Resulting from media exposure and the preaching’s of various health officials, more people than ever are consuming soy foods. Its promise to decrease cholesterol, hold cancer and heart disease at bay and make menopause more manageable has consumers buying up all things soy. Soy yogurt, soy protein bars, soy cheese, soy cereal… the list is endless. Unfortunately (as pointed out in Paul Chek’s article titled "Sans Soy!"), most of the soy that we are now consuming is less than ideal and nothing more than commercial junk. Poor quality food is now being promoted as healthy just because it contains some soy. One needs to keep in mind that traditional Asian diets contain mainly fermented soy food, rather than the overly-processed, genetically modified, non-fermented soy products lining the supermarket shelves in non-Asian markets. Leave it to us to ruin a good thing.
The purpose of this article is to illustrate why the addition of fermented soy products such as tempeh and miso to your diet is a positive alternative when it comes to soy.
The Fermentation Process
Food fermentation employs a wide range of microbes (yeast, molds and certain friendly bacteria) to achieve a desired chemical change to the food or beverage. Depending on the desired end product, different microbes are employed, such as mold to make blue cheese, yeast to make beer and bacteria to make yogurt. During soybean fermentation, items such as tempeh are produced by a host of friendly bacteria such as lactobacillus acidophilus.
Why Fermented Soy is the Best Soy
There are several advantages associated with the consumption of fermented soy over non-fermented soy products such as soy beverage, tofu and soy yogurt. Asian cultures are fully aware of these advantages, which include
During fermentation, the bacteria’s active enzymes break down or predigest complex carbohydrate molecules and proteins, significantly improving ease of digestion. Soy contains carbohydrates called oligosaccharides (e.g., raffinose and stachyose) that are difficult for human digestive enzymes to dismantle for digestion. When these undigested compounds are worked on in the gut by bacteria, the result can be discomfort, gas and diarrhea – a real bummer on a first date. This is why some people who are intolerant to certain soy foods better tolerate fermented soy products. The fermentation process also breaks down larger protein peptides into smaller ones for easier digestion. Trypsin (protease) inhibitors are found in soybeans and are substances that inhibit enzymes like trypsin from breaking down soybean protein properly. Fermentation, and to some degree heating, of soybeans helps remove these inhibitors. Thus, fermented soy products are an excellent source of vegetarian protein and are high in essential amino acids. These digestive advantages are especially important for those suffering from disorders such as IBS, Crohn's, Celiac and Ulcerative Colitis.
Improved Phytoestrogen Absorption
One of the active ingredients in soy that has received considerable research dollars lately are phytoestrogens (an isoflavone), which are bioactive plant compounds. Since phystoestrogens are structurally similar to human estrogen, they act like a weak form of estrogen. This is thought to help reduced hormone-mediated cancers such as breast and prostate cancer, reduce blood pressure, improve bone strength and dampen hot flashes. While the verdict is still out on many of these functions, it would be wise to obtain some isoflavones in your diet. Fermented soy products are a superior source since the fermentation process converts phytoestrogens to a more readily absorbable form (“free” aglycone form). These free forms may exert a cancer-preventive effect by shifting metabolism away from the production of toxic metabolites toward the production of inactive metabolites. (100g of tempeh contains about 53 mg of phytoestrogens.)
However, one needs to proceed with caution as there are concerns about excessive intakes of phytoestrogens (e.g., females with breast cancer). It should be noted that cultures that traditionally include soy products in their diet do not consume large amounts in any given day. In other words, they are not loading up on soy protein shakes and bars.
More Healthy Bacteria
Fermented soy products are an excellent source of healthy bacteria much in the same way that yogurt is; therefore, they can be considered a probiotic. Research shows that the consumption of fermented soy products can increase the levels of "friendly" bacteria that are present in the intestinal tract. This will improve the health of your gastrointestinal tract, which can improve digestion and help fight diseases like cancer.
Better Nutrient Absorption
Soybeans are high in the compounds phytic acid and oxalates that can reduce absorption of minerals including zinc and calcium. The fermentation process reduces the activity of these compounds and thus improves nutrient absorption. In addition, fermented soy products such as natto are an excellent source of a form of vitamin K called vitamin K2. Research shows that the higher the intake of this vitamin, the stronger the skeleton becomes, making it an important addition to bone health along with calcium and vitamin D. The use of antibiotics can decrease the levels of vitamin K2 found in the body.
Types of Fermented Soy Products
Miso is made from concentrated, cooked, fermented soybean paste. It is produced by inoculating a mixture of soybeans, salt and grains (usually barley or rice) with koji, a beneficial mold. The result is a smooth, salty paste. It is aged for up to three years and, although it is salty, a little goes a long way. The grain it is mixed with can affect its taste. Brown rice miso is the sweetest of the misos. Akamiso (red miso), made from barley or rice and soybeans, is salty and tangy and is the most common form of miso used in Japan. This form of miso is often used in marinades for meat and oily fish and in long-simmered dishes. Shiromiso (sweet or white miso), made with soy and rice, is yellow and milder in flavor. Use this form of miso for soups, salad dressings and sauces for fish or chicken.
Used extensively in Japanese cooking, miso can be used in place of salt and soy sauce in various recipes. Many Japanese consume miso soup as their first meal of the day.
Miso is generally added at the end of the cooking process. This also helps preserve the friendly bacteria. Stir it into soups just before removing it from the heat or after it has cooled for a few minutes at room temperature. Miso is a healthy substitution for more common commercial broths.
Tempeh is a traditional Indonesian food made with whole, hulled, cooked soybeans that are exposed to mold and allowed to ferment briefly (a day or two), resulting in a chewy, nut-flavoured soybean loaf. It can be marinated, grilled or sautéed and added to soups, chilli, salads, casseroles or stir fries. You can also crumble some into scrambled eggs. There is no need to be concerned by any blackish spots on the surface as this is just an indication of the bacterial fermentation process.
Tempeh is a better source of protein (improved digestion) and fibre (because it uses whole soybean) than tofu. It is also a good source of vitamin B12, which is especially important for strict vegans.
Tempeh is typically sold in eight-ounce vacuum-wrapped slabs and often in Asian or natural food stores. Tempeh can be stored in the refrigerator for up to five days after opening.
Some tempeh is mixed with grains during the fermentation process, allowing for a more mild taste.
A food particular to Japan for over 2,000 years, natto is a form of fermented soybean where the whole soybeans are cooked and wrapped in a pipe made from straw, then left to ferment. It has a sticky, viscous coating with a cheesy texture. In Asian countries, natto is often used as a topping for rice, in miso soups or stirred into vegetables. It can be found in Asian or natural food stores.
Nattokinase is an enzyme naturally found in natto that appears to be effective at limiting and dissolving blood clots (fibrinolytic activity).
This is the liquid that is left over from the fermentation of miso. It can be used in replacement of soy sauce.
This is the "real" soy sauce that is used in the Far East. Like miso, shoyu is made by combining cooked soybeans, a grain and a mold culture in a salty brine for 12-18 months. The result is a dark, brown liquid. Most commercial shoyu is made by a chemical process in which cereals and soybeans are mixed with acids. This is in contrast to traditional methods of fermentation involving a special koji (Aspergillus oryzae). Shoyu can be stored at room temperature for up to one year. Unlike other soy foods such as tempeh, shoyu (and tamari) does not contain many isoflavones. Because of the salt content, only small amounts should be added to foods for flavoring.
Why Choose Organic?
Organic soy products are grown without the use of pesticides and herbicides. In addition, the soybeans are not genetically modified. It is estimated that up to 70% of all soy grown in America is genetically modified. America is now the largest producer of soybeans in the world. Most of it goes to feed cattle in feedlots.
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