The emblematic feature that everybody knows about comes from soybean's increased content in protein of high biological value. Soy is a considerable source of iron as well whose bio-availability is increased during the germination process.
Glycine max known as soybean (or soya bean) is native to East Asia, nevertheless it is popular all over the Earth. It has been grown for thousands of years in Asia where it is an indispensable aliment, eaten either whole or in extremely tasty traditional foods such as tofu, tamari, miso, various kinds of soy sauce and many others.
In addition to the traditional soy foods the modern agro-food industry has developed new soy-based products (pasta, salami, other meat substitutes) and condiments derived from soy helping those who like a diversified cuisine to create delicious or exotic meals ... and those who eliminated meat from their diet to ensure the right quantity of proteins.
However few people know that most soybean is consumed indirectly since the vast majority of soy crop is used for producing high protein fodder which is fed to the animals we eat. Soy is also in oils, margarine and many other goods such as emulsifier lecithin used in processed foods such as chocolate or ice cream.
The emblematic feature that everybody knows about comes from soybean's increased content in protein of high biological value. Soy is a considerable source of iron as well whose bio-availability is increased during the germination process. Recent studies have drawn even more attention to this interesting plant talking about the high content in isoflavones, some kind of precursors of certain hormones in the body ... which could explain the obvious effects of soy and its derivatives on gynecological diseases and even on cancers.
Soy isoflavones have a chemical structure very similar to estrogen's structure and therefore could decrease the risks of excessive estrogen in the body by competing for the same receptor cells. Soy isoflavones could compensate for the decrease in estrogen levels during menopause and consequently lowering the associated symptoms such as hot flushes, breast pain and sweating.
Other studies stressed that the effect of soy isoflavones combined with calcium on the mineral content of post-menopausal women bones is excellent improving, for example, the mineral content of hip bone. More interestingly, the use of soy products on breast cancer patients pointed out that soy isoflavones intake can be associated with longer survival and a lower recurrence rate, perhaps as a result of the levels of estrogen mimicked by soy (however, further clinical research with a larger sample size will be conducted).
Nevertheless, many studies have been initiated recently to see about soy intake effects from benefits perspective but also taking in account certain imbalances that it can bring into the body. In spite of the large awareness of soy valuable features … there is strong controversy around the subject (for example the pregnant anti-soy position of Sally Fallon and Mary G. Enig thoroughly contested and argued by many pro-soy specialists) which affects the good reputation that soy has gained in many years.
The question is how to get the most benefit of soy foods avoiding the presumed risks? The answer is simple as usual when it comes about healthy eating: moderation. Consume it with judiciousness as part of a balanced diet, which includes plenty of fruits and vegetables, whole grains, low-fat dairy and other sources of lean protein. And do not forget that people from an entire continent use to eat exotic delicious meals where soy is indispensable since hundreds of years.
Soy and Heart Diseases
In November 2000, the American Heart Association advised people with high cholesterol levels to consume more soybean-derived proteins (about 25-50 g/day) rather than those of animal origin as research has shown that soy protein really lowers LDL cholesterol and triglycerides in the blood.
The American Heart Association has warned that soy does not replace standard treatment for cholesterol-lowering. People with high cholesterol levels should continue their prescribed treatment and follow a low-fat diet. A healthy heart diet should include fruit, vegetables, whole grains, skimmed milk, oil, chicken, fish and beef (very low).
Then following thorough studies Food and Drug Administration (FDA) concluded that a low-fat and cholesterol diet with a daily addition of 25 g of soy protein may reduce the risk of cardiovascular disease.
Soy and Cancer
Although there are studies on this subject that failed to demonstrate that soy protects the body against cancer, there is also conclusive evidence of some soy components capable of preventing the development and spread of cancer cells in the body. The following substances have been found to have such capability: protease inhibitors, phytates, phytosterols, saponins, isoflavones, phenols, lecithin and omega-3 fatty acids. However, other research concluded that, in the contrary, some soy components assimilated to a certain level in the body could stimulate the development of cancer cells.
In fact most studies have been focused on the analysis of the possible anticancer effects of soy products centered on soy components that proved this positive potential such as genistein, an isoflavone that has phytoestrogen-like action. The exact mechanism by which soy isoflavones can affect the risk of breast cancer is unknown and requires detailed studies.
Since studies are not really conclusive so far specialists recommend to patients with certain breast cancers and those with a history of breast cancer in close family members avoiding soy consumption (or other products with high levels of isoflavone) or limit it until more detailed results will have been obtained.
Soy and Menopause
Before menopause women experience a variety of disturbing symptoms (such as hot flashes) while the ovaries are slowing down their estrogen production. As soy contains a hormone secreted by plants with an estrogen-like action (phytoestrogen), some experts claim that increased consumption of soy phytoestrogens can help reducing the discomfort caused by menopause.
In fact the research in this area is currently in a preliminary stage. The studies conducted so far showed that soy is reducing the intensity and severity of some symptoms but obviously advanced studies are needed to focus on the disadvantages of isoflavones.
However, it is recommended to take them from food instead of administering dietary supplements, 1 g of soy protein contains 1.2 - 1.7 mg of isoflavones (depending on the type of soybean used).
Soy and the Thyroid
There is currently no conclusive evidence that moderate soy consumption would have an adverse effect on the thyroid gland. The first studies in this subject have associated soybean consumption with the increase in size of the thyroid gland presented as a swelling at the base of the throat. However, experts ensured that healthy people without iodine deficiency who consume soy products moderately are not at risk of developing such condition, which is primarily caused by iodine deficiency in the body not by moderate soy consumption. Therefore, people who do not assimilate enough iodine are at risk, for example vegetarians who have not included iodine-rich foods in their diet are at high risk of experiencing this condition.
Also, increasing soybean consumption as a substitute for meat is not exactly the most appropriate solution. In conclusion, experts believe that soy isoflavones can interfere with the thyroid gland and can affect people who suffer from hypothyroidism or other thyroid disease.
Soy and Infections
Human body needs "healthy bacteria" in order to asure a good digestion and proper functioning of the immune system in the fight against infections. Probiotics are found in some unpasteurized and fermented soy products and contain "healthy bacteria" that offer protection against stomach acids and other harmful bacteria that can destroy them.