Research clearly shows that a combination of mental and physical exercise, stress reduction and a healthy diet, will improve brain function and protect against decline as we age. We sat down with Professor of Psychiatry and Aging Gary Small to find out more.

We’re all going to get older, so what can we do to protect our aging brain?

The good news is that, as the MacArthur Study of Successful Aging shows, genetics account for only part of what contributes to the risk of dementia, and much more of it is about environment. Most people don’t realize how much control they have, but there are lifestyle choices we make every day that can either protect or harm our brain cells.

A lot of the lifestyle strategies that help protect the brain as it ages are actually anti-inflammatory strategies. The first one to think about is physical exercise. Studies are showing that when you exercise your brain actually gets bigger, in the memory centers, and a bigger brain is a better brain.

When we exercise, our brain produces BDNF (brain derived neurotrophic factor), which stimulates our brain cells to sprout branches and communicate more effectively with each other. It also produces endorphins, which elevate mood, which is also good for memory and brain function.

Studies are showing that when you exercise your brain actually gets bigger, in the memory centers, and a bigger brain is a better brain.

What’s the difference between normal aging of the brain, and problematic aging?

We know that by the time the average person reaches the age of 45, there’s going to be an objective decline in their memory performance, but this tends to be relatively stable, and does not cause problems in functioning. But if that progresses, and performing everyday activities becomes troublesome, and a person is no longer independent, that’s when we call it dementia.

The point at which normal aging changes to something problematic can be tricky, but if someone is concerned they should check it out; it’s always better to diagnose a problem earlier, and easier to protect a healthy brain than try to repair damage.

What is actually happening at a physical level as the brain ages?

There are a lot of processes going on, and each of them contributes in their own way to memory loss and other forms of cognitive decline.

One change is a build up of abnormal protein deposits, called tau tangles and amyloid plaques, which accumulate in areas of the brain that control thinking and memory. These proteins define Alzheimer’s disease, the most common form of dementia.

Our neurotransmitters – the molecules that transmit information from one neuron to another – don’t work as effectively as we age. Acetylcholine, for instance, has been found to be less available in an aging brain, and the first medicines developed for treating Alzheimer’s and dementia were those that boosted the availability of acetylcholine. That’s just one example of neurotransmitter abnormalities that occur as we age.

Another process that goes on is heightened inflammation. Inflammation is a normal physiological process, in response to an infection, or when we injure a joint; that’s our inflammatory cells honing in and trying to repair damage. The problem with aging is that there is excess inflammation throughout the body and brain, and the cells used to fight infection start to attack healthy brain cells.

The triple threat against Alzheimer’s is taking a walk with a friend – it’s a cardiovascular workout, the conversation makes it a neural workout, and a friend’s empathy will reduce stress.

Does what we eat affect the way we think?

Mid-life obesity increases risk of late-life dementia, so it’s important to control our portions at meals. You want to eat adequate amounts of fruit and vegetables, which protect the brain from oxidative stress, which is associated with aging. And you want to minimize processed foods and refined sugars, which can increase the risk of diabetes, which doubles the risk of dementia.

Omega-3 fats, found in fish and nuts, are associated with better cognition as well as better mood. Studies have shown that countries that consume more fish have lower rates of depression. Most experts recommend fish, maybe two times a week.

We just did a study at UCLA looking at a bio-available form of curcumin, a component of turmeric, which is anti inflammatory, anti tau, anti amyloidal and antioxidant. And we found that it had a significant effect on memory in people with normal aging or mild cognitive impairment after 18 months, and it also improved mood.

Interest in this area came out of clues from epidemiological studies, showing that people in India who are older have a lower rate of dementia than in other countries, and people in Singapore who ate Indian food had better memory scores. It was a small study, of 40 adults between the ages of 50 and 90 years who had mild memory complaints, but we plan to do a larger trial.

Are supplements, such as curcumin supplements and Omega-3 capsules, as good as the food they come from?

The research is quite complex, and sometimes doesn’t answer the question in a clear way. I encourage people to consume these nutrients in a healthy diet. Take a supplement as insurance if you want to. One of the challenges with supplements is that they’re not as well regulated as drugs, so the ingredients they contain might not be easily absorbed and you might be wasting your money.

You said that a good mood is good for the brain, so presumably a bad mood isn’t?

We know that chronic stress in animals is associated with smaller memory centers in the brain, and studies have shown that human volunteers injected with cortisol, a stress hormone, have temporary memory impairment. Other studies have shown that even ten minutes of meditation a day, or doing tai chi or yoga or relaxation exercises, can improve memory and mood. There are apps now that you can download that have guided meditation, and people can listen to the app for ten minutes a day and get some relief from their daily stress.

Does mental stimulation help maintain cognitive capacity?

People who have a college education, or are bilingual, have a lower risk of dementia, but mental stimulation from conversations, games, puzzles and reading is also important. I tell people to train not strain their brain. Find things that are fun and engaging, not too difficult because that will be stressful, and not too easy because that won’t stimulate your neural circuits.

Going back to the importance of physical exercise – how hard does it have to be?

There’s a lot of research on this, with mixed results. There are studies showing that if you walk briskly for 20 minutes a day it will lower your risk of Alzheimer’s. I like to do interval training, which in terms of brain and body metabolism, gives you four times the efficiency of continuous training. So I get on an air bike, and I’ll cycle really fast for 20 seconds, then let up for ten seconds. Doing that for five minutes might be equivalent to 20 minutes continuous exercise. So you don’t have to be a triathlete, but you have to feel a bit of exertion.

I often say to people that the triple threat against Alzheimer’s is taking a walk with a friend. You will have some cardiovascular workout. If you have a conversation, that’s a neural workout. And if your friend is empathic it will reduce stress.

Gary Small is professor of psychiatry and aging, and director of the Longevity Center at the Semel Institute for Neuroscience & Human Behavior, University of California, Los Angeles

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