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Is sugar good or bad for the brain?

I’m Dr. Jian Liu from Brock University and today I’m answering the question, “Is sugar good or bad for the brain?”

If we revise this question into two questions – “Is sugar good for the brain?” and “Is sugar bad for the brain?” my answer for both questions is “YES, but …” because they are not simple questions.
As an important organ in the body, brain needs energy to fuel it to be functional properly. Protein, fat (lipids) and sugar (carbohydrates) are three important biochemical components in the body and all of them can be involved in energy metabolism and all of them can also be transformed from one form to another. Sugar, however, is the most common forms of energy in the body.

Galactose, fructose, and glucose are examples of basic sugar units in the body. Unlike other organs in the body, which can use different forms of basic sugar units as energy source, brain uses glucose as the primary source of energy. Notably, the sugar level (glucose level) in the body has to be maintained at a narrow range to meet the needs of metabolism; either high or low of sugar level is not good for organs in the body to have a normal function, particularly for the brain.

It is important to be kept in mind, however, that although the sugar we eat can be the same form as in our body, we should to avoid taking it directly because it doesn’t need to be digested and can emerge into blood quickly. As a result, the blood sugar level will rise up dramatically. If this occurs repeatedly, it will be harmful to our circulation, immunity, endocrine, nervous and other systems in the body and become a risk for many chronic diseases such as cancers, stroke, heart disease, diabetes, etc. The best sources of sugar from food are vegetables, fruits, whole grain/wheat, brown rice, etc. Eating too much sugar directly will indeed affect our health; not just our brain, but also our life. Therefore, too sweet is not good!

Hi my name is Alison Duncan. I’m a professor in the Department of Human Health and Nutritional Sciences at the University of Guelph and today I’m going to answer the question “Is sugar good or bad for the brain?”

For anything in our daily diet, it is important to recognize the universal concepts of a healthy diet -- moderation and variety. These concepts also apply to sugar. The answer to your question is that sugar is not bad for the brain, and in fact can be used for energy, if consumed in moderation.

Sugar can be naturally occurring (such as in fruit) or added (such as in sweets and desserts). Although Canada does not have specific recommendation levels for sugar, The World Health Organization (WHO) recently released dietary recommendation to limit added sugar intake to 5-10% of daily energy intake, which would be 6-12 tsp of sugar per day. Since a can of pop contains 10 g of sugar, you can see how easy it is for people to exceed the WHO’s recommended intake of sugar. In fact, 2004 data from Statistics Canada shows Canadians ingest 18 tsp per day!

In terms of what consuming excess added sugars can do directly to your health, research shows the most clear impact is the consequent unhealthy dietary pattern that can occur. When you consume foods with excessive added sugars, you are less likely to eat healthy foods. This unhealthy dietary pattern can increase your risk of disease and can cause you to be overweight, obese and have dental issues.

A healthy diet can include added sugars but when added sugars become excessive, it is more challenging to maintain a healthy diet and body weight. However sugar in moderation is just fine and is not bad for the brain.


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