IODINE IN BRITISH FOODS AND DIETS

Levels of I were determined in selected foods and dietary supplements, and in samples of the British 'Total Diet'. The average concentration of I in British milk collected in thirteen areas on four occasions during 1990 and 1991 was 150 mu g/kg (range 40-310 mu g/kg), compared with 230 mu g/kg in 1977-79. No difference was found between skimmed and whole milk. Winter milk contained 210 mu g/kg while summer milk contained 90 mu g/kg. Regional differences were less pronounced than seasonal differences. Levels in fish and fish products were between 110 and 3280 mu g/kg. Edible seaweed contained I levels of between 4300 and 2660000 mu g/kg. Kelp-based dietary supplements contained I at levels that would result in a median intake of 1000 mu g if the manufacturers' recommended maximum daily dose of the supplement was taken, while other I-containing supplements contained a median level of 104 mu g in the manufacturers' maximum recommended daily dose. Intake of I, as estimated from the Total Diet Study, was 173 mu g/d in 1985 (277 mu g if samples with very high I contents were included) and 166 mu g/d in 1991. These levels are above the UK reference nutrient intake of 140 mu g/d for adults but well below the Joint Expert Committee on Food Additives provisional maximum tolerable intake of 1000 mu g/d.