Since the early 1980’s, you have been hearing health experts advocate that we decrease our consumption of salt due to the risk of high blood pressure. But you should also keep in mind that in the 1920’s, the government mandated that iodine be added to table salt due to a growing number of iodine-deficiency diseases, especially goiters.
Iodine is critical to the function of the thyroid gland, and goiters typically result from too little iodine or an imbalance of the two thyroid hormones, thyroxine (T4) and triodothyronine (T3). T3 and T4 refer to the number of iodine molecules in the thyroid hormone.
Goiters may appear as an alarming swelling at the base of the neck (where the thyroid gland is located) but may also have no visible symptoms other than a tight feeling in the throat, coughing, hoarseness, and difficulty when swallowing or breathing.
Almost all of us who do not eat fish on a regular basis essentially rely on iodized salt to maintain our thyroid function. However, iodine comes in several forms, and one study suggests that when we consume iodized salt, only 10% of the iodine is bioavailable (Original Internist 2004; 11:29-38). Therefore, when we tell people to lower their salt intake, it concerns me because iodine deficiency is a real possibility. Iodine has been associated with effects from a bad taste in the mouth to stomach cancer. Not only goiter, but short stature, brain disorders, neurological disorders and low thyroid are also among the risks. Furthermore, iodine protects women from breast cancer and is especially important for pregnant women for reasons I will not list here.
The recommended daily allowance for iodine in the United States is 150mcg per day and according to many nutritionists, this is overly low, just like the RDA for vitamin C is only 60mg per day. As a comparison, the typical dietary intake of elemental iodine is as high as 13.8mg in the Japanese population, because our Japanese counterparts eat a lot more fish than Americans typically do. Also, the current holistic/organic food trend in this country is to swap common table salt for sea salt, which is not typically iodized.
It is well known that the thyroid works to control our metabolism and we have iodine-containing thyroid hormone in every single cell in our bodies. However, iodine is also required for the normal growth and development of a woman’s breast tissue. High levels of iodine by Japanese women is associated with low incidence of both benign and malignant breast tissue. Medical evidence associates iodine deficiency with an elevated risk of breast, endometrial and ovarian cancer. (Lancet 1976;1:890-891). Multiple women have benign fibrocystic breast disease and their doctors instruct them to avoid caffeine and inform them that after menopause, the fibrocystic changes in their breasts will shrink and will no longer be of any concern. In Cancer Research 1975; 35:2332-2339 it is noted that in rats, blocking iodine in the breast tissue caused fibrocystic breast disease. Some women have breast pain especially in and around their periods, and supplementation with 3–6mg of iodine per day significantly decreases the pain, tenderness and nodularity.
Multiple studies show that hypothyroidism in pregnancy results in babies with a low IQ. It has also been associated with ADHD, bilateral hearing loss, difficulty speaking and mental deficiency. The take-home point for us is that inadequate iodine’s effect on the thyroid hormone molecule does affect all of our organs, most importantly the brain.
Even when we do eat iodized salt, other chemicals such as chlorine and fluorine that are in our drinking water, and bromide (which replaced iodine in many baked goods) compete with the absorption of iodine and decrease its bioavailability.
Since a lack of dietary iodine may lead to low thyroid hormone, decreased sex drive, fatigue, lethargy, weakness of the immune system, slow metabolism, autism, ADHD, weight gain and possibly mental status changes such as short temper, anxiety and depression, it is worthwhile to consider consuming more of the following foods:
- Sea vegetables, especially kelp. One tablespoon of kelp contains about 2000mcg of iodine. If you don’t like kelp, there are other sea vegetables that are rich in iodine and you can look up that information.
- Cranberries. Cranberries are high in antioxidants and four ounces of cranberries contain 400mcg of iodine.
- Yogurt. One cup of yogurt contains about 90mcg of iodine.
- Organic navy beans.
- Organic strawberries.
- Himalayan crystal salt. One gram contains approximately 500mcg of iodine.
- Potatoes. The skin of a medium-sized potato holds approximately 60mcg of iodine.
I personally prefer to get my iodine from saltwater fish. Saltwater fish that have very high iodine concentration in their tissues are sea bass, haddock, cod and perch. If a tuna fish sandwich is the most you can stomach, there is still a large amount of iodine in tuna since it is also a saltwater fish. It is worth while to mention that turkey breast and eggs contain a small amount of iodine. For example, three ounces of turkey breast has 34mcg of iodine, which is 23% of the recommended daily amount. One large egg has 25mcg of iodine, which is 17% of the recommended daily amount. Even though these foods are beneficial, their daily value of iodine is grossly inadequate, and we would have to eat dozens of eggs in order to get the same amount of iodine that is in a very small amount of kelp.
There are several ways that your doctor can measure iodine deficiency and some of the methods are a bit cumbersome. Personally, I have no idea what my iodine level is, but because it is so vital to our bodies, I eat fish at least three times a week and I do use iodized salt.
I tell my patients who do not have high blood pressure to go ahead and enjoy table salt. If your diet does not involve eating fish from the sea, seaweed, kelp, etc. and you are feeling slightly lethargic, I would recommend going to a health food store to purchase supplemental iodine. It’s generally best to start with a small supplement and gradually increase the amount to prevent taking an amount that makes you uncomfortable. Stomach upset and diarrhea are common indications that you are taking too much. As to how much to supplement, I will leave that to your own research, as everybody is different and it is impossible for me to recommend a specific number.
Dr. John Alevizos is Board Certified in Family Practice and specializes in Anti-Aging Medicine in Irvine, California.