SOYABEANS: A CASE OF MIXED BAG
-By Dr. Nitin Mehta

The use of soya in our daily diet appears to be in disarray after few conflicting reports on our health. The health benefits reported in last ten or fifteen years, limitless – boosting bone strength, relieving menopausal symptoms, preventing breast cancer, lowering of cholesterol levels in blood and definitely used in hamburgers, meatballs, kebabs, sausages and bread. Recently, soybean has been reported to have more soluble dietary fiber [SDF] . There are mainly two types of soya beans – black and yellow. Black variety is very rarely available in our country. Yellow variety is used like any other beans or in powder form mixed in recipes.

Now there’s mounting evidence that soya is not healthy and to some extent have adverse effects. The fact that soya contains large quantities of chemicals that cannot be fully destroyed even by a long cooking process Soy processors have worked hard to get antinurients out of the finished products, particularly, soy protein isolates [SPI], this is a key ingredient in most soy foods, imitating meat, dairy products, baby formulas, soymilk etc. SPI, is not something one can produce in kitchen. This is prepared/ manufactured in industrial factories and by using high temperature; high-pressure extrusion processing finely textured vegetable protein [TVP] is the final product. High temperature processing has the side effect of denaturing the other proteins; much of the trypsin inhibitor content is also removed Nitrites, which are carcinogens, are formed during spray drying and a toxin lysinoalanine is formed during alkaline process. Numerous artificial flavorings,Particularly MSG, are added to SPI, and TVPs to mask their strong taste and to impart the flavor of meat. The use of SPI increased the requirement of vitamins and create the deficiency symptoms of calcium, copper iron zinc etc. The phytates or phytic acid remaining in soy products greatly inhibits absorption of iron and zinc.

Soya contains large quantities of chemicals that cannot be fully destroyed even by a long cooking process. Enzyme inhibitors hamper protein digestion, phytates blocking the absorption of minerals and haemagglutin hinders the body’s use of oxygen. Soya also contains high contents of isoflavines-- genistein and daidzein that mimic the female sex hormone estrogen, and this may affect the development and fertility in women. The protective effects of soflavine chemicals derived largely from soy foods is strongest in men who are older than 60 and may not have a protective effect in the early stages of prostate cancer. Or according to the stage of the disease. For example, in Japan, consuming soya bean in diet is about 8gms a day, while Westerner consume nearly 220 gms a day. Further, these Japanese do have lower rates of cancers – breast, uterus, colon and prostrate probably due to different diet than Westerners have.

Yet SPI and TVP are extensively used in school lunch programmes, commercial baked goods, diet beverages and fast food products, they are heavily promoted in the third world countries. The dietary fiber {DF} has shown beneficial effects in human nutrition in decreasing the risks from disorders e.g. coronary heart diseases [CHD], diabetes, diverticulosis and obesity etc. Even though the crude fiber {CF} content of soybean [Gycine Maxmerrill] is similar to those found in groundnut[Arachis Hypogaea ], fresh coconut [Cocos Nucifera], and lesser than Sesame [Sesamum Indicum],the soluble dietary fiber content is very high 5.1 g/ 100g.of oilseeds.

The recommended dietary allowance [RDA] or dietary reference value of DF intake for Indians is not available, even in most developing countries. On an average intake of 25 –40 g DF/day from all sources is recommended for deriving the health benefits from dietary fiber. Selection of appropriate food rich in SDF required for inclusion into the Indian diets to promote healthy life of people. particularly diets for diabetic and hyperlipidemic subjects.