How does excess sugar affect the developing brain in childhood and adolescence?

Parents often stress about their kids’ sugar intake, but it can be difficult to know how much is too much—or what to do about it.

Glucose – a simple sugar that forms the basis of most carbohydrate-rich food – is the primary source of energy for the brain. A healthy brain needs a constant source of energy and nutrients to fuel growth, learning and development.

However, this does not mean that excess intake of sugar is good for the developing brain. In fact, too much sugar can actually be harmful to the normal development of the brain.

I am a Clinical Nutritionist and Nutrition Scientist with a focus on neuroscience, whose research revolves around understanding the impact of diet and lifestyle on brain function and mental well-being. Preliminary results from my research indicate that consumption of sugary foods is associated with mental distress – such as anxiety and depression – and sleep disturbance.

Sources of sugar in children’s diet

Processed foods, such as donuts, sodas and sweetened cereals often contain added sugars. Unfortunately, these foods become readily available to children and teens—be it after a sports game or at birthday parties.

Chemically processed foods are those that have been altered by adding ingredients that are not naturally occurring. These foods often contain added sugars, preservatives, salts and trans fats – all of which are intended to enhance flavor, texture or shelf life.

As a result, processed foods tend to have less nutritional value than whole foods, such as fruits, vegetables, and whole grains. One of the most common sweeteners in American food products is high-fructose corn syrup, which not only contains glucose but also another simple sugar called fructose. Too much fructose is associated with an increase in body fat. High fructose corn syrup is found in sodas and baked goods such as muffins and doughnuts.

Diet, brain and function

Certain dietary components such as amino acids, which form the basis of proteins, act as precursors to brain chemicals. Amino acids also play an important role in mood, learning and cognitive functions.

Like car engines that require proper fuel to run efficiently, the brain also needs adequate nutrition for optimum functioning. The brain is made up of nerve cells, or neurons, and housekeeping cells, called glial cells. Although the metabolic requirements of these two types of brain cells differ, glucose is the primary source of energy for both.

Despite the fact that the brain accounts for only 2% of the human body’s weight, it requires about 20% of the human body’s energy to perform all of its functions, including learning, memory, and cognitive processes. Research suggests that this number is even higher in children whose brains and bodies are developing rapidly.

Brain function and development are controlled by brain chemicals known as neurotransmitters, which should determine the developmental architecture of the brain. Depending on the stage of brain development, an imbalance of important neurotransmitters can lead to a myriad of diseases affecting learning, mood, and behavior.

Similarly, a low-quality or unbalanced diet, such as one high in processed sugar, can upset the chemical balance of the brain.

Excess sugar sharpens the mind

Since glucose is the primary source of energy for the brain, too much sugar can put it into overdrive mode. When the brain is overstimulated, it can lead to hyperactivity and mood swings. However, these behavioral changes are only short-term consequences. Some evidence suggests that this brain hyperactivity in adolescents is associated with cognitive deficits in adulthood.

Sugar also has an addictive effect because it stimulates neurons in the brain’s reward system, known as the limbic system. When activated, the limbic system generates higher feelings of pleasure, which further fuels sugar consumption.

In addition, within the limbic system is a smaller structure called the amygdala, which processes emotional information. Overactivity of the amygdala is associated with exaggerated emotions such as fear and anxiety.

Research shows that there is a strong link between high sugar consumption, altered behavior, and poor emotional regulation. Although sugar consumption can boost mood momentarily, chronic sugar consumption has been linked to an increased risk of mental health problems.

Studies in laboratory animals also show that high sugar intake impairs learning and memory. Interestingly, daily consumption of sugar-sweetened beverages during adolescence is associated with deterioration of performance on the learning and memory task during adulthood. Researchers in that study suggest that this impairment may be due to changes in gut bacteria.

Given the growing body of evidence, the seemingly irresistible sweetness of sugar may translate into a bitter aftermath for the developing brain.

This article is republished from The Conversation under a Creative Commons license. Read the original article.