Fact Check

Soy and Thyroid Problems

Are soy food products linked to thyroid cancer?

Published May 1, 2005


Claim:   Soy food products are linked to thyroid cancer.

Status:   Undetermined.

Example:   [Collected on the Internet, 2003]


Please pass this info to your female friends........ Something to take note of.

This is my true story, nothing altered. These are facts, as they relate to my experience, my opinions based on what I have read and felt. I am relating them to warn other young health-conscious women who are unwittingly harming themselves.

In 1989, I graduated from high school in Texas and couldn't wait to hit the big college city. One of the changes I wanted to make was to eat healthier. Once I moved to health-conscious Austin, Texas, I began to fortify my body with the best and healthiest foods I could find. Tofu was the main ingredient in every healthy dish, and I bought Soya milk almost every day.

I used it for everything from cereal to smoothies or just to drink for a quick snack. I bought Soya muffins, miso soup with tofu, soybeans, soybean sprouts, etc. All the literature in all the health and fitness magazines said that Soya protected you against everything from heart disease to breast cancer. It was the magical isoflavones, the estrogen-like hormones, that all worked to help you stay young and healthy. I looked great, I was working out all the time, but my menstrual cycle was off.

At 20, I started taking birth control pills to regulate my menstrual cycle. In addition to this, I began to suffer from painful periods. I began to get puffy, it was as though I was losing my muscle tone, began to suffer from depression and getting hot flashes. I mistook all this for PMS, since my periods were irregular. By the time I was 25, my periods were so bad I couldn't walk. The birth control pills never made them regular or less painful, so I decided to stop taking them. I went on like this for another two years until I realized my pain wasn't normal.

At 27, my gynaecologist found two cysts in my uterus. Both were the size of tennis balls. I went through surgery to have them removed and thank God they were benign. The gynaecologist told me to go back on birth control pills. I didn't. In 1998, he discovered a lump in my breast. Again, I went through surgery and again it was benign.

In November 2000 my glands swelled up and my gums became inflamed. Thinking I had a tooth infection, I went to the dentist who told me that teeth were not the problem. After a dose of antibiotics the swelling still did not go down. At this point I could feel a tiny nodule on the right side of my neck.

I told my mother I had thyroid trouble. She thought I was being silly. No one in the family suffered from thyroid trouble.

Going on a hunch, I saw a specialist who diagnosed me with Papillary Thyroid Carcinoma. After a series of tests he told me it was cancer. My fiancé and I sat stunned. We were not prepared and I was so scared. We scheduled surgery right away. The specialist told us that it would only be after the operation that a pathologist would be able to tell us for sure if it was cancer. They found a tumor at my right lobe composed of irregular cells and another smaller tumor growing on the left, so the entire thyroid was

They told me that after undergoing radioactive iodine I would be safe and assured me that I could live a long life. After treatment I began to search for the cause of all these problems. I never once thought it could be all the Soya I had consumed for nearly ten years. After all, Soya is healthy.

I came upon a web page that linked thyroid problems to Soya intake and the conspiracy of Soya marketed as a health food, when in fact it is only a toxic by-product of the vegetable oil industry. This was insane, after all, the health and fitness magazines had said nothing about Soya being harmful.

I visited a herbalist who was diagnosed with thyroid cancer in 1985. She informed me that Soya was the culprit. She had a hysterectomy due to cysts and other uterine problems. A few months later another acquaintance who had consumed Soya came down with thyroid cancer. A girl in England I met through the internet in a thyroid cancer forum had just undergone surgery, she was only 19. What was going on????

Breast cancer is linked to estrogen. What mimics estrogen in the female body, SOYA! But I never suspected Soya because until now I never once found single article that stated Soya could be dangerous. Women who took Soya prior to thyroid problems will continue to take it after if they are not aware of what Soya actually does, what it contains and how it reacts in the female body. I think this is the reason that women with thyroid cancer often develop breast cancer later.

My co-worker is big into Soya and I see her losing hair and gaining weight despite a walking workout during her break and after work, and apples and oranges for lunch. She just had cysts removed from her uterus, too. I warn her to stay off Soya. I referred her to websites, but until it is in the evening news on all four networks, women will suffer. Since the thyroidectomy, I do not touch Soya, haven't for two years.

Dear readers, please use my story in any way you can. There are so many young girls who are consuming Soya because they think they are taking care of themselves, and women taking Soya because they want to be healthy. It is so unfair that the information about the dangers of Soya isn't more widely circulated. It is sad. There are many out there who feel this way and it is a terrible blow when you realize you are not as healthy as you thought and that the information that you depended on was wrong.

Origins:   Food

Soya Plant

products made from the soybean have long been touted as healthy additions to Western diet. Tofu, soy milk and other soy products work to promote healthy cholesterol levels and have been said to help protect from certain types of cancer, including breast, colon, and prostate cancer.

However, soy (or soya, if you will) has its dark side: it has a weak estrogen effect, and its long-term effects on breast cancer are not known. Soy may also decrease the absorption of thyroid medication, so the combination of the two should be avoided.

In a nutshell, at least at this time there is no clear answer to the question of soy's potential contribution to, or protection from, breast cancer. The experts are split on this question. What research does exist on this topic is conflicting and confusing. Hundreds of small studies on isoflavones and breast cancer have found dramatically different results.

Soybeans are a melange of complex chemical components. Their main components are protein, essential fatty acids, and to a lesser degree what are known as isoflavones. While isoflavones are found in other legumes, the versions in soybeans are also phytoestrogens: plant-derived weak estrogens, chemically similar to the female hormone estrogen. Because isoflavones behave like estrogen, in certain situations, they could stimulate the growth of estrogen-dependent


Research data, however, is far from conclusive, and some studies show just the opposite: that under some conditions, soy may help prevent breast cancer.

Some physicians caution breast cancer patients against eating too much soy for fear it could promote tumor growth in women whose disease is sensitive to estrogen. In addition, health agencies of New Zealand, Australia, and Great Britain have voiced concern about the safety of soy-based infant formula for fear that it might spark reproductive or thyroid problems in babies in later life. Yet approximately 18 million U.S. children have grown up on soy formula since the 1960s, and the scientific literature says there are perhaps 12 cases of abnormalities in infants possibly traceable to soy formula.

In 1999 the Food and Drug Administration allowed food manufacturers to claim that soy-based foods help lower the risk of heart disease.

Barbara "soy confusing" Mikkelson

Last updated:   1 May 2005

  Sources Sources:

    Henkel, John.   "Soy: Health Claims for Soy Protein."

    FDA Consumer.   May-June 2000.

    Mestel, Rosie.   "Moderation Seen As Key to Using Soy."

    Chicago Sun-Times.   26 April 2000   (p. 62).

    Rosenberg, Eric.   "Rethinking Soy."

    Pittsburgh Post-Gazette.   21 May 2001   (p. F1).

    Thomas, Lou Ann.   "Soy: Hope or Hype?"

    Topeka Capital-Journal.   3 November 2003   (p. B1).

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