What are soy proteins?
Soy proteins are extracted from soybeans. They contain a very high content of proteins, even higher than that of meat and fish. For this reason they are used as supplement since many years. Soybeans are deprived of the hull and then defatted. From these processes is obtained soy flour, and this can be manipulated to realize two main forms of soy supplements: soy protein isolate and soy protein concentrate.
Soy protein isolate derives from soy flour, which contains soluble and insoluble materials. The insoluble part is extracted, acidified and then centrifuged. This is the most purified form of soy proteins, in fact it has been deprived of fats and carbohydrates, so it in contains about 90% of proteins. For this reason it is possible to reduce bloating caused by legumes. It is particularly used by food industries as additive or emulsifier, to enhance taste and consistence of aliments.
Soy protein concentrate is less pure then the isolate form, in fact it contains about 70% of soy proteins. It derives from soybeans without carbohydrates, so it still contains fibers. It can be found in many products, as cereals for breakfast, meat, pet foods, powder milk.
Soy proteins benefits
Soy proteins can be very helpful for many reasons. In fact they have a high amount in proteins, but they have no fats and cholesterol. For this reason they can be ingested without increasing the risk of cardiovascular problems, and it seems that they can also help to decrease the levels of cholesterol in blood vessels. This aspect is enhanced by the presence of isoflavones, that can prevent heart diseases, but also other problems, as cancer and cellular damages caused by free radicals.
It seems that soy proteins can be also used to prevent osteoporosis, because isoflavones can reduce the mobilization of calcium from bones.
Soy proteins and foods
Soy proteins are normally present in soybeans. They can also be found in many foods as additive. For example they can be used in many foods as dressings, creams, preparations with meat, baking foods, pet foods and children foods and also in sports supplements whit whey proteins, egg proteins or milk proteins.
Soy proteins properties
Soy proteins are usually considered incomplete in comparison to animals proteins, because they contain many essential amino acids, but they have less methionine, essential to start protein synthesis. This aspect can be opportunely integrated associating cereals or animal proteins, that can provide amino acids less present in soy. Soy protein isolate contains proteins with higher quality in comparison to soy flour or soy protein concentrate. In fact the isolate form is rich of glutamine, arginine and branched-chain amino acids.
An important aspect of soy proteins is that are defatted, so they contain a very low amount of fats, in particular cholesterol, which can be very dangerous for cardiovascular system functioning. Moreover soy proteins are rich in isoflavones, that are antioxidant substances, very helpful to prevent cancer. They also contain phytoestrogens, that can be useful for many reasons, for example in women in menopause or with an excessive hormonal activity, but they can also be dangerous. For this reason there are conflicting opinions on the benefic effects of soy, especially in subjects who suffer for thyroid glands problems.
Soy proteins supplements are also enriched with different minerals, as calcium, iron, magnesium, and vitamins of the B complex. For this reason they can be very useful for athletes, because they consent to enhance protein synthesis, increasing muscle volume.
Soy proteins side effects
Soy proteins can cause allergic reaction is subjects sensitive to this substance. The other side effects can include digestive problems, due to the presence of lectin, and bloating. There are many opinions about the potentially dangerous effects of fhytoestrogens, present in soy proteins. In fact it seems that they can cause thyroid hyperactivity, leading to hyperthyroidism.