//fpnotebook.com/
Soy Protein
Aka: Soy Protein, Phytoestrogen, Glycine Max, Soy Isoflavone
- Precaution
- Soy lacks the amino acids cysteine and methionine
- Combine with rice, corn or wheat
- To supply all essential amino acids
- Mechanism
- Weak Estrogen and anti-Estrogen effects
- Weaker than estradiol by factor of 1/1000
- Phytoestrogen Sources
- Lignan in seeds and grains
- Isoflavone (genistein, daidzein) in legumes
- Soybeans
- Red Clover
- Inhibit tumor growth in culture
- Dietary sources
- Soy-rich foods (richest sources)
- Soy milk (1 cup): 3-10 grams Soy Protein (90-140 cals)
- Tofu (3 oz): 10 grams Soy Protein (90 cals)
- Tempeh (1 ounce): 5 grams Soy Protein (55 cals)
- Soy flour (1/2 cup): 20 grams Soy Protein (220 cals)
- Soy Protein (2 tbs): 25 grams Soy Protein (110 cals)
- Edamame (1 cup): 22 grams Soy Protein (250 cals)
- Licorice
- Red clover
- Thyme
- Tumeric
- Hops
- Verbena
- Alfalfa
- Beans
- Benefits: Potential
- Associated with significant reduced Breast Cancer risk
- Initial Retrospective Studies (needs confirmation)
- However, avoid in those with Estrogen receptor positive Breast Cancer
- Decreased lipid levels (Soy Protein - not subcomponents)
- Decreases LDL Cholesterol (up to 13%)
- Decreases Serum Triglycerides (up to 10%)
- Reynolds (2006) Am J Cardiol 98(5): 633-40 [PubMed]
- May increase Bone Mineral Density
- Soy Protein decreases Fracture risk
- Zhang (2005) Arch Intern Med 165(16): 1890-5 [PubMed]
- Soy Isoflavone decreases postmenopausal spinal bone loss
- Ma (2008) Clin Nutr 27:57-64 [PubMed]
- Benefits: Variable
- Hot Flushes
- Effectiveness appears dependent on pharmacogenomic factors
- Equol is a soy metabolite with Estrogenic Activity
- Only 40% of North American women convert Soy Isoflavone (daidzein) to equol
- Conversion is most common in Asian and Hispanic women
- The majority who lack this conversion are unlikely to see benefit from soy
- References
- Clarkson (2011) Menopause 18(7):732-53 [PubMed]
- Some studies show benefit in Hot Flushes
- Faure (2002) Menopause 9:329-34 [PubMed]
- Han (2002) Obstet Gynecol 99:389-94 [PubMed]
- Howes (2006) Maturitas 55:203-11 [PubMed]
- Welty (2007) J Womens Health 16:361-9 [PubMed]
- Other studies suggest no benefit in Hot Flushes
- Nikander (2003) Obstet Gynecol 101:1213-20 [PubMed]
- Requires large, often intolerable doses (60 g/day)
- Albertazzi (1998) Obstet Gynecol 91:6-11 [PubMed]
- Adverse Effects
- Most common side effects
- Diarrhea
- Menstrual irregularities (Amenorrhea or prolonged periods)
- Thyroid suppression may occur
- Recent flawed study showed adverse neurologic effects
- Further well performed studies required
- Unknown longterm effects on Estrogen receptors
- Caution in Estrogen receptor positive Breast Cancer
- Does not appear to increase endometrial thickness at typical isoflavone doses (40-80 mg)
- Penotti (2003) Fertil Steril 79:1112-7 [PubMed]
- Dosing: Sources of dietary Soy Protein and isoflavone
- Recommended doses for Hot Flashes in Menopause
- Soy Protein 25-60 g/day
- Isoflavone 60 mg/day
- Equivalent sources to meet 25-60 gram daily intake
- Soy Milk (4 glasses)
- Tofu 2 portions or one third brick
- Edamame 1/2 cup
- Soy Protein powder in shake (1 serving)
- References
- Albertazzi (1998) Obstet Gynecol 91:6-11 [PubMed]
- Ingram (1997) Lancet 350:990-4 [PubMed]
- Morelli (2002) Am Fam Physician 66(1):129-34 [PubMed]
- Potter (1998) Am J Clin Nutr 68(suppl):1375-9 [PubMed]