Milk sugar is the natural carbohydrate of milk. Around 4.7 percent are contained in whole milk, 4.8 percent in low-fat milk (1.5 percent fat). Milk sugar is broken down about four times more slowly and is introduced into the metabolism as an energy source as table sugar. For many everyday situations, such as the office job, this is an advantage: Rarely is a quick "energy injection" needed. What is more in demand are small portions of sugar that are available throughout the day as an energy source.
Metabolism: processing of lactose in the body
Milk sugar is a double sugar and consists of glucose and galactose. By the enzyme ß-galactosidase (lactase) the milk sugar is split during the intestinal passage into its building blocks. Glucose is introduced directly into the energy metabolism. Not so the galactose, it has to be further degraded to glucose. Then it is also used for energy.
The lactase is much less active than the enzyme sucrase, which breaks down the double sugar sucrose (table sugar) into its building blocks. The slower degradation is due to the necessary further remodeling of galactose and the lower enzyme activity of lactase. The protein and the fat in the milk additionally delay the breakdown and the introduction of the sugar into the metabolism.
Milk as a sustainable energy supplier
This delayed release of milk sugar has a positive effect: milk gives energy over a longer period of time and it only comes back later on hunger.
Incidentally, even before or after the sport milk or milk sugar paid as an energy supplier. Energy is released in small portions, be it before training for the subsequent athletic performance or after training for regeneration.
Lactose for a healthy intestinal flora
Milk sugar causes a pH reduction in the intestine via its degradation product lactic acid. This fights off germs and fungi that are less likely to multiply in the gut.
Milk sugar helps to restore a healthy intestinal flora after intestinal infections. It is positively associated with the gut-localized immune system. Bacteria are essential for a healthy intestinal flora. Part of the lactose is not split, but serves as a food for the bacteria of the large intestine. Above all, the beneficial for the intestinal flora lactic acid bacteria use lactose.
Lactose promotes calcium absorption
Lactose promotes the absorption of the important mineral calcium from the intestine. Responsible is probably the lactic acid. It ensures a low pH in the intestine. The acidic environment improves the availability and solubility of calcium.
Lactose for a controlled digestion
Milk sugar has long been known as a home remedy for controlled digestion. And this is how it works: The lactic acid produced during bacterial decomposition binds water in the intestine. The effects are similar to those of fiber: The stool volume increases and the intestinal muscles are stimulated, so that the chyme is quickly transported on.
Lactose - the one joy, the other suffering
In some people, lactase activity decreases over the course of life, it is called lactose malabsorption. About 15 percent of the German population are affected. Only when so much lactose gets undigested into the large intestine, that it comes to complaints such as painful flatulence or diarrhea, it is called lactose intolerance.
Lactose intolerance does not mean that dairy products are no longer tolerable per se. Dairy products with lower milk sugar content, for example sour milk products or hard cheese, can often be eaten without any problems. The tolerability is individually different and must be determined individually.