As you age, the cells in your central nervous system may decline in function, even though you have no degenerative brain diseases such as Alzheimer’s or Parkinson’s. One possible reason: With age, the neurotransmitter receptors on cell membranes lose sensitivity, so they no longer process messages as efficiently. An underlying cause of that diminution in communication among cells appears to be both increased attacks by free radicals and a diminished supply of protective antioxidants. A research team headed by James A. Joseph at Tufts theorized that they might be able to block that normal age-related loss of brain function by feeding laboratory animals spinach, strawberries, or vitamin E to buck up antioxidant defenses. It was a stunning idea with a remarkable outcome and exciting implications.
The animals started eating four different diets (control or ordinary, spinach, strawberries, or vitamin E) at six months of age or about age twenty in human terms. They continued on the diets for eight months—into middle age. When the rats reached fifteen months (forty five to fifty years in human terms), an age when their memories were expected to decline, they were put through a battery of tests. One test, in which the animals paddle around a deep pool to find a submerged platform where they can rest, measures changes in long-term and short-term memory.
No question, animals fed spinach for about half their lifetimes showed superior long-term memory; they remembered where to find the hidden platforms much better than those fed the other diets, meaning the spinach-eaters retained more of their learning ability. Next best at boosting memory: strawberries.
To see if extraordinarily vigorous memory was reflected in brain cell biology, Dr. Joseph examined specific areas of the animals’ brains, particularly the region that controls cognitive function—the neostriatum. Cells in this area become insensitive or sluggish in releasing chemical messengers, such as dopamine, as animals and humans age. In fact, by middle age, rats’ striatal cells have lost about 40 percent of their ability to respond. And, not unexpectedly, this did happen in rats fed an ordinary “control diet.”
But, amazingly, animals fed spinach, strawberries, and vitamin E did not lose such brain cell power; they released dopamine as they did when younger. They, indeed, scored twice as high in performance tests of their striatal brain cells as those on “control diets.” Most effective of all in protecting brain cells in this aspect was spinach. The spinach-eating rodents also scored best in a test of nerve cells in the cerebellum, an area of the brain that controls balance and coordination.
For the first time, scientists proved that eating spinach and strawberries had a dramatic impact in averting the expected decline in brain function and memory that comes with age. Dr. Joseph credits the foods’ long-term antioxidant activity that prevented brain cell damage. But he also notes that the flavonoids in the spinach and strawberries can also increase fluidity of brain cell membranes (like fish oil does), thus suggesting another way of blocking age-related brain deficits.
Of course, the big implication is that if spinach and strawberries work such miracles in the brains of small mammals, they will also do the same in the brains of large mammals, namely humans. How much spinach or strawberries did it take to prevent decline in brain function? Not much. The human equivalent of only a pint of strawberries a day or a large spinach salad. Dr. Joseph contends that “nutritional intervention with fruits and vegetables may play an important role in preventing the long-term effects of oxidative [free radical] stress on brain function.”
Interestingly, vitamin E, a known strong antioxidant, had only a moderate effect in protecting animals’ brains from decline. It was less effective than spinach or strawberries. Dr. Joseph speculates that the foods worked better because they possess multiple antioxidants that interact to produce a synergistic effect (a more potent effect combined than each alone).
BOTTOM LINE: To save your brain from disintegration, you need to eat lots of berries, spinach, and other deeply colored fruits and vegetables with high antioxidant activity.