Like so many nutrition topics, there is misinformation circulating about iodine. Some folks may indeed have lower levels of iodine than is recommended in these days of sea salt and Paleo diets. It is important, however, to
look at the dietary sources of iodine
to consider whether you may be at risk for a deficiency before considering a supplement.
Iodine is an essential mineral with a recommended dietary allowance (RDA) of 150 micrograms for adults (levels are different for children, pregnant, and lactating women). This is the average daily requirement to prevent a deficiency in the majority of the population. Most micronutrients (vitamins and minerals) do not require strict daily consumption, but rather an overall average is sufficient. For most healthy (non-pregnant) adults, eating a variety of nutritious foods will meet all micronutrient requirements without supplementation. If you have been told to take a supplement by your doctor, please follow such instructions, as the previous statement may not apply to you.
While an extreme thyroid deficiency would result in a visible goiter (you can Google this—you most likely do not have one), iodine is essential to thyroid function and deficiencies may hamper optimal hormones and other functions of the thyroid gland. Many of the wellness headlines about iodine these days are related to thyroid function and its subsequent impact on metabolism. If you are concerned about your thyroid function, hormone levels, or metabolism, please consult your doctor.
It is important to note that the tolerable upper intake level for iodine is 1,100 micrograms per day. To exceed this level can cause physiological problems, just as a deficiency can. For an average human, the only way to exceed this level would be through regular seaweed consumption (a single serving has variable levels, with some exceeding 1,100 micrograms) or by taking too much of an iodine supplement. Some supplements provide the body with nutrients in a format that cannot easily be excreted, as they might be when consumed in food. For this reason, any time a supplement is considered, care should be taken not to exceed the tolerable upper limits.
Back to the question: Are you getting enough iodine in your diet? While iodine levels are not always labeled, some foods consistently provide high levels. Seaweed, as previously mentioned, iodized salt, dairy products (including milk, yogurt, cottage cheese, cheese, and ice cream), seafood (including cod, tuna, and shrimp), enriched bread products, eggs, and many fruits and vegetables contain 10% or more of the daily recommended value.
Half a teaspoon of iodized salt, alone,
meets the daily requirement.
If you regularly consume any food from a box or a package, you are probably meeting your iodine requirement. Likewise, if you regularly consume dairy products along with a healthy smattering of vegetables and seafood thrown in the weekly mix, you are probably covered. For vegetarians or non-dairy eaters, purchasing iodized salt instead of sea salt may be enough to meet daily needs. If none of these foods are a regular part of your diet, perhaps consider an iodine supplement from a reputable company at a level around 150 micrograms per day (micrograms are also written as μ), not to exceed 1,000 micrograms per day.
Keep in mind that one teaspoon of salt provides the maximum recommended daily sodium intake, so I would not recommend that anyone increase their salt intake in order to meet their iodine requirements. However, replacing current healthy levels of salt intake with an iodized version may be a good option.
Goitrogens are foods that may inhibit the absorption of iodine. These include many healthy vegetables, such as broccoli and other leafy greens. As this article suggests, there is probably no need to remove such foods from your diet, but rather to consume vegetables that contain goitrogens in their cooked form (rather than raw) and to eat a varied diet. There are many nutritious foods that become “unhealthy” if we eat too much of them: Rather than try to keep track of all these tiny details, simply aim to eat a variety of fruits, vegetables, whole grains, legumes, and lean protein in moderation.
If you are considering supplementation of iodine or any other vitamins or minerals, consider checking these reputable sources first:
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