World Milk Day has been celebrated on 1 June every year since 2001, organised by the Food and Agriculture Organisation of the United Nations. The aim is to recognize the importance of milk as a nutritious food worldwide, highlight the role of the dairy sector in nutrition, and promote the consumption of dairy products and their benefits. Furthermore, it seeks to promote food security, economic development and the consumption of dairy products worldwide.
However, it’s no secret that for many people, having a latte or a yoghurt can be a real nightmare. It’s likely that your body isn’t processing lactose properly, and this is where we want to help you understand why this happens and what’s going on inside your body.
The reason: The key lies in lactase
Lactose is a complex sugar that the body cannot digest. The enzyme lactase is responsible for breaking down lactose into two simple sugars: glucose and galactose.
The lactase enzyme is encoded by the LCT gene. In many people, its expression declines after childhood, leading to lactose intolerance. This expression depends on variants in a regulatory region located within the neighboring MCM6 gene, which controls (increases or decreases) the activity of the LCT gene. Thus, LCT produces the enzyme, whilst variants of MCM6 determine how much is produced.
Polymorphisms in the MCM6 gene, such as 13910C>T, allow LCT to remain active into adulthood (lactase persistence):
- T allele: associated with the persistence of lactase in adulthood.
- C allele: associated with a decrease in LCT expression after infancy, leading to lactose intolerance.
This polymorphism (13910C>T) is the most commonly used genetic marker for diagnosing a genetic predisposition to lactose intolerance.
Another significant polymorphism in the MCM6 gene is 22018G>A:
- A allele: associated with the persistence of lactase in adults
- G allele: associated with a decrease in LCT expression after childhood, leading to lactose intolerance.
OPERON’s LactoStrip is a test designed to identify the two MCM6 gene polymorphisms associated with the persistence of lactase activity in adults: 13910C>T and 22018G>A. This makes it possible to identify a genetic predisposition to lactose intolerance quickly and reliably, making it a useful tool for molecular diagnosis.
