MS is a chronic, inflammatory condition that affects the brain and spinal cord, causing lesions and affecting muscle strength and movement. Loss of the myelin sheath around the nerves in the brain and spinal cord (demyelination) impairs the conduction of nerve impulses. Certain lifestyle factors, such as low sun exposure, low vitamin D levels and smoking have been shown to increase the risk of developing MS. Although nutritional factors have long been of interest in MS, the link between diet and MS remains unclear.
This project used dietary intake information and blood samples from people with early signs and symptoms of MS, available through studies in Australia and in the US, to investigate whether specific foods or nutrients can help reduce the risk of disease onset and progression in MS. The impacts of dietary factors such as following a Mediterranean diet, consuming foods with anti-inflammatory properties, blood levels of omega-3 polyunsaturated fatty acids and other fats, ultra-processed foods and dairy foods were assessed.
To examine the relationship between diet and MS risk, the researchers studied the first clinical diagnosis of demyelination in the brain and spinal cord (FCD), which is a common precursor to MS. They found that a healthy dietary pattern (high in poultry, fish, eggs, vegetables, legumes) and a Mediterranean diet, including unprocessed red meat, was associated with reduced likelihood of FCD. In contrast, and ultra-processed food intake was associated with higher likelihood of FCD, and a more pro-inflammatory diet was associated with higher likelihood of FCD in women. Total intake of dairy foods was not associated with FCD, but higher consumption of yoghurt was associated with lower risk of FCD.
The researchers also looked at the association of diet with the risk of relapse in early MS, and with disability. A healthy dietary pattern was associated with lower relapse risk in the 5 years following FCD. There was no association between a Mediterranean diet and relapse rate, and no association between dairy consumption and relapse rate or disability. A proinflammatory diet was associated with an increased relapse rate and size of MS lesions in early MS. Higher consumption of ultra-processed foods was also associated with higher relapse rate. These findings suggest that diet may play a role in MS onset and disease progression.
The team also explored the challenges faced by adults with MS when making dietary decisions, and their perceived dietary education needs. People with MS are highly motivated to make dietary changes and improve their health. Interestingly, in this vein, the team looked at associations between omega-3 polyunsaturated fatty acids in the blood, fish oil supplement use and fish consumption, and first clinical diagnosis of central nervous system demyelination (FCD). Having an FCD is associated with increased use of fish oil supplements, suggesting a behaviour change in response to this health event.
Results from this project so far provide new insights into the role of diet in the risk of MS onset. Going forward, further research could also provide evidence that could lead to the development of a clinical trial to test appropriate dietary strategies to reduce progression in the early stages of the disease. The results of this study could also potentially lead to evidence-based dietary recommendations for people with MS and those at high risk of MS.
