Tofu is a familiar home-cooked food. It is not only delicious and affordable, but also has good nutritional value. In 26, the guidelines published by the Nutrition Committee of the American Heart Association believed that soy products are rich in soy isoflavones, polyunsaturated fatty acids, dietary fiber, vitamins and minerals, which are beneficial to the heart.
What benefits can tofu bring to us, and how can it protect the heart and cardiovascular health? How to eat and how much to eat can have a tonic effect? Let's take a look!
1. Research shows that isoflavones protect cardiovascular system
Recently, a study was published in the international journal Circulation. Researchers from Harvard University and domestic universities conducted a data survey on 2, participants, and found that compared with people who don't eat tofu, people who eat more than 15g of tofu every week may have a 18% lower risk of coronary heart disease! Among them, soybean isoflavone plays a major role.
1, what is soybean isoflavone
Isoflavones are secondary metabolites of plants, which are widely distributed in herbs, and are also called "phytoestrogens" because of their similar structures to human estrogens. Isoflavones can affect human body's hormone secretion, protein synthesis, growth factor activity and metabolic substance circulation.
Among the known foods, soybean is the main source of isoflavones for human beings. Soybean not only refers to soybeans, but also includes green beans and black beans.
2. Tofu is the "treasure house" of soybean isoflavones.
Every 1g of soybean contains 128mg of isoflavones, every 1g of soybean milk contains 9.65mg, while every 1g of tofu (wet) contains 27.74mg, and tofu (dry) contains more than 2mg of isoflavones. Tofu can be said to be a "treasure house" for isoflavones.
3, soybean isoflavone protects cardiovascular
Soybean isoflavone can protect cardiovascular health in four aspects:
Auxiliary prevention of thrombosis
Soybean isoflavone can reduce platelet activity by inhibiting tyrosine kinase and reducing tyrosine protein phosphorylation in platelets. This will reduce the coagulation level, and harmful substances in the blood will not easily deposit and accumulate on the blood vessel wall, thus helping to prevent the formation of atherosclerotic plaques and thrombi.
reducing bad cholesterol
soybean isoflavone can play an estrogen-like role, promote thyroid and bile excretion, and increase the metabolism of low-density lipoprotein cholesterol, but it will not reduce the amount of high-density lipoprotein cholesterol, and maintain the stability and health of blood lipid level.
biological antioxidation
after oxidation, low-density lipoprotein cholesterol is easy to develop into foam cells in the arterial wall, and then form atherosclerotic plaques, which is the key factor to cause atherosclerosis. Soybean isoflavones have biological antioxidant effect, which can enhance the activity of antioxidant enzymes, inhibit the oxidation of bad cholesterol, and enhance the elasticity of arterial wall.
Intervention of blood sugar
Studies have shown that soybean isoflavones can inhibit the absorption of sugar in the small intestine and better adjust the balance of sugar metabolism in the body. The decrease of blood sugar is helpful to reduce blood viscosity and prevent atherosclerosis induced by high glucose.
2. Tofu not only protects blood vessels, but also has five benefits.
Besides protecting cardiovascular system and reducing the risk of coronary heart disease, tofu also has other benefits:
1. Two-way regulation of estrogen
Studies show that soybean isoflavone can competitively occupy the position of estrogen receptor and play a role of weak estrogen when the estrogen level of human body is too high; When the level of estrogen is too low, it can supplement the functional deficiency of estrogen.
2, improving female osteoporosis
After the ovarian function of middle-aged and elderly women declines, the estrogen level decreases, which leads to a negative balance of bone metabolism and an accelerated decline of bone mineral density, which is more prone to osteoporosis and fractures. Soybean isoflavones can help reduce bone loss, increase the body's absorption of calcium and improve bone mineral density by playing an estrogen-like role.
3. Supplementing high-quality protein
The content of protein in soybeans and bean products is 2 times higher than that of pork and 2.5 times that of eggs, and its amino acid composition is similar to that of animal protein, which is close to the ratio needed by human body, so it is easier to be digested and absorbed.
4. Supplementing high-quality fatty acids
Soybean fat is also high-quality fat, which contains a lot of unsaturated fatty acids, while tofu is a high-quality food without cholesterol but rich in lecithin, which can help enhance brain vitality, eliminate brain fatigue and promote brain cell repair, and has a certain role in preventing Alzheimer's disease.
In addition, lecithin can also promote gastrointestinal blood circulation and gastrointestinal peristalsis, which is helpful to prevent or improve constipation.
5, helping to reduce the risk of cancer
Soybean products contain five known anti-cancer factors, which are helpful to inhibit the proliferation of undesirable masses and the spread of cancer cells, and can reduce the incidence of breast cancer, ovarian cancer, colon cancer, gastric cancer, prostate cancer and skin cancer.
3. Although tofu is good, you should pay attention to how to eat it.
Although tofu has high nutritional value, it is not recommended to eat it without restrictions. Everything should be well controlled. When eating tofu or other bean products, it should be noted that:
1. Tofu contains high purine < P > Tofu can be roughly divided into north tofu, south tofu and lactone tofu. Among them, the purine content of Beidoufu is low, containing 68 mg of purine per 1 g; South tofu and lactone tofu belong to high purine foods, which contain 96 mg and 1 mg of purine per 1 g respectively.
The purine in tofu belongs to plant purine, which has a low absorption rate in human body. Patients with high uric acid and gout can eat it in small quantities, and avoid eating during gout attack.
2. It is better to eat more often
Eating a lot of tofu at one time or for a long time is also a burden to the body's metabolism. First of all, excessive plant protein may hinder the human body's absorption of iron and cause indigestion; A large amount of nitrogen-containing waste produced after its metabolism is easy to increase the burden on the kidneys.
Secondly, the soybean used to make tofu usually contains saponin, which can promote the excretion of iodine in human body. Long-term excessive consumption of tofu is at risk of iodine deficiency. Therefore, it is recommended that you eat tofu in moderation, rather than eating too much at one time. Healthy people can eat no more than 4 grams a day.
3, Japanese tofu is not tofu
The main raw materials of Japanese tofu are eggs and water, and only a small amount of soybean raw materials are added, or they are not added at all, so they cannot be eaten as a substitute for tofu. Moreover, the calcium content of Japanese tofu is usually less than half that of North and South tofu, but the sodium content is 53 times that of lactone tofu, so you should put less salt when eating.
4, choose good tofu by simple 4 tricks!
Tofu and cabbage have their own tastes. You can choose according to your own tastes, but you must buy fresh ones.
the difference between 1 and 3 types of tofu
South tofu is usually solidified with gypsum powder, with a delicate texture and a moisture content of about 9%; Beidoufu is made with bittern or sour paste, which is more tough and easier to cook, and its moisture content is 85% ~ 88%. Lactone tofu is formed by adding gluconic acid-δ-lactone, which is smoother and more delicate than both, and has higher water content.
Lactone tofu can be stored at room temperature of 25℃ for two days without deterioration, while ordinary tofu may only be stored for 5~6 hours, so it is recommended to put it in the refrigerator in time in hot weather. But the content of protein and calcium in lactone tofu is lower than that in North and South tofu.
2. Choose tofu to look at these four samples.
Look at the color.
Fresh and high-quality South tofu has no water lines, no impurities, and is white and delicate. North tofu is yellowish with a small amount of bubbles in the middle; The texture of lactone tofu is delicate, soft and smooth, and it is light yellow. Poor tofu may be dull in color, uneven in texture and not delicate enough.
Look at the cross section
The cross section of fresh tofu is smooth and tidy, and there are few crumbs after cutting. If there are sandy crumbs, the cross section is pitted, hard and rough, it is not fresh.
Smell
Fresh tofu has a faint bean smell, while stale tofu may have a bad smell or foul smell in protein.
Look at the ingredient list
Many foods marked with "tofu" don't actually add much soy ingredients, such as konjac tofu and milk tofu, so you should pay attention to the ingredient list when buying sealed tofu.
3, "Chinese cabbage and tofu keep safe"
Chinese cabbage and tofu are classic collocations, which are simple and affordable, with high nutritional value, and are suitable for almost everyone to eat.
stewed tofu with Chinese cabbage
1 materials
kelp, Muyu flower, Chinese cabbage, tofu, dried seaweed, ginger and garlic.
2 Practice
Soak kelp and Muyu flowers in a bowl of boiled water in the morning (scallops and kelp can also be used instead), and take out the ingredients when you come back at night, leaving the soup for later use; Tear the Chinese cabbage into large pieces by hand, dice the tofu, and blanch it with hot salt water; Boil the soup, add 2 or 3 grains of dried seaweed, and a little garlic and ginger slices to boil; Add tofu and cabbage and stew for 5-7 minutes; Cut the soaked kelp into shreds, put it in a pot and cook it a little. Efficacy < P > Regulate blood lipid and blood sugar, which is suitable for patients with "three highs", obesity, fatty liver and diabetes, but not for those with deficiency of spleen and stomach.