Before we present today’s regularly scheduled article, some very good news! The U.S. Army Corps of Engineers has determined the plan for the proposed Pebble mine does not comply with the Clean Water Act, and has denied the long-debated project a permit. This is a major development in the ongoing effort to protect wild salmon runs in the pristine waters of Southwest Alaska. For details see The Anchorage Daily News' update and our most recent article on the mine’s threat to the Bristol Bay watershed.
No, you needn’t add iodized salt to your food to get enough iodine. Seafood is one of the best sources of this necessary and often overlooked trace element.
This is especially true of seaweeds such as kelp, which are so iodine-rich that it’s possible to eat too much. However, eating a few grams daily, as the Japanese have done for centuries, is a good way to get your iodine and unlikely to cause harm.
You can also choose to enjoy three ounces of baked cod, which supplies the adult daily requirement of 150 mcg. The same amount of cooked oysters will give you 93 mcg, or 62 percent of what you need. A sushi roll wrapped in seaweed could supply about the same amount. A small can of salmon gives you roughly 60 mcg. And three ounces of shrimp contain about 35 mcg. (NIH Office of Dietary Supplements, 2020, Food Standards, Australia, 2020).
Iodine is important in pregnancy to protect babies from brain damage. It’s also essential throughout your whole life. It keeps your thyroid healthy and allows you to remain vibrant as you age, avoiding common later-years issues like fatigue, dry skin, and sexual problems.
Why Your Thyroid Needs Iodine
The thyroid, a butterfly-shaped endocrine gland in the lower front of the neck, makes hormones that travel through the blood to every body tissue. You need iodine to produce those hormones, and deficiencies have been a global public health challenge. Around the world, about 30 percent of the population is at risk.
Our soil and seawater contain iodine, which makes its way into our food. In the United States, the soil lacked iodine in some areas, but iodine deficiencies largely disappeared after the introduction of iodized salt in the 1920s.
Today, a teaspoon of iodized table salt usually contains approximately 250 mcg of iodine. Or you can take a multivitamin. Most that are marketed in the U.S. have at least 150 mcg, the minimum daily requirement (American Thyroid Association, 2020, NIH Office of Dietary Supplements, 2020).
Over time, however, people have been using less table salt because they eat more processed food, which usually contains un-iodized salt. Some avoid salt to manage high blood pressure (though the connection between salt consumption and high blood pressure has been questioned by researchers).
You might think about getting more iodine if you are vegan or vegetarian because meat and dairy are top iodine sources besides seafood. Iodine deficiency might also be the culprit if you have symptoms of a thyroid problem. About one in eight women do, often after pregnancy or menopause (Office on Women’s Health, 2019).
Historically, inland mountainous regions were the areas most likely to have iodine-deficient populations (Cooper, et al., 1943). That’s possible because the mineral leaches easily from water runoff on sloped land, and inland farms receive little airborne iodine from rainwater, as farms nearer to oceans do. (Iodine Global Network, N.D.)
Individuals aren’t tested directly for iodine deficiency but instead for blood levels of TSH, thyroid-stimulating hormone, which is produced by a different gland. Small changes in iodine intake can change blood TSH levels (Chung, 2014).
Symptoms of iodine deficiency
The classic symptom is a visibly swollen thyroid gland known as a goiter, which can be harmless if small. Within a goiter, nodules can develop that alter your hormone levels. If you have a large goiter, you may have trouble swallowing and breathing, especially when lying down.
Should you develop hypothyroidism, an underactive thyroid, your body processes slow down and you may feel colder, tire more easily, develop dry skin, and become forgetful, depressed, or constipated. Those are potential symptoms of many illnesses, so your doctor will need to order a blood test for TSH to be sure your thyroid is the problem.
Normal TSH levels may fall between 0.5 and 2.5 milli-international units (mIU) per milliliter (Sheehan, 2016). However, labs now use a larger range, marking as normal 0.4 to 4 mIU. From 4 to 10 indicates hypothyroidism. A low score indicates hyperthyroidism, an overactive thyroid (Medical News Today, 2020). Your levels normally get higher with age.
Doctors monitor TSH in pregnant or nursing women because even a mild deficiency can affect a child’s intellectual development. Lack of iodine is the globe’s most common preventable cause of intellectual disabilities. A severe problem is linked to miscarriage, stillbirth, preterm delivery, and damaged babies.
People who move from an iodine-short region, which includes many countries in Europe, to the U.S. may develop hyperthyroidism and be overly “revved up,” as their thyroids have become accustomed to absorbing and efficiently using small amounts of iodine.
In later years, thyroid dysfunction could affect your sexual health, especially in men. Both hypo- and hyperthyroidism can cause sexual dysfunction (The Sexual Medicine Society of North America, 2020). The good news is that these problems usually go away when your thyroid is treated, typically with medication.
Don’t forget the cod dinner, either. Although we can’t promise that an iodine boost will turbocharge your sex life, it’s important not to underestimate the power of suggestion, aka the placebo effect. Let a meal of bacalao or cod beautifully baked in garlic butter inspire you and your date.
Cooper LF, Barber EM, Mitchell HS. Nutrition in Health and Disease, 9th ed. J.B. Lippincott Co, Philadelphia. 1943, pg 66.
Chung HR. Iodine and thyroid function. Annals of pediatric endocrinology & metabolism. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049553/. Published March 2014.
Iodine. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Iodine-Consumer/. Accessed November 11, 2020.
Iodine Deficiency. American Thyroid Association. https://www.thyroid.org/iodine-deficiency/. Accessed November 11, 2020.
Iodine in Food. Food Standards, Australia, New Zealand. https://www.foodstandards.gov.au/consumer/nutrition/iodinefood/Pages/default.aspx Accessed November 11, 2020.
Iodine Global Network (IGN). Retrieved November 24, 2020, from https://www.ign.org/4-where-do-we-get-iodine-from.htm
Sheehan MT. Biochemical Testing of the Thyroid: TSH is the Best and, Oftentimes, Only Test Needed - A Review for Primary Care. Clin Med Res. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5321289/ Published June, 2016.
TSH levels: What do normal, high, and low levels mean? Medical News Today. https://www.medicalnewstoday.com/articles/326774. Accessed November 11, 2020.
Thyroid disease. womenshealth.gov. https://www.womenshealth.gov/a-z-topics/thyroid-disease. Published April 1, 2019.
Thyroid Disorders and Men's Sexual Health. Sexual Medicine Society of North America. https://www.sexhealthmatters.org/sex-health-blog/thyroid-disorders-and-mens-sexual-health/single Accessed November 11, 2020.
Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. https://pubmed.ncbi.nlm.nih.gov/25591468/ Published January 13, 2015.