Decrypt soy protein
Abstract: Soy protein is a kind of plant protein found in soybeans, which is a complete protein (contains all essential amino acids). Soy protein is very suitable for bodybuilders, especially those who are lactose intolerant and the elderly. However, in recent years, rumors about soy and soy protein (such as more soy can increase breasts) have emerged one after another. It’s time to put an end to these rumors!
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1.Soy protein has a very high protein digestibility
Soy protein and whey protein have the same protein digestibility (100%). The protein digestibility of black beans is only 85%.
2.Soy protein can better improve immunity and body recovery
The amino acid composition of soy protein is similar to that of whey protein, but contains more arginine and glutamine than whey protein.
Arginine is very important for the production of nitric oxide. It helps to expand blood vessels, enhance the delivery of nutrients, and promote muscle synthesis and body recovery. Glutamine can promote muscle growth, prevent muscle breakdown, enhance immunity, delay fatigue, and promote fat burning.

- Soy protein helps promote muscle growth
Research from Ohio State University showed that male subjects who consumed 33g of whey protein or soy protein daily had a significant increase in muscle circumference after 9 weeks of strength training. Those who did not consume whey protein or soy protein had no significant increase in muscle content.
Research by Indiana University School of Medicine has shown that whey protein or soy protein in mice after exercise can promote protein synthesis. However, whey protein is indeed slightly better (better stimulating a certain key substance that promotes protein synthesis).
- Soy protein is suitable for people who are lactose intolerant
Soy protein is very suitable for people who are lactose intolerant. Lactose is a carbohydrate found in milk and dairy products. Some people (especially Chinese) cannot fully digest lactose due to lack of lactase.
Since whey protein and casein are proteins extracted from milk, people who are lactose intolerant may also experience diarrhea and other related symptoms when they use certain whey protein and casein powders.

- Breast enhancement, promoting the secretion of female hormones, and affecting the secretion of male hormones? All rumors!
The female sex hormone content is closely related to the breast size. When a woman enters puberty, estrogen begins to secrete in large quantities, which will directly cause the development of the breast and promote the growth of breast tissue. During pregnancy, the female hormone content in the body will be slightly higher than usual, which will also promote the growth of the breasts. In the medical field, the main methods to increase female hormones in the body are oral contraceptives and hormone replacement therapy.
Because soybeans contain soy isoflavones (phytoestrogens), many people claim that eating more soy can increase breasts. And many male bodybuilders are afraid that eating more soybeans will affect the secretion of male hormones in their bodies.
In fact, these are all rumors! Let me talk about the rumor that soybeans can enhance breasts:
First of all, phytoestrogens are not hormones. They are called phytoestrogens because they have the [weak] effect of promoting the secretion of estrogen in the body.
The isoflavones in soy protein can bind to the estrogen receptor protein in the human body, mimicking some of the physiological effects of natural estrogen.
There are two types of estrogen receptor proteins in the human body, but isoflavones can only bind to one of them, so its biological activity cannot be compared with natural estrogen (natural estrogen can be affected by two types of estrogen in the body). Body protein binding).
A study published in the journal Cancer Epidemiol Biomarkers Prevention in 2004 showed that after 220 healthy premenopausal women ingested 50 mg of isoflavones (phytoestrogens) a day for 2 years, the level of estrogen in the blood did not change.

A study published in the journal Cancer Epidemiol Biomarkers Prevention in 2005 showed that high-dose isoflavone intake has no effect on the estrogen levels in postmenopausal women.
A study published in the journal HumanReproduction Update in 2009 showed that for premenopausal women, the consumption of soybeans cannot increase the level of estrogen in the body. For postmenopausal women, although the consumption of soy can increase the content of estrogen in the body, this effect is negligible.
A study published in the American Journal of Clinical Nutrition in 2014 showed that the isoflavones in soybeans are beneficial to the health of postmenopausal women.
Summarizing the above research, we can get the following answers:
- For premenopausal women, soybeans cannot increase the content of estrogen in the body;
- For postmenopausal women, although the effect of soybean on female hormones in the body is negligible, it is good for women’s health;
- The isoflavones in soybeans cannot effectively increase the content of estrogen in the body, nor can it achieve the purpose of breast enhancement.

Let me talk about the rumors that soy/soy protein will affect the secretion of male hormones:
A study published in the journal “Experimental Biology” showed that after 12 weeks (twice a day) of 3 groups of male bodybuilders using whey protein, soy protein, and soy/whey mixed protein, the male hormones and estrogen in their bodies There was no change in the content of sex hormones.
Research by Ohio State University and Indiana University School of Medicine also shows that soy protein can effectively promote muscle growth.
All in all, soy isoflavones are powerful antioxidants with great health benefits. They have the functions of fighting cancer, lowering cholesterol content, and reducing the risk of cardiovascular disease.
