In humans as in other animals, the “normal” process of aging can produce gradual declines in motor functions, such as balance, speed, strength, and coordination. These declines may be the result of a lifetime of accumulated wear-and-tear on the body. Similar, accumulated wear-and-tear on the brain may lead to gradual decline in cognitive functions such as the ability to learn new information and the ability to recall old information quickly on demand. One factor that may contribute to this brain aging is oxidation. Chemically, oxidation is the same process that rusts iron and makes sliced apples turn brown when exposed to the air. In living tissue, such as the brain, oxidation damages living cells.
Fortunately, there are other chemical compounds in nature that fight against or protect against oxidation. These compounds are called antioxidants, and there is now accumulating evidence that various antioxidants can help protect against the cognitive deficits observed in aging. Some of the most powerful and effective antioxidants, called flavonoids, are found in brightly-colored fruits and vegetables, particularly berries.
In the laboratory, mice fed standard diets supplemented with extracts from strawberry, blueberry, or spinach show much slower age-related cognitive decline than mice fed standard diets without these supplements. In other studies, aged mice fed blueberry, strawberry, cranberry, or grape extract show better balance and coordination than their peers who did not receive these extracts. There is even evidence that such extracts may help protect the brain against the ravages of Alzheimer’s disease. In at least one study, the benefits appeared within 24 hours after consumption of blueberry extract.
And in humans? There is no good reason to believe the same plant-derived chemicals that protect the aging mouse brain would not have similar benefits for the aging human brain. Several studies are now providing reasonable evidence that people who regularly eat two or more daily servings of antioxidant-containing fruits or vegetables show less age-related cognitive decline than people who less than one complete serving per day. Interestingly, dietary supplements (such as vitamin pills containing the antioxidants vitamin C, vitamin E, or beta-carotene), don’t seem to provide the same benefit as the whole foods do – which suggests that the fruits and vegetables may contain multiple naturally-occurring chemicals that work together for maximal effect.
The good news here is that the brain benefits seem to come after relatively modest intake – as little as 2 or more servings a day in humans – and to come quickly – within 24 hours of consumption in mice. So for a quick boost in cognitive function, and a long-term weapon against the ravages of age, berries (and other brightly-colored fruits and vegetables) may be powerful allies.
To read more about berries and brain health:
- J. A. Joseph and others (2007) “Fruit polyphenols and their effects on neuronal signaling and behavior in senescence.” In, Annals of the New York Academy of Sciences, vol. 1100, pp. 470-485
- D. Barros and others (2006). “Behavioral and genoprotective effects of Vaccinium berries intake in mice.” In, Pharmacology, Biochemistry and Behavior, vol. 84, pp. 229-234.
