Casein antibodies and spinal cord damage in mice and MS patients
What it found
Antibodies made against the milk protein casein also attacked a nerve-coating protein, causing spinal cord damage in mice.
People with multiple sclerosis had more of these casein antibodies than people with other brain conditions.
What they found
Studies in people
Higher antibodies in MS patients
Blood from 39 people with multiple sclerosis contained significantly higher levels of antibodies against casein compared to blood from 23 people with other neurological diseases. Among 45 people with multiple sclerosis, 42% had immune cells that reacted to casein, compared to 28% of 35 people with other conditions.
Animal and lab studies
Spinal cord damage in mice
Mice injected with casein developed severe damage to the protective coating of their spinal cord nerves. The damage got worse over time, reaching its peak by day 40. Mice injected with other milk proteins showed no such physical problems.
Cross-reactive antibodies found
In lab tests, antibodies made against casein also stuck to a nerve-coating protein called MAG. This happened because parts of the casein protein look similar to parts of MAG. When researchers removed the casein antibodies from mouse blood, the leftover blood stopped reacting to MAG as well.
Antibodies killed nerve cells
In cell culture dishes, casein antibodies killed nerve-coating cells when a blood protein called complement was present. The dying cells shrank and lost their branches. Blocking complement in living mice reduced the spinal cord damage caused by casein injections.
What the authors conclude
- They suggest that drinking cow's milk might worsen symptoms in some people with multiple sclerosis who have already lost their natural tolerance to casein.
- The authors advise that people with multiple sclerosis who carry casein antibodies might benefit from cutting dairy products out of their diet.
- They call for personalized dietary advice based on each patient's individual immune response.
How it was done
Scientists have long debated whether drinking cow's milk is linked to multiple sclerosis. They wanted to find out if an immune reaction to casein, a common milk protein, could damage the protective coating around nerves.
They injected groups of 4 to 18 mice with cow casein or other milk proteins and examined their spinal cords over 13 to 60 days. They also tested blood samples from 39 to 45 people with multiple sclerosis and 23 to 35 people with other neurological conditions.
What it can’t tell you
- The mice were injected with casein along with strong immune-boosting chemicals, which is not how people consume milk. This means the animal results may not reflect what happens when someone drinks milk normally.
- Finding more casein antibodies in people with multiple sclerosis shows a link, but it cannot prove that milk causes or worsens the disease.
- Only a fraction of the patients tested carried these specific antibodies, so the findings may not apply to everyone with multiple sclerosis.
Who paid
- Conflicts
- The authors declare no competing interest.
- Authors work at
- University of Bonn, Germany; Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany; Rheinische-Friedrichs-Wilhelms University of Bonn, Germany
The paper
- Title
- Antibody cross-reactivity between casein and myelin-associated glycoprotein results in central nervous system demyelination
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Chunder R, Weier A, Mäurer H, et al (2022). Antibody cross-reactivity between casein and myelin-associated glycoprotein results in central nervous system demyelination. Proceedings of the National Academy of Sciences of the United States of America. doi:10.1073/pnas.2117034119Free full textPubMed 35235454DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error