Many people older than 50 years still remember the days of goiters, enlarged thyroid glands that developed due to iodine deficiency. Up to a third of the population in many parts of the U.S. were affected with goiters, an unsightly bulge in the neck. With goiter comes thyroid dysfunction of a variety of types, usually low thyroid (hypothyroidism).
Way back in 1924, the FDA instituted a voluntary program to encourage salt manufacturers to add iodine to salt as a public health measure to address this widespread problem. Over the years, especially during the 1950s to the 1970s, most Americans willingly complied and liberally salted anything and everything. Overt iodine deficiency largely became a thing of the past, goiters a rarity.
FDA guidelines suggest iodine content in salt of 45 mg/kg; this means that slightly over one half teaspoon of salt per day, or 3000 mg (1,150 mg sodium), provides the Recommended Daily Allowance of iodine of 150 mcg per day.
But most of us have heard the advice repeated often over the past 20 years to reduce sodium and salt intake ¾minimize salt use, avoid salty foods ¾since salt raises blood pressure, causes water retention, and can accelerate osteoporosis.
Most people I talk to today are quite serious about avoiding salt, avoiding use of the salt shaker at the table or in cooking almost entirely. Others have switched to sea salt, Kosher salt, or salt substitutes, none of which contain significant iodine.
So where does your iodine come from?
Indeed, iodine deficiency is on the upswing, having quadrupled since the 1970s, with 11% of the U.S. population now severely iodine deficient (National Health and Nutrition Education Survey, or NHANES).
Because thyroid function cuts across so many facets of health, iodine deficiency can also exert wide-ranging health effects, from weight gain, to cholesterol abnormalities, to increased risk for heart disease. While having adequate iodine is only one part of an overall program of thyroid and heart health, it is an important part.
The recommended daily allowance (RDA) for iodine for non-pregnant adults is 150 mcg per day, a quantity that can be easily obtained with an iodine-containing multivitamin, multi-mineral, or supplements like kelp tablets (seaweed). That simple amount is enough to eliminate the prospect of goiter for the majority of adults and remove any question of iodine deficiency.
What is not clear, however, is whether greater quantities of iodine provide even greater benefits. (There are even some authorities who argue that far higher doses can yield greater benefits, doses as high as 10-50 mg (10,000-50,000 mcg). I believe this interesting proposal needs to be explored before mainstream adoption.)
Nonetheless, a little attention to your iodine intake can help prevent this otherwise prevalent deficiency from seizing hold of your thyroid gland and health.