Soybean and health

Soybean

Soybean (in US and soya bean in UK) is an edible bean native to East Asia. UN FAO classifies soybean as an oilseed rather than as a pulse. It is classified so because much of the soy produces in USA goes to make vegetable oil. What is left over after processing oil is converted into fat free protein. Unfermented soy products are consumed as soy milk, tofu, sprouts and tofu skin. Fermented products include soy sauce, tempeh, miso, bean paste,  natto and other products. Ninety percent of the soy is produces in the US, Brazil and Argentina.

Tofu

Nearly 90% of the soybean produced in the US is genetically modified (GM).

Soybean is an important element in Chinese diet. Soybean originated in China and was later adopted by Japan and Korea. Early Chinese documents show the picture of the root only and not the beans. This probably indicates that Chinese used soybean to fix nitrogen in the soil. All legumes do this. The soil becomes fertile.The soybean was not consumed as a food until the fermentation techniques were developed during the Chou Dynasty. The first soy foods were fermented products like tempeh, natto, miso, and soy sauce.

Tempeh

Tofu stir-fry

 Long later and probably around 2nd Century BC, Chinese scientists discovered a way of precipitating the soymilk to form a pale curd.

Soybean sprouts

 Cooking traditions of soy have evolved over hundreds of generations in the East. These traditions are nonexistent in US and Europe. Findings on health benefits of soy differ widely between Asia and the West (America and Europe). This may be due to the difference in the culinary traditions between East and West.

Mixed vegetable soup

Soybean oil accounts for about 20% of the dry seeds. Protein content of the dry seeds is about 40%. The balance consists of about 35% carbohydrates and 5% ash. The nutrition content of the soybean is given in the USDA database. http://ndb.nal.usda.gov/ndb/foods/show/4820?qlookup=16108&format=Full&max=25&man=&lfacet=&new=1

Many health agencies consider soybeans as a source of complete protein because they contain significant amounts of all the essential amino acids that is required by the human body. Replacement of meat and dairy with soy will improve the intake of folate and vitamin K, calcium, magnesium and iron. At the same time it will reduce cholesterol intake by 123 mg per day and 2.4 grams of saturated fat. Protein content will be reduced by 8 grams per day or 9% of the average daily consumption.

Tofu patty

College of Medicine at the University of Kentucky found that daily intake of 30 grams of soy protein reduced the risk of coronary heart disease and also lowered the LDL cholesterol level. Soy also has significant antioxidant properties.

Soybeans contain phytic acid, alpha-linolenic acid, and isoflavones. Soybean oil contains four phytosterols: stigmasterol, sitosterol, campesterol, and brassicasterol accounting for about 2.5% of the lipid fraction. The lipid fraction can be converted into steroid hormones.

Not all agree on these findings.

The popularity of soy in the US is due to massive advertising campaign by the industry.
There are always good and bad about all food products. Dr. Mercola argues that the risks of consuming unfermented soy products far outweigh any possible benefits.  http://articles.mercola.com/sites/articles/archive/2010/09/18/soy-can-damage-your-health.aspx
The Whole Soy Story by Dr. Kaayla Daniel pints to several research studies linking soy to malnutrition, digestive distress, immune-system breakdown, thyroid dysfunction, cognitive decline, reproductive disorders and infertility—even cancer and heart disease.

Here are some disadvantages of soy as pointed out by Dr. Mercola and others:

·         High in Phytates – Inhibits absorption of calcium, magnesium, copper, iron and zinc.

·         Trypsin inhibitors found in soy may inhibit protein digestion and may cause pancreatic disorders. Long fermentation process may remove trypsin inhibitors and improve protein digestion.

·         Goitrogens may contribute to hypothyroidism and thyroid cancer.

·         Isoflavones may block normal estrogen and inhibit endocrine function, cause infertility, and may contribute to breast cancer. In the very early days Chinese monks took pureed soybean to help them in their sexual abstinence.  Fermentation may convert the isoflavones to a form that can be easily digested by the body.

·         Vitamin B12 found in soy cannot be used by the body. This may lead to B12 deficiency.

·         Aluminum may wreck your nervous system and kidneys.

·         Manganese may hurt baby's immature metabolic system.

·         A woman's menstrual cycle may be altered by taking just two glasses of soymilk daily. Soy is associated with breast cancer. But I am not going to write anything about it because of the inconclusive (conflicting) research findings that have been published.

·         Using soy based infant formula should be avoided. The regulatory bodies in countries such as Great Britain, Switzerland, Australia, and New Zealand, require that soy infant formulas be used only in children who are not breast fed and are definitely intolerant to cow's milk. Take a look at this article. Soy Infant Formula: A Formula For Disaster - http://www.foodrenegade.com/soy-infant-formula-formula-for-disaster/

·         Those who are on medication for thyroid problems should avoid soy products.

·         Soybean lectins may cause cell injuries and adversely affect the gastrointestinal, immune systems of the body.

The soybean oil is made by solvent extraction process. The solvent is hexane. Hexane is a petroleum product which is harmful to the body. Even if a small trace of hexane is found the product will not qualify as organic.Alcohol extraction may help in removing phytoestrogens. .

There are tons of information in Dr. Mercola’s website.

This is an informative podcast from Youtube. This is lengthy - takes about 42 minutes. If you have the time please watch it.

If you want to consume unfermented soy products do it wisely. Consuming unfermented soybean products three times a week may be acceptable. Soy has good and bad effects. Vegetarians tend to eat soy often as they look for protein. Soy has been used in cooking in some communities from ancient times. Anything is bad when we consume over. It is left to us to  decide when and how to eat.