Soy is undoubtedly one of the most controversial foods in the world. Depending on each person, it is a great food or poison that causes hormonal disorders.
Like most nutrition, soy is debated on both good and bad sides and each has reasonable arguments.
What is soybeans and how is it used?
is a legume native to East Asia, but is now produced on a large scale in the United States.
Soybeans are used to prepare many different foods. Soybeans can be eaten even if boiled beans (edamame). Soy bean right cooked because they are toxic when alive.
Soybeans are used as tofu, soymilk and many dairy products and meat substitutes. It is also used in fermented foods such as miso, natto and tempeh; they are often consumed in some Asian countries.
More than 90% of US soybeans are genetically modified and sprayed with herbicides ; This drug may be associated with adverse health effects .
Interestingly, whole soybeans are rarely consumed in Western countries. They mainly eat soy in refined products.
Most soybeans in the United States are used to produce soybean oil by solvent extraction chemistry. Soybean oil provides about 7% ca in the American diet in 1999 .
The rest of soybeans, after extracting fat, are called soybean residues in volume the protein accounting for about 50%. Most soybean residues are used to feed cattle but it can also be further processed to produce isolated.
Because of its low cost and some practical properties, soybean oil and soy protein have been included all processed foods, so most people in the United States are consuming a significant amount of soybeans without knowing it.
Soy protein is also the main ingredient in soy milk powder.
Key thing: Most soybeans in the United States are used as soybean oil. The discarded product is then used to feed cattle or produce soy protein. Raw soybeans are rarely consumed.
Nutrients in soybeans
Whole soybeans contain a variety of important nutrients.
100g (about 3.5 ounces) of cooked soybeans contains a large amount of manganese, selenium, copper, potassium, phosphorus, magnesium, iron, calcium, vitamin B6, Folate (folic acid), riboflavin (B2) , thiamin (B1) and vitamin K.
Soybeans also contain 173 calories, with 9 grams of fat, 10 grams of carbohydrates (6 of them are fiber) and 17 grams of protein .
To absorb a significant amount of nutrients, it is necessary to use soy with salt because soybeans also have a high content very high, this is a substance that binds minerals and reduces their absorption.
Soybeans contain a lot of protein. They are not as good as meat or eggs but are better than most other plant proteins. However, processing soybeans at high temperatures can alter some proteins and reduce their quality.
Soy fatty acids are mainly omega-6 polyunsaturated fats. This can cause problems because too much omega-6 in the diet can lead to inflammation and other health problems .
Therefore, it is important to avoid eating soy oil (and other types vegetable oil Other rich in omega-6) and processed foods contain it.
Note that the nutritional composition of soybeans depends very much on the type of food it contains. Whole soy beans can be very nutritious, while refined soy-based products such as protein and soybean oil are not nutritious.
Key thing: Raw soybeans are rich in micronutrients, but they also contain phytates that can absorb minerals. Soybeans are rich in omega-6 polyunsaturated fatty acids, which can cause some health problems.
Soybeans may have some health benefits
Talking about all the bad elements without mentioning the good side is not right. The truth is that there is some evidence that soy has health benefits in some people.
Soybeans have been carefully studied for cholesterol-lowering effects and some studies have shown that soy protein may reduce both total cholesterol and LDL cholesterol even if others are not effective at all .
The important thing to remember is that, even if soy helps to lower cholesterol (which studies don't agree on), there's no guarantee that it will help reduce heart disease.
Observational studies show a mixed result. Some studies show that soy helps reduce the risk of heart disease while others don't .
There are also some observational studies that show that soy may reduce the risk of prostate cancer in older people, the most common type of cancer in men .
Key thing: There is some evidence that soy can lower cholesterol levels even though the results of the studies are contradictory. Men who eat soy have a lower risk of developing prostate cancer.
Soybeans contain Isoflavones that function to endocrine disorders
is steroid hormone mainly found in women, where they play an important role in regulating sex development and reproductive cycle. Estrogen is also found in men although at a lower level.
Estrogen (and other steroid hormones) works by going into the cell nucleus and activating estrogen receptors. When that happens, there are changes in the transformation of genetic information in cells leading to some physiological effects.
The problem with estrogen receptors is that without the need for selective substances can also activate it. Some substances in an estrogen-like environment can also activate it.
This is where raw soybeans become interesting ...
Soybeans contain a large amount of bioactive compounds called function as phytoestrogen ... meaning plant-based compounds can activate estrogen receptors in the human body .
These isoflavones are classified as hindering the normal function of hormones in the body. The main isoflavones in soybeans are genistein, daidzein and glycitein.
They may reduce estrogen activity due to isoflavones, which prevent estrogen from having a high potential to combine, or it may increase estrogen activity because receptor isoflavones .
Key thing: The isoflavones in soybeans can activate and / or inhibit estrogen receptors in the body, as well as can disrupt the body's normal function.
Isoflavones in soybeans can lead to a risk of breast cancer
Due to estrogen activity, these isoflavones are often used as natural substitutes for estrogen to reduce menopausal symptoms.
In fact, isoflavones can reduce symptoms when women are in menopause, as well as reduce the risk of osteoporosis in older women like estrogen replacement therapy .
However, this usage is controversial and many believe that risk is greater than any potential benefit.
Animal studies show that soy isoflavones can cause breast cancer . There are also human studies that show that isoflavones in soybeans may stimulate the proliferation and activity of breast cells.
In one study, 48 women were divided into two groups. One group ate their normal diet, the other group added 60 grams of soy protein. After only 14 days, the group using soy protein significantly increased the amount of epithelial cells in the breast, which are cells that are more likely to turn into cancer .
In another study, 7 out of 24 women (29.2%) had an increased number of breast epithelial cells when supplemented with soy protein .
These changes may indicate an increased risk of breast cancer, the most common type of cancer in women. However, many observational studies show that women who eat soybeans are actually at risk for breast cancer .
It is best not to make decisions based on observational studies ... because they tend to be unreliable. Biological changes in the chest and studies of soybeans that cause breast cancer in rodents are a major cause of concern.
There are also some small studies on humans. At this time, soy causes a slight interruption in the menstrual cycle, resulting in delayed menstruation and prolonged menstruation .
Key thing: Soy isoflavones can promote cell replication in the breast. However, observational studies have shown that it reduces the risk of breast cancer. Soybeans can cause mild disruption of the normal menstrual cycle.
Soybeans, testosterone and male reproductive health
Although men also have a small amount of estrogen, a significant increase in estrogen is not normal. Therefore, increasing estrogen activity from soy isoflavones may have some impact on men which is very likely.
In rats, exposure to soy isoflavones in the womb may lead to adverse effects on sexual development in males .
One study followed 99 men who visited a sterile clinic. Those who ate soybeans the most in 3 months had the lowest sperm count .
Of course, this study is only a statistical and does not prove that it is soy that reduces sperm count.
Another study showed that consumption of 40 mg of soy isoflavones / day for 4 months did not affect hormones or semen quality .
Many people believe that soy can lower testosterone levels, but the effect seems rather fuzzy and inconsistent. Some studies show a slight decrease, while others do not see any effect .
Key thing: Exposure to estrogen-like compounds in the uterus can lead to side effects on men. Research on the effect of soy on testosterone and sperm quality does not work.
Soybeans can interfere with the function of the thyroid gland
Soy isoflavones also function as goitrogen, which is a barrier to thyroid function.
They can inhibit the function of thyroid peroxidase enzyme, which is needed for thyroid hormone production .
A study of 37 adult Japanese showed that eating 30 grams of soybeans for 3 months increased intake signs that thyroid function is impaired.
Many research subjects have symptoms of hypothyroidism, including depression, constipation, drowsiness and enlargement of the thyroid gland. These symptoms disappear after they stop eating soy .
However, there are other studies that show that soy does not work or has only a very slight effect on human thyroid function .
Key thing: Although soy isoflavones have been shown to inhibit the function of a key thyroid enzyme, there is not enough evidence to conclude that they contribute to hypothyroidism in adults.
Recipe soy milk for children is a bad idea
The introduction of infants to isoflavones by feeding children Soybeans can have harmful effects.
One study showed that newborn babies fed soy milk had more breast tissue growth at age 2 than those who were breastfed or formula milk .
Another study showed that girls who drank soy milk were more likely to get up early .
There is also evidence that using soy milk during the neonatal period can cause prolonged menstrual periods and pain increases during that time .
Soybeans also contain very high levels of manganese, much higher than breast milk; This can cause neurological problems and ADHD (attention-deficit hyperactivity disorder) . Soy milk for babies also has high aluminum content, which can cause a lot of problems .
Clearly hitherto Breast milk is the best food for babies. For women who cannot breastfeed, formula is much better than soy milk which should only be used as a last resort.
Key thing: There is considerable evidence that infant formula can be harmful, both through isoflavone content and high levels of manganese and aluminum.
Fermented soybeans can be safe in small amounts
It is true that many Asians have used soybeans without having any obvious health problems.
In fact, these population populations tend to be healthier than Westerners, although they have begun to suffer from many similar diseases when the Western diet has swept into these countries.
The problem is that these populations often consume soy products ferment like natto, miso and tempeh. Soy fermentation reduces some phytic acid even though it does not remove isoflavones .
Natto can be particularly beneficial for health because it also contains a significant amount of vitamin K2, which is important for cardiovascular and bone health. However, many people do not supplement these vitamins .
Using too much will cause toxicity ... and phytoestrogen can be very good if you don't eat much. If you plan to eat soy, choose fermented soy products and use them in volume small .
The main message to note
Examining the understanding of soy makes us extremely confused. Each study shows that soybean harm is equivalent to another study showing it is beneficial.
However, I would like to point out that in each study I consider to have a beneficial effect, it is supported by the soy industry, or the authors have some kind of financial relationship. with the soy industry.
This does not necessarily mean that their studies are unfounded. They are merely things to remember.
After careful consideration, it is important that pregnant women, planning to become pregnant, or breastfeeding their babies should avoid soy and other endocrine disruptors.
It is also important to avoid giving your baby formula soya milk. It should only be used when there is no other way.
However, the evidence is too faint and inconsistent so it cannot be concluded that adults taking a moderate amount of soy will be harmful.
I personally choose to stay away from soybeans even though the evidence is not convincing. The fact that it is a relatively new food in the diet containing endocrine disordering compounds is enough for me.