Soy is generally promoted as healthy, but it can be controversial when it concerns the thyroid. It’s a controversy that has gone on for a decade or more about whether or not soy can negatively affect your thyroid gland.

Soybeans are legumes. They have been found to be high in protein, phytoestrogens, and plant-based estrogens. You may know you can buy it in traditional forms such as tofu, but it is now in a lot of processed foods you eat every day.

Though soy is commonly thought of as “healthy” there isn’t evidence that supports its assertion to having explicit benefits for weight loss, cancer prevention, or heart health.

Soy is also a goitrogen. These types of foods promote goiters or enlarged thyroid. If you eat a lot of soy, it can have a negative effect on your thyroid. It will slow down the function of the thyroid and can even cause thyroid disease.

Research has found that soy can have many different negative effects on the function of your thyroid, especially in areas that are iodine deficient. It can even inhibit your body’s ability to absorb thyroid medicine properly.

If you’ve sworn off meat and are used to eating a lot of soy, there are some guidelines you should follow. Here are a few:
• Make sure you aren’t iodine deficient—Have a urinary iodine clearance test to determine for sure. Don’t just supplement with iodine and think you’re safe. Iodine deficiency can cause thyroid problems, but so can excess iodine. If the test shows deficiency, you can take proper supplementation to help your thyroid. This should reduce potential risk of problems from soy.
• Know that soy can cause hypothyroidism if you have elevated thyroid antibodies or untreated autoimmune thyroid disease.,
• In some instances, consider eliminating soy—This is especially true if you are a thyroid patient and have optimized thyroid treatment but are still experiencing the symptoms of hypothyroidism.
• Consider avoiding genetically-modified soy—If you’re a soy eater, the genetically-modified version could cause problems. This includes soy powders and protein shakes. You may want to avoid it until the controversy has been solved. Stick with fermented and food forms like tofu, miso, and tempeh.
• Only consume 30 mg each day—You can overconsume soy. If you have a daily diet of soy milk, edamame, tofu, soy burgers, soy bars and/or soy ice cream, you’re probably overdoing it. You should limit isoflavones consumption to less than 30 mg each day.
• Wait three to four hours after or eat three to four hours before you take your thyroid medication—This will avoid the interference soy can have with your thyroid medication absorption. .
• Limit raw goitrogenic foods—If you are eating these in addition to soy, be careful how many you eat raw. Cooking them is fine.
• Remember that soy a very common allergy-triggering food—It might not be affecting your thyroid right now, but it can cause problems with allergic reactions including swelling, stuffy nose, acne, diarrhea, stomach pain, skin rashes, itching, hives, heart palpitations, fatigue, and low blood pressure.
• Be careful even if your thyroid has been removed—You may think you don’t have to worry about the effects on your thyroid if you don’t have one. That may be true, but it can still interfere with your body’s absorption of your thyroid medication. Follow the three-four hours before and after rule.

The thyroid has a big responsibility for such a small organ. Because of this, you need to do everything you can to help it. Avoiding soy products, especially in processed foods, is probably a good idea.