Soy and hypothyroidism

Type A, Thyroid And Soy

March 17th, 2004 , by Peter D'Adamo

QUESTION: I am A and hypothyroid. You state soy is excellent for A's but, from my researching and reading, most sources state that hypothyroid should avoid soy. Any suggestions as how to get protein and vitamins without using soy?

ANSWER: In a recent response to many of the off-handed accusations about the effects of soy on the thyroid Clare Hasler, Ph.D., one of the world's experts on soy and human nutrition had the following to say:

"There is no convincing evidence that soy protein has an adverse effect on thyroid function, particularly at the moderate level of consumption (25 grams) that would occur due to the approval of a health claim for coronary heart disease.

There is evidence that animals exposed to large amounts of soy protein (e.g., 40%) will develop goiter, particularly when fed an iodine deficient diet (Kimura et al., 1976; Filisetti and Lajolo, 1981). The mechanism for this effect can be explained by the fact that the principal isoflavones in soy, genistein and daidzein, have been shown to inhibit thyroid peroxidase (Divi et al., 1997) and 5'-deiodinase (Cody et al., 1989), key enzymes involved in thyroid hormone biosynthesis. The inhibition of these enzymes results in decreased levels of circulating thyroid hormones (e.g., T4 and T3) which leads to increased secretion of thyroid stimulating hormone (TSH) by the anterior pituitary. The increased levels of TSH provides a growth stimulus to the thyroid, resulting in goiter. It must be emphasized, however, that this occurs only with large amounts of soy isoflavones in the diet and/or when the diet is low in iodine. Furthermor, soy isoflavones are not the only dietary flavonoids that can inhibit thyroid peroxidase. A variety of other flavonoids have also been shown to be even more potent in inhibiting the activity of this enzyme, including kaempferol, naringenin, and quercetin (Divi and Doerge, 1996) . Such flavonoids are widely distributed in plant-derived foods and would be consumed daily at relatively high levels (possibly up to 1 gram or more per day) by vegetarians or semi-vegetarians, yet such individuals do not have a significant increased incidence of goiter. Goiter has also been reported in infants where soy has served as the sole source of food (Hydovitz, 1960). However, this situation is hardly comparable to adults consuming soy protein in moderate amounts as a means to lower total or LDL cholesterol levels.

In sum, soy products have been consumed as a dietary staple in Asian countries for hundreds of years with no significant occurrence of goiter in that population. Goiter is primarily due to a deficiency of dietary iodine, not the consumption of moderate amounts of soy protein incorporated into a nutritionally sound diet. That goiter would result in adults consuming 25 grams of soy protein per day in response to an approved health claim for coronary heart disease is ludicrous."

In essence, it you don't consume 40% of your body weight in soy protein daily, you've not got much to worry about.


Eat right 4 your blood type

Dr. Peter D'Adamo is the best selling author of his books on the relationship of diet and blood type. I am AMAZED at the information he conveys about our bodies and the interactions of food!

Go to his site and read about this - you may see yourself and your health problems here.

Wow - I'm A+, and this exactly describes me!

Type A Diet

"When we discuss 'diet,' we are not talking necessarily about a weight loss plan, that's a side benefit to following this plan. We are actually discussing diet in the more traditional sense, meaning a way to eat," explains, Dr. D'Adamo.

Type As flourish on a vegetarian diet - if you are accustomed to eating meat, you will lose weight and have more energy once you eliminate the toxic foods from your diet. Many people find it difficult to move away from the typical meat and potato fare to soy proteins, grains and vegetables. But it is particularly important for sensitive Type As to eat their foods in as natural a state as possible: pure, fresh and organic. "I can't emphasize enough how this critical dietary adjustment can be to the sensitive immune system of Type A. With this diet you can supercharge your immune system and potentially short circuit the development of life threatening diseases."

Handling Stress

In this busy, ever changing world, it's almost impossible to avoid every day stress. Type As have a naturally high level of the stress hormone cortisol and produce more in response to stressful situations. Cortisol is released in 24-hour patterns, typically in the early morning between six and eight A.M. with a gradual decrease during the day. It helps to cue the body's other cyclical rhythms.

Due to the naturally elevated cortisol in type As, additional stress often manifests in several ways; disrupted sleep patterns, daytime brain fog, increased blood viscosity (thickening), and promotes muscle loss and fat gain. In extreme cases in Type As, stress can manifest in more serious ways, causing obsessive-compulsive disorder, insulin resistance and hypothyroidism.

To help balance cortisol levels, Dr. D'Adamo recommends that you limit sugar, caffeine and alcohol. Don't skip meals, especially breakfast; eating smaller, more frequent meals will also help to stabilize blood sugar levels. He also points out that the following factors are known to increase cortisol levels and increase mental exhaustion for Type As - be aware and limit your exposure when possible:
  • Crowds of people
  • Loud noise
  • Negative emotions
  • Smoking
  • Strong smells or perfumes
  • Too much sugar and starch
  • Overwork
  • Violent TV and movies
  • Lack of sleep
  • Extreme weather conditions (hot or cold)