Fermented Soyfoods: Balancing Modern Western Lifestyles with Ancient Eastern Wisdom

RoseMarie Pierce, B.Sc. Pharm., “The Holistic Pharmacist”

For over two thousand years, humans have received generous nutritional and healing benefits from the modest little soybean (Glycine max (L.) Mer., family leguminosae). The latest research shows the greatest benefits are derived from the soybean when it has been traditionally prepared and especially when fermented. Traditional soyfoods are usually divided into two groups: fermented and non-fermented. Miso, soy sauce, tempeh and natto are the most well known representatives of the first group. Non-fermented tofu and soymilks are popular in the West, though fermented varieties also exist. With each passing year, in the name of health, North Americans are developing a growing taste for this Old World staple, in both the traditional and newer forms.

Fermenting the Soybean
In the soybean fermentation process, end results such as miso, tempeh, natto, and soy or tamari sauce are produced by a host of beneficial yeast, mold and bacteria. Whole-food, fermented soy powders, milks and yogurts are also cultured with multiple species of beneficial bacteria.

The Many Benefits of Soybean Fermentation

1. Improved digestibility
Unfermented soybeans are difficult to digest, partly due to the high amount of protein enzyme inhibitors and hard-to-digest sugar structures. During the fermentation process, the enzymes produced by the beneficial bacteria and other microbes break down, or predigest, the specific complex carbohydrates (sugars) found in soy and most other legumes. This process also renders the proteins more digestible and easier to assimilate than those in the whole soybean. This is especially helpful for those who have a compromised digestive system or difficulty digesting protein.

2. Removal of “antinutrients”
The Chinese, Japanese, and other oriental cultures have long recognized that soybeans need careful processing to remove naturally occurring toxins, including phytic acid, lectins, as well as potent protein enzyme inhibitors. Only after sufficient periods of fermentation are the phytates and “antinutrient” levels of soybeans substantially reduced, making their nourishment available to the human digestive system.

3. Enhanced nutrition
Soy fermentation converts minerals such as calcium, iron, magnesium, potassium, selenium, copper and zinc into more soluble forms and can also increase vitamin levels in the final product. Some beneficial yeasts, such as Saccharomyces cerevisiae, are able to concentrate large quantities of thiamin, nicotinic acid and biotin, thus forming an enriched product.

4. Medicinal benefits
Substances in fermented soyfoods have been found to alleviate the severity of hot flushes, to have a protective effect against the development of cancer, to cause a reduction in cholesterol, and to inhibit the progression of atherosclerosis. The probiotic bacteria (bacteria that support life) produced during soy fermentation are known to enhance healthy intestinal flora and correct digestive tract imbalances.

5. Increased bioavailability of isoflavones
The isoflavones (phytoestrogens naturally occurring in soy) are converted by the bacteria into their “free” or aglycone forms for improved absorption and more effective usage within the body.

The Soybean “Conquers” America
In October 1999, the modest little soybean received a great deal of attention in North America when the US Food and Drug Administration authorized use of health claims about the role of soy protein in reducing the risk of coronary heart disease. As a result of this and some over-stated health claims from other studies, the multinational soy industry has multiplied its efforts to find alternative uses and new markets for soybeans and soy protein foods. Billions of dollars have gone into research, manufacturing and advertising of soy-based products. In the past decade, the custom-designed soybean was created. Many top scientists around the world are expressing their concerns regarding genetically manipulated soy and other crops.

Today’s North American soy cuisine has developed into something very different from its Asian predecessor. On supermarket shelves, we can find soy in everything from breakfast cereals to burgers to frozen desserts. Yet, very few of these are natural, whole-food products. The ancient soybean was, for centuries, the quintessential “candidate for fermentation,” requiring time-sensitive, careful processing in the Eastern World. It has now become mass produced and over-processed in the West.

Some health experts, such as well-known author John Robbins, are questioning the validity of consuming these new, non-fermented soy products, made possible by modern food technology, in quantities never seen before in history. Robbins states, “…the best way to take advantage of soy’s health benefits is to follow the example of the traditional Asian diets and stick with whole [organic] foods…These are the soyfoods that I prefer to eat – rather than the soy products made with protein isolates, soy protein concentrates, hydrolyzed soy protein, partially hydrogenated soy oil, etc. Whole soyfoods are more natural, and are the soyfoods that have nourished entire civilizations for centuries.”

How to Obtain the Most Benefit from Soy Products
First, choose organic fermented soy products such as tempeh, miso, natto, tamari, shoyu, and fermented whole soybean powder, milk and yogurt. Genetically manipulated soy ingredients should be avoided whenever possible. In the U.S. and Canada, almost all soy that is not referred to on the label as organic has been genetically manipulated. It is best to avoid hydrolyzed soy (vegetable) protein. New research suggests that soy formulas may be unsafe for infants.

Second, locate health food stores or natural food markets in your area that sell organic, fermented soyfoods and other foods with organic, fermented soy ingredients. Avoid extracts of soy in “pill” form, because the effects of isolated, concentrated forms of isoflavones are not well understood.

Third, learn how to prepare fermented soyfood dishes. It is relatively easy to cook with tofu, tempeh, miso, tamari, shoyu, and natto. Fermented soy powder, milks and yogurt can be made into nutritional shakes and smoothies or included in pancake mixes, muffins, breads and other baked goods. Cookbooks and recipes can make using soy even easier. To find soy cookbooks, check your local natural food store or go to http://www.soyinfo.com/cookbook.shtml#

Guide to Popular Fermented Whole Soyfoods

A rich, salty, fermented paste, made from salted soybeans alone or in a mixture with grains such as wheat, barley, and rice, which is cultured and aged.

Soy sauce (shoyu)
Originally a byproduct drained off the miso, this dark brown liquid is typically used as a garnish to top Asian dishes. Tamari is a byproduct of miso without the added grains.

A sticky, pasty-textured, slightly sweet-tasting soy ferment, eaten for breakfast or dinner as a topping on rice or added to vegetable dishes.

A popular Indonesian food made by combining soybean with either rice or millet and a mold culture for 24 hrs. A hearty, chewy, meat-like cake that can be grilled as a burger or added to a main dish.

Fermented Tofu
First, a tough textured tofu is made from cooked puréed soybeans processed into a custard-like cake, then fermented to make a white, creamy food resembling semi-soft cheese.

Fermented Soymilk or Yogurt
Made from soymilk that is fermented by probiotic bacteria. Can be used as a dessert or to make sour cream, cream cheese or a form of ice cream.

Fermented Soy Powder or Yogurt Powder
A whole-food, bacteria-fermented powder used in nutritional shakes, bars or in baking, with all the nutritional value of traditional fermented soy.

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12. Robbins, J. What About Soy? [Online] Available from:

RoseMarie Pierce, B.Sc.Pharm, earned her degree in Pharmacy from Dalhousie University in 1972. After extensive studies in herbal and nutritional medicine, RoseMarie integrated these disciplinary practices with her pharmacy education to become Canada’s first Holistic Pharmacist.