January 31, 2004
Question: I’m a 70-year-old woman. For thirty years, I took thyroxine [T4] for my hypothyroidism. The whole time, I had fibromyalgia pain. After reading The Metabolic Treatment of Fibromyalgia, my doctor changed me to Armour Thyroid, which has both T4 and T3 in it. He gradually raised my dose high enough to cause a low TSH. To his amazement and mine, my fibromyalgia pain has been gone ever since. I’ve had almost a year now without pain all over my body. My whole family can’t thank you enough for discovering this cure.

My doctor tested me for osteoporosis before prescribing Armour, and my bones were fine. He believes in a high protein, so I’m cooperating with that. I don’t mean I’m pigging out on protein, but I eat more than I used to. He also has me on a high protein diet and lots of nutritional supplements, including calcium, and I exercise a lot.

A month ago, I read an article that said a high protein diet may cause osteoporosis. I told my doctor, and he ordered another bone density test. It was normal like the first one. He disagreed with the article and said my high protein diet should protect me from bone loss. What I want is to protect myself from my low TSH causing my bones to get thin. That way, I’ll be able to keep taking this dose of Armour that keeps me out of pain. I would appreciate your opinion. Do you think it’s best for me to change to a low protein diet, like the article advised?

Dr. Lowe: No, I don’t, not if your high protein diet is working well for you. Some studies have shown that a high protein diet increases calcium loss in the urine.[1][2][3][4] Theoretically, the calcium loss, if severe enough, can cause bone loss. But studies haven’t yet shown this to be true.[2]

With a qualification I mention below, rather than causing bone loss, a high protein diet may instead increase the density of your bones. The reason is that eating large amounts of protein can increase your body’s production of a growth factor called "somatomedin C." As I explain in depth in The Metabolic Treatment of Fibromyalgia, thyroid hormone, like a high protein diet, increases the body’s production of somatomedin C. Thyroid hormone does this by increasing growth hormone production. The increased somatomedin C stimulates bone-forming cells called "osteoblasts." The cells’ increased activity then increases the density of bones[3]—assuming that you’re ingesting enough calcium. And that’s the qualification I mentioned.

You’re said taking a calcium supplement, but not how much. Taking enough calcium (see our nutritional recommendations) can protect you from your high protein diet causing you to lose too much calcium in your urine. It can also protect you from bone loss. In one study, for example, patients with a high protein intake also took calcium citrate and vitamin D. Compared to people taking placebos, the density of their femoral necks and overall skeleton was higher. In another study, elderly hip-fracture patients took both a protein and calcium supplement; as a result, they had less bone loss.[1]

In short, your calcium and high protein diet, along with your effective dose of Armour and exercise, guard you from bone loss. On the other hand, the low protein diet you’re considering may be detrimental to your bones.

In several recent studies, researchers have found reduced bone density in people who had been on a low protein diet long term.[2] In one study, when people were on a high protein diet, they absorbed more of their calcium supplement into their blood; absorption increased from 18% to 26%.[4] In contrast, when people were on a low protein diet, they absorbed less calcium.

People in the study absorbed less calcium possibly because their low protein intake reduced acid secretion in their stomachs. Protein stimulates the stomach to secrete acid, and a low protein intake reduces amount of acid secreted. But for calcium to be absorbed from the small intestine into the blood, stomach acid must first dissolve it. When too little acid is secreted, less calcium is absorbed. So most likely, the people’s low protein intake reduced their secretion of acid, and the reduced acid decreased their absorption of calcium.[2]

The people’s reduced absorption of calcium lowered their blood calcium level. This caused them to secrete more "parathyroid hormone." This hormone increases the calcium level in the blood. It does so in three ways: by increasing absorption of calcium from the intestine; decreasing loss of calcium in the urine; and pulling calcium into the blood from bones. This third way, over the long haul, might reduce the density of bones.[2]

In that a low protein diet might reduce bone density, I agree with your doctor: you stand a better chance of avoiding bone loss by continuing your higher protein intake.

References

[1] Dawson-Hughes, B.: Interaction of dietary calcium and protein in bone health in humans. J. Nutr., 133(3):852S-854S, 2003.

[2] Kerstetter, J.E., O'Brien, K.O., and Insogna, K.L.: Low protein intake: the impact on calcium and bone homeostasis in humans. J.Nutr., 133(3):855S-861S, 2003.

[3] Dawson-Hughes, B.: Calcium and protein in bone health. Proc. Nutr. Soc., 62(2):505-509, 2003.

[4] Kerstetter, J.E., O'Brien, K.O., and Insogna, K.L.: Dietary protein, calcium metabolism, and skeletal homeostasis revisited. Am. J. Clin. Nutr., 78(3 Suppl):584S-592S, 2003.

Question: I’m a bit concerned about your apparent approval of the regular use of soy. Soy is a phyto-estrogen, and there are considerable problems with it. One is that Monsanto has monopolized the production of soy, and very shortly, unless they’re stopped, Monsanto will be forcing everyone to use their genetically-engineered seed and products. I would appreciate your take regarding this.

Dr. Lowe: Aggressive corporate promotion of soy—especially genetically-modified soy—and the overuse of soy concern us, as it does you. I don’t understand, however, why you’re concerned about our well-qualified approval of the regular use of soy. In the Q&A you’re apparently referring to, I stipulated, "Using soy foods is fine, as long as the foods don’t contain genetically-modified soy, and as long as your daily intake is low enough."

We do believe that the phyto-estrogens in soy, when used in moderation, can benefit many people. Thanks to some of the our fine corporations, many—perhaps most—people today are estrogen dominant. Despite this, however, some women have estrogen deficiencies. We prefer that these women relieve their estrogen deficiencies with modest amounts of phyto-estrogens than to brutalize themselves biochemically with products such as Premarin.

Modest soy intake also has other potential benefits. For example, Dr. Nicholas Calvino wrote on drlowe.com: "Simple dietary changes equal profound changes in our health. For example, the combination of eating five servings of fruits and vegetables each day, moderately exercising, and eating one serving of soy per day, can possibly reduce your risk of cancer by 80%." (Italics mine.)

In short, we agree with you on two counts: Many people consume too much soy, and anyone who consumes genetically-modified soy foolishly risks his health. But we also feel that it’s important to keep a balanced view in this matter: Consuming modest amounts of soy foods that haven’t been genetically modified can provide some health benefits. We therefore support the sensible use of soy.

Question: I have a question about using soy foods such as soy milk. For several years, I experienced sinus, headaches, ear aches, and a stuffy nose. These problems disappeared when I stopped using cows’ milk and began using soy milk. I’m concerned, however, because I read that soy foods can cause hypothyroidism. I asked my doctor but he didn't seem concerned. I don't drink much soy milk, but I'm wondering whether it's putting me at risk for hypothyroidism?

Dr. Lowe: Modest amounts of soy milk or other soy foods each day aren’t likely to cause hypothyroidism. But as Dr. Honeyman-Lowe and I explain in Your Guide to Metabolic Health, ingesting large amounts of soy can potentially cause metabolic problems.

In one study, about 50% of participating people developed metabolic problems when they consumed 30 grams of soybeans each day for three months. The people in the study had no history of goiter or elevated thyroid antibodies. Despite this, half of them developed symptoms characteristic of hypothyroidism, including malaise, constipation, and sleepiness. One month after they stopped eating soybeans, their symptoms disappeared.[1]

Symptoms of hypothyroidism, however, aren’t the only potential problem from ingesting too much soy. Taking in large amounts of a soy constituent called "flavonoids" can cause mutations and oxidation reactions that generate free radicals. As Skibola and Smith wrote: "In high doses, the adverse effects of flavonoids may outweigh their beneficial ones, and caution should be exercised in ingesting them at levels above that which would be obtained from a typical vegetarian diet. The unborn fetus may be especially at risk, since flavonoids readily cross the placenta."[2]

Using soy foods is fine, as long as the foods don’t contain genetically modified soy, and as long as your daily intake is low enough. Your moderation won’t please avaricious executives of the soy industry, but it will serve well the function of your thyroid gland.

References

1. Ishizuki,Y., Hirooka, Y., Murata, Y., and Togashi, K.: The effects on the thyroid gland of soybeans administered experimentally in healthy subjects. Nippon Naibunpi Gakkai Zasshi, 67:(5) 622-629, 1991.

2. Skibola, C.F. and Smith, M.T.: Potential health impacts of excessive flavonoid intake. Free Radic. Biol. Med., 29(3-4):375-383, 200.

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