What a person eats in childhood can influence their future risk of developing multiple sclerosis (MS) and its clinical course, according to a recent Dutch study. A poor diet with more fast food, snacks, and candy as a child tended to be associated with a higher risk of developing MS, with greater intake of oily fish being linked to a three times higher risk. However, eating more fruits and vegetables as adults was associated with more positive outcomes on disability and MRI measures among MS patients. "Overall diet quality and individual dietary components during childhood were associated with adult-onset MS and onset type, but not with age of onset," researchers wrote. These findings may help inform the design of larger studies on diet recommendations for MS patients, they noted. The study, “The role of diet in multiple sclerosis onset and course: results from a nationwide retrospective birth-year cohort,” was published in the Annals of Clinical and Translational Neurology. Nutritional status proposed as MS risk factor. MS is a complex neurodegenerative disease, thought to arise from a combination of genetic and environmental factors. Nutritional status has been proposed as one such factor that can influence not only a person's risk of MS, but also its progression after onset. While several studies have examined the role of diet in MS, generally finding that a healthy or Mediterranean-style diet may be beneficial, “insufficient evidence exists to recommend a specific diet ... in clinical practice,” the researchers wrote. The role of diet in early life might be particularly important for determining outcomes in MS, but few studies have looked at how childhood nutrition impacts MS onset and progression. Now, scientists in the Netherlands examined the link between childhood diet and MS onset, as well as how diet in adulthood affected patients’ disability and MRI measures. They looked at data from 361 MS patients and 125 healthy people who were involved in Project Y, a study designed to identify factors that explain differences in disease expression among all MS patients born in the Netherlands in the year 1966. Participants were about 53 years old at the time of the analysis, and their median age of MS onset was 37.1 years. After a one-day study visit to collect imaging data, neurological assessments, and detailed interviews, patients then completed a set of questionnaires about their dietary intake in childhood (age 10) and adulthood (age 50). Results showed that more MS patients reported being overweight in childhood (12.7%) than healthy controls (4.8%) — a difference that was statistically significant. MS was found more prevalent among people who reported poor overall diet quality and higher consumption of fast food, snacks, and candy, as well as more intake of oily fish, during childhood. In turn, the neurodegenerative disease was less prevalent in people with a higher childhood intake of whole-grain bread. Notably, only the findings related to consumption of oily fish and whole-grain bread reached statistical significance. Problems recalling food intake a limitation of study. Given that oily fish intake has been previously linked mostly to a lower MS risk, the team called for caution in interpreting these data. Problems in food intake recall and the lack of analysis with other food products may have influenced these results. When stratifying by sex, “a higher intake of whole-grain bread during childhood was associated with lower odds of MS in female individuals, but not in males,” the researchers wrote. In turn, lower diet quality and higher intake of fast food, snacks, and candy as a boy was linked to a higher likelihood of having MS in men. No individual dietary component or overall diet quality in childhood was linked to the age of onset of MS symptoms or to the type of MS at disease onset. However, eating more fruit in childhood was linked to lower odds of starting off with relapsing MS for men, but not for women. Diet in adulthood was also associated with certain clinical factors. Specifically, a higher intake of fruits was significantly associated with lower disability levels. Eating more fruits or vegetables was also linked to certain MRI measures, particularly those indicating less tissue volume loss in various brain regions. Eating more red meat at age 50 linked to higher brain lesion volume in patients. Eating more red meat at age 50 was also significantly associated with a higher brain lesion volume in MS patients, but no relationships between oily fish or whole grain bread and MRI measures were observed. Some of these adult diet-related findings were also influenced by sex, and were significant in men but not in women. The overall sex-specific differences observed in the study may be related to sex-specific different nutritional needs or responses to nutrients, the researchers noted, adding that “future studies should not only adjust for sex but also explore sex interaction.” MRI patterns in healthy adults were also linked to dietary intake, but the pattern was distinct from that of MS patients, with no relationship between fruits and vegetables and MRI measures. “Associations of individual food products solely found in [people with MS] may indicate a MS-specific effect,” the researchers wrote, noting, however, that overall diet quality at age 50 was linked to lesion volume in both groups. Interestingly, a “paradoxical” positive relationship between intake of snacks, candy, and fast food at age 50 and several MRI measures were observed in both MS patients and healthy people, where intake of those foods was associated with higher brain volume. The researchers noted it is possible that while tissue volumes were higher, it is not completely healthy tissue. Still, those results should be “cautiously interpreted.” Findings could help in design of long-term studies. Among the study’s limitations was the possibility that participants could have inaccurately recalled their childhood diet, or unintentionally biased their answers. Certain nutritional components were also not accounted for. “Therefore ... we do not aim to make any definitive claims based on our results,” the team wrote, adding that the data still offer “valuable insights” into the relationship between MS and diet. Although not definitive, the findings could help in the design of long-term studies that are “better suited to investigate causality,” the researchers wrote. Such studies will be needed to develop comprehensive dietary recommendations for MS patients, the team concluded.