Or better put, are they at a higher risk for goiter than the average meat eater? For those who perhaps stumbled upon this article and aren’t aware of what goiter is, it’s a manifestation of iodine deficiency (among other things). For that reason, goiter and iodine deficiency will be used interchangeably here.
Does the vegan diet cause goiter? No, not characteristically. Some studies such as one conducted by Lightowler et al, have found mean iodine intake of vegans to be less than optimal.1However, this needn’t be the case, and I hope to provide you with some info that should help you avoid this deficiency.
Given that following a vegan diet doesn’t by necessity preclude salt which is often iodized (at least in the US), I’m not sure why I encounter this question regularly, or why I felt compelled to research the matter when I first transitioned to a vegan diet.
But I like that you’re the inquisitive type because I love science-y questions.
So, while goiter isn’t a widespread problem amongst plant-based eaters, ensuring sufficient iodine in a vegan diet may take a bit of proactivity. There are some potential pitfalls to avoid which I’ll cover.
What Exactly is Goiter?
The thyroid gland is located in the neck, and if it’s visible from the outside, that’s not a good thing. Goiter is a term used to describe an abnormally enlarged thyroid gland, and if the gland gets large enough, there will be a visible bulge or lump in the neck.
Conditions related to hyper- and hypothyroidism are the usual suspects, but goiter can occur for reasons unrelated to an underlying thyroid disorder—among which include iodine deficiency.
As mentioned, the gland must be enlarged to a certain point before it becomes visible. The condition does often exist when you can’t tell visibly. Similarly, symptoms may be few to none.
But, when symptoms are present, they may include (among others):2
- Breathing difficulties are relatively common with very large goiters, especially when lying down flat on the back or when reaching up
- A cough
- Swallowing difficulties, especially when eating solid food
- Pain in the thyroid area
Diagnosis and Treatment
As for diagnosis, doctors often just perform manual and visual detection of goiter, though sometimes further tests are needed like hormone panels.
If you have a small, simple goiter with no underlying thyroid disease, your doctor may just have you monitored.
If iodine deficiency is the culprit, you will be given iodine supplementation which usually stops, or at least slows the growth of the gland. It may even reduce the size a bit. Over time, simple goiter may disappear on its own.2
The Iodine-Goiter Mechanism (Brief Overview)
This thyroid gland we keep talking about produces and releases two hormones known as triiodothyronine (T3) and thyroxine (T4). Iodine, the nutrient of focus in this article, comes into play here.
It’s actually the function of the thyroid gland to take the iodine we eat and convert it the two hormones, T3 and T4. Thyroxine (T4) is the main hormone secreted by the thyroid gland into the bloodstream.3
As such, when there’s a low amount of T4 in the blood, one thing doctors look at is whether or not the patient is getting sufficient dietary iodine to make the hormone. Again, other things can cause low levels of T4.
When in fact low T4 levels can be attributed to iodine deficiency, it results in high levels of a hormone called thyroid stimulating hormone (TSH). This hormone stimulates the thyroid gland to rev up certain biochemical processes, one of which being cellular growth and proliferation.
So, goiter is the growth and proliferation—a process called hyperplasia—of the thyroid gland. There are certain compensatory processes that may result in TSH levels that aren’t particularly elevated, but I won’t go into all that here.4
Potential Challenges Related to Vegan Iodine Intake
Most of the points I’ll mention here pertain to salt. Now, it’s not advisable to overdo salt consumption—a topic for another article—but keep in mind other sources of iodine include meat
products, fish, and dairy products. Like it or not, salt is one of the only sources of iodine for vegans.
Lack of Access to Iodized Salt
Now, this isn’t a problem that’s unique to veganism so much but has more to do with geographical location. We vegans in the US need not worry about lack of availability of iodized salt, as it’s pretty widely available here, and in fact, has largely eliminated iodine deficiency in the U.S.
In England, however, only a small percentage of salt is iodized.1 So, be aware of your location, and whether or not the salt sold in your country is iodized by default.
This is important because some data suggest even vegetarians (who aren’t half as restrictive) who don’t use iodized salt may be at an increased risk of developing an iodine deficiency.5
Opting for Natural Salts (Sea Salt, Himalayan, etc.)
Just as animal products are unacceptable to vegans, many forego iodized salt, relying instead on sea salt, as it’s natural, and of course, marketed that way. While the appeal of natural foods is understandable, sea salt may not contribute helpful amounts of iodine.
If you opt for supplementation or get your iodine elsewhere than this isn’t an issue.
Avoidance of Processed Foods
In that vein, because vegans tend to be health conscious, they may limit processed foods which we all know are loaded with salt—often iodized salt. Now, this is a good thing overall, but it’s just something to keep in mind—a factor that may contribute to a vegan consuming less iodine than the average person.
Overreliance on Seaweed
Although respectable levels of iodine can be found in seaweed, this particular food product generally isn’t consumed in high enough quantities to provide the amount necessary to hit the RDA.1
Avoidance of Supplementation
Now, it’s not a given that:
- A given multivitamin/mineral supplement will include iodine. But many do, so if you want to go this route, read the label to make sure this mineral is included. For whatever reason, I’ve found that multivitamins for older adults tend to have it.
- A given supplement will actually contain the nutrients it claims to have on the label. The supplement industry is poorly regulated. In many cases, the purity is low, or the product just doesn’t contain the compounds advertised.
There are quality supplements out there that have passed various tests for label accountability. I eat very little salt but have managed to avoid iodine deficiency for years now on a vegan diet.
And I’d imagine much of that has to do with the fact that I’ve made sure that when buying a multivitamin/mineral supplement it includes iodine.
Anyway, hopefully, that was helpful. Perhaps in the future, I’ll write about hypothyroidism and the vegan diet, including any potential benefits the vegan diet might confer.
- Lightowler, H. J., Davies, G. J., and Trevan, M. D. Iodine in the diet: perspectives
for vegans. J. Roy. Soc. Hlth., Feb: 14, 1996.
- Simple Goiter: Medlineplus Medical Encyclopedia https://medlineplus.gov/ency/article/001178.htm
- Gropper, Sareen S.; Smith, Jack L.. Advanced Nutrition and Human Metabolism (Page 531-532).
- Gropper, Sareen S.; Smith, Jack L.. Advanced Nutrition and Human Metabolism (Page 534).
- Remer T, Neubert A, Manz F. Increased risk of iodine deficiency with vegetarian nutrition. Br J Nutr. 1999;81:45-49