Milk protein found to trigger MS symptoms
Multiple sclerosis (MS) begins in patients when their body’s immune system destroys the insulating layer around nerve fibres or neurons. Researchers from the Universities of Bonn and Erlangen-Nuremberg, Denmark, recently confirmed how dairy products, such as milk, yoghurt, or cottage cheese, can trigger neurological damage associated with MS.
MS patients have long suggested that cow’s milk products exacerbate symptoms: “We hear again and again from sufferers that they feel worse when they consume milk, cottage cheese or yogurt,” said Professor Stefanie Kürten from the Institute of Anatomy at University Hospital Bonn.
Researchers discovered the cow milk constituent casein was the main culprit. Tests with mice administered casein revealed damage to the myelin sheath of nerve fibres, a fatty insulating layer crucial to their stimulus conduction.
“We suspected that the reason was a misdirected immune response, similar to that seen in MS patients,” explained Rittika Chunder, who is a postdoctoral fellow in Prof. Kürten’s research group. “The body’s defenses actually attack the casein, but in the process, they also destroy proteins involved in the formation of myelin.”
The researchers additionally came across a protein similar to casein called MAG, such that antibodies to casein were also seen to be active against MAG in the mice, and further destabilising the myelin.
White blood cells, particularly the B cells, are responsible for antibody production. The B cells in the blood of MS patients are indeed sensitive to casein, producing masses of casein antibodies whenever the patients consume dairy products; due to cross-reactivity with MAG, the antibodies also damage the myelin sheath around the nerve fibres.
The researchers note that this mechanism is only likely to occur in people with a preexisting dairy allergy. The researchers are developing a self-test with which affected individuals can check whether they carry casein antibodies.
While some observational studies have detected higher rates of MS in populations that consume large volumes of cow milk, Prof. Kürten mentioned a casein allergy alone is not enough for someone to develop MS, as there are several other known risk factors that must coalesce for the disease to progress.
