Vegetarian diet and all its variations (f.e. vegan) provides you with plenty of health benefits, if done correctly. When on this diet, you need to pay extra attention to the following vitamins, minerals and microelements to avoid their deficiency: calcium, iron, zinc, iodine, vitamin B12, vitamin D, omega-3 fatty acids and sufficient amount of protein.

This post is about iodine.

The role of iodine in the body

The main role of iodine in our body is to make thyroid hormones. Thyroid hormones regulate how much energy we have. If we don’t have enough thyroid hormone, we start to experience various symptoms, starting from fatique, brain fog, mood issues, and ending by joint and muscle pain and an increased vulnerability to infections.

Iodine is especially important for children. Iodine deficiency can prevent them from attaining their full physical potential and intellectual capacity.

What are the main food sources of iodine?

The most reliable sources of iodine are seafood, commercial dairy products, and iodized salt. That is why vegans who don’t use iodized salt and/or sea vegetables may have low iodine intakes and may be at risk for iodine deficiency.

The most reliable way to get enough iodine is to use iodized salt daily or include seaweed in your diet. An important point of attention about salt is that sea salt as well as Himalayan salt don’t have meaningful amounts of iodine. Why? Because iodine evaporates during the process of making sea salt. Only commercial salt with iodine added to it after it is processed, called “iodized” salt, is a reliable source of iodine. By the way, the salt used in processed foods typically don’t contain iodine.

If you decide to switch to a low-salt diet, be mindful about additional dietary sources of iodine to meet the daily needs.

What can interfere with the iodine absorption?

Soybeans, pearl millet, cruciferous vegetables (f.e. broccoli, brussel sprouts, cabbage, cauliflower), and sweet potatoes contain natural substances that interfere with iodine uptake by the thyroid. However, these foods have not been linked to problems with thyroid in healthy people with an adequate iodine intake.

In one way or the other, crucifers are safe and healthy, if eaten in moderation (1-3 servings a day). Saying that, you need to be careful with:

taking sulforophane supplements (such as broccoli sprout extract) for long time to promote detoxification, and

juicing lots of cruciferous veggies to get much more than you could ever eat as solid food.

How much iodine is sufficient to stay healthy?

The RDA for adults is 150 mcg/d for both men and women. Pregnant women often develop goiter, or an increase in thyroid size that looks like it could turn into goiter. The RDA for pregnant women is increased to 220 mcg/d. The RDA for nursing mothers is based on the amount of iodine lost in milk, and is set at 290 mcg/d.

To give you an example of iodine content in the dietary sources per 100 gram:

commercial milk and yogurt have about 20 mcg, while cheese has about 40 mcg

fish and shellfish have 20-100 mcg

just as little as ½ tsp of iodized salt provides the RDA for adults (150 mcg).

As for kelp, it leads the list of dietary sources of iodine and contains up to 3000 mcg iodine per gram. That is why if you use the seaweed as a vegetable that makes up a major part of a meal, or you eat packaged crispy seaweed snacks, you’d better eat them once a week.

Can too much iodine harm your health?

Yes, it can be a problem. Continuous iodine intakes over 18.000 mcg/d can cause goiter, just like iodine deficiency. Goiter is an abnormal thyroid enlargement. It is usually painless, but it can cause a cough and difficulties with swallowing and breathing.

The Food and Nutrition Board of the Institute of Medicine, who establishes the RDA, set the upper limit at 1.000 mcg/d.

Exposure to grams of iodine at once (1 gram= 1.000.000 mcg) can cause acute poisoning, involving abdominal pain, fever, nausea, vomiting, and coma. Seldom, but people may also have an allergy to iodine, or react to iodine with acne, itching, and hives.

Curious? HERE is the source