Iodine Deficiency

A Lack of Iodine-Rich Foods Can Cause Iodine Deficiency

Worldwide, around 2 billion people have insufficient iodine intake. Populations in South Asia and sub-Saharan Africa are particularly affected and at risk for the symptoms related to iodine deficiency.  In the U.S. and Europe, iodine deficiency is believed to be one the rise, as are instances of iodine deficiency disorders.

Common signs of an iodine deficiency include:

  • Trouble producing saliva and properly digesting food
  • Swollen salivary glands and dry mouth
  • Skin problems, including dry skin
  • Poor concentration and difficulty retaining information
  • Muscle pains and weakness
  • Increased risk for thyroid disease
  • Increased risk for fibrosis and fibromyalgia
  • A higher risk for developmental problems in babies and children

Iodine deficiency and diets low in iodine-rich foods are associated with an increased risk for thyroid disease, but there are also potential thyroid and hormonal risks associated with taking too much iodine, especially from supplements that contain iodine in the form of iodide. Although it seems counterintuitive, research suggests that consuming more than the suggested amount per day is even associated with an increased risk for thyroid disorders as opposed to preventing them. (3)

Although too much iodine is a potential risk for thyroid disruptions, it’s much less common and considered a relatively small risk compared to the substantial risks of iodine deficiency. Plus, consuming very high levels from iodine-rich foods alone is very unlikely. Due to the high prevalence of iodine deficiencies globally, plus the serious health concerns as a consequence, there is much more emphasis in the health community on adding more iodine into the average person’s diet than worrying about removing it.

Why are more people experiencing iodine deficiency?

Several reasons might be to blame: a reduction in the amount of naturally iodine-rich foods in people’s diets (wild-caught fish, green vegetables and sea vegetables, for example), a higher exposure rate to certain chemicals found in processed foods that reduce iodine absorption (especially the compound called bromine, found in many plastic containers and baked goods, for example), and a depletion in the amount of iodine found in soils.

Bromine, found in lots of industrial-produced packaged food products, is of particular interest to researchers, since it’s known to block iodine-rich foods from being useful and absorbable to some degree. Bromine is able to displace iodine and might lead to higher rates of iodine deficiency.

When it comes to soil depletion, research points to the fact that around the world, soils contain varying amounts of iodine, which in turn affects the quantity of iodine within crops. In some areas, iodine-deficient soils are more common, which makes it more likely that people will develop deficiencies.

Efforts to reduce deficiencies, known as “salt iodization programs,” help reduce the rate of iodine deficiency in some parts of the impoverished world that experience high rates of ill health effects. But the surest way to prevent deficiencies (and the safest) is to increase your intake of iodine-rich foods.

What Happens When We Eat Plenty of Iodine-Rich Foods?

Iodine enters the body through iodine-rich foods, including certain food – eggs, sea vegetables  etc.  We rely on iodine to create thyroxine (T4 hormone) and triiodothyronine (T3), two of the main hormones produced by the thyroid that control numerous important functions.

An iodine deficiency can cause an abnormally enlarged thyroid gland (called a goiter), which happens in response to the body trying to “trap” as much iodine within the bloodstream as it can. Iodine is also absorbed and stored within tissue in many other organs, including the stomach, brain, spinal fluid, skin and certain glands. (4)

Iodine present in foods and iodized salt contains several chemical forms of iodine, including sodium and potassium salts, inorganic iodine (I2), iodate, and iodide. Iodine usually occurs as a salt and is called iodide when it does (not iodine).

Iodide is absorbed in the stomach and enters the bloodstream, circulating to the thyroid gland, where it uses appropriate amounts for thyroid hormone synthesis. The unused iodine that we get from iodine-rich foods is then excreted in the urine. A healthy adult usually has about 15–20 milligrams of iodine present within her body at one time — 70 percent to 80 percent of which is stored in the thyroid.

Recommended Daily Amount of Iodine

Iodine recommendations are given in terms of “dietary reference intakes” (DRIs). DRIs were developed by the Food and Nutrition Board at the Institute of Medicine of the National Academies as a set of values used for planning and assessing nutrient intakes of healthy people. According to the USDA, the recommended amount of iodine depends on your age and gender, and are as follows: 

  • Birth to 6 months: 110 micrograms
  • 7–12 months: 130 micrograms
  • 1–8 years: 90 micrograms
  • 9–13 years: 120 micrograms
  • 14 years and older: 150 micrograms
  • Pregnant women: 220 micrograms
  • Breastfeeding women: 290 micrograms

How can you best meet these recommended amounts?

Eat more iodine-rich foods, especially the kind that naturally contain this mineral and aren’t fortified. Including sea vegetables in your diet is one of the best ways, considering their high iodine content along with other important minerals and antioxidants they contain. Various forms of seaweed (such as kelp, nori, kombu and wakame) are some of the best, natural sources of iodine. But like all crops, the exact content depends on the specific food and where it came from.

To some extent, fruits and vegetables also contain iodine. The amount depends a lot on the soil, fertilizer and irrigation practices used to grow the crops.