Iodine is an essential trace element that helps regulate hormone and cell production. Having an iodine deficiency is a severe health condition that is unfortunately common, especially among vegan dieters. Learn more about this vital mineral and how to consume enough of it on a plant-based diet.
What is Iodine?
Iodine is an oft-forgotten but incredibly essential trace mineral - most table salt contains iodine, and people round out their iodine intake naturally with a diet high in fish, seafood, dairy, and eggs.
While we fortify dairy and salt with added iodine, you can also source this mineral naturally.
Vegans aren't going to consume fish and other animal products anytime soon, but there are plenty of lesser-known plant-based sources of iodine.
We're dropping some information below about this hormone balancing mineral and how vegans can best ensure they get their daily RDA of iodine.
What Does Iodine Do For The Body?
This crucial mineral offers plenty of iodine health benefits - it helps the body produce thyroid hormones that control our metabolism, cells, brain, and bone growth.
It's even more important for pregnant women to consume enough iodine, as it helps with a baby's brain development in the womb. This can have lasting effects on their baby's future.
Symptoms of Iodine Deficiency
Iodine deficiency was a common issue until the 1920s when manufacturers started adding it to table salt, which almost every household uses in some capacity.
The tactic worked, and iodine levels improved quickly. Unfortunately, it wasn't the end of the problem - around 30% of the current global population is at risk for iodine deficiency.
Here are the common iodine deficiency symptoms someone might experience from chronically low levels of iodine:
- Goiters. These large, swollen lumps on the front of the neck are puffed up thyroid glands that grow abnormally large when left in a constant, under-functioning state.
- Hypothyroidism. Iodine helps thyroid function, and iodine deficiency means your thyroid will chronically make too few essential metabolic hormones, leading to muscle weakness, weight gain, constipation, cold sensitivity, and a slew of other health conditions.
- Weight Gain. Iodine deficiency will slow the metabolism down significantly, meaning your body won't burn calories at an average rate, storing the extra as body fat. Low energy levels and weakness accompany a slow metabolism, too.
- Hair Loss. Without the proper hormones running through your body, hair follicles will grow slower and shed hair at a faster rate than usual.
- Dry, Flaky Skin. A lack of dietary iodine leads to chronically dry skin that flakes easily.
- Depression. The lack of hormones caused by iodine deficiency can heighten depression as the brain begins to function poorly.
RDI of Iodine: How Much Iodine Do You Need?
Some great news on iodine - you need a relatively small amount of iodine-rich foods in your diet to get a more than sufficient intake of this mineral.
The Institute of Medicine sets the recommended daily intake, RDI, for iodine at 150 mcg per day for the average adult.
For context, there are 1000 micrograms in a milligram, and we need 8-14 mg of iron each day - the amount of iodine we need to get from our food is a very tiny fraction of our other vitamin and mineral needs.
While getting enough iodine seems easy, iodine's natural sources are rarer than other minerals, which provides a bit of a challenge.
You can also overdo the iodine supplementation and develop iodine toxicity, though it's a pretty rare condition.
Excessive iodine consumption will stop thyroid hormone production entirely and leads to hypothyroidism, autoimmune disorders, and even hyperthyroidism.
The US Department of Health allows individuals to consume up to 1,100 mcg of iodine each day, though they don't recommend it for optimal health.
Iodine Intake and Veganism: Two Potential Roadblocks
The importance of iodine is even higher for those who follow a vegan diet and lifestyle. The reasons for astronomically high rates of vegan iodine deficiency are twofold:
#1: Rare Vegan Iodine Sources
Many of the best sources of iodine come from animal-based products, like fish, eggs, and cow's milk. Vegans don't include these foods in their diets, so they have fewer options in the pool when choosing their regular dietary sources of iodine.
#2: Iodine Absorption Antagonists
Iodine is not always readily absorbed by the body, especially for people that consume known iodine antagonist foods that slow iodine's absorption further and counteract its beneficial effects.
The dilemma for vegans is that many of the iodine antagonists are vegan staples - flaxseeds, soy, and raw cruciferous veggies like broccoli, cauliflower, or cabbage all negatively affect your iodine levels.
With these two factors contributing, it means vegans tend to eat less iodine and absorb less of it in their bodies - it's a vicious cycle with a high likelihood of iodine deficiency.
One reason for low vegan iodine is that not enough vegan foods get fortified with this essential mineral. However, we hope that changes, and we begin to see more plant milk and meat substitutes containing iodine and their usual vegan vitamin D and minerals.
Vegan Dietary Sources: Best Iodine Rich Foods
Vegan foods for a healthy thyroid aren't plentiful, but there are still enough options to feel like you're getting some variety of flavor in your diet along with your iodine dose.
#1: Dried Sea Vegetables: Dulse, Kelp, Nori, & More!
The very best vegetarian food rich in iodine is dried seaweed, like kelp, nori, wakame, or dulse. These sea vegetables, much like fish, pick up their iodine from the earth's biggest source of iodine, seawater.
One liter of ocean water contains 50 mcg of iodine, and dried sea vegetables benefit from this essential mineral. With 40 to 60 mcg in a single dried sheet, the dosage is relatively high, so watch your portions closely to avoid overeating iodine.
#2: Fruit Plants High in Iodine: Strawberries, Prunes, & Cranberries
A few of our favorite fruits also happen to be vegan foods high in iodine, along with a load of other essential vitamins and minerals.
Sweet berries, like strawberries, offer a high vegetarian iodine content - eating a small serving of strawberries each day can offer around 8% of your RDI.
Dried prunes are another source of iodine in a vegan diet, with 13 mcg per serving.
Keep your thyroid hormones in check with cranberries, boasting a whooping 400 mcg of iodine in a half-cup serving, almost three times the RDI of most healthy adults.
#3: Vegetables High in Iodine Green Beans, Corn, & Potatoes
Vegetables are moderate sources of iodine in a vegan diet that won't massively pump up your intake but still offer a little boost. Green beans contain 2% of your RDI and plenty of vegan calcium, while a serving of canned corn gives you 14 mcg of iodine.
Some of our favorite foods for healthy thyroid are potatoes - choose the organic kind, and leave the cleaned skin on to reap the most significant benefits from their iodine content.
#4: Leafy Greens: Spring Greens & Watercress
Leafy greens offer some extra iodine for vegans that probably eat a decent amount of these veggies already.
The iodine content in watercress will give your iodine levels a big boost when consumed daily.
#5: Old Faithful: Iodized Salt
Luckily, even vegans can count on the original fix for a low-iodine intake - iodized salt! While we love fancy sea salt or Himalayan salt as much as everyone else, if you're concerned about iodine intake, use iodized salt more often than not.
The iodine in sea salt is lower than iodized salt, and the switch away from table salt may be contributing to our generally low iodine levels.
Sea salt and other salt types contain many other essential trace minerals but may severely lower your iodine daily intake.
The iodine content of fresh-grown iodine plant sources varies greatly depending on the quality of the soil they're grown in - a low-iodine soil will not produce foods containing iodine.
Final Notes: Vegan Iodine Supplement
If you don't feel you'll eat enough vegan foods with iodine or iodized salt, you can also support your body with a good quality vegan supplement that will allow you to hit your iodine RDI daily.
Remember to keep your overall consumption of iodine between your vegan diet and supplements in mind to avoid having too much and risking iodine toxicity.