Soy health

Benefits of soy

There is no denying that soy has many health benefits. These health benefits are mainly coming form the quality of the soy proteins and form the isoflavones genistein and daidzein. These are the main health benefits of soy:

Soy improves bone health Soy products, such as soy milk, do not contain a lot of calcium but the soy isoflavones may help to reduce the osteoporosis risk. Several studies have suggested that soy isoflavones may be a factor in helping to prevent bone loss. The isoflavone genistein seems to inhibit bone breakdown and may have similar effects than estrogens in maintaining bone tissue. Soy can also indirectly improve bone health. Diets which are high in animal protein cause more calcium to be excreted in the urine. Replacing animal protein with soy protein may help to prevent calcium loss from the bones.

Soy relieves menopausal symptoms
Epidemiological data show that Asian women suffer less from hot flashes and night sweats compared to Western women. These symptoms of menopause are caused by low estrogen levels. Estrogens play a role in the body temperature control. Soy isoflavones can through their estrogen-like effect control these menopausal symptoms.

Soy reduces risk for heart diseases
In countries were soy products are ingested regularly, the rates of cardiovascular diseases is low. Research suggests that soy may help to prevent heart disease by reducing total cholesterol, low density lipoprotein cholesterol and preventing plaque buildup in the arteries, which could lead to stroke or heart attack. These health benefits are also mainly attributes to the soy isoflavones. The soy isoflavone genistein may also increase the flexibility of blood vessels.

Soy helps to prevent certain cancers
Several studies have indicated that a regular intake of soy foods may help to prevent hormone related cancers such as breast cancer, prostate cancer and colon cancer.

Soy is very nutritive
Soy products such as tofu, tempeh and soy milk are very rich in protein. This protein is of very high quality because it contains all essential amino acids. The amino acids of soy combine very well with the amino acids of cereals. The soy protein is therefore very important for vegans.
Soy is a good source of lecithin and vitamin E. These natural antioxidants prevent oxidation of LDL cholesterol. Soy is rich in magnesium, which plays an important function for the bones, heart and arteries.

Soy and cholesterol

Cholesterol and your heart

Cholesterol is a soft fatty substance. Cholesterol does not dissolve well in water. This weak ability of cholesterol to dissolve in water is a major factor in the development of atherosclerosis. The body gets cholesterol the food but it is also produced by the body. Cholesterol is mainly produced in the liver, but also in the adrenal glands and reproductive organs. Cholesterol is a necessary component of your body cells and is a building material for hormones such as estrogen and testosterone.
Cholesterol can cause problems when high levels in the bloodstream are present. These high levels lead to hardening of the arteries, coronary heart disease and other vascular disease problems.

When cholesterol is measured in the blood 3 cholesterol levels are determined: LDL-cholesterol (bad cholesterol), HDL-cholesterol (good cholesterol) and triglycerides.
LDL-cholesterol or "bad cholesterol" has the property to build up plaque on the inner walls of the arteries which feed the heart and brain. Together with other substances the LDL-cholesterol forms a plaque that can clog the arteries.
HDL-cholesterol or "good cholesterol" carries cholesterol away from the bloodstream and back to the liver thereby decreasing the risk of plaque build-up.
Triglycerides are the normal fats. Blood triglyceride may also play a role in forming plaque.

Soy can reduce cholesterol
Soy products help to control the cholesterol level because:
soy is cholesterol-free
the soy proteins reduce the cholesterol level
most of the fats in soy products are poly-unsaturated
soy isoflavones prevent atherosclerosis
soy contains soluble fibers which reduces the amount of cholesterol circulating in the blood.
It is known that in countries were traditional soy products are consumed daily, the rates of cardiovascular diseases are low. There is some research that suggests that soy foods may help to prevent heart disease by reducing total cholesterol, low density lipoprotein cholesterol, blood pressure and possibly preventing plaque build-up in the arteries (atherosclerosis). Before the age of 60, man have more problems than women with their cholesterol levels. After menopause, when the production of natural estrogens drops, cholesterol levels in women will go up and the women become more suseptible to heart attacks. The soy isoflavones have a weak estrogen actity which is large enough to help reduce the cholesterol levels.

Meta-analysis of the effects of soy protein intake on serum lipids
JW Anderson examined the relation between soy protein consumption and serum lipid concentrations in human in his meta-analysis of 38 controlled clinical trials, involving more than 730 volunteers. In most of these studies, animal protein was replaced with soy protein (average 47g per day). The intake of energy, fat and cholesterol was similar when the subjects ingested control and soy-containing diets.

These were the findings:
Replacing animal protein with soy protein reduced cholesterol with 9.3%.
Volunteers on the soy diet had their LDL cholesterol levels dropped on average by 12.3%.
The HDL cholesterol increased by 2.4% in volunteers on soy-containing diets.

Soy protein

What is soy protein ?
Soy protein has been used since 1959 as ingredients for its functional properties in a variety of foods such as salad dressings, soups, vegetarian foods and meat imitations. Its functional properties are emulsification and texturizing. Recently the popularity of soy protein is increasing, mainly because of its health benefits. It has been proven that soy protein can help to prevent heart problems and many countries allow health claims for food, which are rich in soy protein.

In the US a soy protein health claim is allowed under the following conditions:
One serving must contain at least 6.25 grams of soy protein.
One serving may contain max 3 grams of fat, unless the product consists of or is derived from whole soy and contains no fat in addition to the fat inherently present in the whole soy. Of these 3 grams of fat max 1 gram may be saturated fat, representing max 15% of the total calories.

The serving must contain less than 20 milligrams of cholesterol.
The food must be low in sodium: less than 480 milligrams for an individual food, less than 720 milligrams for a main dish and less than 960 milligrams for a meal product.

Categories of soy proteins
Soy proteins can be divided into different categories according to their production method:
Soy protein isolate is the most refined form of soy protein and is mainly used in meat products to improve texture and eating quality. Soy protein isolate contains about 90 percent protein.
Soy protein concentrate is basically soybean without the water soluble carbohydrates। It contains about 70 percent of protein.

Textured soy protein, often called TSP, is made from soy protein concentrate by giving it some texture. TSP is available as dry flakes or chunks. It will keep its structure when hydrated. Hydrated textured soy protein chunks have a texture similar to ground beef. It can be used as a meat replacement or can be added to meat. Textured soy protein contains about 70 percent protein.

Soy yogurt

What is soy yogurt ?
Soy yogurt is made by fermenting soymilk with friendly bacteria, mainly Lactobacillus bulgaricus and Streptococcus thermophilus. The process is similar to the production of yogurt from cow milk. Yogurt production was invented probably by accident by Balkan tribes thousands of years ago. Yogurt remained mainly a food of Eastern Europe until the 1900s, when the biologist Mechnikov theorized that lactobacillus bacteria in yogurt are responsible for the unusually long lifespan of the Bulgar people. Mechnikov then popularized yogurt as a foodstuff throughout Europe.


The sugars are fermented by the bacteria into lactic acid, which causes the formation of the characteristic curd. The acid lowers to pH of the yogurt to about 4.0 and restricts the growth of food poisoning bacteria. The bacteria produce lactase which breaks down the lactose in dairy milk. Soy milk does not contain lactose but other sugars such as stachyose and raffinose.

Some countries only allow to use the name "yogurt" for products which have not been pasteurized to kill the bacteria after fermentation. This "live" yogurt is believed to be nutritional superior. The living bacteria are supposed to improve our immune system and the enzymes help to digest food. Sometimes, special probiotic bacteria, which are supposed to improve our gut health, are added to dairy or soy yogurt. These probiotic bacteria, often called good bacteria, are special strains of lactic acid bacteria or Bifidobacterium. A probiotic yogurt contains additional ingredients, such as inuline, that promote the growth of the probiotic bacteria. Soy yogurt always contains natural probiotics: the two soy sugars, stachyose and raffinose, act as probiotics and stimulate the growth of Bifidobacterium in the large intestine. Foods that contains both probiotic bacteria and prebiotic ingredients are called symbiotics.

It is difficult to find soy yogurt in supermarkets but you may find it health food shop. Or you can make soy yogurt at home. You can use store-bought yogurt as starter or even Solgar capsules that contain Lactobacillus bulgaricus and Streptococcus thermophilus. In some countries, soy yogurt is labelled as "cultured soy milk" because the term "yogurt" is reserved for dairy yogurt.

Soy milk

What is soy milk ?
Soy milk is made by soaking soybeans, grinding them with water. The fluid which results after straining is called soy milk. You can make soy milk at home with basic kitchen tools or with a soy milk machine. Soy milk is most commonly found in aseptic cartons. Most of the soy milk available in the market is flavoured and fortified with extra calcium or vitamins. The most popular flavours are vanilla and chocolate. Some producers add thickeners to their soy milk to give it a mouth feel of cow's milk. Traditionally, soy milk has a beany taste which is well accepted by the Chinese, but less by the Western palate. By using correct processing techniques, this beany taste can be reduced or eliminated. Recently, with the recognition of its health benefits and with its improved flavor and texture, soy milk has now a high and rising acceptance. Sometimes, use is made of protein isolates from soy bean which are mixed with water, oils, sugars, stabilisers to give it a milky appearance. This type of product should be described as soy drink and is not as wholesome as real soy milk.

Nutritional values of soy milk
Plain soy milk is very nutritive: it's an excellent source of high quality proteins, isoflavones and B-vitamins. Soy milk is free of the milk sugar (lactose) and is a good choice for people who are lactose intolerant. Also, it is a good alternative to those who are allergic the proteins of cow's milk.

Making your own soy milk
In China and Japan fresh soy milk is made daily using a simple, centuries-old process of grinding soaked soybeans and pressing the soy milk out of the beans. There, soy milk is sold by street vendors or in cafes. Soy milk is served hot or cold and is often flavored with soy sauce and vegetables to produce a spicy soup.

Many people find the cost of commercial soymilk to be prohibitive and make soy milk at home. They soak and crush soy beans and filter the liquid, which is soy milk. Some have invested in a soy milk machine that cooks and grinds the soy beans and makes soy milk, fresh in your own home. There are different brands of soy milk machines on the market (Miracle Soy Wonder, SoyJoy Automatic Soy Milk Maker, SoyToy Soy Milk Machine, Soyapower). You don't need these machines to make good quality soy milk, but they make life easier and give a high yield.

Soybeans

What are soybeans ?
Soybeans belong to the legume family and are native to East Asia. They have been an important protein source in the Orient for over five thousand years. Soybeans have only been introduced to the Western world since the 20th century. Soybeans grow on a variety of soils and a wide range of climates, ranging form tropical Brazil to the snowy island Hokkaido in the north of Japan. As soybeans mature in the pod, they ripen into hard, dry beans. Although most soybeans are yellow, there are also rare varieties which are black, brown or green coloured. A given area of land planted with soybeans can produce much more protein than land planted with other crops, or if the land were used to raise cattle.
Storing soybeans - Fresh soybeans, or edamame, should be refrigerated and used within two days. Frozen edamame can be stored in the freezer for several months. Dried soybeans can be kept in an airtight container for a very long period.

Cooking soybeans - Soybeans are most often transformed in other foods such as Tempeh, Tofu, miso, shoyu, soy milk or other food ingredients. However, cooked soybeans can also be used as an ingredient in soups, sauces and stews. To prepare two cups of soybeans for cooking, soak them in about six cups of water for about eight hours. This soaking shortens the cooking time, improves the texture and appearance of the beans and removes some of the indigestible sugars. Drain, rinse and cook the soaked soybeans in about six cups of fresh water. Do not add salt at this point or it will delay the softening of the soybeans. Pressure-cook the soaked soybeans for about 40 min. When you cook soybeans, make it worth your while by cooking two or three times what you need and freezing the rest for later use.

Protein source - Whole soybeans are an excellent source of protein and dietary fibre. Soy protein is the only vegetable with a complete protein. Soy protein has recently attracted a lot of attention because of its ability to lower LDL (bad cholesterol) levels. Results from research have prompted health professionals to request the government to officially give a stamp of approval for soy's cholesterol-lowering effects. The Food and Drug Administration approved the cholesterol-lowering health claim for soy, indicating that daily consumption of 25 grams of soy protein (6.5 grams of soy protein per serving) may lower LDL cholesterol.