Products
Glucose is found in numerous medicines, medical devices, in dietary supplements, and in countless natural and processed foods (e.g., bread, pasta, candy, potatoes, rice, fruits). As a pure substance, it is available as a pharmacopoeia-grade powder in pharmacies and drugstores.
Structure and properties
D-glucose (C6H12O6, Mr = 180.16 g/mol) is a carbohydrate belonging to the monosaccharides (simple sugars) and to the aldohexoses (aldehyde, C6 sugars). It exists as a white, crystalline powder with a sweet taste and is easily soluble in water. Glucose monohydrate (- 1 H2O), which contains one molecule of water. Glucose is usually obtained from starches by enzymatic or acid hydrolysis. Glucose syrup is also added, especially for food, which is an aqueous and viscous solution produced from starch and may contain oligo- and polysaccharides in addition to glucose. Glucose is a natural substance found, for example, in sweet fruits such as grapes and in honey. The household sugar (sucrose) consists of a molecule of glucose bound to a fructose (fruit sugar). In milk sugar it is bound with galactose. Maltose is a disaccharide with two glucose molecules. Oligosaccharides such as maltodextrin are composed of a few and polysaccharides such as starch and glycogen are composed of hundreds to thousands of glucose units linked together. The most abundant glucose in plants is cellulose, but it is indigestible to humans.
Effects
In the human body, glucose plays a central role in energy production and the synthesis of the energy carrier adenosine triphosphate (ATP), and as a substrate for the biosynthesis of numerous metabolites (e.g., fatty acids, lipids, amino acids, carbohydrates, neurotransmitters). This in the context of glycolysis (glucose breakdown), the citrate cycle and the respiratory chain in the mitochondria. Glycolysis produces pyruvate, which is important for biosyntheses. In the form of polymeric glycogen, glucose is also used as a carbohydrate and energy store and is stored for this purpose in the liver, for example. Finally, the body can also produce glucose itself with the help of gluconeogenesis (formation of new glucose). This is necessary because the concentration in the blood must always be maintained. Thus, the brain depends on a continuous supply and consumes over 120 g per day. If the blood glucose level drops sharply, for example due to an insulin overdose, dangerous hypoglycemia (low blood sugar) results. Conversely, an excessively high glucose concentration in the blood caused by an insulin deficiency and insulin resistance leads to diabetes mellitus. This is referred to as hyperglycemia. Blood glucose levels are regulated by the hormones insulin and glucagon, among others. The glucose in the body therefore comes mainly from three sources. First, from food; second, from the breakdown of glycogen (glycogenolysis); and third, from the formation of new glucose (gluconeogenesis).
Indications for use (selection)
Pharmaceutical, medical and food technology applications of glucose include (selection):
- As a sweetener, sweetener, flavor corrector and preservative.
- As a tonic.
- In infusion solutions, among other things, for the supply of carbohydrates and for parenteral nutrition.
- For the treatment of diarrhea and vomiting in the form of oral rehydration solution.
- For the treatment of hypoglycemia (low blood sugar).
Dosage
Nutrition societies recommend that about 50% of daily energy needs should be met with carbohydrates. This includes other representatives from this group.
Adverse effects
Glucose is essential for life and not unhealthy per se. However, it has a high calorific value and, if consumed in excess, especially in the form of sucrose, can contribute to the development of obesity because it can be metabolized to fatty acids in the metabolism. It can also promote the development of caries.