Those episodes of forgetfulness—the name you can’t recall, the missing keys, the quart of milk you didn’t buy—loom larger as you pass your fiftieth birthday. The brain does change with age. Gradually, it begins to process information more slowly. You don’t learn and retain new facts as well as you used to, and it takes longer to summon things out of the memory bank. This can be unsettling, but it is quite normal and does not usually signal the onset of disease. In fact, it has been shown that the brain keeps making new cells, and connections among them, throughout life: retrieval from memory does slow, but the ability to learn is still there.
Dementia, including Alzheimer’s disease, is not a normal part of aging, though the risk rises rapidly in the very old. Then there is the gray area known as mild cognitive impairment (MCI), which involves memory problems more severe than those seen with normal aging, but less severe than dementia; people with MCI can still do their daily activities on their own. It’s estimated that 20% of people over 70 have MCI, and about 5% of those with MCI progress to dementia each year, according to a recent British review of 15 long-term studies. But many people with MCI remain stable for years, and some actually improve, thanks to treatment of conditions that can impair memory and cognition, such as depression, hypothyroidism, or vitamin B12 deficiency.
Anyone who promises you guaranteed ways to protect and preserve your mind and prevent dementia is either trying to sell you something or suffering from wishful thinking. Still, scientists all over the world have been working to solve the mysteries of the aging brain. Why do some people experience greater “cognitive decline” than others, and why do some develop dementia? Your genes clearly play a large role. One important thing researchers have learned is that what helps your cardiovascular system also seems to benefit your brain and helps protect it from disease.
Here’s the latest thinking:
Exercise. Research has consistently found that staying physically active is a key to preserving brain function. Studies have shown that older people who get regular exercise are less likely to decline mentally and/or develop dementia. Aerobic exercise such as running or cycling seems especially beneficial, but any activity can help, including strength training and ballroom dancing (these two were the focus of recent studies). Exercise probably benefits the brain just as it helps the cardiovascular system—by lowering blood pressure, improving blood flow, controlling weight, and improving cholesterol levels and blood sugar. In addition, brain scans show that aerobic exercise can actually improve brain activity and produce new brain cells and connections between them.
Mental activity and lifelong learning. Use it or lose it: the old adage also applies to mental ability. Read, take a class, work a puzzle, pursue an absorbing hobby—whatever makes you think. Exercising the brain can enrich your life, banish boredom, help treat depression, confer a sense of accomplishment, and be a way to make new friends—all good for mental health. A few recent studies on commercial “brain fitness” programs—including one in the Journal of the American Geriatrics Society in April—have yielded promising results, but usually the benefits are short-term and involve a limited set of mental skills.
Controlling blood pressure. Untreated hypertension can increase the risk of cognitive decline as well as dementia. Lowering high blood pressure is almost certainly as good for the brain as for the heart—whether you control your blood pressure by diet, exercise, and weight loss, or by taking medication.
Preventing/controlling diabetes. The evidence that Type 2 diabetes (and possibly even prediabetes) increases the risk of cognitive decline and dementia is strong. This may be because diabetes damages blood vessels, including those in the brain. Also, the high levels of insulin characteristic of Type 2 diabetes appear to go along with declining memory.
Weight control. Obesity, especially in the abdomen, has been linked to an increased risk of dementia. Since obesity often goes along with other factors that can increase dementia risk—such as diabetes, hypertension, and lack of physical activity—it is hard to know which is the main culprit.
Cholesterol-lowering drugs. Despite some anecdotal reports that statin drugs may increase memory loss in some people, studies over the years have not found a link. In fact, some research suggests that statins reduce the risk of cognitive decline and dementia. High blood cholesterol may contribute to the brain plaques typical of Alzheimer’s. People taking cholesterol-lowering statin drugs may get an additional benefit against dementia.
Raising HDL (“good”) cholesterol. Several studies have found that HDL positively influences mental performance. One theory: it may help block the formation of plaques in the brain. A 2008 study found that lower levels of HDL before age 60 increase the risk of memory loss in middle age as well as later in life.
Aspirin and similar drugs. Nonsteroidal anti-inflammatory drugs (NSAIDs, such as aspirin, ibuprofen, and naproxen) may help by reducing the chronic inflammation that plays a role in Alzheimer’s. But the picture remains muddy. While early research was promising, most clinical trials have yielded disappointing or conflicting results. However, studies have consistently found that low-dose aspirin does not help the brain.
Healthy diet. A 2007 review of population studies concluded that a heart-healthy diet based on vegetables, fruits, and whole grains is good for cognition and may well help protect against dementia—while a diet rich in saturated or trans fat may have a negative impact. It’s not known which nutrients or phytochemicals are most beneficial. Several recent studies have found a link between fish consumption and reduced risk of cognitive decline. A moderate alcohol intake has also been linked with better cognitive functioning and a reduced risk of dementia.
Dietary supplements. There’s no solid evidence that vitamins or other supplements (including ginkgo and ginseng) or special “memory formulas” (such as Focus Factor) can prevent mental decline. Exception: a vitamin B12 deficiency can cause confusion and memory loss that can be misdiagnosed as Alzheimer’s; large doses of B12 supplements, under a doctor’s supervision, may alleviate this.
Treating depression. Not only does depression impair mental vitality, it can actually cause severe memory problems.
Bottom line: Research into memory loss and dementia is intense, and hardly a week passes without some news. Memory problems and dementia often have multiple causes. Protecting your cardiovascular system, as outlined by many of the steps above, is probably your best bet for keeping your mind sharp and disease-free.