Soy’s Key Nutrients

Published by Jayce Brandt

Written by Chelsey Amer, MS, RDN, CDN.

Key Takeaways:

  • Soy provides a unique combination of high-quality protein, healthy fats, fiber, and essential micronutrients—all in one bean.
  • Naturally-occurring isoflavones act as antioxidants and anti-inflammatory compounds and are linked to improved bone health, cardiovascular protection, and potential cognitive and cancer-related benefits, particularly in postmenopausal women.
  • Soybeans are predominantly unsaturated fats which help lower LDL cholesterol and reduce cardiovascular disease risk when included as part of a balanced diet.

Soy is one of the most nutrient-dense plant foods you can consume. Different from other legumes, soy has higher protein and fat content while containing fewer carbohydrates.1 In the U.S., most soy is used in processed food products such as tofu, tempeh, soybean oil, soymilk and more.2 When you consider the nutritional profile of soy, it’s easy to see why soy should be included in your diet. Here are 5 key components in soy:

1. Protein

Soy is a high-quality plant-based protein, containing all 9 essential amino acids that your body needs. Studies show that increasing your plant-to-animal protein ratio may be associated with a lower risk of heart disease.3

One ½ cup of edamame contains about 9.9 grams of protein.4 Soy protein has been associated with several health benefits, most notably supporting muscle and heart health.

Soy protein consumption has been found to improve blood lipid levels, which can reduce the risk of heart disease.5,6 One meta-analysis published in the New England Journal of Medicine found that soy protein decreased total cholesterol, LDL (“bad”) cholesterol, and triglyceride levels, while increasing HDL (“good”) cholesterol levels.7 Furthermore, supplementation with soy protein has been found to support lean muscle mass and reduce oxidative stress.8

2. Fiber

Unlike many other sources of protein, soy contains fiber. One 1/2 cup serving of edamame contains 6 grams of fiber.4 Soy contains both soluble and insoluble fiber. Seventy to 75 percent of the fiber in a soybean is composed of insoluble fiber, which promotes bowel regularity and contributes to feelings of fullness.9

The remaining 20-25% of fiber in soybeans is from soluble fiber, which has been shown to help regulate blood sugar and lower cholesterol.9 Considering most Americans are not eating enough fiber, adding soy to your diet can be a helpful addition to meet your needs.10,11

Different soy foods contain varying amounts of fiber due to the cooking and heating processes used. Tofu, for instance, contains <1 gram, whereas 3 oz. of tempeh contains 6.7 grams of fiber.4 Check the Nutrition Facts label to see the amount in that particular food.

3. Isoflavones

Soy isoflavones are natural compounds found in soy commonly referred to as plant estrogens. Studies have shown that these compounds are anti-inflammatory and act as antioxidants. Furthermore, research supports that the isoflavones in soy may play a beneficial role in supporting bone health, cognitive health, and even inhibit some types of cancer cell growth.12

Furthermore, some evidence demonstrates that the isoflavones in soy protein can improve blood lipid metabolism, reducing the risk of cardiovascular disease in post-menopausal women and in men.13,14

4. Iron

Soybeans contain more iron than other legumes.1 While it is largely thought that iron intake in plant-based diets is lower than that of omnivorous or carnivorous diets, it is often adequate. Iron absorption, however, may be of concern.

Although there are many factors that influence iron absorption, including iron stores in the body, studies show iron absorption from soy in the form of ferritin to be sufficient.1,15 Consuming soy foods with vitamin C-rich foods (including bell peppers, oranges, strawberries, and more) can also enhance iron absorption.

5. Unsaturated Fats

Soybean oil, from soybeans, is a source of both polyunsaturated and monounsaturated fats, while containing 2g of saturated fats per serving. This fatty acid profile can support an overall healthy diet. Data indicate that soybean oil may lower LDL cholesterol and reduce overall heart disease risk.16

Soybean oil, also labeled “vegetable oil”, contains both essential fatty acids, linoleic acid (omega-6 fatty acid) and alpha-linolenic acid (omega-3 fatty acid).1 Soybean oil is responsible for 40% of the essential fatty acid intake among U.S. consumers.16 

Soybeans are incredibly versatile and can be transformed into tofu, soymilk, tempeh, soybean oil, and miso, as well as soy ingredients found in many pantry-ready beverages, bars, and burgers. Soy foods are an easy way to add a variety of vital nutrients to your diet.

Sources

  1. Messina M. Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature. Nutrients. 2016 Nov 24;8(12):754. doi: 10.3390/nu8120754. PMID: 27886135; PMCID: PMC5188409.
  2. Messina, M. (2016, May 4). Soybeans and the U.S. food supply. Soy Nutrition Institute Global. https://sniglobal.org/soybeans-and-the-u-s-food-supply/
  3. Glenn AJ, Wang F, Tessier AJ, Manson JE, Rimm EB, Mukamal KJ, Sun Q, Willett WC, Rexrode KM, Jenkins DJ, Hu FB. Dietary plant-to-animal protein ratio and risk of cardiovascular disease in 3 prospective cohorts. Am J Clin Nutr. 2024 Dec;120(6):1373-1386. doi: 10.1016/j.ajcnut.2024.09.006. PMID: 39631999; PMCID: PMC12121410.
  4. https://sniglobal.org/wp-content/uploads/2026/02/2026_SNIGlobal_HPG_Final_ForWeb.pdf
  5. Baum JA, Teng H, Erdman JW Jr, Weigel RM, Klein BP, Persky VW, Freels S, Surya P, Bakhit RM, Ramos E, Shay NF, Potter SM. Long-term intake of soy protein improves blood lipid profiles and increases mononuclear cell low-density-lipoprotein receptor messenger RNA in hypercholesterolemic, postmenopausal women. Am J Clin Nutr. 1998 Sep;68(3):545-51. doi: 10.1093/ajcn/68.3.545. PMID: 9734729.
  6. Sirtori, C.R., Lovati, M.R. Soy proteins and cardiovascular disease. Curr Atheroscler Rep 3, 47–53 (2001). https://doi.org/10.1007/s11883-001-0010-2
  7. Anderson JW, Johnstone BM, Cook-Newell ME. Meta-analysis of the effects of soy protein intake on serum lipids. N Engl J Med. 1995 Aug 3;333(5):276-82. doi: 10.1056/NEJM199508033330502. PMID: 7596371.
  8. Zare R, Devrim-Lanpir A, Guazzotti S, Ali Redha A, Prokopidis K, Spadaccini D, Cannataro R, Cione E, Henselmans M, Aragon AA. Effect of Soy Protein Supplementation on Muscle Adaptations, Metabolic and Antioxidant Status, Hormonal Response, and Exercise Performance of Active Individuals and Athletes: A Systematic Review of Randomised Controlled Trials. Sports Med. 2023 Dec;53(12):2417-2446. doi: 10.1007/s40279-023-01899-w. Epub 2023 Aug 21. PMID: 37603200; PMCID: PMC10687132.
  9. Redondo-Cuenca, A., Villanueva-Suárez, MJ, Rodríguez-Sevilla, MD, Mateos-Aparicio, I. Chemical composition and dietary fibre of yellow and green commercial soybeans (Glycine max). Food Chemistry. 2007; 101(3): 1216-1222. https://doi.org/10.1016/j.foodchem.2006.03.025.
  10. U.S. Department of Health and Human Services, U.S. Department of Agriculture. Dietary Guidelines for Americans, 2025–2030. U.S. Government; 2026. https://cdn.realfood.gov/DGA.pdf.
  11. McKeown NM, Fahey GC Jr, Slavin J, van der Kamp JW. Fibre intake for optimal health: how can healthcare professionals support people to reach dietary recommendations? BMJ. 2022 Jul 20;378:e054370. doi: 10.1136/bmj-2020-054370. PMID: 35858693; PMCID: PMC9298262.
  12. Wang Q, Ge X, Tian X, Zhang Y, Zhang J, Zhang P. Soy isoflavone: The multipurpose phytochemical (Review). Biomed Rep. 2013 Sep;1(5):697-701. doi: 10.3892/br.2013.129. Epub 2013 Jun 3. PMID: 24649012; PMCID: PMC3916987.
  13. Barańska A, Błaszczuk A, Kanadys W, Baczewska B, Jędrych M, Wawryk-Gawda E, Polz-Dacewicz M. Effects of Soy Protein Containing of Isoflavones and Isoflavones Extract on Plasma Lipid Profile in Postmenopausal Women as a Potential Prevention Factor in Cardiovascular Diseases: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. 2021 Jul 24;13(8):2531. doi: 10.3390/nu13082531. PMID: 34444691; PMCID: PMC8398438.
  14. Ma L, Liu G, Ding M, Zong G, Hu FB, Willett WC, Rimm EB, Manson JE, Sun Q. Isoflavone Intake and the Risk of Coronary Heart Disease in US Men and Women: Results From 3 Prospective Cohort Studies. Circulation. 2020 Apr 7;141(14):1127-1137. doi: 10.1161/CIRCULATIONAHA.119.041306. Epub 2020 Mar 23. PMID: 32200662; PMCID: PMC7138725.
  15. Collings R, Harvey LJ, Hooper L, Hurst R, Brown TJ, Ansett J, King M, Fairweather-Tait SJ. The absorption of iron from whole diets: a systematic review. Am J Clin Nutr. 2013 Jul;98(1):65-81. doi: 10.3945/ajcn.112.050609. Epub 2013 May 29. PMID: 23719560.
  16. Messina M, Shearer G, Petersen K. Soybean oil lowers circulating cholesterol levels and coronary heart disease risk, and has no effect on markers of inflammation and oxidation. Nutrition. 2021 Sep;89:111343. doi: 10.1016/j.nut.2021.111343. Epub 2021 May 16. PMID: 34171740.

Author Bio:

Chelsey Amer, MS, RDN, CDN, is a registered dietitian nutritionist, Certified Intuitive Eating Counselor, cookbook author, food photographer, and owner of Chelsey Amer Nutrition, an online nutrition counseling and consulting business based in New York. She obtained a Bachelor of Science in psychology from the University of Michigan and received her Master’s of Clinical Nutrition from NYU.