Diet Quality Scores and Disability Status in People with Multiple Sclerosis

Background: People with multiple sclerosis (pwMS) often express concern as to whether diet could influence their MS. However, little is known as to whether diet quality is associated with disease status in pwMS.

Objectives: To assess the association between overall diet quality and disability and physical/mental functioning in a large cohort of pwMS.

Methods: In 2015 we conducted a cross-sectional study of the North American Research Committee on MS (NARCOMS) registry participants who completed a dietary screener questionnaire (DSQ). The DSQ was originally developed by the National Health and Nutrition Examination Survey (NHANES) to provide an assessment of diet composition when full information on diet is unavailable. It estimates intakes of fruits, vegetables and legumes (FVL), whole grains, added sugars, and red/processed meats. We constructed an overall diet-quality score based on responses to the DSQ by assigning participants to sex-specific quintiles of each of the five DSQ food-groups. We assigned scores for FVL and whole grains based on the individual’s quintile ranking. Scores for red/processed meats and added sugar intake were inverted [e.g. individuals in the lowest quintile received a score of 5] as lower intake is desired. We summed individual food-group scores to obtain an overall diet score, ranging from 4 (poor diet quality) to 20 (high diet quality). We assessed the association between diet quality and disability status (using the Patient-Determined Disease Steps) and mental/physical functioning (depression, fatigue, cognition, mobility, vision, pain, spasticity, tremor and sensory) using proportional odds models adjusting for age, gender, income, body mass index, smoking status and disease duration.

Results: The 7418 (68%) responders had average diet quality-scores of 11.9 (SD: 3.1). Individuals with higher scores tended to be older, leaner and non-smokers. Participants with diet-quality scores in the top quintile had lower levels of disability (proportional odds ratio [OR] for Q5 vs. Q1: 0.80; 95% CI: 0.69-0.93; P_trend=0.005) and lower depression scores (proportional OR for Q5 vs. Q1 1: 0.82; 95% CI: 0.70-0.97; P_trend=0.01). Diet quality scores were not associated with other physical or mental functioning scales.

Conclusions: Our large cross-sectional survey suggests diets characterized by high intakes of FVL and whole grains and low intakes of sugar and red meat are associated with lesser disability and depressive symptoms in pwMS.