Nutrition & Health Info Sheets for Consumers - Soy

Soy milk and soy beans (edamame)

Nutrition & Health Info Sheets contain up-to-date information about nutrition, health, and food. They are provided in two different formats for consumer and professional users. These resources are produced by Dr. Rachel Scherr and her research staff. Produced by Israel Chavez, BS, Lucas Camacho, BS, Bruno Lima, BS, Rosie Alaniz, BS, Taylor Berggren, MS, Anna Jones, PhD, Rachel E. Scherr, PhD, Sheri Zidenberg-Cherr, PhD, Center for Nutrition in Schools, Department of Nutrition, University of California, Davis, 2018.

What is soy?

Soy is the protein that comes from soybeans, a type of legume. High-quality soy protein can be found in soy milk, soy beans (or edamame), and tofu. Soy foods are a great source of plant protein because they are low in fat and rich in fiber. Soy also contains essential vitamins and minerals.

Soy protein has been consumed for hundreds of years by various Asian nations. Regular intake of soy is thought to be a part of the reason for the lower rates of heart disease, stroke, and cancer in these countries (1).

Why should we eat soy?

Studies show that eating soy products lowers risk for chronic disease like heart disease, cancer and diabetes. Soy can provide the body with vitamins, minerals, and fiber. Other compounds in soy called flavonoids may also be beneficial to your body (2-8).

  • Soy and Heart Disease: Soy, when eaten instead of animal protein with saturated fat, may reduce the risk of heart disease.2-3 Some compounds in soy have also been shown to lower “bad” LDL cholesterol and increase “good” HDL cholesterol (2-4).
  • Soy and Cancer: Studies show that soy may help reduce the risk of breast and prostate cancer by acting as an antioxidant (5-6). Some compounds in soy may also help your DNA repair itself, and stop cancer cells from growing (6).
  • Soy and Diabetes: Eating soy regularly may reduce the risk of Type 2 Diabetes (7). Soy has also been shown to help manage diabetes by:
    • Lowering blood sugar levels right after a meal.
    • Improving overall glucose tolerance
    • Decreasing HbA1C, which measures blood sugar levels over time (8).

What are high-quality sources of soy?

  • Edamame (soy beans)
    • Least processed form of soy
    • Often sold in fresh, frozen, or roasted forms
    • Can be eaten on its own, added to salads, or added to stir-fries
  • Tofu
    • Bean curd made from mashed soybeans
    • Can be used to replace meat or dairy products in certain recipes
    • Good source of calcium (½ cup serving can contain 130 mg of Ca) (12)
  • Soymilk
    • A great source of calcium (1 cup serving can contain 300 mg of Ca) (12)
    • Can be used to replace milk
    • Often sold in a variety of flavors including plain, vanilla, and chocolate

How can I add soy into my diet?

  • Add tofu or soy crumbles to spaghetti sauce, soup, casseroles, chili, tacos, or meatloaf to reduce the amount of meat in the dish.
  • Try drinking soy milk. Soy milk is high in protein, calcium, essential nutrients, and omega-3 fatty acids. You can also add soy milk to your smoothies, coffee, tea or cereal.
  • Use silken tofu to replace sour cream, yogurt, or cheese in recipes.
  • Eat tempeh, which is made from soybeans and is used in many vegetarian cuisines. It’s high in protein, high in fiber, and can be used to substitute for meat.
  • Veggie burgers are also popular, and they are another way for people to avoid eating too much saturated fat and cholesterol.
Table 1: Commond foods and their soy protein content (12)
Food Serving Soy protein (g) Calories
Soy Burger 1 patty 8 100
Soy Nuts 1 oz 12 150
Soy Milk 1 cup 8 100
Texturized Vegetable Protein (TVP) 1/4 cup 14 50
Tofu 3 oz 9 45
Protein Bar 1 bar 6 180
Soy Breakfast Patties 2 patties 16 160
Soy Flour 1/4 cup 12 90
Soybeans (Boiled) 1/2 cup 7 190
Tempeh 1/2 cup 18 200
Soy Nut Butter 2 Tbsp 8 160

Is it possible to eat too much soy?

Evidence to suggest that you can get too much soy is very limited. Claims that large amounts of soy intake will lead to negative health effects in breast cancer patients or those at risk of breast cancer have not been backed up by research (10-11).

 

References:

  1. Messina M, Nagata C, Wu AH. Estimated Asian Adult Soy Protein and Isoflavone Intakes. Nutrition and Cancer. 2006;55(1):1-12. doi:10.1207/s15327914nc5501_1.
  2. Anderson JW, Bush HM. Soy Protein Effects on Serum Lipoproteins: A Quality Assessment and Meta-Analysis of Randomized, Controlled Studies. Journal of the American College of Nutrition. 2011;30(2):79-91. doi:10.1080/07315724.2011.10719947.
  3. Eilat-Adar S, Sinai T, Yosefy C, Henkin Y. Nutritional Recommendations for Cardiovascular Disease Prevention. Nutrients. 2013;5(9):3646-3683. doi:10.3390/nu5093646.
  4. Rangel-Huerta O, Pastor-Villaescusa B, Aguilera C, Gil A. A Systematic Review of the Efficacy of Bioactive Compounds in Cardiovascular Disease: Phenolic Compounds. Nutrients. 2015;7(7):5177-5216. doi:10.3390/nu7075177.
  5. Yu Y-C, Zheng D, Sun J-J, Zou Z-K, Ma Z-L. Meta-analysis of studies on breast cancer risk and diet in Chinese women. International Journal of Clinical and Experimental Medicine. 2015;8(1):73-85. PMID:25784976 PMCID:PMC4358431.
  6. Mahmoud AM, Yang W, Bosland MC. Soy isoflavones and prostate cancer: A review of molecular mechanisms. The Journal of Steroid Biochemistry and Molecular Biology. 2014;140:116-132. doi:10.1016/j.jsbmb.2013.12.010.
  7. Mueller NT, Odegaard AO, Gross MD, et al. Soy intake and risk of type 2 diabetes mellitus in Chinese Singaporeans. European Journal of Nutrition. 2011;51(8):1033-1040. doi:10.1007/s00394-011-0276-2.
  8. Bhathena SJ, Velasquez MT. Beneficial role of dietary phytoestrogens in obesity and diabetes. The American Journal of Clinical Nutrition. 2002;76(6):1191-1201. doi:10.1093/ajcn/76.6.1191.
  9. Sacks FM, Lichtenstein A, Van Horn L, et al. Soy Protein, Isoflavones, and Cardiovascular Health: An American Heart Association Science Advisory for Professionals From the Nutrition Committee. Circulation. 2006;113(7):1034-1044. doi:10.1161/circulationaha.106.171052.
  10. Messina M. Soy foods, isoflavones, and the health of postmenopausal women. The American Journal of Clinical Nutrition. 2014;100(suppl_1). doi:10.3945/ajcn.113.071464.
  11. Steinberg FM, Murray MJ, Lewis RD, et al. Clinical outcomes of a 2-y soy isoflavone supplementation in menopausal women. The American Journal of Clinical Nutrition. 2010;93(2):356-367. doi:10.3945/ajcn.110.008359.
  12. Food Composition Databases Show Foods List. Food Composition Databases Show Foods -- Oil, soybean, salad or cooking. https://ndb.nal.usda.gov/ndb/search/list. Accessed Jan 24, 2018.


The University of California prohibits discrimination or harassment of any person on the basis of race, color, national origin, religion, sex, gender identity, pregnancy (including childbirth, and medical conditions related to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related or genetic characteristics), ancestry, marital status, age, sexual orientation, citizenship, or service in the uniformed services (as defined by the Uniformed Services Employment and Reemployment Rights Act of 1994: service in the uniformed services includes membership, application for membership, performance of service, application for service, or obligation for service in the uniformed services) in any of its programs or activities.

University policy also prohibits reprisal or retaliation against any person in any of its programs or activities for making a complaint of  discrimination or sexual harassment or for using or participating in the investigation or resolution process of any such complaint. University policy is intended to be consistent with the provisions of applicable State and Federal laws.

Copyright © The Regents of the University of California, Davis campus, 2018. All rights reserved. Inquiries regarding this publication may be directed to cns@ucdavis.edu. The information provided in this publication is intended for general consumer understanding, and is not intended to be used for medical diagnosis or treatment, or to substitute for professional medical advice.