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The connection between heart health and Alzheimer’s that nobody talks about

National Public Radio’s Daniel Schorr is the kind of guy who would make any aging news junkie stand up and cheer. On July 19, 2006, Schorr turned 90, yet he still performs at an undiminished level in one of the most demanding jobs in today’s media. He began his career at CBS News in 1953 and joined NPR as its senior news analyst at 69, an age at which many of his colleagues had long been put out to pasture. In his position, he has to pack his cerebral hard drive with massive amounts of information, and then he has to possess the Pentium-esque agility to mine that information for insights worthy of NPR’s highly educated listeners. Schorr pulls off the challenge with effortless grace.

But Schorr’s beat-the-clock competence calls attention to an issue with implications for everything from lifestyle choices to national social policy. Because of advances in medical science, people are living much longer than ever before. The US Census Bureau projects that the number of elderly aged 85 and older will more than triple from about 4 million today to about 14 million by 2040. That includes many of us reading this article.

Unfortunately, we won’t all age like Daniel Schorr. Some of us will live out our dotage without all our marbles. Alzheimer’s disease or other forms of dementia will rob us of our intellectual abilities, our short-term memories, our personalities, and even the ability to recognize the people we love the most. The prospect is terrifying—especially because researchers don’t yet understand exactly what causes Alzheimer’s (or dementia) or how to prevent it or even slow the destruction.

But they are making progress on those fronts. Lots of indicators point toward a health regimen that may preserve your mental capacities well into old age, and perhaps indefinitely. The even better news? If you’re already practicing a healthy lifestyle as that concept is currently understood, you may be most of the way home.

A New Understanding

No one fully knows what causes Alzheimer’s but the research community is beginning to feel it’s at least driving in the right neighborhood. Current thinking suggests that the disease results from a complex dance between several partners: lifestyle factors such as food choices, environmental factors such as educational level and previous head injuries, and a person’s inherited genes. Recently, scientists have focused on the strong link between cardiovascular disease and Alzheimer’s. Mounting evidence suggests that cardiovascular risk factors such as high cholesterol, high blood pressure, and poor dietary habits also significantly boost the risk for Alzheimer’s in particular and cognitive decline in general.

For instance, a Finnish study involving nearly 1,500 subjects found that high cholesterol and blood pressure were even more tightly tied to Alzheimer’s than the so-called APOE-4 gene, the genetic risk factor associated with the most common form of the illness. Other studies corroborate this connection by showing that controlling cholesterol and blood pressure levels helps keep the brain healthy.

In a similar vein (so to speak), researchers are also exploring a connection between diabetes and Alzheimer’s. They’ve known for a while that having diabetes nearly doubles an individual’s chance of developing Alzheimer’s. Diabetes, itself a cardiovascular risk factor, can create vascular problems, and vascular disease increases the risk of Alzheimer’s. Some scientists have also proposed that Alzheimer’s may be a third form of diabetes (besides Type 1 and Type 2) that directly leads to brain cell death and other abnormalities associated with Alzheimer’s. And poorly controlled diabetes—with wildly fluctuating blood sugar levels—is also thought to heighten the risk of getting Alzheimer’s.

The most current study in this area points to increased Alzheimer’s risk for people with high blood sugar or “pre-diabetes.” Elevated blood sugar sends an early signal that Type 2 diabetes lurks on the horizon. The social implications for the US look ominous given the fact that many more people currently suffer from pre-diabetes than Type 2 diabetes, which currently runs rampant in this country, the end result of the obesity epidemic. The diabetes findings, from a Swedish study, were presented at the Tenth International Conference on Alzheimer’s Disease and Related Disorders, a major conference held in Madrid in July 2006. The essential message to the public is clear: If you protect yourself against diabetes by controlling your weight, exercising, and eating a healthy diet (see below), you may as a bonus preserve your gray matter, as well.

One last uncomfortable thought: Scientists now recognize that Alzheimer’s can be present in the brain without seeming to affect a person’s thinking or behavior. “You could be completely normal and have that pathology,” says leading Alzheimer’s researcher David Bennett, MD, director of Rush University’s Alzheimer’s Disease Center, “so I think that the biggest thing that is changing is the recognition that the disease is a much larger problem than has historically been recognized.”

Keeping Dementia at Bay

As researchers’ understanding of Alzheimer’s and other forms of cognitive decline grows, so does their confidence in a group of lifestyle options that may ratchet down the risk for these diseases. Students of healthy living will find the laundry list that follows pretty darn familiar, at least those items related to diet and exercise. When it comes to these two lifestyle categories, one size seems to fit nearly all.

For instance, a previous article in this magazine (Fall 2006) suggested that a heart-healthy diet not only offers protection against cardiovascular disease but also colon cancer, diabetes, and prostate cancer. Add Alzheimer’s to the pile. Here are the details, plus the rest of the easy steps that can, as the Alzheimer’s Association puts it, “maintain your brain.” Healthy Eating Low fat. Low cholesterol. Dark-skinned veggies and fruit. Cold-water fish such as halibut, mackerel, salmon, trout, and tuna. Nuts such as almonds, pecans, and walnuts. If you’ve studied healthy eating and applied what you’ve learned, you’re already eating this way. And recent research suggests that your brain will thank you.

For example, Finnish researchers presenting at the above-mentioned Madrid conference discovered that subjects whose diets included loads of saturated fat (mainly fats from meat and dairy products) performed less well on memory or thinking tests and had double the risk of mild cognitive impairment, which can foreshadow Alzheimer’s. On the other hand, people who consumed more polyunsaturated fats or fish did better on tests of memory, coordination, reasoning, and decision-making.

Many scientists believe the antioxidant properties of the fruits and vegetables contribute to brain health. Same with the nuts, which contain the antioxidant vitamin E. And the fish teem with omega-3 fatty acids, which the human body apparently needs but doesn’t make.

Some research suggests that the B vitamins, especially B6, B12, and the folates, also provide protection, but the results are confusing. In observational trials, in which researchers gather data on a group of healthy people over a span of years without any intervention, the vitamins seem to have had a beneficial effect. In interventional trials, that is where the researchers give the subjects supplements, the vitamins have either shown no effect or, in the case of B6, an unexpectedly negative one. What seems to matter most is the food on your plate, not the pills in the bottle. “I wouldn’t particularly advise the vitamin supplements because I don’t think there is any great evidence that if you eat a balanced diet that vitamin supplements would provide anything else,” says Hugh Hendrie, MB, ChB, DSc. Hendrie recently headed a comprehensive review of research on cognitive and behavioral changes in aging people for the NIH.

Exercise

Well-regarded research led by Eric Larson, MD, MPH, of the GroupHealth Center for Health Studies in Seattle, Washington, has shown that people who exercise regularly lower their risk of Alzheimer’s disease and other forms of dementia, or at least delay the onset by several years. People who have Alzheimer’s also do better with exercise such as walking—it slows the rate of physical decline and seems to prevent some behavioral problems associated with the illness, such as agitation. “Just doing things that keep a person active and engaged and allow their muscles to stay as strong as they can at the end stages of life in many cases seems to improve their lives,” says Larson.

Of course, exercise also helps stave off cardiovascular disease, weight gain, diabetes, and stroke, all of which are themselves risk factors for cognitive decline, including Alzheimer’s. Keep in mind, though, that the research showing the beneficial effects of physical activity pertains only to leisure-time exercise. In studies of work-related physical activity, no similar impact has shown up.

Mental Stimulation

A widely held line of thinking among Alzheimer’s researchers called the “cognitive reserve” hypothesis goes like this: If you build up your brain through mental stimulation throughout your life and keep mentally active, you also build a bulwark against the illness—so much so, in fact, that even if you have Alzheimer’s-type damage in your brain, it may not show up in your actual mental abilities or behavior.

Not surprisingly then, higher levels of education are also associated with significantly better protection against the disease. Larson has done studies that compare largely uneducated, rural populations in Taiwan to populations in the US and Japan, where the education level is high. Dementia occurs 10 to 20 years earlier in the rural Taiwanese than in comparably aged residents of the other two countries, he says. In fact, education offers so much protection, well-educated folks can more or less become couch potatoes late in life and not suffer that much or at all for it. In research with older subjects doing crossword puzzles, playing Go, and the like, it’s the less-educated, blue-collar types who show the most benefit.

Social Interaction

People with active social lives seem to age better with respect to dementia. The effect compares to that produced by education, says Bennett: “The larger your social network, the less effect a unit of Alzheimer’s pathology.”

The entire Alzheimer’s and dementia picture is clouded with paradox. As Bennett puts it, “Almost everyone [of a certain age] has the pathology of Alzheimer’s disease but in fact some people’s memory is quite well preserved in spite of having a lot of pathology, and other people’s memory is impaired despite having just a little bit.” You could argue then that whether or not you get Alzheimer’s boils down to luck. But too many studies suggest otherwise. If you eat well, exercise—both your body and your brain—and take part in a wide mix of social activities, you stand a better chance of dodging Alzheimer’s and dementia—and you’ll be a healthier and happier old codger to boot.

By Allan Reder

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