Soybeans reached the western world by the early 1700s and were first grown in North America by 1804. Benjamin Franklin appears to have been involved in introducing soybeans from France to Philadelphia at that time. A number of varieties were grown and evaluated in the United States during the 1800s. The primary use for the crop was for forage, hay and green manure.
In the 1880s, French scientists discovered that the soybean contains practically no starch so its use in diabetic diets began. Later its high protein content was recognized.
Modern uses. In the early 1900s the first processing of seeds for oil and meal was done in England. For the most part soybeans were a neglected crop until World War II. Germany developed a soy oil lard substitute and a meat substitute. In the U.S. increasing amounts of soybean meal were used as livestock and poultry feed, especially after 1945 when consumption of meat increased dramatically. More recently, an increasing proportion of American soybean production has been used by the food processing industry--in such foods as margarine, shortening, ice cream, salad dressings and mayonnaise. Industry uses lesser amounts in products including paint, ink, putty, caulking, wallpaper, rubber substitutes, adhesives, fire extinguisher foam, electrical insulation and gasoline. The versatile soybean is a part of everyone's life in developed countries.
At present, most soybeans (over three-fourths of the world supply) are grown in the United States (especially in the cornbelt and Mississippi Valley), in Brazil and Argentina. China produces most of the soybeans grown in the Orient, while only a few are grown in Europe. In the U.S., the soybean is third in production (corn and wheat are first and second) and second in value (corn is first) of crops grown.
TO YOUR HEALTH
Soybeans are members of the pea (legume) family of vegetables. Eating soybean-based foods may reduce the risk of a range of health problems, including coronary heart disease. More research is needed, but the evidence so far suggests that it could be wise to include whole soy foods in the daily diet. Soybeans also contain hormone-like substances called phytoestrogens that mimic the action of the hormone oestrogen. The health benefits of soy for menopausal women could include fewer hot flushes, protection from coronary heart disease and lowered risk of osteoporosis. However, while whole soy foods have been shown to have health benefits, the benefits of taking phytoestrogen supplements are unproven. See your doctor or dietitian for further guidance. Nutrition profileSoy is a high quality protein. It is one of only two known plant foods to contain all the essential amino acids, similar to those found in meat (the other plant food is amaranth seed, a wild green). Some soy products can be a source of calcium and iron, such as Chinese tofu or tempeh (made with a calcium coagulant) and calcium fortified soy drinks. The soybean is:
High in fibre
High in protein
Low in saturated fat
A good source of omega-3 fatty acids
High in phytoestrogens.Phytoestrogens explainedSoybeans are thought to be of some health benefit to menopausal women. Soybeans contain hormone-like substances called phytoestrogens (‘phyto’ means plant). Given the right conditions, these compounds mimic the action of the female hormone oestrogen, but with much lower potency - about 1,000 times less. There are two types of phytoestrogen: isoflavones and lignans. Soybeans contain about 50 times more isoflavones than other members of the legume family, such as lentils and peanuts. (Lignans are found in cereals, vegetables and fruits.)Soybeans and menopausal hot flushesWomen in Japan and China typically have fewer hot flushes during menopause than their Western counterparts. This observation led to research into dietary differences, including the fact that Asian women tend to have soy-rich diets, while Western women have meat-rich diets. It is thought that a soy-rich diet helps reduce menopausal symptoms such as hot flushes because the phytoestrogens act like a mild form of hormone replacement therapy. The reduction rate of hot flushes varies from one study to the next, from 1.9 per cent to 45 per cent. However, it should be noted that some women in the studies experienced a reduction in hot flushes while taking dummy treatments too (the placebo effect). More research is needed, but soybeans seem to offer promise in helping some women to manage menopausal hot flushes. If phytoestrogens do work, studies suggest that you need at least 2-3 serves of soy products daily. This would mean either:
500ml soymilk per day
100g tofu per day
4-5 slices of soy linseed bread per day (depending on the brand).Soybeans and coronary heart diseaseOestrogen may protect women against coronary heart disease during their reproductive years, but rates of heart disease increase remarkably after menopause. Soybeans have been shown to lower blood cholesterol levels as well as lipoproteins, both known risk factors for heart disease. A meta-analysis (an analysis of a number of studies on a topic) of 38 clinical trials found that 31-47g of soy protein can reduce blood cholesterol levels by as much as 20 per cent. This amount of soy protein is found in two to three serves of soy products. It isn’t known whether the phytoestrogens or the soy proteins (or both, working in combination) are responsible for this health benefit. However, studies have shown that eating soy protein without isoflavones results in only small cholesterol reductions and isoflavone supplements alone have minimal cholesterol lowering effects. The cholesterol lowering benefits of eating soy foods may be better if the total diet is high in carbohydrate. This seems to help with the breakdown of the isoflavones. In recognition of the evidence, the United States Food and Drug Administration approved a health claim in 1999 acknowledging the heart health benefits of including at least 25g soy protein daily in a diet low in saturated fat.Other possible health benefits of soyThe soybean needs further research before its health benefits are conclusively known. The health benefits of soy are not without controversy. Some research suggests that it may adversely affect thyroid function in some people. The suggested health benefits of whole soy foods include:
Lowered blood pressure
Improvements to blood vessels, such as greater elasticity of artery walls
Reduced risk of osteoporosis
Protection against various cancers, including those of the breast, colon, prostate and skin
Management of endometriosis.