The Good And Bad About Soy ”first part”
Soy has been promoted as a health food for many decades. Due to its high protein content, soy is also very popular among vegans and vegetarians. So is soy really a health food? Are all soy products the same? What is the latest research regarding soy and disease?
Soy is cheap to grow and cheap to process, so it is truly a food manufacturer’s dream. The industry has marketed soy as an ancient health food. They claim that Asian cultures have eaten soy for thousands of years and associate their longevity and health with the consumption of soy. But if you examine the diets of Asian cultures closely, you will discover that:
first, they only use soy as a condiment and do not eat it as a main item or in large quantities,
second, they eat fermented soy which is remarkably different from the unfermented soy that Americans typically eat, such as the following:
Examples of Unfermented Soy Foods
soy ice cream
soy protein isolate in energy bars and protein powders
textured vegetable protein (TVP)
edamame (green soybeans)
soy hot dog or sausage
soy nut butter
In traditional Asian diets, people eat soy which has been fermented, that means the soy food has been cultured with beneficial bacteria, yeast, or mold. This type of soy is entirely different from the unfermented, processed soy products (like the ones listed above) that are sold in American grocery stores.
Why Unfermented Soy Is Not Recommended
Humans do not have a history of eating much unfermented soy. It was not until the last fifty years that we have introduced a variety of processed, unfermented soy foods.
If you are getting more than 35 grams of soy protein each day from unfermented soy, you should be aware of the following anti-nutrients that are present in this type of soy and their potential effects on your health.
Phytic acid that impairs mineral absorption. Plant seeds, such as nuts, edible seeds, beans/legumes, and grains contain phytic acid. Soy is particularly high in phytic acid, which impairs the absorption of iron, zinc, manganese, magnesium, and calcium. Mineral deficiencies caused by phytic acid are rarely a concern among meat-eaters because their diets are more diverse. However, vegans and vegetarians who consume a lot of high phytic acid foods at every meal can be at increased risk of developing mineral deficiencies overtime.
Oxalates that have been linked to kidney stones. Calcium oxalate stones are the most common type of kidney stones. Oxalate is a natural substance found in many foods but highest in spinach, wheat bran, nuts, beer, coffee, soybeans, and chocolate. Oxalate cannot be metabolized by the body and is excreted through urine. When there is too much oxalate and too little urine, the oxalate can bind to calcium in the urine and form crystals that stick together into a solid mass (kidney stone). To prevent calcium oxalate stones:
Drink enough fluids like water.
Reduce sodium in the diet as salt causes more calcium to be excreted in the urine.
Eat high calcium foods with oxalate-rich foods (e.g. spinach salad with cheese) so that the oxalate can bind with calcium in the stomach and intestines rather than in the kidneys.
Cut down on the oxalate-rich foods.
Goitrogens that suppress the thyroid gland. Goitrogens may prevent the thyroid from getting the necessary amount of iodine and disrupt the normal production of thyroid hormones. Raw vegetables from the cruciferous family (e.g. broccoli, kale, cabbage) and soy contain goitrogens. An overconsumption of soy may eventually lead to an underactive thyroid creating symptoms like weight gain, mood swings, feeling cold, fatigue, insomnia, and an inability to concentrate and remember details. To overcome this problem, make sure your iodine intake (eg. seaweed, seafood, dairy) is adequate when consuming soy.
Trypsin inhibitors that interfere with digestion. Trypsin is a digestive enzyme needed to properly digest protein. Trypsin inhibitors are a plant’s defense mechanism. By having this harmful component, wild animals learn that any food with trypsin inhibitors is a food to avoid. Soybeans are rich in trypsin inhibitors, hence, taking in too much soy may lead to gastric distress like bloating and gas in some individuals.
Lectins that clump red blood cells. Plants produce damaging proteins called lectins as self-defense against hungry animals. Soy contains a specific class of lectins called hemagglutinin that promotes clotting in the blood and impairs blood flow. Hemagglutinins can also tear holes in the gut lining, allowing bacteria to get into the bloodstream and causing autoimmune and allergic problems for people who are sensitive to lectins..
Why Fermented Soy Is Better
Fermented soy is much healthier than unfermented soy. The lengthy fermentation process reduces some of its anti-nutrients, resulting in a form of soy that is:
rich in probiotics or healthy bacteria that is extremely important for gut health and the immune system,
lower in phytic acid that prevents the absorption of minerals,
easier to digest and less likely to cause gastric distress,
lower in lectins (hemagglutinins) that promote clumping of red blood cells, and
high in the MK-7 form of vitamin K2, an important nutrient for supporting bone and heart health. (Unfermented soy does not contain vitamin K2.)
Top 4 Fermented Soy Foods
Natto. Fermented soybeans that are sticky and gooey with a strong, distinctive taste. A popular breakfast side dish in traditional Japanese cuisine.
Tempeh. Originated from Indonesia, it is a fermented soybean cake with a firm texture and an earthy flavor.
Miso. Fermented soybean paste with a salty, buttery texture. It is commonly used to make miso soup in Japanese cooking.
Soy sauce. Originated from China, it is a liquid condiment made from fermented soybeans and roasted grain (wheat). Tamari is soy sauce made without the grain, hence, it is gluten-free.
Considerations When Eating Fermented Soy
Quantity may be the key. Asian cultures do not eat a huge amount of soy. They generally use fermented soy foods as a condiment rather than as a main item. The average intake of soy protein in Asian populations is about 10-20 grams per day. This is in stark contrast to how much unfermented soy Americans consume.