The Effects of Sugar on the Brain

Regular consumption of sugar can lead to activation of the sympathetic nervous system, resulting in stressful situations leading to withdrawal symptoms.

Written and verified by el nutricionista Saúl Sánchez.

Last update: 20 March, 2023

Sugar is one of the worst classified ingredients today. There are several investigations that affirm that its continued intake can generate an increased risk of developing complex and chronic pathologies. But, in addition, there are several effects of sugar on the brain that you should know about too.

For this reason, we’re going to tell you the implications of regular sugar consumption on the central nervous system, as well as what science tells us in this regard. We don’t mean that you can never take this substance, but we do need to moderate its consumption.

What do we mean by sugar?

Under the name sugar we include a set of nutrients composed mainly of glucose in different spatial configurations. The most typical is table sugar as such.

However, both fructose and various syrups can be included in this group, since the effects they cause in the body are similar. There is evidence, for example, that the regular intake of free-form fructose is capable of causing damage to the functioning of the liver.

For this reason, it’s important to read the food labeling carefully. The fact that a substance called sugar doesn’t exist among the components on a food label doesn’t mean that it’s free of simple sugars, which can cause a negative impact on the body.

The effects of sugar on the brain

The consumption of sugar presents a series of repercussions in the brain. In the first place, there are several studies that affirm that its habitual intake can create a certain addiction. This certainly happens in animals. However, in humans, it seems to also develop withdrawal syndrome in people who regularly consume it.

According to research published in the journal Frontiers in Bioscience, a continued intake of sugar has an impact on the brain and behavior. In addition, it increases the levels of inflammation in the body.

The presence of this ingredient in the diet is even related to worse decisions from a dietary point of view. In this sense, the consumption of sugar encourages frequent eating of unhealthy foods.

On the other hand, the effects at the brain level caused by this substance also differ according to the population group. Activations of the sympathetic nervous system have been associated in children after the consumption of sugar. This could condition the reactions and even the mood.

It’s also possible that a greater feeling of stress is produced. It should be noted that this nervous branch is responsible for controlling all involuntary functions. This activation seems more evident after the consumption of drinks that contain the ingredient.

Inflammation can affect cognitive function

Beyond the direct effect that sugar consumption has on cognitive performance or on the autonomic nervous system, it should be noted that it generates an increase in inflammation that has repercussions at all levels. This is confirmed by a study published in Nutrients. In it, a frequent intake of the ingredient is related to an increase in markers that denote inflammatory states.

Anything that produces inflammation could have an impact on brain function, based on worse neuronal connections. This situation conditions the transmission of information, as well as the appearance of premature aging. In fact, frequent sugar intake has been linked to an increased risk of developing neurodegenerative pathologies.

The physiological mechanism responsible for the aforementioned consequence has to do with a change in the intestinal microbiota. The consumption of sugar in a chronic and abundant way generates a change in the intestinal flora, which increases the inflammation of the organism and the permeability of the intestinal barrier.

From here, a greater number of amyloid beta compounds pass into the systemic circulation and reach the cerebrospinal fluid. This accumulation is the cause of a large number of pathologies that have to do with failures in brain function.

Where is sugar found?

Sugar can be found in a large number of common consumer products, not only in industrial ultra-processed products and sweets. This ingredient is also added to many preserves, including pickles. Yogurts are other foods likely to contain sugar in large quantities.

For this reason, it’s essential to read the labels carefully before purchasing the products in the supermarket. Keep in mind that they always appear ordered from largest to smallest in terms of quantity.

It’s also necessary to know that, as we mentioned, there are several names by which sugar can be recognized. The industry has created homologous products to add as ingredients. Panela, coconut sugar, honey, and fructose develop all these aforementioned effects in the brain.

Other implications of sugar consumption

Sugar not only affects brain health, but it can also damage the function of other organs. In fact, continued consumption of it increases the risk of excess weight and metabolic pathologies in sedentary individuals.

Finally, it should be noted that the inflammatory effects of sugar don’t only affect brain function. Other systems, such as the cardiovascular system, can also be affected.

The importance of sugar in athletes

Although we consider sugar as an ingredient that we should limit in the diet, it’s true that there are cases in which its consumption can be increased. An example would be that of many athletes, who use glucose as the main fuel to carry out their activities.

Within the intake of carbohydrates in the athlete, those of a complex type should always be prioritized. However, sugar has a place before, during, and even after strenuous physical activity. In this way, blood glucose increases, and glycogen stores are replenished, which delays the onset of fatigue once the activity has begun.

Fruit and its carbohydrates

One of the controversial issues today is whether or not to consume fruit, as this food has sugar in its composition. The truth is that vegetables are characterized by their water content. In addition, they have fiber; the fructose inside isn’t representative and is absorbed gradually.

The key is to always consume the whole fruit, avoiding juices or smoothies. In juices, the fiber is discarded, and it generates a higher blood glucose peak. In smoothies, the fiber structure is broken, causing a faster absorption of fructose. Neither of the two scenarios is advisable.

However, it’s important to avoid eating fruit at night. At this time the body tends to metabolize glucose worse due to the natural hormone production that takes place at this time.

This nutrient can also generate an increase in insulin resistance in the medium term, with all that this entails. During the hours of darkness, it’s preferable not to eat food. However, if you do, it should be based on proteins and fats.

Sugar is a harmful substance in large quantities

As you have seen, the effects of sugar go beyond an impact on body composition or metabolic health. There are plenty of effects of sugar on the brain, which increase inflammation and trigger sympathetic nervous system signaling. This situation is related to an increase in stress, as well as a slight feeling of addiction.

For these reasons, it’s important to limit the consumption of sugar in your diet, especially in sedentary people. Athletes can be more permissive about it. It’s essential to ensure adequate nutritional education to learn to read labels.

In this sense, it’s important not to get carried away by marketing and correctly interpret nutritional claims. Sometimes they can lead to error and the industry takes advantage of these situations to increase sales of unhealthy food. If you have any questions about this, don’t hesitate to consult a nutritionist.