Right-handed lactic acid is said to be healthier than left-handed. But, is this really the truth? We explain how the two lactic acids differ and what is behind them.
Lactic acid is found in a wide variety of foods. It is not only found in dairy products, but also in sauerkraut, for example, and as an additive in jams and preserves. Lactic acid is formed in dairy products when lactic acid bacteria convert lactose. The acid ensures that the food does not spoil as quickly and tastes sour. There are two different types of lactic acid: left-handed and right-handed lactic acid. We explain how they differ.
Left-handed and right-handed lactic acid
When scientists want to find out whether they are looking at left- or right-handed lactic acid, they shine light on it. Because the two lactic acids change certain properties of light in different ways: Strictly speaking, light is a wave that oscillates up and down in a certain way. This is called polarization. Left-handed lactic acid turns this polarization (i.e. the direction of oscillation of the light) to the left and right-handed ones to the right.
How can that be? Both types of lactic acid have a slightly different structure. They both contain two bonded carbon atoms, to which one oxygen and one hydrogen atom are attached. In the left-handed lactic acid, both of these little oxygen-hydrogen arms are on the same side, but not in the right-hand one. The right-handed lactic acid is “twisted in on itself”.
Left-handed and right-handed lactic acid: Mixed in nature
Lactic acid is not the only substance that can exist in different forms. Another example is amino acids. What is unique, however, is that both left- and right-handed lactic acid occur in nature. When you eat a food that has lactic acid, it’s usually a mixture of both.
But there are also yoghurts on which the manufacturers advertise that they contain a particularly large amount of dextrorotatory lactic acid. This variant is considered healthier. But is that true?
Is dextrorotatory lactic acid really healthier?
It seems logical that right-handed lactic acid is healthier than left-handed. According to Stiftung Warentest, it is the only one that is a product of human metabolism. In addition, the human body can break down dextrorotary lactic acid more quickly. The body must first convert left-handed lactic acid into right-handed ones in order to metabolize it.
For a long time there was a suspicion that left-handed lactic acid could acidify the blood. However, scientists could not confirm this suspicion. Instead, both variants are considered equally healthy.
Exception: Babies lack the enzyme that converts left-handed into right-handed lactic acid. Therefore they do not tolerate left-turning lactic acid. The Federal Center for Nutrition recommends giving small children sour milk products such as yoghurt only from their first birthday and then only in small quantities. People who are missing part of the intestine sometimes cannot tolerate levorotatory lactic acid either.
Lactic acid for a good intestinal flora
It doesn’t matter whether it’s left-handed or right-handed: lactic acid is healthy.
According to the UGB health platform, lactic acid stimulates digestion, regulates the body’s acid balance and has positive effects on the intestinal mucosa.
In addition, lactic acid occurs together with its producers, the lactic acid bacteria. These support a healthy intestinal flora.
