different brain regions demonstrated that those fed with [the food paste] had a significantly higher amount of stem cells, as well as new differentiated cells, in the olfactory bulb and hippocampus." The olfactory bulb and hippocampus are the areas of the brain most effected by Alzheimer's Disease.

In the second arm of the study, the researchers exposed brain cells to oxidants in vitro ("test tubes"). Using living hippocampal and cortical cell cultures, the researchers exposed cells to hydrogen peroxide, a powerful oxidant. The cells were exposed "as is", with either no pretreatment or pretreatment with the food paste. The untreated cell cultures had 40% of the cells in the culture die. The pretreated cells saw far less damage, completely preventing oxidative damage in some cases. After conducting the test with hydrogen peroxide, the researchers repeated the same test with amyloid beta, the compound that is a major component of the plaques associated with Alzheimer's Disease, and found similar results.

The researchers concluded that a diet rich in polyphenols and fatty acids "dramatically protected against damage caused by both hydrogen peroxide and [amyloid beta], demonstrating a potent antioxidant effect that could play a major role in the normal adult neurogenesis" and "could have a significant effect combating the cognitive function decline during both aging and neurodegenerative diseases such as Alzheimer's Disease."

While this is a study on mice and may not transfer to humans, it adds to the ever-increasing body of evidence that a diet rich in a wide variety of plant foods and the polyphenols they contain, combined with polyunsaturated fatty acids, may confer significant health benefits.

Learn more about antioxidant polyphenols here and fatty acids here.

1. Valente, T., J. Hidalgo, et al. (2009). "A Diet Enriched in Polyphenols and Polyunsaturated Fatty Acids, LMN Diet, Induces Neurogenesis in the Subventricular Zone and Hippocampus of Adult Mouse Brain." J Alzheimers Dis.