1. What is soy protein and where does it come from?
Soy protein is a complete protein that ranks right up there with the best in the Protein Digestibility Corrected Amino Acid Score, which is a method of evaluating the protein quality based on the amino acid requirements of humans. Soy protein is generally very low in or free of fat, cholesterol, and lactose.
Soy protein is approved for those who are lactose intolerant, and can be used as a meat substitute. Much more than just an ingredient for a protein shake, soy protein can be used for cooking instead of flour, producing high protein foods that are extremely low in fat. A bodybuilder's dream come true! Soy protein is derived exclusively from soy beans.
2. What does soy protein do and what scientific studies give evidence to support this?
Soy protein provides a healthy way to get non-animal protein into your diet. It is great tasting, natural and can have many healthy effects on the body. It is ideal for high protein/low carb diets! It's valuable constituents include saponins, phytosterols, and isoflavones.
Saponins are one of the best things about soy protein! Saponins support healthy immune system function and combine with cholesterol to reduce it's absorption into the body through the small intestine. Phytosterols have also been shown to help maintain cholesterol levels already within normal range.
The anabolic isoflavones in soy (genistein and daidzein), not only have exhibited effects as powerful antioxidants but have been shown to exhibit positive health benefits for both men and women.
Scientists have also discovered in the last few years phytochemicals, which are plant or fruit derived chemical compounds, and the profound benefits that soy protein has on human health due to phytochemicals occuring naturally in soy. These additional benefits, along with those listed above, also include:
- Many soy foods are naturally high in calcium (some fortified with calcium because it is a good source of a particular coagulating agent). In addition, soy also contains magnesium and boron, which are important co-factors of calcium for bone health.
- Isoflavones in soy foods may inhibit the breakdown of bones. Daidzein, a type of isoflavone, is actually very similar to the drug ipriflavone, which is used throughout Europe and Asia to treat osteoporosis. One compelling study completed by Erdman in 1993 focused on post-menopausal women who consumed 40 grams of isolated soy protein daily for 6 months. Researchers found that these subjects significantly increased bone mineral density as compared to the controls.
- Another study published in the Archives of Internal Medicine in September 2005 also found that intake of soy food was associated with a significantly lower risk of fracture, particularly among early post-menopausal women.
- Among all cancers, data on soy and prostate cancer seems to be the most promising; many studies support its role in the prevention and possible treatment of prostate cancer.
- While some studies showed soy offers a protective effect against breast cancer, a few studies showed the estrogen-like effects in isoflavones may be harmful for women with breast cancer. American Institute for Cancer Research stresses that data on soy and breast cancer are not conclusive, and more work is needed to be done before any dietary recommendations can be made.
- What we know at this point is the phytoestrogens in soy foods are "anti-estrogens". In other words, they may block estrogen from reaching the receptors - therefore potentially protecting women from developing breast cancer. Studies found that pre-menopausal women may benefit from eating soy foods as their natural estrogen levels are high.
- However, this may not be true to post-menopausal women. Studies found that soy could become "pro-estrogen" in women with low levels of natural estrogen. In other words, concentrated soy supplements may add estrogen to the body and hence increase breast cancer risk in post-menopausal women.
- Therefore, post-menopausal women should avoid taking concentrated soy supplements until more is known. Eating soy products, however, is not harmful.
Alleviating Menopausal Symptoms
- In Japan, where soy foods are commonly consumed daily, women are only one-third as likely to report menopausal symptoms as in the United States or Canada. In fact, there is no word in the Japanese language for "hot flashes".
- Current studies showed that soy only helps some women alleviate menopausal symptoms. Indeed, soy is more effective in preventing than alleviating hot flashes. Despite these findings, the North American Menopause Society in 2000 recommended that 40 - 80mg of isoflavones daily may help relieve menopausal symptoms.
A report in American Journal of Clinical Nutrition in 1993 reported a 12 percent drop in cholesterol when 20 to 25 grams of soy protein were included in their diet! This is because soy beans and soy protein contain soluble fiber, which has been shown to interfere with the absorption and metabolism of cholesterol.
3. Who needs soy protein and how much should be taken? Are there any side effects or symptoms of deficiency?
As soy is not a required nutrient, it is not associated with deficiency. However, if you don't take soy, you'll miss out on the associated benefits. Women can benefit with it the most, although men can experience the positive benefits of soy as well.
Soy may be safely taken in a wide range of doses. Only a very small percentage of people are allergic to soy. Be sure to consult your physician if you're on any prescription drugs, as soy may have positive or negative interactions with those drugs. Soy contains phytic acid, a compound that may interact with mineral absorption.
Soy protein can also be very beneficial for people that are active either through cardio or weight lifting. It can be used as a healthy meal replacement or a mid-day snack to replenish and re-fuel your body's nutritional needs.
Although it is still inconclusive that soy can prevent any diseases, many studies have shown promising results. Include soy products such as edamame, tofu, tempeh, soy milk, soy protein powder in your diet and enjoy the possible health benefits they may bring!
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.