Nutrition facts in multiple sclerosis

Multiple sclerosis (MS) is a chronic and autoimmune disease of the central nervous system, leading to focal breakdown of the myelin sheath and axonal damage. There are two main forms of MS: relapsing-remitting (RRMS) and primary-progressive (PPMS). Both forms are inflammatory in nature, but disease-modifying therapies are currently available only for RRMS, not for PPMS. However, MS is a complex and multifactorial disease, with a possible influence of environmental factors, including dietary habits and lifestyle, and it may be expected now that they may exacerbate or ameliorate MS symptoms by modulating the inflammatory status of the disease, both in RRMS and in PPMS. This can be achieved by controlling the metabolic and inflammatory pathways in the human cell, as well as the composition of commensal gut microbiota and intestinal inflammation. What increases inflammation are energy-dense Western-style diets, characterized by high salt, animal fat, red meat, sugar-sweetened drinks, fried food, low fiber, and lack of physical exercise. The persistence of this type of diet, on one hand up-regulates the metabolism of human cells toward biosynthetic pathways, including the synthesis of pro-inflammatory molecules, on the other hand leads to a dysbiotic gut microbiota, alteration of intestinal immunity, and low-grade systemic inflammation. Conversely, exercise and calorierestricted diets based on the assumption of vegetables, fruit, legumes, and fish act on nuclear receptors and enzymes that up-regulate oxidative metabolism, while down-regulating the synthesis of proinflammatory molecules, and restoring or maintaining a healthy symbiotic gut microbiota. Dietary supplements, such as polyphenols, omega-3 long-chain polyunsaturated fatty acids, alpha-lipoic acid, vitamin D, vitamin A, niacin, vitamin C, prebiotics and probiotics may be added to the diet to achieve a more robust anti-inflammatory nutritional intervention. Taken together, we have now a better knowledge of the possible influence of dietary factors on cell metabolism and gut microbiota, and thus on their possible effects on MS. Nutritional clinical trials are needed, but in the meantime it is possible to provide nutritional guidance and physical activity opportunities to MS patients helping them to stay healthy.