For young nonsmokers, following Mediterranean diet may slash MS risk
New Swedish study finds risk cut by over 70% for adults 45 and younger
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- Following a Mediterranean diet may significantly lower a person's risk of developing multiple sclerosis, according to a new study from Sweden.
- The benefits of closely adhering to this diet were most pronounced among nonsmokers and people younger than 45.
- The study found high adherence to the diet can reduce MS risk by more than 70% for young nonsmokers.
Closely following a Mediterranean diet — which involves eating lots of fruits, vegetables, and whole grains, and limiting intake of processed and sugary foods — is associated with a significantly lower risk of developing multiple sclerosis (MS), a large Swedish study has found.
The benefits, however, were seen mostly among nonsmokers and people younger than 45. Reductions in MS risk were not observed for smokers and older people, the researchers noted.
“In this large prospective … study, a higher Mediterranean diet [adherence] score was associated with a substantially lower risk of MS. The association was particularly strong among nonsmokers, whereas no association was observed among smokers, suggesting a potential interaction between dietary patterns and smoking,” the team wrote.
According to the researchers, “these findings underscore the significance of lifestyle factors as potential modifiers of diet-disease relationships” in MS.
The study, “Mediterranean diet and risk of multiple sclerosis: A prospective cohort study,” was published in the Multiple Sclerosis Journal.
MS is known to be influenced by several genetic and environmental factors, and diet may be one of them. Some dietary patterns may increase the risk of obesity, which causes chronic inflammation and sets the stage for MS. Other diets, meanwhile, can boost the body’s anti-inflammatory and antioxidant defenses and help protect from the disease.
Little data on Mediterranean diet’s impact on MS risk
The Mediterranean diet, based on foods commonly eaten in countries and cultures surrounding the Mediterranean Sea, is an overall eating plan rich in fruits, vegetables, lean proteins, and whole grains. It uses olive oil as the main source of fat. Conversely, it limits red meat, sweets, and animal fats.
This diet has been linked to a lower risk of Alzheimer’s and Parkinson’s disease, likely due to its anti-inflammatory and antioxidant properties. Emerging evidence suggests it may also reduce the risk of developing MS, but data to date have been limited.
To learn more, a team of researchers in Europe examined data from the Swedish National March Cohort, which collected medical and lifestyle data — including dietary information from the previous year — from more than 43,000 participants at a single point in time in 1997. These individuals were then followed over the ensuing decades.
Of the 41,428 participants eligible for analysis, 89 developed MS over a mean follow-up of 17.6 years, the researchers found.
Adherence to the Mediterranean diet was assessed using the Mediterranean Diet Score, which ranges from zero to nine and assigns points for greater intake of foods considered beneficial, such as fruits, vegetables, fish, and healthy fats. It also gives point scores for less favorable foods, such as meat and dairy products. Moderate alcohol intake was also scored positively in this study.
The results showed that each one-point increase in Mediterranean diet adherence was associated with a 14% lower risk of developing MS after adjusting for potential confounding factors, according to the researchers.
“Adherence to the Mediterranean diet was inversely associated with MS risk, supporting its potential neuroprotective role,” the team wrote.
When participants were categorized as having low, medium, or high adherence to a Mediterranean diet, only the high adherence group had a lower risk of MS compared with the low-adherence group, though these results failed to reach statistical significance.
Smoking eliminates any benefits gleaned from diet: Study
When the researchers looked more closely, they found that the protective effect of the Mediterranean diet depended strongly on smoking status.
“We found a 26% lower risk among nonsmokers … while no risk reduction was seen among smokers,” the team wrote.
Specifically, among nonsmokers, each additional point on the Mediterranean diet score was associated with that 26% lower MS risk. Those with the highest adherence had a significant, 81% lower risk compared with individuals with the lowest adherence, the researchers noted.
Age also played a role, according to the team. Among participants ages 45 or younger, a one-point increase in the Mediterranean diet score was linked to a 23% reduction in MS risk. Those in the highest adherence group showed a 72% lower risk compared with the group with the lowest adherence.
Similar to the smoking findings, no lower association between diet and MS risk was seen in participants older than 45, the team noted.
Our findings suggest a potential protective effect of the Mediterranean diet against MS, particularly among younger individuals and nonsmokers.
Additional analyses excluding MS patients diagnosed within the first two years of follow-up produced similar results, suggesting the findings were unlikely to be explained by early, undiagnosed disease affecting dietary habits.
“Our findings suggest a potential protective effect of the Mediterranean diet against MS, particularly among younger individuals and nonsmokers,” the researchers wrote, stressing, however, that these results “must be interpreted with caution.”
Among the study’s limitations were the narrow participant group and the patients’ overall somewhat older age at the start of the assessments.
The team noted that additional studies tracking dietary habits over time, particularly in younger and more diverse populations and accounting for genetic and environmental risk factors, are needed to confirm these findings.
