Despite this confusion, a study of 1,368 patients with fibrocystic disease of the breast published in 1993 reported the beneficial effects of 5mg iodine ingested daily for approximately one year.
No adverse affect on the thyroid was observed in some 4,000 patients supplemented with iodine for as long as three years with a daily intake ranging from 12,500µg to 50,000µg (126, 127).
Literature research conducted by Dr Guy Abrahams* showed that 60 million Japanese consume a daily average 13,800µg (13.8mg) of elemental iodine, and Japan is one of the world’s healthiest nations based on overall well-being and cancer stastistics (119).
“Either the Japanese are mutants, capable of thriving on toxic levels of iodide, or we have been grossly deceived, and the human body needs at least 100 times the RDA, which was established very recently in 1980 and confirmed in 1989” (120).
There is no international agreement on a maximum safe daily intake of iodine. World Health Organisation guidelines place a safe maximum daily intake at 1000µg.
The UK Government adheres to an RNI of 150µg over 10 years of age whilst in America this is 200µg. UK Government statistics place the average daily consumption of iodine from ‘an average diet’ at 250µg per day.
The British Health Food Manufacturers Association advises that food supplements should not deliver more than 500µg per day which would deliver about 750µg (0.75mg) per day if the government’s ‘population average daily intake’ is added to the HFMA figure.
Few cases of toxicity have been reported in people with intakes of up to 5,000µg (5mg or 0.005g) per day although transient mild effects have been demonstrated in individuals who were previously deficient in iodine.
Normal subjects with an intake of 1000-2000µg per day showed increased iodine concentration in the thyroid but no other changes. In 1991 the UK Government’s Department of Health’s Panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy recommended that the safe upper intake should not exceed 1,000µg (1mg) per adult per day over 10 years of age - or 17µg (0.017mg) per kilogram of body weight (121).