Common Name Soy

Latin Binomial Glycine max L. Merr
Family: Fabaceae

Food use Soy is an excellent source of dietary protein, including all essential amino acids. In addition, soy is a source of lecithin.

Active Constituents Soy contains protein, isoflavones, and fiber.
Isoflavones

Biochanin A
Sissotrin
Genistein
Genistin
Daidzein
Daidzin
Glycitein
Glycitin
Formononetin
Ononin

Dosage Soy is consumed as soy protein, soy flour, or soy milk. Typically 10-100 g per day is recommended. This is equivalent to 40-120 mg of isoflavones per day.

Side effects Soy may act as a food allergen.
Soy has been a dietary staple for over 5000 years and does not appear to cause long-term toxicity.

Herbal Use/Indication Genistein, a phytoestrogen and major constituent of soy, is used to treat menopause, cardiovascular disease, osteoporosis, and cancer (breast and prostate). Soy formula may be substituted for cow's milk to treat diarrhea in infants.

Contra-Indications Drug-Interactions
The use of soy should be discouraged in patients with hormone sensitive cancers (breast, ovarian, and uterine).
Substituting soy milk for cow's milk in an infants first year of life may result in significantly lower bone mineral density.
Pregnancy and lactation

Dietary soy is commonly considered to be safe, although research is limited.
Isoflavones are transferred through breast milk.

Pharmacological Actions Soy protein may moderately decrease blood levels of total cholesterol and low-density lipoprotein. Small reductions in triglycerides may also occur, while high-density lipoprotein is altered in some studies. (54)
The isoflavones, including genistein and daidzein, may be responsible for the cholesterol lowering properties of soy. (54) Dietary soy protein has not been proven to effect long-term cardiovascular outcomes, such as heart attack or stroke. (54)
It has been theorized that the phytoestrogens in soy may increase bone mineral density in post-menopausal women and reduce the risk of fractures. More research is needed before a conclusion can be made. (54)
Several large population studies have reported that individuals with high soy intake have a decreased risk of developing breast, prostate, or colon cancer. It is unclear if dietary soy or soy isoflavone supplements increase or decrease the risk of these cancers. More studies are needed.

Soy. [Internet] Available from: http://www.mayoclinic.com/health/soy/NS_patient-soy