One of the few beneficial claims made by advocates of raw milk is that drinking it helps alleviate the symptoms of lactose intolerance due to the presence of the lactase enzyme.
This enzyme is thought to break down lactose sugar thus, reducing the symptoms of lactose intolerance such as bloating, abdominal discomfort, nausea, diarrhoea and flatulence.
But how much of this is true and based on actual scientific evidence?
Breakdown of lactose
All mammalian milk including breast milk contains lactose – it is the principal carbohydrate and energy source within milk.
Lactose is synthesised in the mammary epithelial cells from the glucose and galactose in our diet that is absorbed from the blood.
When we consume this milk, the lactase (β-galactosidase) hydrolyses it back into glucose and galactose. It is then absorbed by the body of the consumer for energy.
People with lactose intolerance are unable to break down lactose sugar due to problems with their lactase enzyme. This in turn usually stems from the lack of production of the lactase enzyme by the small intestine.
Debunking the myth
So, does raw milk alleviate lactose intolerance symptoms?
A randomised controlled trial studied the effect of raw milk on 16 lactose-intolerance individuals using self-reported lactose intolerance and lactose malabsorption confirmation tests via hydrogen (H2) breath test.
The study found that raw milk failed to reduce lactose malabsorption or lactose intolerance symptoms compared with pasteurised milk among adults positive for lactose malabsorption.
This was because there is no β-galactosidase enzyme present in raw milk to begin with hence, there is no obvious reason why raw milk could assist with lactose intolerance.
The study found that raw milk failed to reduce lactose malabsorption or lactose intolerance symptoms compared with pasteurised milk among adults.
As there is no β-galactosidase enzyme present in raw milk, there is no reason why raw milk could reduce the symptoms of lactose intolerance.
Although raw milk does contain low levels of some proteases and lipases, it does not contribute to any significant physiological role in human digestion and this enzyme would not be denatured by the process of pasteurisation because they are relatively heat-stable.
Furthermore, raw milk enzymes are likely to be hydrolysed because of our stomach acid and pepsin.
Instead, dairy products that do contain this β-galactosidase enzyme is yogurt. Yogurt contains bacteria that produces this enzyme, making it tolerable to individuals who are lactose intolerant.
This article first appeared in hellodoktor.com and was reviewed by Panel Perubatan Hello Doktor. The Hello Health Group does not provide medical advice, diagnosis or treatment.