It is well known that our brain needs a certain amount of sugar to thrive. Those resulting from the metabolism of carbohydrates in food are glucose, fructose and galactose.

Glucose is the most common monosaccharide in food and is used by our brain to produce energy. We find it in various foods, from flour to fruit. Once taken with food, glucose is absorbed by the cells of the intestinal wall and, through the circulatory stream, reaches the cells of the various organs, where it is metabolized to produce energy.

Due to its high metabolic requirements, the brain depends on a continuous supply of substances from the blood. As a fairly delicate organ, its protection is entrusted to the blood-brain barrier, which is responsible for regulating the exchange of molecules between blood and brain fluids.

The entry of monosaccharides into cells is done by different specific transporters: sodium-dependent glucose transporters and independent sodium transporters. The latter are called GLUT transporters. Among all of them, GLUT4 transporters, present in the brain in astrocytes, neurons and endothelial cells, are clinically relevant, as they allow glucose to enter cells only after activation by the insulin molecule.

The high concentration of insulin that is released after a meal, when the concentration of circulating glucose in the blood (blood sugar) is high, triggers a series of reactions that leads to the storage of glucose in the form of a reserve molecule called glycogen. Insulin also regulates the functions of brain cells, strengthens the synaptic connections between neurons, helping them to communicate better and consequently remember more easily. Consequently, the drop in insulin caused by excessive sugar intake damages cognitive abilities (Kullmann 2016).

But what happens to glucose once it gets into nerve cells?

In neurons, every molecule of glucose is oxidized through various metabolic processes, through which we get to generate ATP, the true energy molecule of our body.

So the brain relies on sugar to function. This means that the blood glucose level must remain stable. Any decrease in blood glucose levels has an immediate impact on brain function. However, that’s not all! Increased glucose levels can also have consequences, as long-term sustained hyperglycemia damages our cells, causing various diseases (Haghighatdoost 2015).  The brain therefore plays a key role in regulating the level of glucose in the blood to ensure the homeostasis of glucose, its correct balance within our body.

Surely you have experienced a drop in blood sugar at least once. High and low blood glucose peaks and troughs can cause you to experience symptoms such as irritability, sudden mood swings and confusion. Very sugary foods cause an increase in blood sugar levels, followed by a rapid drop. When blood sugar levels drop, you may feel anxious, moody or depressed. This is precisely the symbol of a glucidic imbalance our body is experiencing.

Sugar-rich foods can also interfere with the functioning of hormones and neurotransmitters that help stabilize our moods. Swallowing sugar stimulates the release of serotonin, a neurotransmitter whose effects improve mood. However, constantly activating its production can deplete its reserves, causing symptoms that can contribute to depression.

Chronic blood sugar levels too high have also been linked to brain inflammation. As suggested by several studies, neuroinflammation could be one of the causes of depression and anxiety and can lead to dementia. A group of American researchers found that higher glucose levels are associated with an increased risk of dementia in populations with and without diabetes (Crane 2013). The data found suggest that higher glucose levels may have deleterious effects on brain aging and highlight the potential relationships between elevated levels of glycated or postprandial hemoglobin, glucose levels and dementia-related outcomes. Higher glucose levels may contribute to an increased risk of this disease through several mechanisms, including acute and chronic hyperglycemia, insulin resistance and increased microvascular disease of the central nervous system.

The food choices we make on a daily basis are therefore linked to the likelihood of triggering brain inflammation and causing cognitive decline.

Contrary to popular belief, even consuming excessive amounts of fruit can be harmful to our nervous system. If consumed in low quantities, the liver metabolizes fructose into glucose, but if consumed in excess, the fructose pours into the bloodstream and can enter various organs, including the brain. Studies in humans and animals have shown that the brain reacts to high fructose intake. Studies show that fructose activates areas of the brain other than those activated by the ingestion of glucose; in addition, the fructose load does not decrease the feeling of hunger compared to the decrease we feel if we “eat” glucose (Page 2013; Lowette 2015). The excessive consumption of fructose therefore pushes our organism to the constant search for food. In addition to this effect that leads the population to hyperphagia, it has been shown that excessive fructose consumption alters other brain functions including cognition and mood (Wu 2014).

In addition, as described in our previous article, a growing body of research suggests that a sugar-rich diet may be one of the factors increasing the risk of Alzheimer’s disease. Help could come from galactose, which does not require insulin to enter cells. In this regard, Cerebro® has developed Brain Aktiv, composed of strong D-galactose with 100% vegetable extraction.

However, in some areas of the brain, neurons can use “other fuels” than glucose. This is the case with ketone bodies, which we will talk about soon.

What can be deduced from the various researches that are emerging in the thriving field of neuronutrition is that a correct supply of sugars to the brain is important to maintain homeostasis and avoid large oscillations that can cause neuronal damage. Therefore, a correct lifestyle is crucial in determining a healthy aging of our brain.

eat less sugar written on sugar over black background

All these topics were covered in the webinar, promoted by Cerebro® on May 15.

If you are interested in purchasing Brain Aktiv click on the link.

Dr. Rosjana Pica


In collaboration with Staff Cerebro®

Cerebro®, Start-Up in High-Tech and Innovative Neuroscience aims to help and support patients in associated studies and clinics through different methods and approaches to improve the perception and quality of life of each individual