Vegans May Be Missing This Key Nutrient—And It's Not Vitamin B12

Iodine can be hard to come by, especially for those on a vegan diet. Here are food sources and more to help you meet your daily needs.

seaweed salad in bowl
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Those who follow a vegan diet refrain from eating any foods from animal sources. This can make it difficult to get adequate amounts of several nutrients like vitamin B12, iron and vitamin D. However, there is one nutrient vegans (and others) may be missing that is often overlooked: iodine. A new study in Germany found that only eight percent of vegans and 25 percent of omnivores had adequate levels of iodine. What is iodine and why is it so hard to get enough of it? We dove into the research to find out why we need iodine and how all of us, including vegans, can make sure they are getting enough of it.

What is iodine?

It may make you think of salt if you're used to grabbing iodized table salt, but what is iodine used for in the body? Iodine is a micronutrient that works with our thyroid hormones. It helps the body regulate several biochemical reactions, including protein synthesis and metabolic activity. It is also important for pregnant women and infants, as it is crucial for the development of the fetus's nervous system. It can be consumed in some foods, certain varieties of salts and also as a dietary supplement.

Food sources of iodine

There are several food sources of iodine that can help us get to the recommended daily amount of iodine (150 micrograms for adults and 220 micrograms for pregnant woman). Unfortunately, many are not vegan-friendly.

Here are a few examples of iodine-rich foods that omnivores may eat:

  • Cod: 158mcg per 3 ounces
  • Greek yogurt: 116mcg per cup
  • Milk: 85mcg per cup
  • Egg: 26mcg

Vegan sources of iodine

Fortunately, there are a few sources of iodine that fit into a vegan diet. They are primarily seaweed and iodized table salt. Seaweed can come in many forms, including kelp, nori, kombu and wakame. Seaweed is one of the most potent food sources of iodine, providing around 232 micrograms per ten grams of dried seaweed (learn more about why seaweed is so good for you). Iodized salt provides 76 micrograms per ¼ teaspoon, and can also help people following a vegan diet reach their iodine requirements. However, eating excess sodium can have negative effects on heart health, so be sure to look out for the signs if you are eating too much. Vegans might want to double check they're not only using sea salt or kosher salt in their kitchens. Both have become more popular in recent years and they aren't always iodized, although you can find versions at the store that are fortified with iodine.

Another way for people to meet their iodine requirements, regardless of if they are vegan, is by taking a supplement. Supplements aren't always well regulated, so it can be hard to tell what is worth your money. Try to find those with a USP seal, which shows they were tested by a third-party to ensure their labeling is accurate. You'll also want to chat with your doctor first, before deciding if a supplement is right for you.

Can you get too much iodine?

Yes. If you get too much iodine in your diet you can see similar side effects to getting too little iodine. That includes goiter and hypothyroidism. It's especially important to watch your iodine intake if you have Hashimoto's Disease, the most common cause of hypothyroidism. The upper limit for iodine, what's deemed safe, is 1,100mcg for most adults. It's not likely that you'll go over that with food or supplements, but it is something to be mindful of—especially if you're actively working on adding more iodine to your diet.

Bottom line

Iodine is important for a variety of body functions, from metabolic control to nervous system development. Since most food sources of iodine are from animal products, many vegans may not be getting enough. Vegans should consider adding foods like seaweed and iodized table salt to their eating pattern. If you are concerned about your intake of iodine, talk to your doctor to see if a supplement is right for you.

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