The variation in torus palatinus (TP) prevalence was investigated among a total of 2010 dental patients over 10 yr of age native to two different regions in Norway, the Lofoten Islands in northern Norway and the Gudbrandsdalen valley, an inland area in the southeastern part of the country. The two groups were presumed to belong to the same Caucasian stock, but were extremes with regard to the fish-to-meat ratio of the diet, which was 3:1 in Lofoten and 1:3 in Gudbrandsdalen, respectively representing a soft type of diet, and a tough type requiring greater muscular forces during mastication. The study revealed: 1) the prevalence of TP was higher among women than men; 2) TP seemed likely to arise from a multifactorial liability, with part of the genetic factors residing on the X chromosome; 3) the prevalence of TP appeared to be higher among natives of Lofoten, who consume the softer food, than among natives of Gudbrandsdalen, the higher prevalence being hypothesized to have some connection with nutrient substances present in saltwater fish, possibly omega 3 polyunsaturated fatty acids and vitamin D; and 4) TP seemed to be a dynamic phenomenon capable of growth and subject to resorption remodeling.