What is Fermentation?

Fermentation is the process where a substance will undergo a chemical reaction. Usually a sugar is converted into an alcohol or acid with the help of a living organism such as a bacteria.

Where does soy come from?

  • Soy comes from soybeans, the beans are then processed into soy protein powder. 

Although beans contain a lot of soluble fiber, protein, carbohydrates, folate and iron. Soy protein is hard to digest, fermentation is used to break soy down. Miso is a type of fermented soy.

It is thought that soy needs to be broken down or fermented to enjoy most of its health benefits. Fermentation involves soaking and or adding bacteria or fungus to help break the soy down.

    • Different products can be made depending on what bacteria or fungus is added.
    • Miso can be made with Koji bacteria.
    • Soy sauce can be made with aspergillus bacteria.

Miko – Awase Miso Soyabean Paste (Aka + Shiro) – 500 Gram – GMO Free Japanese Miso Paste

Why should soy be fermented?

There is a concern that unfermented soy can cause thyroid dysfunction, deplete needed minerals and increase risk of kidney stones.

Soy Information

Soy contains isoflavones  including daidzein and genistein.

What is a isoflavone?

Isoflavone is a type of antioxidant which may have some anti-cancer properties.

Miso soup, as a fermented soybean product, is also a source of probiotics.

What are probiotics?

Probiotics are microbes found in food that help keep the friendly bacteria in your gut healthy. 

Benefits of  fermented soy such as miso,

  • Soy contains anti-oxidants.
  • Antioxidants increase with prolonged fermentation.
  • Soy miso is a very good source of manganese, copper and zinc.
  • Soy is full of nutrients, protein, vitamin B12, vitamin B2, vitamin E, vitamin K, dietary fiber.
  • Soy may strengthen the immune system.

American Diabetes Association, the American Heart Association, and the American Cancer Society all recommend legumes which includes soybeans to optimize health.

What about the salt intake?

  • Several studies have shown that the increased salt content does not increase risk of high blood pressure.

Soy and memories 

Studies are inconclusive, there is no definitive studies showing that memory was improved.

Soy and hot flashes

Studies showed that hot flashes were not reduced.

Soy and thyroid function

Soy may affect thyroid function but the research is conflicting.

Soy and cardiovascular disease

The research does not support that soy can lower cholesterol. The American Heart Association  stated, that soy “decreased LDL cholesterol concentrations; the average effect was &3%. This reduction is very small relative to the large amount of soy protein tested in these studies, averaging 50 g, about half the usual total daily protein intake. No significant effects on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure were evident.”

Reference The American Heat Association

Soy and breast cancer

Although soy has phytoestrogens, Phytoestrogen may block estrogen rather than mimic it. 

  • A study out of Shaghai (Shanghai Women’s Health Study) showed that soy consumption during adolescence may decrease risk of premenopausal breast cancer.
  • Asian women had a 30% lower risk of breast cancer with a higher intake of isoflavones. 
  • Western women did not have a reduced risk of breast cancer although the study did show that the soy intake was less among western women which may help explain the discrepancy.


  1. Wu AH, Yu MC, Tseng CC, Pike MC. Epidemiology of soy exposures and breast cancer risk. Br J Cancer 2008; 98:9.

soy informationDownside of soy

  • Soybeans can cause food allergies
  • Most of the soy grown in the United Staes has been genetically modified to tolerate  pesticides such as Round Up.
  • Soy should not be used to replace infant formula. A baby who is placed on a soy diet may be more sensitive to the estrogen side effects of soy. Regular soy milk could lead to nutrient deficiencies. Children who are allergic to milk may also be allergic to soy.
  • Large doses of soy have been shown to increase endometrial tissue.
  • Beans contain lectins which can cause damage to the intestines
  • All plants and grains contain lectins. Lectins may affect insulin resistance.
  • The harmful effects of lectins may be lessened by eating fermented soy.
  • Patients with cystic fibrosis may have a hard time breaking down soy’s proteins.
  • Patients with kidney failure have a hard time breaking down soy’s protein.
  • Soy may interfere with different medications that are used to treat diabetes and depression as well medications used to thin the blood and treat hormone imbalance.

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