Every man has probably heard a horror story about soy and erectile dysfunction. How accurate are these claims? Can you grow breasts from eating too much tofu or soybeans?
In this article, we’ll look at soy protein and assess its effect on testosterone. We’ll also explore if soy increases estrogen in men, and if so, to what level.
Key Takeaways: What Does Soy Do to Men?
- Soy proteins do not increase or reduce testosterone levels in men and women.
- Although they contain phytoestrogens, soy foods do not increase the amount of estrogen in men or women.
- There are many types of soy food, varying based on cooking, fermentation, and preparation.
- Soy proteins have many nutritional benefits to the body.
- Unless consumed in excess quantities, soy proteins are generally safe to eat.
Is Soy Bad for Men?
Soy consumption isn’t bad for men. In fact, soy is a rich source of high-quality proteins and other nutrients with massive health benefits. Because of large amounts of isoflavones and plant estrogens, soy can help protect you from many chronic illnesses.
Although many studies on high soy intakes show that these phytoestrogens can mimic estrogen, they do not increase the level of estrogen or reduce testosterone levels in men.
These misconceptions about soy arose from two unique cases where two men experienced a hormonal imbalance because of their high soy consumption.
A 19-year-old man with type 1 diabetes on a vegetarian diet reported loss of libido, hypogonadism, and erectile dysfunction [1]. A second 60-year-old man reported gynecomastia (man breasts) [2].
It’s essential to understand that these men consumed extreme amounts of soy leading up to their diagnoses. Despite that, plenty of studies and scientific data show no connection between soy or isoflavone supplements and testosterone or estrogen levels in men [3].
Here are some quick ways to boost testosterone naturally.
How Much Soy Is Too Much for a Man?
Anything that ranges from 450 to 900 mg of soy isoflavones has been shown to cause side effects in men according to some studies [4].
That’s anywhere between 18 and 36 times the recommended daily intake. Thankfully, it’s unlikely that you’d consume that much soy in a day, anyway.
With the average soy meal averaging about 25 mg of isoflavones, you’re well within the safe range of soy intake. The typical Japanese intake is much higher, yet they report no adverse effects. Check out these activities that help you increase testosterone naturally.
Even if you ate a soy meal three times a day, you’d only have consumed approximately 75 mg of soy isoflavones. In this regard, you have little to worry about.
Is Soy Bad for Boys Going Through Puberty?
Soy is not bad for boys going through puberty. It does not exert any adverse effects on the hormonal balance of boys or affect their pubertal development [5].
Much fewer studies on the effects of soy and phytoestrogens include children. Where they’re included, sample sizes are also small.
Children who consume soy significantly reduce their risk of developing breast cancer [5]. Besides that, soy remains a source of many nutritional benefits for children.
Soy protein isolates are also ideal for infant formula. Isolated soy protein has a purity of up to 90%, and soy formula is an excellent substitute for cow’s milk, especially if the infant is lactose intolerant [6].
Soy, Estrogen, Men: What’s the Relationship?
Scientific evidence shows no relationship between soy, estrogen, and men. Neither soy nor soy isoflavones increase the level of estrogen in men [7]. Unless consumed in morbid amounts, they have no observable effects on the hormonal balance of males. Soy does not increase or reduce testosterone levels either. Here’s how to increase testosterone naturally.
Can Soy Increase Estrogen Levels?
Soy cannot increase estrogen levels in men. Although the phytoestrogen isoflavone is present in soy, it does not increase or reduce male reproductive hormone levels either [7]. Its effects are weaker than natural human hormone estrogen, and its effects can sometimes counter normal estrogen activity.
Which of the following two do you think increased estrogen in men?
Learn more about how to increase testosterone naturally here.
How Did the Soy Estrogen Myth Start?
The Soy Estrogen Myth began when a popular online newspaper cited a 2008 study that found that among men with low sperm counts, eating soy lowered their sperm counts even further. The study noted that soy did not lead to infertility.
However, this study had some serious limitations. They limited it to 99 men, with about 70 of them obese or overweight. It did not use a multivariate approach and soon, other studies emerged, finding no association between soy and low sperm counts.
Researches noted that there were no notable effects of soy protein on testosterone, sex hormone-binding globulin, or free testosterone levels [8].
Is Soy Healthy for Males?
Soy is a healthy food for males.
Isoflavone in soy has no adverse effects on testosterone or estrogen levels in men, making it a safe food to consume. Even when consumed in relatively high quantities, it still has marginal effects on the hormonal balance in men [8].
Men can draw many health and nutritional benefits from soy protein. You can gain muscle mass much better using soy protein than using whey protein. We look at plenty of other effects of soy protein in the next section below. Also, find out how certain diets can inhibit your ability to boost testosterone naturally here
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057888/
The Facts on Soy
Here are some amazing facts about soy:
Soy Nutrition
Soy is a rich source of proteins and contains all nine essential amino acids your body requires, along with abundant plant fats and vitamins. As a protein supplement, it can help men engaged in weight and resistance training improve their strength and lean muscle.
The USDA estimates that 100 grams of cooked but unsalted green soybeans contains [9]:
- 6.5 grams of fat
- 4.2 grams of fiber
- 11.04 grams of carbs
- 12.4 grams of proteins and;
- 141 kilocalories
Soy is also rich in minerals including:
- Calcium
- Phosphorus
- Potassium
- Iron
- Thiamin
Many soy sources also contain sufficient amounts of polyphenols. As a type of antioxidant, polyphenols have several benefits, including protecting your body from heart disease, stress, and cell damage.
Isoflavones, the phytoestrogens present in soy foods, can attach themselves to estrogen receptors, causing many health benefits.
Types of Soy Products
You can find soy in many products including [10]:
- Soybeans: These are whole soy seeds that grow in a pod and mature into hard dry beans similar to other legumes. Soybeans are usually yellow, although some are brown or black.
- Edamame: These are soybeans harvested while still green and sweet-tasting. Many people consume edamame as a snack or vegetable after boiling for about 20 minutes in slightly salted water.
- Soy milk: When you soak soybeans, grind them until fine and strain them, you end up with soy milk or soybean milk.
- Tofu:Tofu is soybean curd, made from fresh soy milk and a coagulant. It has a mild flavor and can absorb the flavors of other foods, including spices and marinades.
- Soy Nuts: Soy nuts result from soaking whole soybeans in water and roasting them until brown
- Miso: This Japanese soy paste has a rich salty taste and is often used to flavor a variety of foods, sauces and dressings. It can also be an excellent marinade.
- Soy sauce: This popular sauce results from fermenting and straining soybeans. It has a rich salty flavor. You can also mix it with other ingredients to end up with Tamari, Shoyu or Teriyaki sauce.
- Tempeh: You can mix soybeans with other grains (like rice or millet), ferment and press them into a cake with a nutty or smoky flavor. It has a chunky and tender texture and can be cut into slices, used as a marinade or grilled. You can also add it to casseroles and soups.
- Textured soy protein (TSPs): TSPs are products made from textured concentrates, soy flour and spun soy fiber.
- Meat alternatives: Many animal protein substitutes use soy protein or tofu to imitate meat in burgers, sausages, hot dogs, and bacon.
Find out more about other cereals that can hinder your ability to boost testosterone naturally.
Soy Benefits
Here are the benefits of adding soy to your varied diet:
- Reduces risk of heart disease
- Helps lower blood pressure
- Helps reduce blood sugar
- May improve bone health
- May help in managing obesity
- May help reduce cholesterol levels
- May reduce risk of some cancers
Reduces Your Risk of Heart Disease
Adding soy to your traditional diet can significantly reduce your risk of cardiovascular disease. Soy isoflavones help prevent your blood vessels from swelling and also improve their elasticity. These two factors help protect your heart from strain.
Other studies also show that soy food can reduce your risk of stroke and heart disease by 20% and 16% respectively. Soy-rich diets reduce your risk of death from heart disease by up to 15% [11].
Helps Lower Your Blood Pressure
Isoflavones play a massive role in lowering your blood pressure. In some studies, a daily intake of up to 153 mg of soy isoflavone can reduce your blood pressure by 3- and 6-mm Hg in people suffering from hypertension [12].
Source: https://pubmed.ncbi.nlm.nih.gov/21310599/
However, the jury is still out on whether these findings apply to people with normal blood pressure.
Fermented soy foods contain healthy amounts of arginine, an amino acid that helps reduce blood pressure. It also has other health benefits, like helping injuries heal, improving blood flow, and boosting the function of your immune system.
Arginine present in soybeans can also help with erectile dysfunction and help the kidneys in removing waste.
Helps Reduce Your Blood Sugar
Isoflavones also help you reduce insulin resistance, a condition that often leads to type 2 diabetes. Adding soy protein to your diet can lower blood sugar in people with this type of diabetes [13].
It also helps people with metabolic syndrome reduce their risk of type 2 diabetes, heart disease, and stroke. While there isn’t a strong link between blood sugar control and soyfoods in type 2 diabetics and healthy people, more research will help establish a better relationship.
May Improve Bone Health
Low estrogen levels can cause osteoporosis in postmenopausal women [14]. This condition results from reduced estrogen production which causes calcium to leach from the bones. Isoflavones contain phytoestrogens, which bind with estrogen receptors the same way human estrogen would.
Soy foods can be a useful alternative to hormone replacement therapy, which aims to replace estrogen in the body. It helps premenopausal women reduce side effects like hot flashes. Unlike HRT which may have some severe side effects, soy isoflavones are a better option for postmenopausal women.
May Help in Managing Obesity
A study conducted in 2019 on rats showed that soy isoflavone intake helped prevent fat from building up around body organs [15]. Although these results need further review and research, they look promising in helping human beings manage obesity.
May Help Reduce Cholesterol Levels
Diets rich in soy proteins can help you reduce LDL (bad) cholesterol and improve HDL (good) cholesterol levels. Besides that, soy-based foods have extremely low amounts of saturated fat.
While some studies show that an intake of about 25 grams of soy food may help reduce LDL cholesterol by about 3%, these reductions may be larger especially where people replace animal protein with soy protein [16].
A reduction in LDLs and an increase in HDL cholesterol is beneficial to people with high-risk factors of type 2 diabetes, obesity, and heart disease.
May Reduce Risks of Some Types of Cancer
In men, soy consumption helps reduce the risk of prostate cancer. It also helps reduce breast cancer risk, as well as risks of other cancers like digestive tract and cardiovascular cancers.
Dangers of Soy
Soy is safe, but it may have mild-to-moderate effects on other people:
- Effects on thyroid function
- Many soy products are genetically modified organisms (GMOs)
- Can effects digestion
- Soy can interfere with certain medications
- Allergy
Effects on Thyroid Function
Some types of isoflavones, like genistein, may prevent thyroid hormone production in some cases. Furthermore, goitrogens present in soy can prevent iodine absorption, inhibiting thyroid function.
However, these studies involved animals, many of which need more analysis. Studies carried out on human subjects show that soy isoflavone intake has little effect on thyroid hormone levels or thyroid function [17].
Most Soy Products Are Genetically Modified Organisms (GMOs)
90% of all soybeans produced in the US are genetically modified—so stick to organic whenever possible. There’s much controversy surrounding GMOs, including their short- and long-term effects on humans. Besides that, their levels of intake are still debatable [18].
Certain soy GMOs can withstand the glyphosate pesticide, they may also contain glyphosate residue, which can have adverse effects on your health. Additionally, they have poorer nutrient quality when compared to organically produced soybeans.
Effects on Digestion
Soybean agglutinins are an antinutrient that can negatively affect digestion by altering the structure and barrier function of the human gut. It may also destroy the healthy microbiome in your digestive system [7].
However, you can easily counter these negative effects by cooking, processing, soaking or fermenting soybeans before you eat them.
Contraindications With Certain Medications
Fermented soy proteins in soy sauce and tofu have high levels of tyramine, an amino acid that helps regulate blood pressure. Your body breaks down tyramine to monoamine oxidase. However, some depression medication can cause your body to decrease the breakdown of tyramine.
This hindrance has the potential to raise your blood pressure to dangerous levels. If you’re taking depression medication such as phenelzine (Nardil) or tranylcypromine (Parnate), avoid soy products with high levels of tyramine.
Soy Allergy
Some people may have allergic reactions to soy proteins. These allergies are often triggered by glycinin and conglycinin, proteins found in almost all soy products. However, soy allergy is quite rare in adults, and most children grow out of it by the time they’re 10 [5].
FAQ
Here are some questions people often ask about soy.
Is Soy Bad for Testosterone?
No, soy isn’t bad for your testosterone levels. Besides that, soy protein does not increase or reduce t levels in the human body.
Although its phytoestrogens can bond with estrogen receptors in similar fashion to human estrogen, they produce marginal effects. They neither increase or reduce estrogen levels in men or women. Sometimes, soy even has antiestrogenic effects.
Does Soy Cause Erectile Dysfunction?
No, it does not. There is no scientific basis to back this claim up. In the singular case where a young man reported erectile dysfunction and hypogonadism due to soy protein, it had little to do with soy. When he changed his diet, these symptoms disappeared. Phytoestrogens do not inhibit or weaken testosterone function, and therefore cannot cause ED in men.
Instead, soy protein can reduce the risk of prostate cancer by producing a prostate-specific antigen that stops the growth of cancer cells.
Does Soy Really Increase Estrogen?
No, soy does not increase estrogen in men or women. While phytoestrogens can activate your body’s estrogen receptors, it has a much weaker chemical composition than human estrogen. If there’s little estrogen, isoflavones activate estrogen receptors to mitigate this shortage. Where estrogen is abundant, isoflavones work against natural estrogen and limit its effects.
Can Soy Make a Man Feminine?
Soy cannot feminize a man. The phytoestrogen present in soy is too mild to influence any real hormonal changes. The isoflavones present in soy, even in excess amounts are unable to reduce testosterone levels in men or increase estrogen enough to make a change. On the rare occasion they reduce testosterone levels or increase estrogen, the effects are mild and easily reversible.
Does Soy Cause Man Breasts?
No, soy cannot cause man breasts. There aren’t enough isoflavones in soy foods or soy supplementation to make any physiological changes in men. Soy consumed even in excess amounts cannot reduce your t levels or increase your estrogen levels in a significant way.
Is Soy Bad for Your Gut?
No, soy isn’t bad for your gut. Although many fermented soy foods may contain agglutinins that may affect your body’s ability to absorb some essential nutrients, you can often cook, boil or ferment these antinutrients away before consuming soy proteins. Other than that, soybeans are a rich source of proteins, minerals, plant fats, and fiber, all of which are good for the gut.
Conclusion
Unlike popular belief, soy proteins are generally safe to consume, even in large quantities. They do not destroy testosterone or increase estrogen in men. Instead, soy proteins are a rich source of proteins and other nutrients.
Their phytoestrogens have many health benefits, preventing people with metabolism risk factors from dangerous illnesses and cancers. Supplement your diet with soy proteins, there’s nothing to worry about. If you’re looking to increase your t-levels further, you can use a natural testosterone booster like Testogen.
References
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- JE;, Martinez J;Lewi. “An Unusual Case of Gynecomastia Associated with Soy Product Consumption.” Endocrine Practice : Official Journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/18558591.
- “Straight Talk about Soy.” The Nutrition Source, 3 Mar. 2021, www.hsph.harvard.edu/nutritionsource/soy/
- Messina, Mark. “Soybean Isoflavone Exposure Does Not Have Feminizing Effects on Men: a Critical Examination of the Clinical Evidence.” Https://Www.fertstert.org/Article/S0015-0282(10)00368-7/Pdf, MODERN TRENDS, 1 May 2010, www.fertstert.org/article/S0015-0282(10)00368-7/pdf.
- D;, Messina M;Rogero MM;Fisberg M;Waitzberg. “Health Impact of Childhood and Adolescent Soy Consumption.” Nutrition Reviews, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/28838083/.
- Astawan, Made, and Ayu P.G Prayudani. “The Overview of Food Technology to Process Soy Protein Isolate and Its Application toward Food Industry.” World Nutrition Journal, vol. 4, no. 1, 2020, p. 12., doi:10.25220/wnj.v04.s1.0003.
- Barrett, Julia R. “The Science of Soy: What Do We Really Know?” Environmental Health Perspectives, National Institute of Environmental Health Sciences, June 2006, www.ncbi.nlm.nih.gov/pmc/articles/PMC1480510/.
- Reed, Katharine E., et al. “Neither Soy nor Isoflavone Intake Affects Male Reproductive Hormones: An Expanded and Updated Meta-Analysis of Clinical Studies.” Reproductive Toxicology, Pergamon, 28 Dec. 2020, www.sciencedirect.com/science/article/pii/S0890623820302926.
- “FoodData Central Search Results.” FoodData Central, fdc.nal.usda.gov/fdc-app.html#/food-details/1100447/nutrients.
- UCSF Health. “A Guide to Foods Rich in Soy.” Ucsfhealth.org, UCSF Health, 22 June 2021, www.ucsfhealth.org/education/a-guide-to-foods-rich-in-soy.
- Yan Z;Zhang X;Li C;Jiao S;Dong W; “Association between Consumption of Soy and Risk of Cardiovascular Disease: A Meta-Analysis of Observational Studies.” European Journal of Preventive Cardiology, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/28067550/.
- Liu XX;Li SH;Chen JZ;Sun K;Wang XJ;Wang XG;Hui RT; “Effect of Soy Isoflavones on Blood Pressure: A Meta-Analysis of Randomized Controlled Trials.” Nutrition, Metabolism, and Cardiovascular Diseases : NMCD, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/21310599/.
- Fang K;Dong H;Wang D;Gong J;Huang W;Lu F; “Soy Isoflavones and Glucose Metabolism in Menopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.” Molecular Nutrition & Food Research, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/27004555/.
- Sathyapalan T;Aye M;Rigby AS;Fraser WD;Thatcher NJ;Kilpatrick ES;Atkin SL; “Soy Reduces Bone TURNOVER Markers in Women during EARLY Menopause: A Randomized Controlled Trial.” Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/27465911/.
- Velasquez, Manuel T, and Sam J Bhathena. “Role of Dietary Soy Protein in Obesity.” International Journal of Medical Sciences, Ivyspring International Publisher, 26 Feb. 2007, www.ncbi.nlm.nih.gov/pmc/articles/PMC1838825/.
- Tokede, Oluwabunmi A, et al. “Soya Products and Serum Lipids: A Meta-Analysis of Randomised Controlled Trials.” The British Journal of Nutrition, U.S. National Library of Medicine, 28 Sept. 2015, www.ncbi.nlm.nih.gov/pubmed/26268987.
- Otun, Jemiliat, et al. “Systematic Review and Meta-Analysis on the Effect of Soy On Thyroid Function.” Scientific Reports, Nature Publishing Group UK, 8 Mar. 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6408586/.
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