Soy And Your Thyroid
BY KITT WALSH
When I was a kid, I remember my mother saying that women who blamed their being fat on “thyroid issues” were just covering up the fact they ate too much. My mother was wrong and now, I too, suffer from thyroid issues, as do many of us over 50 (more women than men, by the way.)
In my case, I had hypothyroidism, which caused my thyroid to produce too little hormone (a slowed metabolism) and eventually my thyroid gland had to be removed. Women who suffer from hyperthyroidism produce too much hormone causing them to have a fast metabolism and they may struggle to maintain a healthy weight.
In either case, when we have thyroid problems, our metabolism setting is not working well and it may take some tinkering with medication to set things right again. But we may be inadvertently screwing up our own thyroid production without realizing it through use of what has been touted as a wonder ingredient to help heart disease, prevent cancer, fix menopausal systems, even (ironically), handle weight gain—taking soy.
Soy products from foods and drinks to supplements are big business and with so much money on the line, a blizzard of claims about the miraculous powers of soy keep on coming. But can soy really harm you and your ongoing battle with your thyroid heath?
Here’s the information you need to consider: Soy contains isoflavones, which are plant-based estrogens. These isoflavones lead to concern about the negative effects on thyroid function and hormonal health. This is partially because soy is a goitrogen – a food that promote the formation of goiters (enlarged thyroids). FDA researchers found that in order for soy to cause such toxicity, several factors had to be present, including some defect in the ability to synthesis hormones and an iodine deficiency.
Dr. Andrew Wei, MD, the famous holistic doctor, was a big proponent of soy, but had to adjust his views when it came to thyroid issues.
“Excess consumption of soy can affect thyroid function, if you have a thyroid disorder to begin with or if you’re not getting enough iodine in your diet… At this point, I can only recommend that you avoid soy supplements entirely,” he wrote on his website.
So does this mean only overconsumption of soy is a problem?
Some experts take that view along with warnings against genetic modification of soy. In unadulterated food form, like tempeh, miso and tofu, soy can be eaten in moderation—as an additive, not a primary protein source—but we Americans overdo it, gobbling up soy shakes and candy bars, soy milk and cereal and soy-enriched food and supplements—up to 100 milligrams a day unlike the 10-30 milligrams consumed by Asians. Anything about 30 milligrams causes concern. Some experts who remind us that isoflavones work like a drug in the body even though they are labeled a food additive only.
On the other side of the debate are the experts who claim soy does no harm at all (the findings of a study in the journal Thyroid show no effects as the result of soy consumption in iodine-replete individuals) but that soy foods may inhibit absorption of thyroid medications. Regular testing and dosage changes of all thyroid medication are recommended.
What is important to note is that it is estimated that a quarter of the US population is now iodine deficient.
So where does that leave you in deciding if soy is safe for you? Here are some things to consider:
If you are a thyroid patient and you still have symptoms, cut soy out of your diet and see if the symptoms lessen or disappear.
Don’t eat genetically modified soy. Read the labels.
Limit the amount of soy you eat to 30 milligrams a week and only intake food-based soy like in miso or tofu. Avoid shakes, powders and other processed soy products.
Leave four hours between eating soy and taking any thyroid medication.
If you have been tested and shown to have elevated thyroid antibodies, pay attention to the fact that soy may cause you to develop hypothyroidism.
Have your medical practitioner order a urinary iodine clearance test for you to see if you are iodine deficient. Don’t just supplement your own iodine, because excess iodine can make thyroid problems worse, just as an iodine deficiency can cause a thyroid problem.
If you have no thyroid (due to surgery) or a totally non-functioning one, soy can’t harm you, but it can still interfere with thyroid medication you are taking, so be sure to leave time between eating soy and taking your meds.
As always, check with your doctor or medical practitioner if you are experiencing potential thyroid problems (fatigue, weight changes, muscle and joint pain, swollen neck, changes in skin and hair, bowel disturbances, depression, carpal tunnel, difficulty controlling body temperature or if you have a family history before adding substantial soy foods or particularly soy supplements to your diet.