Dopamine and berries

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Using an imagining technique known as PET, scientists at Brookhaven National Laboratory discovered an aging-related decline in dopamine D2 receptors. This receptor loss makes dopamine less available to brain cells. The exciting part of this finding was a newly discovered connection between dopamine and glucose metabolism. Lower dopamine activity apparently leads to a decrease in neural glucose metabolism, which results in less energy production in the brain. This decrease in energy output was found to be regional, affecting the frontal lobes and the anterior cingulate gyrus.

When a decrease in metabolism leads to an energy shortage, cells cannot function properly. Hence the observed cognitive deterioration related to lower activity in the frontal lobes, an area involved with thinking, learning, memory and the ability to coordinate multiple tasks. The cingulate gyrus plays an important role in governing attention span, the ability to focus, mood and impulse control.

The study was carried out on 37 healthy volunteers, ranging in age from 24 to 86 years old. The researchers discovered that we tend to lose dopamine D2 receptors at the rate of about 6% per decade. This is considered a significant decline, particularly in the light of the enormous importance of dopamine, our "reward" neurotransmitter, known to be related to pleasure, motivation, zest for life, ambition and sex drive, as well as to motor function. Lower availability of dopamine in critical brain regions results in cognitive deterioration, less ability to concentrate, and a tendency toward depression.

In the Brookhaven study, the effects of dopamine availability on glucose metabolism remained even after the effects of age were accounted for. This suggests that dopamine increases brain metabolism regardless of age.

It has been known for a long time that dopamine is an energizing, stimulatory neurotransmitter. Now its mechanism of action has been further elucidated. Either an increase or decrease in energy output by brain cells produces a far-reaching cascade of events. By increasing brain energy production, dopamine exerts an extremely important anti-aging effect, since maintaining youthful brain function is a key factor in longevity. One clinical user of PET testing for brain function, Dr. Eric Braverman, believes that when the brain activity of a relatively young person is slowed down as if due to premature brain aging, this is a grim predictor of susceptibility to serious degenerative disorders. In fact, the correlation between depression and higher morbidity and mortality is well established.

Dopamine also stimulates the pituitary to release growth hormone, which may be an important part of its anti-aging benefits. Dopamine also appears to be involved in lowering insulin levels (insulin rises with aging), and in improving the immune response. The production of dopamine is known to decrease with aging, perhaps due to the oxidative damage to cells that synthesize dopamine. Now it appears that we also lose dopamine receptors as we age, which intensifies the problem.

How does this relate to the potent antioxidant polyphenols found in blueberries and bilberry extract? Dr. Joseph found an increased ability to release dopamine in certain types of brain cells in rats fed blueberry extract. Only the rats fed blueberries (and not spinach, strawberries, or vitamin E) showed a significant reversal in motor dysfunction that correlates with aging and dopamine deficiency. The implications for anti-aging benefits are far-reaching. However, much research still needs to be done to further clarify the connections between dopamine loss and aging.

Sources: "Brookhaven lab collaboration determines how aging affects brain chemistry." eurekalert.org, December 1999 (the study was published in the January 2000 issue of The American Journal of Psychiatry,' Khalsa DS, Brain Longevity, Warner Books 1997. The study also served as a basis for a lecture by Dr. Eric Braverman at the A4M Conference, Las Vegas 1998.)

Life Extension Foundation.

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