Food for Thought: Can what you eat affect your brain health? Baycrest scientists say yes!
Some old wives tales hold up better than others. There’s now proof chicken soup has antihistamine properties that work against colds. And carrots contain beta-carotene, which is good for your vision.
But is it true that eating fish is good for your brain?
According to Dr. Tiffany Chow, a neurologist and scientist at Baycrest’s Rotman Research Institute, current scientific evidence links brain health to the consumption of fish, as well as other foods.
“Fish that are high in omega-3 fatty acids, like salmon, mackerel, sardines and bluefin tuna, protect against inflammation and are good for the brain,” she says. “Fish is also a good source of protein instead of red meat, which is laced with the kind of fat that gets you into trouble in the long run in terms of stroke and brain maintenance.”
Dr. Carol Greenwood, a senior scientist at Baycrest’s Kunin-Lunenfeld Applied Research Unit and professor of nutritional sciences at the University of Toronto, agrees. “You want a fattier fish, like those who inhabit cold water environments. They use their oils as a natural insulator to improve survival.”
Both Drs. Chow and Greenwood also encourage people to eat more fruits and vegetables.
“There’s good epidemiological data out there to argue that people with a higher intake of fruits and vegetables have a lower risk of dementia,” says Dr. Greenwood. “We attribute this in part to the anti-oxidants.”
Research has shown that virtually any disease process will involve an “oxidating reaction” that causes cell damage. “If you want to look at how to minimize cell damage, you want to protect it from oxidative reactions,” she says. “That’s why anti-oxidants, commonly found in fruits and vegetables, are not only good for your brain they’re good for many other systems in your body, as well.”
Sometimes, it’s what you don’t eat that matters. That means trying to keep your sweet tooth in check! “Your brain is only two per cent of your body mass, but it consumes 20 per cent of your glucose intake, and doesn’t cope well with major fluctuations caused by foods with a high glycemic index,” says Dr. Chow. “That means watching your intake of sweets.”
Foods can be categorized by a ‘glycemic index,’ which groups foods according to their carbohydrate qualities. Foods with a high glycemic index include the usual suspects – ice cream, chocolate, croissants, but also bananas, carrots and dried fruit – and can result in large increases in blood glucose after they are ingested.
“There are going to be special occasions when you just have to have that slice of apple pie with ice cream. But over long periods of time, if you indulge in foods with a very high glycemic index, which can cause major downswings in glucose in between, you may be increasing your risk of getting Alzheimer’s disease,” says Dr. Chow.
In the last two years, research has indicated that high levels of insulin released by your body in response to high glycemic foods can eventually contribute to the presence of Alzheimer’s plaques in the brain.
Additionally, eating habits which increase the risk of Type 2 diabetes – including the consumption of high glycemic foods – also increase the risk of Alzheimer’s disease.
Red wine has been touted as being good for the heart and circulation in general, and more recently, there has been proof that one component of red wine may prevent the development of Alzheimer’s.
Dr. Chow describes a New York Mount Sinai School of Medicine study done with transgenic mice. “These mice were bred to develop the same types of plaques found in the brains of patients with Alzheimer’s disease. Although Alzheimer’s involves two important proteins, (plaques and tangles), these mice just developed plaques.”
When the mice had their caloric intake reduced by one-third, they developed fewer plaques in their brains. “But knowing that most people would not be willing to reduce their diet so drastically, the researchers decided to study the mice more carefully. What they found was that a substance called “resveratrol” was responsible for the decrease in plaque levels,” says Dr. Chow.
“Dr. Chow recommends smaller and more frequent portions spread throughout the day.”Resveratrol can be found in red wine, the skin of grapes, and pomegranate juice. “The next phase of the experiment was to take these mice and tank them up with wine,” says Dr. Chow. “The researchers actually made their own special Cabernet in the lab for the mice so they could carefully control the resveratrol. The mice that drank it did better.”
Although people who drink red wine became very excited by this news, Dr. Chow remains cautious. “You’d have to drink a lot of red wine in order for it to protect you against Alzheimer’s. People shouldn’t be drinking that much alcohol on a daily basis,” she says.
She predicts the resveratrol component will come out in a tablet form in the near future. “It’s not as much fun as drinking a bottle of red wine in good company, but it will hopefully get across the blood-brain barrier and have an effect on whether you develop plaques and therefore Alzheimer’s.”
“In the beginning, before research factored out socio-economic status, red wine was said to help prevent cardiac disease and stroke. But generally speaking, those people who have a glass of red wine or two before dinner at night usually have a higher educational level and better opportunities for exercise during the day, all factors that have an impact on how you age, let alone develop Alzheimer’s,” she says.
Dr. Chow strongly recommends a Mediterranean-style diet, based on fruits, vegetables, olive oil, legumes, grains and fish. She also recommends smaller and more frequent portions spread throughout the day to regulate glucose levels.
Our society has become accustomed to “supersized” portions, says Dr. Greenwood. “Historically, supersizing at restaurants has come out of competition, but we also supersize at home.”
She defines a serving of vegetables as about half a cup, while one piece of fruit is considered a serving of fruit.
Dr. Chow says one serving of protein is what you can fit onto the palm of your hand. “That’s one chicken breast, or three pecans, not half a can,” she says.
Dr. Chow insists that diet alone is not enough to protect your brain. “Exercise is important for your circulation, reducing stress and reducing body-mass index, which is a standard measure of a person’s weight in relation to his or her height.”
She refers to a study that found an association between large body-mass index and atrophy, or loss of volume in the brain. “Women who had a larger body-mass index than normal for their age and height lost brain volume over a two-year period,” she says.
In addition to lowering your body-mass index, Dr. Chow says exercise has psychosocial benefits that are linked to the development of Alzheimer’s. “Plugging into a local gym and exercising with other people is great for your social life. After all, feeling lonely or depressed, is also a risk factor for Alzheimer’s.”
“You may start out exercising and eating right for your brain, but you’ll benefit other aspects of your body and life, as well,” she says.
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