Classic sugar: where does its dubious reputation come from?

Sugar has always been one of the most important sources of energy for humans. At the same time Classic types of sugar such as glucose, fructose, sucrose and lactose are now heavily criticized. The reasons for this are their high consumption, their widespread use in processed foods and their impact on teeth, digestion and metabolism.

Glucose (dextrose)

Glucose is the body's most important source of energy and is contained in many foods - for example in the form of starch in bread, pasta, rice or potatoes. Sucrose, lactose and malt sugar also partly consist of glucose.
Glucose is viewed critically because it is absorbed into the blood very quickly and can therefore lead to severe fluctuations in blood sugar levels. It also serves as an ideal food source for caries-causing bacteria in the mouth. As it is found in high quantities in low-fiber products such as white bread or sweet drinks, it contributes significantly to excessive sugar consumption.

Fructose (fruit sugar)

Fructose occurs naturally in fruit, vegetables and honey. In the modern diet, however, the majority comes from Sucrose or from industrially used Glucose-fructose syrup. As a result, the intake is significantly higher than originally intended by nature.
Fructose is mainly criticized because the intestine can only absorb limited amounts at a time. Excess fructose ends up in the large intestine, where it can cause symptoms such as flatulence and diarrhea. In addition, fructose is almost exclusively broken down in the liver. If fructose intake is high over a long period of time, this can put a strain on this organ and contribute to increased fat levels.

Sucrose (household sugar)

Sucrose consists of glucose and fructose and is widely used worldwide as household sugar. Annual per capita consumption is over 30 kg - the majority of which comes from finished products such as confectionery, baked goods, muesli and soft drinks.
Sucrose is particularly criticized because it combines several negative aspects: it promotes tooth decay, causes severe fluctuations in blood sugar levels and at the same time supplies large amounts of fructose, which can put a strain on the liver's metabolism.

Lactose (milk sugar)

Lactose is a natural sugar from milk, composed of glucose and galactose. Many adults worldwide can only digest lactose to a limited extent, as the enzyme Lactase decreases in the course of life. With a Lactose intolerance the lactose reaches the large intestine undigested, where it is fermented by bacteria. This leads to flatulence, abdominal pain and other digestive problems.
Lactose is therefore criticized less for its general metabolic effects than for the high number of people who cannot tolerate it.