A recent study in the Archives of Neurology shows that muscle strength is related to risk for Alzheimer’s disease. In a group of persons with an average age of 80 years, those with the greatest muscle strength had the lowest chance of developing Alzheimer’s over up to six years. About one in five of the people with the lowest muscle strength (the lowest 10%) developed Alzheimer’s disease over the study follow up, while fewer than one in ten of those with the greatest strength (the highest 10%) developed Alzheimer’s in the same time – about half the risk.

Does this mean that weight training will keep you from getting Alzheimer’s or other memory problems? It’s not clear. Endurance training has been shown to increase brain-derived neurotrophic growth factor (BDNF), a substance that facilitates the growth of new nerve cells in the brain. This increase in BDNF may be part of the reason why exercise improves cognition. But a recent study of weight training with middle-aged men and women didn’t show any change in BDNF with weight training.

Given the association of mood, cognition, and loss of muscle tissue in frailty (see another blog post about frailty here), though, maintaining muscle mass through weight training may be an important way to maintain and improve physical and cognitive functioning.

References:

Boyle PA, et al. (2009). Association of muscle strength with the risk of Alzheimer disease and rate of cognitive decline in community-dwelling older persons. Archives of Neurology, 66, 1339-1344.

Levinger I, et al. (2008). BDNF, metabolic risk factors, and resistance training in middle-aged individuals. Medicine and Science in Sports and Exercise, 40, 535-541.

The second study, by Feart and her colleagues, looked at adherence to the Mediterranean diet and risk for having problems on certain mental ability tests. Here again, the study suggests that following the Mediterranean diet was associated with a reduced risk of developing certain kinds of cognitive problems.

The study was discussed by Dr. Nancy Snyderman on the Today Show. You can find a link to a page that will let you see the segment from the show here.  (Look for a link to “Study: Mediterranean diet cuts Alzheimer’s risk.” You also have to watch a commercial; that’s NBC, not me).  I think that she may overstate the case based on the research; there’s a very nice editorial in this same issue of the Journal by well-known neurologist David Knopman. He points out a number of possible reasons for these findings that might affect the conclusion that the Mediterranean diet and exercise reduce the risk of Alzheimer’s. He suggests we should “nibble and savor” the results of these studies, not “swallow them whole.”

It’s still premature to be sure that following the Mediterranean diet or being physically activity will prevent Alzheimer’s disease. Given what we know about the relation of cardiovascular health and risk for Alzheimer’s, and what we know about diet and exercise and cardiovascular health, though, I think it’s a good idea to pay close attention to your diet and to exercise safely.

What are the basics? I think they start with essential health care that will make sure your brain is in a health body. Maybe the single most important basic is to take care of your blood pressure. Besides being a risk factor for heart attack, high blood pressure is a risk for stroke. Studies have suggested that high blood pressure is a risk factor memory problems. You should know your blood pressure, and if it’s high, you should discuss it with your doctor. A number of effective treatments are available for high blood pressure. You can find out more about high blood pressure on the web site of the American Heart Association by clicking here.

One risk for memory problems that seems to be more and more common is the metabolic syndrome. The metabolic syndrome is a group of characteristics that includes abdominal obesity (fat around the waist), problems with blood lipids (the special substances in the blood that carry fats around the blood stream), insulin resistance (your body doesn’t take care of sugar very well), and increases in the substances in your blood that cause blood clots. People with the metabolic syndrome may be at higher risk for diabetes and heart attacks. The American Heart Association also has a good page on metabolic syndrome here. It may be possible to reduce the effects of the metabolic syndrome by maintaining a health weight, getting regular exercise, and following a healthy diet.

We know that the basics include a lot of things we’ve been hearing for years. What has become more clear over the past few years is that there are clear reasons for the links among obesity, low physical activity, and several diseases. One of the most intriguing links is the fact that all these conditions are associated with markers of inflammation in the blood. Inflammatory markers have complicated names like cytokines and interleukins. You don’t have to know all the specific names to know that high levels of these markers go along with memory problems. More and more, then, there’s a clear link between your basic health and your brain’s fitness.

1. Very little research shows that any supplement has a positive effect on brain fitness, and
2. Many supplements are costly, and some may have negative side effects such as interactions with prescription medications.

The first fact means that it’s very hard to know whether any supplement measures up to the claims that some people at least make for it. The second means that you may have to make a substantial investment in something that may or may not help you, and that the makers of the supplements may have a lot of money to promote them.

Having said that, some dietary supplements have limited evidence to support their inclusion in a brain fitness program. Probably the best-supported supplement for heart health, omega-3 fish oils, is a likely candidate for brain health. The American Heart Association recommends that everyone get some omega-3 fish oils from their diet, and from supplements if they to lower their triglycerides.

Another supplement that has been touted as possibly effective in reducing your risk of getting Alzheimer’s disease is curcumin. It’s a substance that occurs in turmeric, a common spice. Consumption of turmeric in some parts of India, some researchers have suggested, may account for low rates of Alzheimer’s disease in those areas. In one study with mice, those fed curcumin seemed to have a reversal of amyloid plaque formation in their (those are one of the key things that happen in the brain in Alzheimer’s).

Large scale studies have shown that people who get more antioxidants in their diet, and possibly those who take supplements of antioxidants like vitamins C and E, may have lower risk for developing Alzheimer’s disease. A group of researchers in New York have shown that people who follow the antioxidant-rich Mediterranean diet more closely have a lower risk for Alzheimer’s disease.

At the moment, these are our best guesses for supplements that may help maintain brain fitness. As interest increases in brain fitness, we may know more about these and other supplements.

First, I warn everyone that supplements aren’t as well researched as regular drugs. This may mean that some supplements work better than we know. It may also mean that they have side effects that we don’t know about, or that may interact with other supplements or regular prescription drugs. So if you intend to take any supplement, be aware of the risks.

Of all the supplements for brain fitness, one of the most promising is already recommended by the American Heart Association. Omega-3 fish oils have been shown to have benefits for the cardiovascular system. Although it may be possible to get enough fish oil from eating fish several times a week, many people can’t eat fish so regularly or are worried about how much mercury they might get from the fish. Fish oil are readily available as capsules. Depending on your condition, you may want to take from 1 to 4 grams of fish oil every day. You can read the AHA’s recommendations here.

As I mentioned, there is little information about any supplement and brain fitness. In one study, a small group of people with very mild cognitive problems appeared to benefit from fish oil supplements. More and more, it’s becoming apparent that there is a close link between cardiovascular risk factors and brain fitness. This means, I believe, that most of the things we can do to improve cardiovascular health are probably good for the brain. The same blood vessels that are critical to keep blood flowing to the heart and the rest of the body are present in the brain. In fact, the most metabolically active organ in the body is the brain. So anything you can do to improve vascular health is likely to help your brain.