Eating a healthful diet that is rich in vegetables, fish, legumes, eggs, and poultry is tied to a lower risk of multiple sclerosis, a long-term disease that affects the brain, spinal cord, and optic nerve in the eyes.
This was the conclusion that researchers from Australia came to after studying links between diet and central nervous system (CNS) demyelination, which is often the first stage of multiple sclerosis (MS).
The condition occurs when there is loss of, or damage to, the fatty insulation surrounding nerve fibers that carry signals to and from brain cells.
The researchers analyzed data on nearly 700 people across Australia. They report their findings in a paper now published in the Multiple Sclerosis Journal.
"There are a number of known environmental risk factors for MS," explains lead study author Dr. Lucinda J. Black, from the School of Public Health at Curtin University in Perth, Australia.
However, as she and her colleagues note, the evidence on links between diet and MS was "inconclusive."
MS and demyelination
MS is a long-term and unpredictable disease. Its symptoms might persist and gradually worsen, or they may come and go. There are four types of MS, depending on the pattern of symptoms and how they progress.
Many researchers believe that in MS, the immune system attacks healthy myelin in the brain, spinal cord, and optic nerve as if it were a threat. Eventually, the damage also affects the fibers and cells and disrupts signals from the senses and for controlling movement.
Symptoms vary widely, depending on the location and severity of the myelin damage. They include but are not limited to: vision problems, loss of coordination and balance, speech difficulties, numbness, tremors, memory and concentration problems, acute fatigue, and paralysis.
According to the National MS Society, there are more than 2.3 million people worldwide living with MS.
An accurate official figure for the number of people diagnosed with MS in the United States is not available, but a study that released preliminary findings in 2017 suggests it is around 1 million.
While MS can develop at any age, most cases are diagnosed in people aged 20–50. Women are three times more likely to develop MS as men.
Dr. Black and her colleagues investigated links "between dietary patterns and risk of a first clinical diagnosis" of CNS demyelination.
They analyzed data from the 2003–2006 Ausimmune Study, which took place in several centers across Australia.
The data included answers to detailed questionnaires about the types of food that people ate and how often they ate them. By analyzing the main food components, the researchers identified two main eating patterns.
One "dietary pattern" was a healthful diet that was high in fish, eggs, poultry meats, legumes, and vegetables.
The other was a "Western-style" diet that was high in full-fat dairy foods and red meats and low in nuts, fresh fruits, wholegrains, and low-fat dairy foods.
The researchers note that the two diets accounted for 9.3 and 7.5 percent of the variability in the eating patterns, respectively.
A 50 percent reduction in MS risk
Of the 698 people whose data the team analyzed, 252 were diagnosed with CNS demyelination and 446 were "healthy" controls.
The results showed that a higher consumption of healthful foods was linked to a lower risk of a first diagnosis of CNS demyelination.
Compared with the individuals who consumed the least, the reduction in risk in those people who consumed the highest amounts of healthful foods was around 50 percent, says Dr. Black.
"This finding is especially relevant to those who currently consume low amounts of these foods," she adds.
The scientists suggest that there is a need to improve education about how to follow a healthful diet for those who are at high risk for MS.
"As MS is a condition that currently cannot be cured, it is important to provide accurate advice to people who are at a higher risk of getting the condition, as this could help to improve their lifestyle and diet."
Dr. Lucinda J. Black