Wednesday, March 21, 2007 Dangers of therapeutic soybean isoflavone doses By Zosimo T. Literatus, R.M.T. Breakthroughs
NATURE has its own rules and manipulating them by human design can be quite dangerous.
“Now this is the Law of the Jungle—as old and as true as the sky,” wrote Rudyard Kipling in his book The Second Jungle Book, “and the Wolf that shall keep it may prosper, but the Wolf that shall break it must die.”
Soybean is a good dietary supplement as its dietary dose can improve bone mineral density (BMD) even among postmenopausal women (PMW). But clinical studies on soya isoflavones in long-term therapeutic dose have shown subclinical (no symptom) side effects.
In a 1995 multicenter study, H. Ben Hur and colleagues used 234 PMW volunteers to check the effects of 600 mg ipriflavone taken daily for three years. Ipriflavone is a synthetic isoflavone whose metabolites include daidzein, a major isoflavone in soya.
Results published in American Journal of Reproductive Immunology showed 13.2 percent of volunteers developed subclinical lymphocytopenia (abnormally low counts of lymphocytes). Lymphocytes are critical to the function of the immune system.
In a D. Agnusdei-L Bufalino study (1997), lymphocytopenia occurred in three percent of PMW volunteers in two years. Results were published in Calcified Tissue Internist.
In a study (2006), Do Y. Soung and colleagues used 25 grams (g) of soy protein containing 60 milligrams (mg) isoflavones (effective dose: 1.1 mg isoflavones per kilogram of body weight) daily for one year. Soung is a professor at the Department of Nutrition, Food and Exercise Sciences in Florida State University (FSU) in Tallahassee, Florida (USA).
Results published in the Nutrition Journal showed no effect on the monocyte, lymphocyte, and basophil counts and the MCHC (average hemoglobin concentration per RBC).
“The higher doses of ipriflavone (600 mg) that raised concerns related to lymphocytopenia,” noted Soung, "may be considered a pharmacologic dose, which is not likely to be achieved with dietary soy supplementation.” However, there is no indication that being synthetic or natural makes a difference in this adverse effect.
Nonetheless, maintenance dose of 600 mg soy isoflavones must be avoided. It’s safer to stick with 60 mg (or 28 g soy protein) daily for a year without having to monitor your complete blood count (CBC). Above this, get a CBC regularly.
Alexander Pope, in his book Epitaphs, put it lightheartedly: “Nature, and Nature’s laws lay hid in night: God said, Let Newton be! And all was light.”
(For comments and suggestions, e-mail to ztliteratus6046@lycos.com or text to 0927-979-3519.)
