People ask if there is a soy-milk estrogen connection frequently, but that may not be what they mean, as there definitely is a connection between soy milk and estrogen. This may be the only portion of the real question not subject to debate. Better phrased, people wonder if the soy-milk estrogen connection is good or bad for their health.
All soy products contain phytoestrogens in the form of isoflavones, which are complex compounds,m and one in particular, which is called genestein. Phytoestrogens are a substance found in edible plants such as clover and soy that mimics estrogen, and can affect estrogen levels in humans and other animals. Phytoestrogens are bio-identical to estrodial, which is a specific component of estrogen and the primary female reproductive hormone.
There have been studies that conclude that isoflavones are anti carcinogenic, and other studies that indicate that they may cause certain cancers. Likewise, while phytoestrogens are commonly used in compounded human growth hormone supplements, the long term consequences are unclear.
The FDA and soy consumption:
As of 1999 the FDA has a dosage suggestion of 25 grams of soy proteins a day. However, in 2008 the FDA commented that soy milk should be avoided and can actually be dangerous for infants unless deemed medically necessary, as it may have long term health consequences.
Japan, Israel, France and Australia, among other countries, have restricted medical use of soy and delivered public health warnings about soy consumption. (References below)
Women’s health and the Soy-Milk Estrogen Connection:
The largest studies of the direct connection of soy milk and other foods and breast cancer were the LACE Cohort (US Population) of 2009 and Shanghai cohort (Chinese population) of 2009. Both studied soy intake in the diet in women recovering from breast cancer who were prescribed tamoxifen. The results were varied. In some women, the soy products reduced the need for tamoxifen, while in others the response was neutral or negative.
The Women’s Sport Health Medicine Center (citation below) recommends soy consumption for post menopausal women, while cautioning that it may have a negative effect on women entering the pari menopausal phase.
According to Web MD (citation below) consumption of soy may increase the risk of endometrial cancer.
Men’s health and the Soy-milk estrogen connection:
A persuasive study detailed in Men’s Health (see citation below) details the study of a man who had taken to drinking several quarts of soy milk a day, and developed a feminizing reaction, including breast enlargement, erectile dysfunction, mood dysphoria, and loss of facial hair due to decreased testosterone.
There is conflicting evidence as to whether soy affects prostate health, according to WebMD’s summary of soy uses and effects (citation below)
A paper published in Harvard’s Journal of Reproductive health (citation below) found that the consumption of soy is related to decreased sperm count. This study of 90 men found that the more soy products the men consumed, the fewer sperm they produced.
Gender transition uses: Soy’s negative influence on testosterone is used to assist male to female sex transition, according to Transidentified. (citation below)
Soy consumption and Heart diseas, prostate conditions:
Soy was initially touted as being beneficial to the heart, but more recent studies indicate that isoflavones don’t act upon the heart independently. Soy does, however, reduce LDL cholesterol and contain HDL cholesterol, as well as saturated fats similar to Omega 3’s, but the ADA has stated that initial claims may have been over exaggerated. (Citation below).
Soy’s effect on prostate cancer remains unclear.
Soy in the public mind:
While among scientists there is an agreement to disagree, and studies the consumption of soy and soy milk is debated in the public arena.
While Asian countries have consumed small amounts of soy products for centuries, the West only recently discovered tofu and soy milk. Soy is now massively consumed as a health panacea. While a few ounces a few days a week may have been normal in an Asian diet, some Americans are drinking quarts a day.
Soy milk is so popular that it has had a distinct impact on consumption of milk, raising the ire of the Dairy Board and causing a war of sponsored studies, advertising, and paid articles hawking one side or another. Yes, there is a soy-milk estrogen connection. The question lies in what this means.
References and Citations:
www.WebMD.com “Soy Uses, Side Effects”
Harvard’s Journal of Human reproduction, Jorge Chavarro, MD, ScD. 2008
ahajournals.org (PDF, Soy_Phytoestrogens)
www.NutritionFacts.org “How much soy is too much?”
www.MensHealth.com “Is Soy the Most Dangerous Food for Men?”, 2009
Eef Hogorvorst, Phd., of Loughborough University, and other researchers. AHA study of 2000.