Healthy Body, Healthy Mind – Both Fueled By Carbohydrates

Dr. Glenn Gaesser, PhD

grains-for-your-brain2Thomas Jefferson advocated that “a strong body makes a mind strong.” At the time, those words could best be described as an opinion based on experience. Some 200 years later, we now know from scientific studies the wisdom of those words. Not only is exercise good for your heart and muscles, it’s good for your brain. Exercise improves mood, vitality, alertness and overall feelings of well-being. Exercise has also been shown to be effective for treating depression and for reducing stress.

Just as exercise strengthens the heart and skeletal muscles, the use of advanced neuroimaging technology shows that exercise increases the size of certain brain areas such as the prefrontal cortex and hippocampus. These areas of the brain are key for problem solving and complex thought. This may help explain why high levels of physical activity are associated with improved academic performance in children and reduced risk of cognitive decline in adults. Longitudinal studies show that people who engage in more physical activity earlier in life have larger prefrontal cortex and hippocampal brain areas; these areas of the brain are implicated in cognitive decline and Alzheimer’s disease.

A 2012 study published in the American Heart Association journal Stroke found that regular physical activity in older adults reduced the risk of dementia by 40 percent and cognitive impairment of any kind by 60 percent. A number of articles published in the past decade also show that men and women who engage in regular physical activity have a significantly lower risk of Alzheimer’s dementia.

If you are sedentary, one of the best things you can do for your brain is to increase your level of physical activity. As you become more physically active, your cognitive function improves.  Although aerobic exercise, such as brisk walking, appears to be best, resistance exercise, such as lifting weights, has been shown to provide similar benefits.

How much exercise is enough? Current public health guidelines urge Americans to accumulate at least 150 minutes per week of at least moderate-intensity physical activity (the equivalent of brisk walking), and to also engage in some type of resistance exercise approximately two times per week. This level of physical activity has been shown to be associated with a healthier body and a healthier mind.

Physically active individuals also need to fuel their bodies. The best fuel for your muscles is carbohydrates, and that is also true for your brain. Insufficient consumption of carbohydrates reduces physical and mental performance. Chronic adherence to a low-carbohydrate, high-fat diet, for example, has been shown to precipitate cognitive decline. A 2011 study on sedentary men published in the American Journal of Clinical Nutrition showed that just seven days of consuming a low-carbohydrate, high-fat diet resulted in impaired cognitive function.  A 2009 study on women in the journal Appetite also showed cognitive impairments on a carbohydrate-restricted diet. The adverse effects were quickly reversed when the women consumed carbohydrates.

So the take-home message is clear: If you want to maximize the potential of your brain, regular physical activity is essential. To make sure you have the energy to build and sustain a strong body and strong mind, carbohydrates are indispensable.