Minding your mind: 12 ways to keep your brain young with proper care and feeding

Content provided by the Faculty of the Harvard Medical School

Minding your mind: 12 ways to keep your brain young with proper care and feeding

Time marches on, and the march of time alters every part of the human body. Few of these changes are welcome, but most can be slowed down, minimized, or compensated for. There is no fountain of youth, but the combination of good health habits, good medical care, good genes, and a little good luck can keep most of us bubbling along to ages that were unimaginable to previous generations.

The mind is no exception. Every brain changes with age, and mental function changes along with it. Mental decline is common, and it’s one of the most feared consequences of aging. But cognitive impairment is not inevitable — far from it. Here are 12 ways you can help reduce your risk of age-related memory loss.

1. Get mental stimulation

It’s hardly a new idea; more than 2,000 years ago, the Roman orator Cicero observed, “Old men retain their mental facilities, provided their interest and application continue.” But does mental stimulation actually keep the mind young? Or did Cicero get it backwards, observing increased mental acuity in old men who were simply endowed with healthy brains?

The first scientific answer comes from a study of mice, not men. Researchers randomly divided adult animals into two groups; one continued to live in normal cages, while the other mice were moved to larger cages that held various stimulating toys. After 10 months, the scientists gave the mice a series of behavioral tests and then examined their brains. It was clear that the enriched environment produced a substantial improvement in behavior. More important, the stimulated mice had a striking increase in new nerve cells in the hippocampus, the part of the brain that’s chiefly responsible for memory. The stimulated mice also displayed fewer signs of age-related degenerative changes than the control animals. The researchers concluded that signs of nerve cell aging “can be diminished by a sustained active and challenging life, even if this stimulation started only at medium age.”

It’s not clear how mice will react to this stimulating discovery, but wise men will ask if it applies to humans. The best evidence suggests that it does. Here are some examples.

• A 2005 study investigated the risk of dementia in 10,079 members of the Swedish Twin Registry who were at least 65 in 1998. Even after taking age, gender, and education into account, subjects who had worked at mentally complex tasks enjoyed a lower risk of Alzheimer’s disease than their less mentally active twin. Occupations that involved complex work with people, such as teaching, appeared particularly protective.

• A 2003 study evaluated 469 people who were mentally intact and over 75. During five years of observation, 124 subjects became demented. But not all the elders were equally vulnerable. The people who engaged in mental activities requiring effort, such as reading, board games, playing musical instruments, and dancing, enjoyed a reduced risk of dementia.

• A study published in 2002 evaluated 801 older Catholic priests, brothers, and nuns. Over four and a half years, 111 previously healthy clergy developed Alzheimer’s disease. The subjects who had the highest level of cognitive activity at the start of the research had the lowest risk of developing Alzheimer’s.

• A study published in 2002 of 842 Chicagoans with an average age of 76 evaluated seven common activities, from reading newspapers to visiting museums. All the people scored well on memory tests when the research began, but four years later, 139 had Alzheimer’s. Intellectually stimulating activities were linked to a reduced risk of dementia.

• A 2001 study of 1,772 New Yorkers aged 65 or older found that engaging in mentally challenging leisure activities was associated with a 38% reduction in the risk of developing Alzheimer’s over a seven-year period.

How does this happen? Doctors don’t yet know the precise answer, but they suspect that brainy activities stimulate new connections between nerve cells and may even help the brain generate new cells. If this theory is correct, men respond to mental activity the way mice do, developing neurological “plasticity” and building up a functional reserve that provides a hedge against future cell loss.

Any mentally stimulating activity should help to build up your brain. Read, take courses, and explore new hobbies. Keep learning. Try “mental gymnastics,” such as word puzzles, jigsaw puzzles, or math problems. Play checkers or chess. Use a computer. Experiment with things that require manual dexterity as well as mental effort, such as drawing, painting, ceramics, and other crafts. Do whatever you find interesting, stimulating, and — above all — new.

When Oliver Wendell Holmes was asked why he was reading Plato at the age of 92, he replied simply, “To improve my mind.” The great jurist got it right. And if crossword puzzles don’t interest you, you could do worse than reading Plato (or, for that matter, this article).

2. Get physical exercise

It’s logical that using your mind helps keep it fit. What’s surprising, perhaps, is research showing that using your muscles may also help your mind. Animals who exercise regularly increase the number of tiny blood vessels (capillaries) that bring oxygen-rich blood to the region of the brain that is responsible for thought (the cerebral cortex). Exercise also spurs the development of new nerve cells and increases the connections between brain cells (synapses). The net result, according to researchers at the University of Illinois, are brains that “are more efficient, plastic, and adaptive, which translates into better performance in aging animals.” And a 2005 study from California reports that mice that are genetically prone to neurological problems very similar to Alzheimer’s disease gain protection from damaging brain deposits of amyloid protein by running on exercise wheels.

Men are not mice — but physical exercise helps aging humans stay mentally agile. Ten studies of more than 53,000 elderly Americans, Canadians, and Europeans have all linked regular physical activity with a reduced risk of cognitive decline in “the golden years.” Compared with the least active people, those who got the most exercise were 15%–52% less likely to suffer from mental impairment; in one study, for every mile a woman walked each day, her risk of cognitive decline dropped by 13%. An additional study of 4,055 elderly Chicagoans found that the apparent benefits of physical activity could be explained by other factors. But research from Cleveland found that regular exercise between the ages of 20 and 60 was linked to a nearly fourfold reduction in the risk of developing Alzheimer’s disease in old age.

In case you’ve forgotten, the moral is simple: For your mind as well as your body, exercise regularly. It’s another case of new research confirming old insights, in this case the 18th-century wisdom of Alexander Pope: “Strength of mind is exercise, not rest.”

Regular exercise keeps the body healthy in many ways. It lowers blood pressure, improves cholesterol levels, fights diabetes, and reduces mental stress, all of which can help your brain as well as your heart. Exercise keeps blood vessels healthy, protecting you from strokes and dementia as well as heart attacks. Healthy arteries can give your brain the nourishment it needs — and it needs a lot. Although it accounts for less than 2% of body weight, the brain receives 15% of the body’s blood flow and consumes 25% of its oxygen supply and 70% of its glucose (sugar) supply.

The boys in the locker room know that they must “use it or lose it.” Physical exercise keeps the body strong — and it can also help keep the mind sharp as the years pile on. Physical fitness builds mental fitness; exercise as simple as walking is a big step in the right direction.

3. Improve your diet

Good nutrition can help your mind as well as your body. Here are some specifics:

• Keep your calories in check. In both animals and humans, a reduced caloric intake has been linked to a lower risk of mental decline in old age. In contrast, obesity increases risk — and abdominal obesity (the “beer belly”) is the riskiest of all.

• Eat the right foods. At 9 calories per gram, fats are the most calorie-dense foods. Choose your fats wisely. That means reducing your consumption of saturated fat and cholesterol from animal sources (meat and whole dairy products) and of trans-fatty acids from partially hydrogenated vegetable oils (stick margarine, fried foods, snack foods, and many commercially baked foods). But some fats may help, including monounsaturated fats from olive oil and — especially — omega-3 fatty acids, particularly those from fish. Although the Rotterdam Study of 2002 did not identify any culprit fats, it did report that eating fish was linked to a 60% reduction in the risk of dementia.

• Remember your Bs. High levels of the amino acid homocysteine have been linked to an increased risk of dementia as well as heart disease and stroke. Three B vitamins, folic acid, B₆, and B₁₂, can help lower your homocysteine levels. Fortified cereal, other grains, and leafy green vegetables are good sources of B vitamins — and a daily multivitamin will provide extra insurance. Unfortunately, though, antioxidants have been disappointing.

4. Improve your blood pressure

High blood pressure in midlife increases the risk of cognitive decline in old age. About 65 million Americans have hypertension (blood pressures of 140/90 or higher), and some 59 million have “pre-hypertension” (pressures between 120/80–140/90). Use lifestyle modification to keep your pressure as low as possible.

Stay lean, exercise regularly, limit your alcohol to two drinks a day, reduce stress, and eat right (less salt and more fruits, vegetables, fiber, and low-fat dairy products). And if your blood pressure stays up despite your best efforts, be sure your doctor prescribes medication that will bring it down.

5. Improve your blood sugar

Diabetes is an important risk factor for dementia as well as heart disease and stroke. You can fight diabetes by eating right, exercising regularly, and staying lean. But if your blood sugar stays high, you’ll need medication to achieve good control.

6. Improve your cholesterol

High levels of LDL (“bad”) cholesterol increase the risk of dementia, as do low levels of HDL (“good”) cholesterol. Diet, exercise, weight control, and avoiding tobacco will go a long way toward improving your cholesterol levels. But if you need more help, ask your doctor about medication. Most people with high blood pressure, diabetes, or heart disease and other forms of atherosclerosis will need drugs to bring their LDL levels to the stringent target of 100 or less, and some people without these risk factors will need medication to reduce their LDLs to 130 or less.

The statin drugs are particularly attractive. They are known to reduce the risk of heart attack and stroke, and they may also help prevent dementia. A series of observational studies have linked statin use with a reduced risk of Alzheimer’s disease and other forms of dementia. The protection appears substantial, lowering the risk of dementia by 39%–74%. Since vascular damage is an important component of age-related memory loss, it’s a plausible effect. And the drugs may even protect brain cells as well as the arteries that nourish them. A 2002 German study indicates that these medications can enter nerve cells, affecting cholesterol metabolism in the brain itself. Scientists speculate that the statins may even reduce the brain’s production of beta-amyloid, the protein that causes much of the damage in Alzheimer’s disease.

Doctors should prescribe statin drugs to protect the hearts of people at risk. But should they also prescribe them to prevent dementia? Not yet. The cardiac benefits of the statins have been proven with large, careful, randomized clinical trials that constitute the gold standard of clinical research. But the apparent protection against dementia has simply been suggested by observational studies. This type of research is important and useful, but it’s not always conclusive.

Don’t count on the statins to protect you from dementia — but don’t count them out, either. Randomized clinical trials of statins and dementia are getting under way.

7. Consider low-dose aspirin

Randomized clinical trials have demonstrated that low-dose aspirin therapy can reduce the risk of heart attacks and certain strokes. Observational studies suggest that long-term use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the risk of dementia by 10%–55%.

It’s hopeful information, but it’s preliminary. Experts are not ready to recommend aspirin specifically for dementia any more than statins for the mind. But if you need aspirin or NSAIDs for other good reasons, you may get extra protection against mental decline.

8. Avoid tobacco

It’s the First Commandment of Prevention, and it applies to dementia every bit as much as to lung cancer, emphysema, heart attacks, and so many other major illnesses. According to the Rotterdam Study, smoking doubles the risk of dementia. Avoid tobacco in all its forms.

9. Don’t abuse alcohol

Excessive drinking is a major risk factor for dementia. If you choose to drink, limit yourself to two drinks a day, counting 5 ounces of wine, 12 ounces of beer, or 1½ ounces of spirits as one drink. But if you use alcohol responsibly, you may actually reduce your risk of dementia. At least five studies have linked low-dose alcohol with a reduced risk of dementia in older adults. In this respect, as in others, modern science seems to be confirming the wisdom of Herman Johannsen, the cross-country ski innovator who lived to the age of 111. When asked his secret, Johannsen advised, “Stay busy, get plenty of exercise, and don’t drink too much. Then again, don’t drink too little.”

10. Care for your emotions

People who are anxious, depressed, sleep-deprived, or exhausted tend to score poorly on cognitive function tests. Poor scores don’t necessarily predict an increased risk of cognitive decline in old age, but good mental health and restful sleep are certainly important goals. A study from Harvard suggested that meditation may help preserve brain tissue. Research from Chicago linked psychological distress to an increasing risk of Alzheimer’s. And in a 2005 presentation to the American Academy of Neurology, researchers from the Mayo Clinic reported that pessimism in midlife is associated with a 30% increase in the risk of dementia in old age.

11. Protect your head

You don’t need a doctor to tell you that head injuries are dangerous. But you may be surprised to learn that moderate to severe head injuries early in life increase the risk of cognitive impairment in old age. Concussions increase risk by a factor of 10. Think twice before you exhort your favorite athlete (or relative!) to get back in the game after “having his bell rung.”

12. Build social networks

People are good medicine: Strong social ties have been associated with lower blood pressure and longer life expectancies. Isolation appears to increase the risk of heart attacks. And a Swedish study of 776 people aged 75 or more linked frequent social interactions with a 42% reduction in the risk of dementia.

“No man is an island,” wrote John Donne some 400 years ago. But in 21st-century America, many men seem to be very insular indeed. It’s not a healthy way to live.

Mind, brain, and body

This 12-point program can help keep your mind young in your senior years. It should help keep your body young, too. Although your brain has special needs and functions, it responds best to the same things that keep your other organs healthy. Modern science has confirmed the insight of Hippocrates, who observed that a sound mind and a sound body lead to health and well-being.

Anatomy and physiology of memory Some memories are meant to be retained for a short period and then discarded. But more important memories — information that you use regularly — are stored in the brain and can be retrieved at will. Deep within the brain, a primitive structure, known as the hippocampus, plays a crucial role in acquiring and consolidating new memories. The nearby amygdala is the part of the brain that reacts to emotionally powerful information, helping the brain retain information that has emotional impact. Once a memory is established (consolidated), it is stored mainly in areas of the cerebral cortex, the large, domed outer layer of the brain.

E-mail This | Print This

Last updated:	August 21, 2006