The Brain: scientific facts
Our brain: Small, but with a big appetite
Although the brain represents only 2% of the body mass, it consumes 20% of the energy provided by the diet and 20% of the oxygen inhaled.
(Benton 2001; quoted from Román GC. Nutritional Disorders of the nervous system. In: Shils ME, Shike M, Ross AC, Caballero B, Cousins RJ, Editor Modern Nutrition in Health and Disease. Philadelphia: Lippincott Williams & Wilkins, 2006: 1362-1380.)
How does our brain actually work?
The brain is the most metabolically active organ in the body, accounting for approximately 20% of the basal metabolic rate and only 2% of body weight. Unlike other organs in the body, under normal circumstances, the brain uses glucose almost exclusively as its source of energy. The brain is reliant on a continuous glucose supply although glucose stores are extremely small. Without replenishment, the glucose reserves of the brain will be used in approximately 10 minutes.
(Quoted from Benton D. The impact of supply of glucose to the brain on mood and memory. Nutr Rev, 2001; 59: S20-S21.)
important for the brain
Glucose: a key component in brain function
Our brain needs large amounts of glucose, consuming more than half of the glucose present in the body. In stressful situations – during high mental performances – it can even take up to 90 percent. However, the brain is not able to store glucose – not even small amounts. It can only help itself from blood glucose and from stores that the body has built up in the liver (glycogen).
An important carbohydrate
Glucose: a significant carbohydrate
Carbohydrates are an important part of our diet. They cover 40 to 55 percent of our energy, while fat and protein supply the remaining part. Therefore, carbohydrates build a considerable part of our nutrition.
Carbohydrates are absorbed very quickly by the body when consumed as single building blocks. So-called simple sugar (dextrose or glucose) is the basic unit of carbohydrates. In many foods, however, glucose is not present in this free and easily absorbable form but is instead found as more complex structures. Complex means that the individual building blocks have formed pairs, along with short and long chains. These are called double (di-saccharides) or multiple sugars (polysaccharides). They include different sugars such as malt sugar, beet sugar and starch.
The Effect of
Compared to other nutrients we consume, glucose is absorbed into the blood stream the fastest. In order to verify this, a study was carried out at the University of Freiburg, at the department for sports and sports science (IfSS). The glycaemic index of different foods (such as bananas) was determined and compared to that of dextrose.
Dextrose versus Banana
In line with DIN standardised testing methodology, the panel was first given Dextro Energy tablets followed by bananas, containing a comparable amount of carbohydrates. The blood sugar was then measured after 5 minutes.
The results were statically significant. Five minutes after consuming Dextro Energy tablets the blood sugar rose up to 20% from the initial value, while it rose only up to 5% following the consumption of bananas with a comparable amount of carbohydrates. The blood sugar continuously rose until 30 minutes after sampling – however, the blood sugar level was significantly higher after consumption of dextrose (in average up to 80% from the initial value) than after consumption of bananas (in average up to 40% of the initial value).
The muscles as
the main competitor
The muscles are the brain’s biggest competitors when it comes to dextrose consumption. As a result of physical exertion, their demand also increases rapidly. Unlike the brain, they can store carbohydrate in the form of glycogen.