Dairy fat in junk food linked to bowel disease
A dairy ingredient in junk food may be responsible for rising rates of inflammatory bowel disease and other immune disorders, research suggests.
Scientists believe milk fat upsets the gut ecosystem, causing an influx of potentially harmful bacteria.
In certain individuals, this can trigger an extreme immune reaction, leading to Irritable Bowel Syndrome and conditions such as Crohn's disease and ulcerative colitis.
The discovery may explain why once rare immune disorders have become so common in the West over the past 50 years, US researchers said.
Study leader Professor Eugene Chang, from the University of Chicago, whose findings are reported in the journal 'Nature', said: "This is the first plausible mechanism showing step-by-step how Western-style diets contribute to the rapid and ongoing increase in the incidence of inflammatory bowel disease.
"We know how certain genetic differences can increase the risk for these diseases, but moving from elevated risk to the development of disease seems to require a second event which may be encountered because of our changing lifestyle."
Concentrated milk fat is a powdery substance that is abundant in processed foods and confectionery.
It contains a complex mix of fatty acids, most of which are the unhealthy saturated variety.
Tests carried out by the scientists showed that milk fat alters the composition of bacteria in the gut.
In people with a particular genetic make-up, this can disrupt the delicate "truce" between the immune system and the trillions of bugs -- many beneficial -- that live in the intestines.