Many diets have been proposed as effective MS therapies. For many of these diets, there is no clear underlying rationale or clinical evidence to support their use in MS. Diets for MS that are not supported by a strong rationale or clinical data include allergen-free diets, gluten-free diets, pectin- and fructose-restricted diets, severely sugar-restricted diets, and diets that reduce or eliminate processed foods.

On the basis of scientific, epidemiological, animal model, and clinical trial studies, there is suggestive evidence that diets that are low in saturated fats and high in polyunsaturated fatty acids (PUFAs) may have a therapeutic effect in MS. PUFAs include omega-3 and omega-6 fatty acids. Omega-6 fatty acids include compounds known as linoleic acid and gamma-linolenic acid. Examples of omega-3 fatty acids include eicosapentanoic acid (EPA), docosahexanoic acid (DHA), and alpha-linolenic acid (ALA). The remainder of this section will review three PUFA-related dietary approaches. The first PUFA-enriched diet that was extensively studied in MS was the Swank diet. Subsequently, several MS clinical studies evaluated the effects of supplementation with omega-6 and omega-3 fatty acids.