Soy

BACKGROUND: Soy is a food component and also a supplement of soybeans. One important active component of soy is an isoflavone, a phytochemical that has a structure similar to the hormone estrogen.

HISTORY: The mention of soy’s medicinal properties dates back to 11th century China. In the early 1900s, it was recognized as a great source of protein and even as a meat substitute. Soy had its ups and downs in the American diet but never really gained popularity as a vegetarian food until the 1960s and 1970s. Since then, the uses of soy have grown immensely from use in medicine used to making tires.

PROPERTIES: Antioxidant, antimicrobial, anti-inflammatory

CONSIDERED USES

Respiratory: May help decrease asthma episodes

Cardiovascular: This may help prevent cardiovascular disease and stroke. May also help decrease blood pressure

Gastrointestinal: Pain of irritable bowel syndrome (IBS), liver protection, Crohn’s, diarrhea, indigestion, lactose intolerance, (nonalcoholic) fatty liver

Genitourinary: Mild estrogenic effects - may help with menopausal symptoms. May help decrease symptoms of menopause (esp. hot flashes), postmenopausal symptoms, and PMS. It may reduce some of the effects of chronic kidney disease, possibly useful for enlarged prostate, PCOS, vaginal atrophy

Musculoskeletal: Supports muscle development and strength, may decrease soreness after muscle use, fibromyalgia, hepatitis C, menstrual migraine prophylaxis, osteoarthritis, osteoporosis (may help increase bone density), rheumatoid arthritis

Neurologic: Alzheimer’s, cognitive impairment, and function (remote possiility), decreased risk of stroke

Skin: Wrinkled skin

Mental Health: Possibly lowers risk of depression

Glucose: May help lower blood glucose levels

Cholesterol: May help lower bad (LDL) cholesterol

Immunity: Potential immunity booster

Cancer: It may help prevent certain cancers – particularly breast cancer if taken earlier in life (blocks some estrogen receptors), but may increase risk at an older age.  While direct evidence is still lacking, consideration is still given to the prevention of colorectal, cervical, endometrial, gastric, lung, and thyroid cancers. 

Infectious Disease: Possibly HIV protective

Other: Promotes fat loss while building muscle mass, obesity, longevity

Side Effects: Mild gastrointestinal problems, constipation, nausea, rash/hives, decrease in blood sugar and/or blood pressure.

Cautions and Contraindications: Caution with thyroid problems, hay fever, breast cancer, cystic fibrosis, diabetes, and those taking antidiabetic medication, endometrial cancer, hypothyroidism, kidney stones, milk allergy, kidney failure, and bladder cancer. Maio, Nardil, Parnate, estrogens (i.e. Premarin), levothyroxine, oral antihypertensives (medicine to reduce blood pressure), antibiotics (may decrease effects especially if taken at the same time), progesterone, blood thinners,May interact with other drugs at the P 450 level (2C9); possibly contributes to dementia and decreased memory in those over 65 (this is controversial-some feel it may actually help).

Note: In premenopausal women, soy can be anti-estrogenic, blocking the receptors from the body’s estrogen. During and after menopause, it tends to develop estrogen-like properties

FORMS: Tofu, edamame, soy nuts, capsules, soy milk, vaginal gel, moisturizing cream, powder, liquid, milk powder, textured soy protein, beans, sauce, extracts 

People process isoflavens differently depending on their gut bacteria. Bifidobacterium and Lactobacillus probiotics may help in the conversion to metabolically active compounds with estrogenic effects.

RECOMMENDED BRANDS

SOY

Bayer One a Day® Women's Menopause Formula (also contains vitamins and minerals) - from soy - tablets (available over-the-counter in many retail stores that have OTC medicine products ).

Bluebonnet Non-GMO Soy Isoflavones - capsule - Available over-the-counter in some retail pharmacies

Spring Valley™ [Walmart] Soy Isoflavones - tablets (can buy over-the-counter from in the Walmart pharmacy department)

Whole Foods™ Soy Isoflavones capsules (can be purchased over-the-counter in many 

Whole Foods stores)

Please Note: We only recommend herbal and supplement brands that meet high standards for safety, quality, and transparency. I research each product before sharing. Some links — like those to Amazon or Fullscript— are affiliate links, meaning I may earn a small commission if you buy through them, at no extra cost to you. It helps support my website, Web Guide to Healthcare. Plus, these links often offer discounts for you, fast shipping, and helpful reviews.

DOSAGE: As directed.

The following are reported doses and may NOT be supported by evidence (reported by various sources i.e. WebMD, RxList, Epocrates, ConsumerLabs, German Commission E, NIH publications, and others). Read dosages and instructions carefully when available on the label.

Please Note: Some of these doses are designated in mg (milligrams) and others in gms (grams)

• Cognitive Function: 60-110 mg soy isoflavones by mouth daily

• Diabetes Mellitus: 40-161 mg soy isoflavones by mouth daily

• Hypertension: 18-40 grams of soy protein by mouth daily

• High cholesterol: 20-50 gm soy protein by mouth daily

• IBS: 40 mg soy isoflavones by mouth daily

• Menopausal Symptoms: 34-200 mg by mouth daily

• Menstrual Migraine Prevention: 60 mg soy isoflavones by mouth daily

• Muscle Strength: 25 gm of soy protein by mouth daily

• Obesity: 100 gm of soy fiber by mouth daily or 52 gm of soy protein by mouth twice a day

• Osteoarthritis: 40 gm of soy protein by mouth daily

• Osteoporosis: 50-90 mg soy isoflavones by mouth daily

• PCOS: 50 mg soy isoflavones by mouth daily

• PMS: 68 mg of soy isoflavones by mouth daily

• Prostate cancer prevention: 8 oz soy milk by mouth daily

• Wrinkled skin: 40 mg of soy isoflavones by mouth daily, or apply soy-based moisturizer to the affected area 2 times daily

Isoflavens - responsible for many of the above effects- are also contained in red clover, soy milk, and kudzu

Disclaimer: The material above is for informational purposes only. This information is not intended to diagnose or treat a condition. The uses listed above are tentative; some have or are undergoing research trials, but many are not FDA-approved. It is essential that you investigate these supplements further before deciding to use them. Check interactions and contraindications on sites like Drugs.com or WebMD. Do not attempt to treat a serious condition like liver, kidney problems, high blood pressure, heart disease, cancer, diabetes, or thyroid issues without discussing it with a healthcare provider first. If you are pregnant, do not use supplements without discussing it with your healthcare provider.