Dietary management in multiple sclerosis

Zntroduct ionThere are three current views on the cause of multiple sclerosis (MS): nutrition, viral infection and autoimmune reaction.Interest in nutrition arose from studies on the epidemiology which indicated a high prevalence in countries with relatively high saturated fat intakes; in addition, low levels of essential fatty acids (EFA) were recorded in the blood of MS patients (Swank, 1950;Swank et al. 1952;Sinclair, 1956;Agranoff & Goldberg, 1974).The conclusion was drawn that MS might be related to a dietary deficiency of polyunsaturated or EFA (Swank, 1950;Sinclair, 1956;Allison, 1963; Bernsohn & Stephanides, 1967;Dick, 1976).These findings led to a double-blind trial of linoleic acid supplementation in Belfast and London and later in Newcastle (Millar et al. 1973; Bates et a f .1978), which gave encouraging results.The 'linoleic acid effect' is the reason for the current interest in diet and MS.The interest in EFA centred principally on linoleic acid.However, Bernsohn & Stephanides (1967) suggested that of the two EFAs, linoleic and a-linolenic acids, the evidence pointed more to dietary deficiency of a-linolenic acid.They called attention to epidemiological information which seemed to indicate that the geographical distribution of MS was inversely related to the intake of foods rich in a-linolenic acid and its derivatives ( 0 3 fatty acids), such as fish.This proposition arose because of the relatively low incidence of MS found in the Faroe Islands, compared to the Shetlands.The Islanders came from the same Danish genetic backgrounds but the Faroe Islanders remained as fishermen whilst the Shetlanders adopted a British agricultural practice.Similar contrasts were apparent in Scandinavia.The matter has not been followed up, possibly because of the lack of any supporting evidence that 0 3 fatty acids have a nutritional role.However, there is now a substantial amount of analytical information demonstrating the presence of long chain 0 3 fatty acids in the central nervous system (Crawford, Casperd et al.Dick (1976) suggested that the use of cow's milk as a substitute for human milk might be relevant to the aetiology of MS.Two possible mechanisms could be proposed.First, cow's milk is thought to cause allergies (Gerrard et al. 1973;Walker & Hong, 1973).Secondly, cow's milk has about three times as much .