Soy, nutrition facts and health effects
Soya bean (Glycine max) is a legume native to East Asia.
They are an important part of Asian diets and have been consumed for thousands of years. Today, they grow mainly in Asia and South and North America.
In Asia, soybeans are often eaten whole, but processed soybean products are much more common in Western countries.
Various soy products are available including soy flour, soy protein, tofu, soy milk, soy sauce and soy oil.
Soybeans contain antioxidants and phytonutrients that have been linked to various health benefits. However, concerns have been raised about potential adverse effects.
This article tells you everything you need to know about soy.
To read more, you can refer to the blog of Norozi Nuts and Dried Fruits website.
Nutritional Value
Soybeans are mostly made up of protein, but they also contain good amounts of carbohydrates and fat.
The nutrition facts for 3.5 ounces (100 grams) of cooked soybeans are:
- Water: 63%
- Protein: 18.2 grams
- Carbohydrates: 8.4 grams
- Sugar: 3 grams
- Fiber: 6 grams
- Fat: 9 grams
- Saturation: 1.3 grams
- Monounsaturated: 1.98 grams
- Unsaturated: 5.06 grams
Protein
Soy is one of the best sources of vegetable protein.
Soybean protein content is 36 to 56% of dry weight.
One cup (172 grams) of cooked soybeans contains about 31 grams of protein.
The nutritional value of soy protein is very good, although the quality is not as good as that of some animal proteins.
The main types of protein found in soy are glycinin and conglycinin, which make up approximately 80% of the total protein. These proteins may cause allergic reactions in some people.
Soy protein consumption is associated with a slight decrease in cholesterol levels.
fat
Soybeans are classified as oilseeds and are used to prepare soybean oil.
Fat content is approximately 18% of dry weight - mainly polyunsaturated and monounsaturated fatty acids, with small amounts of saturated fat.
The predominant type of fat in soybeans is linoleic acid, which accounts for approximately 50% of the total fat content.
163 kcal
Because whole soybeans are low in carbohydrates, they have a very low glycemic index (GI), which is a measure of how foods affect blood sugar after a meal.
This low GI makes soy suitable for people with diabetes.
fiber
Soy contains a good amount of soluble and insoluble fiber.
Insoluble fibers are mainly alpha-galactosides, which may cause bloating and diarrhea in sensitive individuals.
Alpha-galactosides belong to a class of fibers called FODMAPs, which may aggravate the symptoms of irritable bowel syndrome (IBS).
Despite causing unpleasant side effects in some people, soluble fibers in soy are generally considered healthy.
They are fermented by bacteria in the large intestine, leading to the formation of short-chain fatty acids (SCFAs), which may improve gut health and reduce the risk of colon cancer.
Summary
Soy is a very rich source of protein and vegetable fat. In addition, their high fiber content is good for your gut health.
Vitamins and minerals
Soy is a good source of various vitamins and minerals including
- Molybdenum. Soy is rich in molybdenum, an essential trace element found mainly in seeds, grains and legumes.
- Vitamin K1. The form of vitamin K found in legumes is known as phylloquinone. It plays an important role in blood clotting
- Folate. Folate, also known as vitamin B9, has various functions in your body and is especially important during pregnancy. Diet is often low in Western populations. A deficiency may have adverse effects on heart health
- Manganese is a rare element found in most foods and drinking water. Manganese is poorly absorbed from soy due to its high phytic acid content.
- Phosphorus. Soy is a good source of phosphorus, which is an essential mineral in the Western diet.
- Thiamine. Thiamine, also known as vitamin B1, plays an important role in many body functions.
Summary
Soy is a good source of several vitamins and minerals, including vitamin K1, folate, copper, manganese, phosphorus, and thiamin.
Other herbal ingredients
Soy is rich in various bioactive plant compounds, including:
- Isoflavones, a family of antioxidant polyphenols, isoflavones have various health effects.
- Phytic acid. Phytic acid (phytate), which is found in all plant seeds, interferes with the absorption of minerals such as zinc and iron. The level of this acid can be reduced by boiling, sprouting or fermenting the beans.
- Heike saponin is one of the main classes of plant compounds in soy, saponins have been found to lower cholesterol in animals.
Isoflavones
Soy contains higher amounts of isoflavones than other common foods. are unique in that they are similar to the female sex hormone estrogen. In fact, they belong to a family of substances called phytoestrogens.
The main types of isoflavones in soy are: Genistein (50%), daidzein (40%) and glycine (10%).
Some people have a special type of gut bacteria that can convert daidzein into equol, the substance responsible for many of the beneficial health effects of soybeans.
People whose bodies can produce the equivalent are expected to benefit more from soy consumption than people whose bodies cannot produce it.
The percentage of equol producers is higher in Asian populations and among vegetarians than in the general Western population.
Summary
Soybeans are a rich source of various bioactive plant compounds including isoflavones, saponins and phytic acid. Isoflavones in particular mimic estrogen and are responsible for many of the health effects of soybeans.
Benefits of soy for health
Like many whole foods, soy has a number of beneficial health effects.
It may reduce the risk of cancer
Cancer is one of the main causes of death in modern society.
Eating soy products has been linked to increased breast tissue in women and hypothesized to increase the risk of breast cancer.
However, most observational studies suggest that consuming soy products may reduce the risk of breast cancer.
Studies also show a protective effect against prostate cancer in men.
A number of soy compounds—including isoflavones and lunasin—may be responsible for potential cancer-preventive effects.
Exposure to isoflavones early in life may be especially protective against breast cancer later in life.
Keep in mind that this evidence is limited to observational studies, which suggest an association between soy consumption and cancer prevention -- but don't prove causation.
Reduction of menopausal symptoms
Menopause is a period in a woman's life when menstruation stops.
It is often accompanied by unpleasant symptoms—such as sweating, hot flashes, and mood swings—that are caused by declining estrogen levels.
Interestingly, Asian women - especially Japanese women - experience less menopausal symptoms than Western women.
Dietary habits, such as greater consumption of soy foods in Asia, may explain this difference.
Studies show that isoflavones, a family of phytoestrogens found in soy, may reduce these symptoms.
Soy products do not affect all women in this way. Soy appears to be effective only in so-called equol producers—those with a type of gut bacteria capable of converting isoflavones to equol.
Equol may be responsible for many of the health benefits of soy.
Taking 135 mg of isoflavones daily for 1 week—the equivalent of 2.4 ounces (68 grams) of soybeans per day—reduced menopausal symptoms only in equol producers.
While hormone therapy has traditionally been used as a treatment for menopausal symptoms, isoflavone supplements are now widely used.
bone health
Osteoporosis is characterized by decreased bone density and increased risk of fractures, especially in older women.
Consumption of soy products may reduce the risk of osteoporosis in postmenopausal women.
These beneficial effects appear to be mediated by isoflavones.
Summary
Soy contains plant compounds that may help prevent breast and prostate cancer. In addition, these legumes may relieve menopausal symptoms and reduce the risk of osteoporosis in postmenopausal women.
Concerns and adverse effects
Even though soybeans have a number of health benefits, some people should limit their intake of soy products—or avoid them altogether.
Suppression of thyroid function
High consumption of soy products may suppress thyroid function in some people and contribute to hypothyroidism—a condition characterized by low production of thyroid hormones.
The thyroid is a large gland that regulates growth and controls the rate at which the body uses energy.
Animal and human studies suggest that isoflavones in soy may suppress the formation of thyroid hormones.
A study of 37 Japanese adults found that eating 1 ounce (30 grams) of soybeans every day for 3 months caused symptoms related to suppression of thyroid function.
Symptoms included discomfort, drowsiness, constipation, and an enlarged thyroid, all of which disappeared after the study ended.
Another study in adults with mild hypothyroidism found that taking 16 mg of isoflavones daily for 2 months suppressed thyroid function in 10% of participants.
The amount of isoflavones consumed was relatively low—equivalent to eating 0.3 ounces (8 grams) of soybeans per day.
However, most studies in healthy adults have found no significant association between soy consumption and changes in thyroid function.
An analysis of 14 studies found no significant adverse effects of soy consumption on thyroid function in healthy adults, while infants born with thyroid hormone deficiency were at risk.
In summary, regular consumption of soy products or isoflavone supplements may lead to hypothyroidism in susceptible individuals, especially those with an underactive thyroid gland.
Bloating and diarrhea
Like many other beans, soybeans contain insoluble fibers that may cause bloating and diarrhea in sensitive individuals. But they can be unpleasant.
Raffinose and stachyose fibers, which belong to a group of fibers called FODMAPs, may worsen symptoms of IBS, a common digestive disorder. Soybeans or limiting them may be a good idea.
Allergy to soy
Food allergy is a common disease caused by a harmful reaction of the body's immune system to certain components in foods.
Soy allergies are caused by soy proteins -- glycinin and conglycinin -- found in most soy products.
Even though soy is one of the most common food allergens, soy allergy is relatively rare in children and adults.
Summary
In some people, soy products may suppress thyroid function, cause bloating and diarrhea, and lead to allergic reactions.
For more information, refer to the blog of Norouzi nuts and dry fruits site.
Source: Healthline website
