Many processed foods use soy protein isolate as an additive and others as an ingredient. It improves the texture, retains moisture, increases protein percentage, and acts as an emulsifier.
Soy protein powder is mainly used as a substitute for dairy based protein isolate since it is plant based and has no cholesterol. However, there has been dissimilarity among nutritionists as to whether soy protein isolate should be considered as part of a healthy diet or not.
What are soy protein isolate dangers? Most common dangers to face when adding soy protein isolate into diet includes upset stomach, digestive issues, toxic compounds, hormonal disruption, infertility, and thyroid impairment.
It is recommended to consume less than 50 grams of soy protein powder per day as there are connections between overuse and safety concerns related to cancer, diabetes, and cardiovascular disease.
Soy protein isolate is rich in protein, but minimizing consumption of soy to small amounts is recommended. If taken in excess, overconsumption of soy-based products can result in a number of adverse effects.
Isolated soy protein has potential advantages in a balanced diet, but there is cause for concern that users should be aware of. Answered below are frequently asked questions about the potential dangers and side effects of consuming soy protein powder.
Is soy protein isolate processed?
Yes, soy protein isolate is processed by defatting soybean, then rinsing away starches and fiber before dehydrating and grinding into a protein rich powder. The highly processed supplement is 95% protein with a tiny amount of fat and carbs remaining.
Its traditionally made from defatted soy meal, which is added into a water based solution to rinse away the carbohydrates.
The carbohydrates are primarily insoluble, forming a residue removed through centrifugation. The remaining protein is removed from the solution through dehydration to concentrate the soy protein with a slight bean flavor.
Is soy protein isolate harmful?
Yes, being rich in high levels of isoflavone compounds, consuming too much soy protein isolate can harm the human body. The potential risk is associated with eating too much soy, not necessarily that the soy protein isolate is so harmful.
As a result of being a soy based product, potential risks of consuming soy protein isolate include:
- Increases the level of isoflavones, which raises the estrogen level. For men, this may decrease the level of testosterone that may cause infertility in men, low libido, and low sperm count. [1, 2]
- Contain trypsin inhibitors which produce chemicals that limit the production of the enzyme trypsin, which digests protein in the stomach. The action can cause stomach upset such as constipation. [3, 4]
- Includes unhealthy additives that leave toxic elements such as aluminum that can trigger cancerous cells and suppress neurological development. 
- Depleting insulin levels in the body, resulting in hypothyroidism and thyroid function becoming impaired. [6, 7]
- During the breakdown of this additive, it can leave behind mucus along the gastrointestinal tract that can cause respiratory disorders such as asthma. 
- People who are allergic to soy products consuming soy protein isolates can trigger allergic reactions such as vomiting, diarrhea, and skin rashes. [9, 10]
Negative effects of soy protein powder
One of the primary dangers of soy protein isolate is that it is a common allergen for those sensitive to soy products and intolerance when digesting soy.
This additive can cause rumbles in the stomach because of its high SPI, which is highly concentrated with trypsin inhibitors. These inhibitors produce a chemical that decreases enzyme trypsin that helps digestion of protein in the stomach.
During the processing of soy isolate, the additive leaves behind a toxic substances in the body, such as aluminum and hexane. Furthermore, the chemicals used to farm soy form a nitrite when consumed in the body and the compound creates carcinogens inside the body.
Soy protein isolate has a chemical compound isoflavone that raises the level of urinary estrogen, increasing the alpha-hydroxy estrone ratio from 2 to 16. The action increases the chances of the prostate or gastric cancer, and also decreases testosterone levels that may lead to infertility, low sperm, and low libido. [11, 12]
When too much soy protein isolate is consumed, it can negatively affect thyroid function. Too much protein depletes iodine levels and may cause thyroid impairment that results in the development of hypothyroidism.
Do soy protein isolates affect estrogen?
Yes, soy protein isolates does affect estrogen. When regularly consumed in a large amount exceeding daily recommended, soy based products may impact estrogen levels in both males and females.
Soy protein isolates have a compound isoflavone that acts like a plant-based estrogen and can slightly raise estrogen levels. Compared to natural estrogen, it’s about 500 to 1000 times weaker.
However, only a large amount can have any impact on the level of estrogen. This can have adverse effects, especially for men, since it can lower their testosterone levels and cause infertility or low libido.
Again, soy protein isolate raises the urinary estrogen levels, which increases the ratio of alpha-hydroxyestrone that can result in prostate cancer in men.
Is soy protein isolate bad for males?
Yes, soy protein isolate may be bad for males. The supplement has chemical isoflavones that affect the levels of phytoestrogen in the body, which can be harmful to males.
First, the chemical increases the urinary estrogen, which affects the ratio of alpha-hydroxyestrone and may cause prostate cancer. As a result, high-level estrogen lowers the level of testosterone in men, which can harm male reproductive health.
Some potential side effects include penis dysfunction, low sperm count, infertility, and low libido.
A high level of estrogen in men can make them possesses more feminine characteristics such as chest broadening and soft voices.
Dangers of Soy Protein Powder: Conclusion
Soy protein isolates are a nutritional additive used in highly processed foods to smoothen meat texture, add flavor, increase water retention, and increase the protein content. Mainly it’s used to substitute dairy milk powder since it is cheaper, has no cholesterol and has a high nutrition value.
The soy derived protein powder has beneficial properties when used in moderation, but there are potential risks with using too frequently.
Too much soy protein powder increases the level of phytoestrogen, which can adversely affect the proper function of some systems in the body, particularly reproductive health in men.
Soy protein is closely linked to affecting estrogen level compared to natural estrogen. As a result, it may lower testosterone levels which leads to infertility and low libido when consuming excessive amounts.
Furthermore, the dehydrated powder is a highly processed food, meaning many unnatural additives are incorporated into the product. When taken in large quantities, some of these additives are known to cause toxic levels that can lead to cancer.
Furthermore, soy is a common allergen that may trigger allergic reactions, especially in people that don’t really know they have difficulties digesting soy protein.
If you have any concerns about incorporating soy isolate protein into your diet, consult a medical professional, nutritionist or dietary specialist. It is better to speak with a person that is knowledgeable in regards to your particular case.