Drinking five cups of coffee a day will help keep dementia at bay, studies suggest. - Jupiter Images

Keeping a brain healthy

Nutrition advice seems to change constantly. Those changes usually occur because we are constantly learning more about how nutrients work in the body. Modern laboratory tests and tracking methods allow researchers to study changes with greater precision. Then, animal and human studies follow changes that occur in volunteers over months or years. Sometimes new research findings appear in news stories and newspapers. Unfortunately, the stories seldom tell how the findings fit into our daily lives. Then, after a few years and more studies, the entire story may change. And, it is confusing.

By Claire Ku'uleilani Hughes, Ph.D., R.D.

For example, years ago, it was thought that vitamin E might protect the brain against aging. Thus, a human study involving 6,300 healthy, older female volunteers was conducted over a 10-year period. Researchers gave the women either a vitamin E tablet or a placebo (a harmless look-alike pill). None of the women knew whether they took the vitamin E or the placebo. After 10 years, researchers found no difference between the two groups of women in memory and other cognitive (thinking) tests. After 10 years, the original theory was not supported and we now know that vitamin E, alone, does not stop aging in the brain.

Vitamin E was discovered in 1922 when laboratory rats were fed a "purified diet" (mixture of separate nutrients) that used lard as the study's source of fat. The rats became infertile and did not reproduce. Vitamin E was found to be lacking in the "purified diet." Soon it became a nutrition fad for men to take supplemental vitamin E, until it was found the effects in man differed from the rats. Too much vitamin E supplementation in humans can cause gastrointestinal upset, interference with blood clotting and interference with absorption of other fat-soluble vitamins, i.e., vitamins A and K. We know that vitamin E acts as an antioxidant in the body, protecting against free radicals (aging factors) and a variety of toxins, i.e., heavy metals, lead and mercury, as well as a number of harmful compounds, like benzene and carbon tetrachloride and a variety of drugs. The usual dietary sources of vitamin E in the U.S. are vegetable oils (salad dressings, margarine), leafy green vegetables, wheat germ, whole grains, liver, egg yolks, nuts and seeds.

Where does coffee fall on the spectrum between "excellent" and "poor" food? Coffee's position has changed several times. Now it appears that coffee provides protection against aging in the brain. Studies in Portugal, Finland and the U.S. found that adults who consumed about five cups of coffee a day for a couple of decades had lower risks for developing Alzheimer's and dementia related to aging. Coffee drinkers did better on memory tests and other cognitive (thinking) tests. We know that caffeine is a stimulant, diuretic and anti-inflammatory. Four or five cups of coffee yield 400 to 500 milligrams of caffeine, which seems to be the daily level needed to protect against aging of the brain. Caffeine is abundant in coffee and much less in tea and chocolate. Only pregnant women and people with hypertension and heart problems are advised to avoid drinking large amounts of caffeine.

Another brain health theory was that three B vitamins: folic acid, B-6 and B12, could preserve the brain because they lower levels of homocysteine, a damaging amino acid. A human research project tested the B vitamins on 2,000 female health professional volunteers age 65 and older who had heart disease or at least three heart-disease risks. The women were given a placebo or a mixture of B-6, B12 and folic acid. After five or more years, the women showed no difference in verbal memory or other measures. However, folic acid does play a critical dietary role for young, childbearing woman as it prevents a serious birth defect, spinal bifida. Food sources of folic acid in the U.S. diet are lentils, asparagus, fortified grains, leafy green vegetables, legumes, seeds and liver.

After all the brain-aging studies, scientists offer recommendations for brain health that should start by middle age. These are: exercise 30 to 60 minutes a day, lose (or don't gain) excess weight, keep blood pressure under control, consider drinking more coffee if it doesn't make you jittery, and stay socially and mentally engaged.

It might also help to: get enough vitamin D, eat more leafy green vegetables and eat more seafood. Does this sound familiar?

These brain health recommendations help keep the entire body healthy. And, except for the coffee, the recommendations were part of the traditional life and diet of our Hawaiian ancestors. The ancient's work was highly physical; they were lean and muscular, and they ate and rested well. Today's Native Hawaiians are different. They don't eat enough leafy greens or other vegetables, their levels of physical activity can't begin to compare to their ancestors', and overweight and severely overweight populations are very evident. Change is needed to protect Hawaiian health and Hawaiian brains.