Throughout Asia, author Kaayla Daniel explains, traditionally fermented whole-bean soybean products — miso, tempeh, natto, and soy sauce, or the “good old soys” — are thought to be “digestive aids, potent medicines, powerful energizers, stamina builders and longevity elixirs.”

Soybeans contain a dangerous set of chemicals that must be neutralized, and the only way to partially defang these chemicals is through traditional fermentation. Modern industrial methods have never accomplished this task and have, in fact, introduced new dangers. Note that tofu is not fermented.

As established in Part I, my soy expert is Kaayla T. Daniel, PhD, CCN, the author of The Whole Soy Story: The Dark Side of America’s Favorite Health Food (2005). Daniel’s credentials, experience, and extensive research on soy make her an expert.

Traditional fermentation can take months or years to complete, and the results, writes Daniel, “bear little or no resemblance to the modern soybean products promoted by the soy industry and sold in the American grocery stores. Further, Asians simply do not eat any soybean products in great quantity. They are used in small amounts as condiments or seasonings, not as main courses, and rarely more than once a day. Even with the finest organic and perfectly prepared soybeans, the lesson is, 'Less is more.’“

Daniel’s quick list illustrates what is at stake when eating untreated soybeans. Soy is one of the top eight allergens. Its goitrogens damage the thyroid. Its lectins cause red blood cells to clump together and may cause immune system reactions. Its oligosaccharides cause bloating and flatulence. Its oxalates prevent proper absorption of calcium and have been liked to kidney stones and a painful disease known as vulvodynia. Its phytates impair absorption of minerals such as zinc, iron, and calcium. Its isoflavones are phytoestrogens that act like hormones and affect the reproductive and nervous systems. Its protease inhibitors interfere with digestive enzymes, leading to gastric distress, poor protein digestion and an overworked pancreas. Its saponins bind with bile, which can lower cholesterol (not a good thing here) and can damage the intestinal lining.

People use soy as a protein replacement strategy. But, writes Daniel, even “fermented soyfoods are not ideal sources of proteins.” Human bodies have “more than 50,000 types of proteins, all built from the building blocks known as amino acids. Nine of these amino acids are considered `essential’ for humans because we cannot manufacture them on our own and must obtain them from the diet. If the `essential’ amino acids are present in sufficient quantities, we can build the `non-essential’ amino acids. But if one or more are missing or low in quantity, the body will fail to synthesize many of the enzymes, antibodies and other proteins it needs.”

Animal proteins (eggs, milk, fish, meat) contain a “'complete’ set of the essential amino acids in desirable proportions.” Plant proteins are “incomplete” because they are “low in some of the essential amino acids.” Soybeans and other legumes are low methionine. And grains are low in lysine. Thus, in most traditional cultures, beans and rice are combined and served with small amounts of animal foods to insure sufficient protein intake. Soybeans are often fermented with a grain.

Daniel cautions that the practice of combining beans and grains to create a complete set of amino acids is vexed since how the food is cooked or industrially processed can affect the protein presence or availability—which gives rise to the statement that not all protein eaten is protein digested and used by the body. Regardless, it is important to understand that the Net Protein Utilization (NPU) of animal proteins is much higher than any of the plant proteins, and traditionally raised animal protein does not involve ingesting dangerous chemicals.

So, what’s good about traditionally fermented soy products? The microorganisms and enzymes that form can help prevent disease and can impact food poisoning and dysentery. The products contain essential fatty acids (EFAs) in undamaged forms. (Organically grown soybeans are definitely preferable, notes Daniel, in that “many pesticide and fertilizer chemicals accumulate in the fat portion.”) The products are almost never contaminated with aflatoxin—which has “been identified recently as a major problem in modern soy and peanut products.”

Miso. Traditionally fermented miso takes from one to three years to make and is the most digestible (90 percent) fermented soy product. “During aging,” writes Daniel, the bean-rice or bean-barley nuggets turn to paste, while flavors and aromas develop. The process takes place at the natural temperature of its environment, slowing down in the winter and speeding up in the summer.” Hundreds of distinct varieties are produced, and none are ever pasteurized.

American industry started producing pasteurized quick misos around 1960. These misos are “fermented for three to 21 days in temperature-controlled, heated environments. To improve flavor, aroma and appearance, sweeteners (usually sugar or caramel syrup), bleaches, sorbic acid preservative, food colorings and MSG are likely to be added.

Daniel cautions that “the most common quick misos are dehydrated instant powders and dried soup mixes.” Heat drying deploys 482 degrees F heat, which kills everything, so the freeze drying method is preferred. Nevertheless, dried miso products contain many additives and are, in essence, fake foods.

Tempeh. The traditional process for tempeh is much quicker than miso—it’s less than a week. During the fermentation period, numerous bacteria, yeast, and other microorganisms begin to proliferate on the inoculated, cooked whole beans.

Daniel cautions that “news stories reporting high levels of vitamin B₁₂ in fermented soyfoods—particularly in tempeh—are not usually accurate. The most common molds used to manufacture tempeh…produce analogues of B_12, not the physiologically active forms. These analogues actually increase the body’s need for B₁₂.”

Natto. I’ve eaten natto in the home of a Japanese friend more than once. It’s bitter, slimy, smelly, and definitely an acquired taste. Natto is not commercially produced in America.

Shoyu. Traditional Japanese soy sauce is fermented for six to eighteen months, using roasted soybeans, roasted cracked wheat, and mold spores. Tamari is an Americanized term for soy sauce signifying a supposed “natural” product.

American soy sauce is a chemical brew made in two days or less using “automation, chemicals, preservatives, pasteurization, artificial colorings, sweeteners and flavor enhancers such as MSG.” American soy, cautions Daniel, may “also contain dangerous levels of chemicals”: chloropropanols, furanones (mutagenic to bacteria, causes DNA damage in lab tests), salsolinol (neurotoxin linked to DNA damage and chromosomal aberrations, Parkinson’s disease, and cancer), and ethyl carbamate (linked to cancer).

Tofu. Tofu curd is precipitated from cooked whole beans. Daniel explains that the “unwanted components….concentrate in the soaking liquid…so they are reduced in quantity, but not completely eliminated.” Silken tofu is made by pouring thick soymilk or soy yogurt directly into a package along with a curdling agent. This tofu has “more of the unwanted antinutrients.”

In 1999, Lon R. White, MD, a neuro-epidemiologist with the Pacific Health Institute in Honolulu announced results from his longitudinal study of 8,006 Japanese-American men and about 500 of their wives, each of whom ate two or more servings of tofu per week in midlife. Data showed these folks were “more likely to experience cognitive decline, senile dementia, and brain atrophy later in life than those who ate little or no tofu.” White thinks that soy isoflavones are impacting the area of the brain involved with learning and memory. For White, soy phytoestrogens are drugs, not nutrients.

Here in Maine, traditionally fermented soy products can be found at local co-ops or farmers’ markets.

Next: Part IV: The American soy products

More Tipping Points

The Paleo Diet, part one

The Paleo Diet. What's wrong with grains?

The Paleo Diet. What’s wrong with legumes?

The whole soy story, Part 1

Louisa Enright: How soy got into our food chain (Part II)