Like regular exercise, eating a healthy, balanced diet is one of the pillars of good health – and of good brain health.
Eat your vegetables
The latest news from neuroscience confirms what mother always said: eat your vegetables! For all the interest in individual vitamins and supplement formulas, the best advice is to eat a variety of colourful, cruciferous and leafy green vegetables.
A recent US study of 13,388 nurses that has tracked their eating patterns for 10 years found that women who ate more cruciferous and leafy vegetables (such as broccoli, cauliflower, green lettuces and spinach) in their sixties had a lower rate of decline on learning and memory tests. The more of these vegetables they ate, the better they performed.
A diet rich in fruits and vegetables has long been promoted for its heart-healthy and cancer-fighting potential, so it’s not surprising that such a diet is also good for your brain. Vegetables and fruits are packed with antioxidants and other essential vitamins and minerals, are low in fat and are generally low in calories.
Of all the dietary factors that are being investigated for possible roles in staving off mental decline with ageing, antioxidants have received the most attention. Antioxidants, which include vitamins C, E and beta carotene (a form of vitamin A), reduce oxidative damage to cells from “free radicals”, unstable molecular fragments. Oxidation, which can be thought of as the biological equivalent of rusting, seems to contribute to ageing and cognitive decline, in addition to a number of diseases.
While there’s little question that antioxidants consumed as part of a healthy, balanced diet are a good thing, popping antioxidant pills is another matter altogether.
Caution! Don’t run out to the health food store and start loading up on vitamins. Too much of some vitamins or minerals can actually be harmful. The best way to get antioxidants (or any other nutrient) is not by popping supplements, but by eating a variety of whole foods, especially dark, leafy greens and berries.
There is however, a growing recognition that as we age, our bodies are less efficient at absorbing dietary nutrients from food. This fact, combined with the observation that older adults’ diets may be less than ideally balanced nutritionally, has led many experts to recommend supplements for older people. If you want to take vitamins, experts recommend taking a standard multivitamin, which typically provides the recommended daily allowances for each ingredient.
Animal studies have shown pretty consistent benefits for diets rich in antioxidants, but human studies of antioxidant use have yielded ambiguous results. In fact, most well-designed studies of antioxidants have failed to show a benefit. This is partly because our diets are generally quite varied, and it’s very difficult to prove that health benefits are the result of any one dietary factor.
In animals however, it’s much easier for researchers to carefully control dietary elements in order to tease out effects.
For example, a series of studies in beagles found that an antioxidant-rich diet prevented or slowed age-related declines in various learning tasks. The animals that were fed the special diet had improved performance on both simple and complex cognitive tests. In fact, aged dogs that could not perform one of the more difficult tests at all in the beginning of the study could do so after three years on the diet. “We actually resurrected function out of the ageing brain,” says Carl Cotman, who led the study “That just blew us away.”
A series of studies out of Tufts University has shown that animals fed diets high in blueberries had improved short-term memory and balance. The ingredient that gives blueberries their colour appears to endow them with potent antioxidant properties.
Common foods high in antioxidants
|Listed from greater to lesser amounts|
|Plums||Red bell peppers|
Omega-3 fatty acids
Omega-3s are a particular type of polyunsaturated fats that are found in fatty fish. A growing body of scientific literature indicates that omega-3s are important to maintaining brain function in early development and throughout life, and may help protect the brain from ageing. They seem to work in part by counteracting free radicals that cause oxidative damage to brain cells. Some research suggests they also may benefit the non-neuronal brain cells called glia, which help improve the efficiency of nerve signal transmission at synapses. The best dietary sources of omega-3s are mackerel, herring, sardines, tuna, anchovies, whitefish and sablefish.
The caveat: There is increasing concern about the levels of organic mercury in some of these same fish, leading some experts to caution against eating such fish more than three times a week. Pregnant women should eat such fish even more sparingly due to concerns about the toxicity of mercury to the developing foetus.
B vitamins are of interest because of their effectiveness in lowering levels of homocysteine, a blood protein that is associated with increased risk for cardiovascular disease as well as Alzheimer’s and other types of dementia. In particular, scientists are investigating whether folate, or folic acid, may have a role in preventing Alzheimer’s disease; it and other B vitamins are currently being evaluated in a clinical trial for people with Alzheimer’s.
Most experts are comfortable recommending that older adults take a daily multivitamin as a supplement to a healthy diet. Claudia H.Kawas, MD says “I’m not opposed to multivitamins at all. I don’t think any of our diets are that good, and as people get older and are eating less, they may have diets that are lower in various nutrients.” Still, the best advice, she says “is to do what your mother told you to do: eat all those healthy fruits and vegetables.”
A common misperception is that if taking some vitamins is good, taking more may be better. This is not always the case and some vitamins can be dangerous in high doses. A recent study found that people taking moderately high doses of vitamin E, an antioxidant vitamin that is being studied for health-protective effects in a number of clinical trials, were slightly more likely to die than those not taking the pills. Vitamins and herbal supplements can also interact with prescription medications, lowering their effectiveness or causing adverse effects, so be sure your health care provider knows about any of these you may be taking.
The material on this page “Brain Health – Food” has been used with the kind permission from the Dana Alliance for Brain Initiatives. www.dana.org/stayingsharp