There's still no cure for Alzheimer's or known way to prevent it. But if you're worried about developing the disease, your doctor just might give you an unexpected prescription. She might urge you to exercise regularly, eat a diet rich in whole foods, and watch your weight. She might even recommend taking a language class or some dance lessons. Or having a fish dinner twice a week. Thanks to many recent studies, researchers now have several promising theories on preventing Alzheimer's. In fact, a report in the Annual Review of Public Health stressed that researchers are increasingly looking at Alzheimer's the way they do other chronic conditions in which lifestyle plays a role. Many feel that it's not too soon to take action -- especially if you have a family history that puts you at risk.

Obesity, high cholesterol, and high blood pressure all significantly raise the risk of Alzheimer's, reported researchers at the 9th International Conference on Alzheimer's Disease and Related Disorders in 2004. The Swedish and Finnish researchers followed a group of 1,500 older subjects for an average of 21 years. A combination of all three factors increased the risk by six-fold.

These same risk factors also contribute to heart disease, the number-one killer in this country. Doctors have long encouraged patients to protect themselves from heart disease with regular exercise and a healthy diet. Now there's growing evidence that a heart-healthy lifestyle may also be good for the brain.

Even if you're not technically overweight, having excess belly fat may considerably increase your risk of Alzheimer's disease. A long-term study of more than 6,500 people published in the March 26, 2008, online issue of Neurology, found that those who had the most abdominal fat between the ages of 40 and 45 were about three times more likely to develop dementia in later life than those with the least.

More and more evidence suggests that people who exercise regularly into their later years are less likely to develop Alzheimer's: In a recent study, older women who were physically active during the six to eight years of follow-up were less likely to suffer from impaired memory and reasoning. In addition, several case-control studies suggest that a sedentary lifestyle is a risk factor for the disease.

But it's never too late to get started -- exercising in midlife can significantly reduce your risk of Alzheimer's, especially if you're at genetic risk for the disease. Swedish researchers, for example, studied the health of nearly 1,500 people aged 65 to 79 whose lifestyle had been monitored for almost 35 years. In a study released in a 2005 issue of The Lancet Neurology, they reported that older people who exercised at least twice a week had approximately a 60 percent lower risk of suffering from Alzheimer's and dementia than their less active peers. Carriers of the Apo-E gene, which puts people at high risk of developing Alzheimer's, reaped the largest benefits. Exercise may ward off Alzheimer's by boosting blood flow to the brain and helping protect blood vessels there, researchers speculated.

And even a little exercise may yield tremendous gains. In a recent U.S. study involving more than 1,700 adults followed over a six-year period, adults over 65 who exercised for 15 minutes three times a week reduced their risk for dementia by one-third.

"This study adds to growing evidence that moderate exercise is the closest thing we have to a magic wellness bullet for everyone," said William Thies, vice-president of the Alzheimer's Association for medical and scientific affairs, in a press release following the report. "Moderate physical activity has all kinds of benefits and almost no downside."

If you don't enjoy the thought of working out, consider this: A recent study that extolled the possible virtues of board games and reading to prevent cognitive decline also found that a certain physical activity -- dancing -- was especially valuable for preventing Alzheimer's. Whether it's a waltz, salsa, cajun two-step, or hip-hop, dancing seems to be good medicine.

As recently reported in the newspaper of the American Medical Association, a healthy diet may turn out to be a strong defense against Alzheimer's. A four-year study of 815 Chicago seniors published in the Archives of Neurology found that a diet high in artery-clogging saturated fat doubled the risk of the disease. (A diet high in trans fats was also linked to a strong increased risk.) At the same time, a diet high in unsaturated vegetable fats -- such as those found in vegetable oils -- lowered the risk.

Fish -- a rich source of omega-3 fatty acids -- may turn out to be particularly effective for lowering the risk of developing Alzheimer's. A study in the Archives of Neurology compared the consumption of tuna, fish sticks, and other seafood meals among the Chicago seniors in the Alzheimer's study. Researchers found that those who ate one serving or more of fish each week had a 60 percent lower risk of developing Alzheimer's than those who seldom or never ate fish.

It's always a good idea to eat healthy, and B vitamins are an essential part of a well-balanced diet. B vitamin sources include whole grains (such as wheat and oats), eggs, poultry, dairy foods (like yogurt and milk), green leafy vegetables, beans, and peas.

But whether or not these foods can prevent or stop the progression of Alzheimer's is still debatable. Some recent studies have found that folate and other B vitamins may help slow mental decline as people age. A small study published in the American Journal of Clinical Nutrition found that men aged 50 to 85 who had more folate in their diets did better on a variety of cognitive tests over a three-year period. Other research suggests that low levels of folate, B12, and B6 are also a risk factor for Alzheimer's disease.

Heart researchers have found that an amino acid called homocysteine -- normally broken down in the body with the aid of folic acid and two B vitamins -- can accumulate in the blood if the breakdown isn't completed. In the Framington Heart Study, researchers measured homocysteine levels in more than 1,000 people whose average age was 76. After eight years, adjusting for risk factors including age, smoking, blood pressure, alcohol use, and diabetes, they found that people with average blood levels of the amino acid were only half as likely to develop Alzheimer's as those with levels in the top 15 percent.

However, a 2008 study published in the Journal of the American Medical Association examined people already suffering from Alzheimer's who had normal levels of folate, B12, and homocysteine in their blood. The researchers gave study participants extra folate or B vitamins and, in spite of a 31 percent drop in homocysteine levels, found that there were no significant changes in their cognitive decline or behavior.

Other plant chemicals, such as quercetin in apples (mostly the peels) and red onions, beta-carotene, and polyphenols (found in red wine) may protect against dementia.

In some people, having high blood pressure may also set the stage for memory loss. According to a study from the National Institute on Aging, people in their mid-50s and older with high blood pressure scored lower on memory tests than people with normal pressure. Other studies, however, have found no association between high blood pressure and cognitive decline.

The possible connection between Alzheimer's and vascular disease, however, intrigues researchers. According to the Progress Report on Alzheimer's Disease, issued by the Alzheimer's Disease Education and Referral Center, "Cerebrovascular disease is the second most common cause of dementia and there is some evidence that brain infarctions (strokes) and AD may possibly be linked. Although major strokes have obvious consequences, small ones may go undetected clinically." According to the report, another lifestyle factor that may turn out to influence Alzheimer's is blood cholesterol levels. Among other things, it says, scientists have found that high blood cholesterol levels may increase the rate of plaque deposition in laboratory mice.

"It's definitely a good idea to keep blood pressure under control if you already have memory problems, because poorly controlled hypertension can lead to multi-infarct dementia and therefore worsening memory," says Dr. Michael Potter, an associate professor and attending physician at the University of California at San Francisco Medical Center. "This may be especially important in people who already have poor memory due to Alzheimer's."

If you've ever felt guilty for spending a few "unproductive" hours on a board game or a good book, rest assured: You probably weren't just wasting time. According to the latest research, activities that stimulate the mind just might help ward off dementia. In a five-year study of 469 seniors published in the New England Journal of Medicine, researchers found that playing board games, reading, and playing a musical instrument all lowered the risk of dementia. In addition, subjects who solved four crossword puzzles a week were about 50 percent less likely to develop dementia than those who tried just one puzzle each week.

Though doing mental exercises will not necessarily prevent dementia, the New England Journal of Medicine's study is one of several to suggest that active minds may help provide extra protection against it. French researchers have found that knitting, gardening, doing odd jobs, and traveling all help keep the mind sharp and reduce the chances of all types of dementia. Other studies suggest that higher education and a mentally challenging job may also protect against the disease. Researchers believe that mind-stimulating activities help to create a rich network of connections between brain cells. If some of these connections break down, the theory goes, others will take over.

Of course, the research on mental activity and Alzheimer's prevention is not conclusive. The association may simply boil down to this: older people may be more likely to play chess or engage in mentally challenging jobs because they don't have Alzheimer's, whereas those who've unknowingly experienced early, insidious changes in the brain caused by Alzheimer's may withdraw from those activities at an earlier age. Likewise, the evidence linking diet and Alzheimer's prevention is based partly on peoples' memories of what they've eaten -- not the most reliable source of information.

But whether or not these lifestyle changes prevent dementia, they'll help keep you healthy in other ways. So eat well, stay active, and keep your mind busy. It's more than just a promising way to avoid Alzheimer's. It's a good way to live.

-- Chris Woolston, MS, is a health and medical writer with a master's degree in biology. He is a contributing editor at Consumer Health Interactive, and was a staff writer at Hippocrates, a magazine for physicians. His reporting on occupational health earned him an award from the Northern California chapter of the Society of Professional Journalists.

References

Last updated March 3, 2009
Copyright © 2003 Consumer Health Interactive

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