Milk fat may cause digestive problems
Dairy product consumption is far higher in the West than in areas such as the Middle East, Asia and Africa and studies have shown that many people whose ancestors are not from the West may have problems digesting milk products. Now research from the University of Chicago, US, to be published in Nature, indicates that saturated fats from milk products can lead to inflammatory bowel disease.
Diseases such as inflammatory bowel are a result of immune disorder and they’ve become more common in Westernised societies within the last 50 years or so. While scientists were aware that some people were genetically predisposed to this kind of disease, they couldn’t understand why some genetically-predisposed individuals didn’t get IBD. A diet high in dairy products, they thought, could be the cause. While previous research has shown that milk may contain anti-inflammatory substances – conjugated linoleic acid, for example, has been proven to reduce inflammation – this new research indicates that other substances within milk may do exactly the opposite.
Saturated fat, which makes up about 60% of the total fat in full-fat milk, appears to disrupt the balance of bacteria in the intestines, leading to a detrimental effect on the immune system. By upsetting the balance, harmful bacterial strains are allowed to flourish and can trigger an immune response. Once this immune response has begun it’s very difficult to switch off.
Using mice on low-fat diets as subjects, the researchers ‘turned off’ a gene that usually slows the body’s immune response to bacteria in the intestines. WIthout it, about 25% of the mice developed colitis (inflammation of the large intestine). The same was true when the mice were on a diet high in polyunsaturated fats. But when the mice were put on a diet high in saturated milk fats, the rate of colitis soared to 60%. Their symptoms were also more severe.
The researchers then went on to pinpoint a specific microbe – Bilophila wadsworthia – that appeared to do particularly well when mice had a diet high in milk fat. This bacteria has been linked to intestinal inflammatory disorders. "Unfortunately, these can be harmful bacteria," says study author Dr Eugene B. Chang. "Presented with a rich source of sulfur, they bloom, and when they do, they are capable of activating the immune system of genetically prone individuals."
We in western Europe consume more dairy produce than people in areas such as the Middle East, Asia and Africa and studies have shown that many people whose ancestors are not from the West may have problems digesting milk products. Now research from the University of Chicago, to be published in Nature, indicates that saturated fats from milk products can lead to inflammatory bowel disease.
Such conditions are a result of immune disorder and they’ve become more common in Westernised societies within the last 50 years or so. While scientists were aware that some people are genetically predisposed to this kind of disease, they couldn’t understand why they don’t all get IBD. A diet high in dairy products, they thought, could be the cause. While previous research has shown that milk may contain anti-inflammatory substances – conjugated linoleic acid, for example, has been proven to reduce inflammation – this new research indicates that other substances within milk may do exactly the opposite.
Saturated fat, which makes up about 60% of the total fat in full-fat milk, appears to disrupt the balance of bacteria in the intestines, leading to a detrimental effect on the immune system. By upsetting the balance, harmful bacterial strains are allowed to flourish and can trigger an immune response. Once this immune response has begun it’s very difficult to switch off.
Using mice on low-fat diets as subjects, the researchers ‘turned off’ a gene that usually slows the body’s immune response to bacteria in the intestines. Without it, about 25% of the mice developed colitis (inflammation of the large intestine). The same was true when the mice were on a diet high in polyunsaturated fats. But when the mice were put on a diet high in saturated milk fats, the rate of colitis soared to 60%. Their symptoms were also more severe.
The researchers then went on to pinpoint a specific microbe – Bilophila wadsworthia – that appeared to do particularly well when mice had a diet high in milk fat. This bacterium has been linked to intestinal inflammatory disorders. "Unfortunately, these can be harmful bacteria," says study author Dr Eugene B Chang. "Presented with a rich source of sulphur, they bloom, and when they do, they are capable of activating the immune system of genetically prone individuals."