The prevalence of memory and thinking problems—including Alzheimer’s disease and other forms of dementia—declined in the US by nearly 30% during a recent nine-year period.

Why did this happen? Partly because many adults are doing a better job at controlling significant dementia risk factors, including blood pressure (below 120/80 mm Hg is optimal) and cholesterol (below 200 mg/dL is the target for most people’s total cholesterol).

But there are other strategies to reduce dementia risk even further. Although some vulnerability to Alzheimer’s and other forms of dementia can be genetic, an ever-increasing body of evidence shows that adopting a healthful lifestyle often can cut a person’s risk by half. What you need to know…

OVERLOOKED RISK FACTORS

Dementia occurs when brain cells are progressively damaged by excessive accumulation of proteins, such as amyloid. These proteins trigger inflammation, causing more damage to nearby brain cells. But that’s not the only trigger. The brain needs a constant supply of oxygen, hormones and nutrients such as blood sugar (glucose). Interruptions in the supply—due to narrowed and blocked blood vessels, multiple small strokes that may pass unnoticed and even heart failure, kidney disease and chronic lung disease—can kill brain cells.

Other dementia risk factors that are sometimes overlooked…

Belly fat. Abdominal fat is strongly linked to an increased risk for heart disease, and two recent studies have shown an association between belly fat and dementia.

Evidence: A study of more than 6,500 men and women, published in Neurology, found that those with the most belly fat during their 40s were nearly three times as likely to develop dementia over the next 30 to 40 years, compared with those who had the least belly fat.

Alzheimer’s prevention step: Regardless of your age, strive for a fit body. Your waist measurement in inches should be no more than half your height, in inches.

Diabetes. Research supports a link between diabetes and dementia. One Swedish study of 2,269 men found that those whose secretion of the hormone insulin was low in response to glucose at age 50 (a sign of impaired glucose metabolism that is likely to progress to diabetes) were significantly more likely to develop dementia over the next 32 years.

Alzheimer’s prevention step: Your blood glucose level after fasting overnight should be less than 100 mg/dL. People with levels of 100 mg/dL to 125 mg/dL may be at risk for diabetes and should be closely monitored by their physicians. Levels of 126 mg/dL and higher indicate diabetes. Follow your doctor’s advice on the frequency of fasting blood-glucose testing.

Smoking and heavy drinking. People with a history of smoking or heavy drinking appear to develop Alzheimer’s sooner than others.

Evidence: In a Florida study of nearly 1,000 people diagnosed with Alzheimer’s, those who smoked more than a pack per day developed Alzheimer’s 2.3 years before those who were not heavy smokers. Those who drank more than two drinks per day developed it 4.8 years earlier than those who drank less.

Alzheimer’s prevention step: If you smoke, quit now. If you drink, ask your doctor whether moderate drinking is beneficial for you. Moderate alcohol consumption has been shown in some studies to help prevent cognitive decline. Women should not exceed one drink (wine, beer or hard liquor) daily… men, no more than two drinks daily.

EXERCISE REALLY DOES HELP

Even if you’re aware that exercise helps protect against dementia, few people realize just how important it is. Besides maintaining good circulation to ensure a steady supply of nutrients and oxygen to the brain, physical activity increases production of brain-derived neurotrophic factor—a protein that triggers brain cell growth.

Evidence: Sedentary retirees started walking three times a week. Six months later, their brains—as measured by magnetic resonance imaging (MRI) scans—had grown by 3%, on average, roughly the equivalent of taking three years off the age of their brains.

Alzheimer’s prevention step: Get at least 30 minutes of moderate exercise (such as brisk walking) most days of the week. If you don’t like walking, try dancing, cycling or golf. Any physical activity is better than nothing—and the more, the better.

GET THE RIGHT BRAIN FOODS

Foods that help protect your brain…

Omega-3 fatty acids are the most abundant of the polyunsaturated fatty acids that comprise up to 20% of the brain’s volume. Some people get their omega-3s from fish-oil capsules—which contain both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DHA is the most important for brain health and is recommended (along with EPA) for heart health by the American Heart Association.

Alzheimer’s prevention step: Ask your doctor about taking an omega-3 supplement that contains at least 400 mg of DHA per daily dose. Or eat two to three servings of cold-water fish (such as wild salmon, mackerel and sardines) weekly.

Antioxidants protect the brain against cumulative damage caused by highly reactive chemicals known as “free radicals.” An eight-year study of 5,000 people identified vitamins E and C as particularly important for brain health.

Alzheimer’s prevention step: Whenever possible, get your vitamins E and C from fruits and vegetables—this also will increase your intake of other powerful antioxidants. Kiwifruit, papaya and pomegranates are particularly good sources. Aim for four to five servings daily of fruits and vegetables. If you prefer a supplement, take 300 international units (IU) of vitamin E and 500 mg of vitamin C daily.

Curcumin is the yellow pigment of turmeric, the primary ingredient in curry powder. Laboratory tests have shown that curcumin helps dissolve the abnormal amyloid formations of Alzheimer’s disease.

Alzheimer’s prevention step: Cook with curcumin (try it in curried chicken, soups and vegetables) or take a 200-mg supplement daily.

Also helpful: A regular regimen of “brain fitness” activities.

MEMORY SELF-TEST

Questions to ask yourself…

  1. Have you ever gotten lost when you drive home?
  2. Have you forgotten being at major appointments or events? Forgetting names of people you met at a recent party is not cause for concern, but forgetting that you attended the party could signal a possible memory problem.
  3. Has anyone around you complained that you tend to repeat the same questions four or five times?
  4. Have you stopped any of your hobbies or routines because of memory problems?
  5. Have you reduced your work responsibilities or hours mainly due to poor memory? For example, did you take early retirement because you can’t keep up with the same work you’ve done for years?

If you answered “yes” to any of these questions, speak to your doctor about getting a neurological evaluation.