The increased prevalence of multiple sclerosis among people who were born and bred in areas where goitre is endemic.

The adverse effects of feeding vitamin A deficient diets to newborn infants are found to include an increased propensity for them to fall victim to multiple sclerosis (MS) later in life. When they are artificially fed on cow's milk, this deficiency is accentuated by a number of factors such as the need to dilute the milk in view of its high protein content, births occurring during the winter when the vitamin A content of the milk reaches its lowest value, insufficient selenium (Se) in the cow's forage which is otherwise required to safeguard the vitamin against peroxidation, and finally a lack of iodine in the soil which deprives the cattle of the thyroid hormone thyroxin necessary to effect the conversion of the carotene in their diet to vitamin A. Whichever of these factors preponderates, newborn infants who are fed on cow's milk for the normal period of approximately six months are at risk of suffering from MS.