Soy milk and its health benefits
Soy milk is a beverage product produced from soy beans. Different manufacturing processes produce soy milk with varying levels of protein and fat. Generally speaking, the greater the protein content (generally at least 4%) the higher the isoflavone content. Fat content usually ranges from 1-3%. All soy milk is lactose- and cholesterol-free. Most soy milk is now fortified with calcium, vitamin D and other nutrients, and many flavors are available. Soymilk can be packaged in aseptic cartons with a shelf life of a year or kept refrigerated like cow's milk.
More and more people replace cow milk with soy milk for its health benefits. These benefits are due to some functional components in soy milk, soy proteins, soy compounds, isoflavones, essential vitamins, etc.
Soy milk contains powerful antioxidants that help fight disease and aging. Soy milk drinking has been found to increase bone density and strengthen the immune system. Adequate soy protein has been proven to lower and stabilize cholesterol levels and can be effective in preventing heart disease.
Soy milk is rich in protein, and contains soluble fiber. Vegetable proteins have the advantage that they cause less loss of calcium through the kidneys. In addition to being cholesterol-free, studies have shown that a diet including soymilk actually helps lower levels of LDL (bad) cholesterol.
In addition, soy milk contains the prebiotic sugars stachyose and raffinose which boost immunity and help decrease toxic substances in the body.
About 75 percent of the world population, 75 percent of Africans and 90 percent of Asians have lactose intolerance. As a result, they can not drink cow milk. Soy milk is a wonderful replacement for cow milk because soy milk is lactose-free.
Isoflavone is an important and unique component of soy milk. Isoflavones, also known as phytoestrogens, may be responsible for some of soy's anti-carcinogenic properties. Isoflavones can reduce cholesterol, prevent osteoporosis and reduce the risk for certain cancers (prostate cancer and breast cancer). Isoflavones bind to estrogen receptors and are thought to possibly block some of the detrimental effects of estrogen including the promotion of cancer cell growth. Incidents of these cancers are very low in countries with high intake of soy products, including soy milk. Isoflavones may also play a role in reducing hot flashes in some post-menopausal women and promoting good prostate health for men. Each cup of soy milk contains about 20 mg isoflavones (mainly genistein and daidzein). Isoflavones are also antioxidants which protect our cells and DNA against oxidation.
In a research paper published in The New England Journal of Medicine 333:5 p276(1995), Anderson et al confirmed that soya protein consumption significantly decreases serum cholesterol concentration, low density lipoprotein (LDL) cholesterol, and the serum triglycerides, without reducing the high density lipoprotein (HDL) which is protective against heart disease. Many researchers reported that in fact soya protein intake actually increases the good cholesterol. Nilausen and Meinertz (University of Copenhagen, School of Medicine) found that 5 out of 9 subjects who were fed soya protein experienced a 21% decrease in LDL cholesterol, but also an increase of 11% in HDL. In 3 other subjects LDL was unaffected but HDL increased by 18%.
Recent research has shown that certain soybean isolfavones may inhibit bone breakdown and even stimulate bone formation. In a study by Erdman et al (University of Illinois at Urbana-Champaign, USA) post-menopausal women were fed diets containing 40g of dry milk, 40g of soya protein with moderate level of isoflavones or 40g of soya protein with high level of isoflavones for a six-month period. The results indicated that bone density and bone mineral content increased in the lumber spine region in the women consuming soya protein with a high level of isoflavones. Other skeletal areas showed similar trends.
The consumption of soyfoods has been associated with a reduced risk of several types of cancer. In one study Bennink et al (Michigan State University, East Lansing, USA) found the animals fed soya flour, soya flakes, or the soybean isoflavone - genistein - had 35 to 40% fewer ACF (Aberrant Crypt Foci - which are considered to be the beginning stages of colon tumors) compared to the animals fed soya protein concentrates. Since the concentrates are low in soybean isoflavones compared to other soya products, soya isoflavones may be responsible for this observation. Similar affect of genistein was observed by other researchers in controlling breast cancer and prostate cancer.
Anderson et al showed that animals consuming soya protein had lower level of blood urea nitrogen and serum creatinine than those consuming animal protein. This is good news for diabetes patients.
Soy milk has many health benefits as discussed above. Therefore, drinking soy milk regularly is a good practice to boost our health.