People who consume more milk may be at lower risk of developing diabetes, study finds

The researchers found a very high prevalence of lactase non-persistence in the Thai population. However, they failed to find a significant difference in milk consumption frequency with the lactase non-persistence status.

Lactose is found in mammalian milk such as human milk or cow’s milk, and is one of the most commonly consumed disaccharides in humans. Lactose digestive and absorptive capacity is dependent on the proper gene expression of lactase-phlorizin hydrolase (LCT), also called as ‘lactase’ enzyme, at the enterocytes in conjunction with an intact small intestinal mucosa.

Previous studies have revealed that people with genetically defined lactase non-persistence have a lower intake of dairy which may increase the risk of several non-communicable diseases. Also, lactase non-persistence itself has been linked with insulin resistance. However, data is limited on lactase non-persistence status and dairy intake in developing countries.

Wichai Aekplakorn, Mahidol University, Bangkok, Thailand, and colleagues, therefore, aimed to define 1) the prevalence of lactase non-persistence in people with diabetes and without diabetes in Thai population 2) the links between lactase non-persistence, milk consumption, and diabetes risk.

For this purpose, the researchers conducted a case-control study including participants of the National Health Examination Survey. DNA isolation was done from the blood for LCT −13910C>T (rs4988235) polymorphism and processed using the MALDI-TOF Mass Spectrometry MassARRAY Typer v4.0 and Bio-rad c1000 touch thermal cycler at the Center for Medical Genomics, Faculty of Medicine Ramathibodi Hospital.

Cases were the 1,756 participants with a previous diagnosis of diabetes or fasting plasma glucose ≥126 mg/dL versus 2,380 controls. A total of 4,136 participants were included 62% female, and 98.8% were > 30 years old.

The study led to the following findings:

• Homozygous CC genotype (i.e., lactase non-persistence) was noted in 98.6% and only 1.4% carried heterozygous CT.
• 76% of the participants consumed milk <1 portion/month.
• Participants with either CC or CT genotype had comparable milk consumption and the risk of diabetes mellitus.
• Males, lower education, and older adults had a lower chance of consuming milk at least one portion per month.
• Besides various baseline variables, higher milk consumption was found to be associated with a lower risk of diabetes

"We found a very high prevalence of lactase non-persistence as defined by CC genotype in the Thai population with a small proportion with CT genotype (i.e., LP population)," the researchers wrote.

The team failed to demonstrate a significant difference in the frequency of milk consumption and DM risk concerning the LNP/LP genotypes. However, they noted that higher milk consumption showed a tendency to attenuate the risk of hyperglycemia and metabolic syndrome and hyperglycemia.

"There is a need for further population-based studies on milk consumption associated with the risks of subsequent hyperglycemia or DM," the team concluded.

Reference:

Tanpowpong, P., Aekplakorn, W., Chariyalertsak, S., Kessomboon, P., Assanangkornchai, S., Taneepanichskul, S., & Neelapaichit, N. (2023). Higher milk consumption is associated with a lower risk of diabetes mellitus: A case-control study. PLOS ONE, 18(8), e0289762. https://doi.org/10.1371/journal.pone.0289762