As we all know, you may get skin cancer if you don't wear sunscreen for a long time. But you certainly don't know that if you don't wear sunscreen in the sun, it may also prevent many cancers, including skin cancer.
Anti-cancer "sunshine vitamin"
Scientists are excited about vitamins again. Previous studies on vitamins were often too much thunder and too little rain, and the results were not as good as people expected. And this time the evidence is getting more and more conclusive. If confirmed, it will subvert the most basic common sense in the medical field: in the sun, people must wear sunscreen to prevent skin cancer. Now, some researchers believe that doing so will lead to cancer, far exceeding what it can prevent.
This time, the protagonist is vitamin D, which is also called "sunshine vitamin" because skin can naturally produce by absorbing ultraviolet radiation in the sun. Dermatologists and health institutions have long advocated the use of sunscreen to prevent skin cancer. But recently, some scientists began to question this suggestion. The reason is that sunscreen will hinder the production of vitamin D, which may have the effect of preventing and even treating various cancers.
In the previous three months, four independent studies showed that vitamin D could help prevent and treat lymphoma, prostate cancer, lung cancer and even skin cancer, especially colon cancer.
Dr. peter green Greenwald, director of cancer prevention at the National Cancer Institute of the United States, said that at present, more than a dozen experiments are testing the anti-cancer effect of vitamin D, and some experiments are testing its therapeutic effect on cancer.
Although everything has yet to be verified, there are already many reasons for people to believe this:
Some studies have observed a large number of people and found that people with higher levels of vitamin D in their bodies have lower cancer rates. Some of these studies collected blood samples to measure the content of vitamin D, which made the research results more conclusive.
Laboratory and animal studies show that vitamin D can inhibit the growth of abnormal cells, make them die, and hinder the formation of tumor blood vessels.
With the increase of age, vitamin D produced by skin decreases, and cancer is more common in the elderly.
Pigment will hinder the production of vitamin D. Black people have more pigment in their skin and are more prone to cancer than white people. The effect of vitamin D will be inhibited by fat, so the blood vitamin D content of obese people is low, and they also have a high incidence of cancer; Diabetic patients with kidney damage have difficulty in converting vitamin D into usable forms, and they are also prone to cancer. People living in the northeastern United States and the northern part of the earth, such as Scandinavia, have a higher cancer rate than those who can enjoy the sunshine all the year round.
How much is the intake of arms?
Recently, the American Association for Cancer Research held a meeting in Anaheim, California. During the meeting, Dr. Edward Chovan Nussy, a professor of medicine and nutrition at Harvard University, gave a keynote speech. His research shows that vitamin D can prevent 30 cancer deaths in every 1 case of skin cancer caused by sun exposure.
Chovan Nussy said: "I dare say that no one can find other methods or nutrients with such remarkable anti-cancer effect as vitamin D."
Chovan Nussy's comments touched Michael Duane, chief epidemiologist of the American Cancer Society, which is reassessing their sun protection guidelines. Duane said: "Vitamin D can not only prevent some cancers, but even have a therapeutic effect." Even some dermatologists are beginning to agree with this. Dr. Allen Harpon, who is in charge of dermatology at the new york Memorial Loan-Kettering Cancer Center, said: "I have found more and more evidence and more attention."
American government health consultants disagree with the recommended daily intake of vitamin D. They think that the "appropriate intake" should be 200IU for people under 50, 400IU for people aged 50 to 70, and 600IU for people over 70. Many scientists advocate higher intake. They think that adults need 1000IU of vitamin D every day. Research in Chovan and New Zealand shows that if you want to suppress cancer, you need to supplement vitamin D up to 1500IU every day.
In winter with short sunshine time, the angle of sunlight is too inclined, so it is difficult to stimulate the skin to produce vitamin D. Therefore, nutrition experts believe that people should take vitamin D-3 tablets in winter, but the problem is that too many tablets will lead to calcium accumulation in the body. The US government thinks that 2000IU is the upper limit of daily intake of vitamin D for people over 1 year.
Intake route > > > rely on the sun or diet?
Could vitamin D be the second folic acid (a vitamin B)? In the past, people thought that taking more folic acid was mainly beneficial to pregnant women and could prevent birth defects of babies. However, from 65438 to 0998, after food manufacturers added folic acid to flour, the incidence of heart disease, stroke, hypertension, kidney cancer and osteoporosis decreased. It turns out that everyone lacks folic acid.
Duane and others worry that the recent research results will make people overcorrect. He prefers that people take more vitamin D through food and pills. But it's not easy, Chovan Nussy said. The intake of daily food after entering the blood circulation is too small.
Nutritional supplements contain this nutrient, but most of them are added with older D-2, and D-3 is much more effective than it. Multi-vitamin supplements usually contain only a small amount of D-2, and the vitamin A contained in them will also offset most of the effects of vitamin D, so these tablets can't actually increase the intake of vitamin D. Let's go back and think about supplementing vitamin D with natural sunlight.
No one advises everyone to lie on the beach until they eat "roast suckling pig". How much you enjoy the sunshine depends on the season, the time of day, where people live, skin color and other factors. Many scientists believe that "safe sunbathing" means enjoying about 15 minutes of sunshine several times a week without sunscreen. This is not only feasible, but also healthy.
There are different opinions about whether to bask in it.
Thirty years ago, Michael Horrick helped discover how vitamin D was produced. Now, he is a professor of dermatology at Boston University, and he is also responsible for studying endocrinology, nutrition and diabetes. Last year, he published a book entitled "Advantages of Vitamin D", urging people to enjoy enough sunlight to produce vitamin D.
"I advocate that everyone get more sunshine," Hoorik said, "but not for a long time." He pointed out that skin cancer is rarely fatal. It is estimated that only 7,770 of the 570,280 people who died of cancer in the United States this year were due to melanoma (a kind of skin cancer). There will be more than 6,543,800 cases of mild skin cancer this year, which is mainly caused by too long sunbathing time.
Hoorik claims that repeated tanning-especially for some children, people with red hair and fair skin-is easy to get melanoma, but there is no credible scientific evidence that mild sunshine will lead to these results. Now, people are afraid of the sun. He said, "The problem is that the American Academy of Dermatology has been in an indisputable position for twenty years. They brainwashed the public. "
Horrick's point of view naturally makes manufacturers of sunscreen products very unhappy. The Sunshine Safety Alliance, funded by Coppertone brand and drug chain stores, sarcastically said: "People are no different from taking vitamin D supplements by sunbathing and letting them relieve their worries by smoking."
Even among dermatologists, it is difficult to reach an agreement.
Dr Barbara Giltrist, the head of Horrick's department, called his book embarrassing and dismissed him as a professor of dermatology. At the beginning of this month, colleges and universities studying dermatology launched an activity called "Don't look for the sun". "Under no circumstances should people be misled into thinking that natural sunlight is a better source of vitamin D than food and nutritional supplements," said Vincent Drew, a dermatologist at Columbia University.
However, Dr. Henry Lin, director of dermatology at Henry Ford Health System in Detroit, believes that "it is right to stop thinking that' not being in the sun is good'."
Until more evidence is obtained, experts advise people to get moderate sunshine. James Righton, emeritus professor of dermatology at the University of Pennsylvania, said: "The skin can handle these things just like the liver can handle alcohol." But he also said, "I like to drink some wine with meals, but I don't think I should drink four bottles a day."
What is ultraviolet light?
Ultraviolet light is a kind of light, which can be divided into three types according to its wavelength: UV-C waves with a wavelength below 290nm; UV-B wave, UV-A wave with wavelength of 290 nm ~ 320 nm, UV-A wave with wavelength of 320nm~400nm. Among them, UV-C wave is harmful to human body, but it is absorbed by the ozone layer in the atmosphere and generally does not reach the surface. Part of UV-B wave is reflected and absorbed by the atmosphere, and part of UV-B wave irradiates the surface. Excessive irradiation will do harm to the skin. UV-A wave stimulates the activity of subcutaneous pigment cells to produce pigment, which makes the skin black, which is often called tanning. Sunbathing is indispensable in human life activities. By sunbathing, the human body produces vitamin D that is difficult to be absorbed by the outside world, making the skin and bones healthy and strong.
UV-A waves in ultraviolet rays are harmless. However, with the destruction of the environment by human activities, the ozone layer in the atmosphere gradually became thinner, and local holes appeared, which increased the UV-B waves that rarely reached the surface in the past, and even made the UV-C waves blocked from the atmosphere illuminate the surface.
Melanin and skin tanning
Although everyone has different skin color, the number of pigment cells is basically the same. The difference lies in the quality of pigment cells. When the human body is irradiated by ultraviolet rays, the pigment cells are stimulated. In order to protect the skin, they begin to move and produce melanin, and the skin color naturally turns black, which is often called skin tanning. Some people often go to the seaside or the open-air swimming pool, but they can't get the sun. The reason is that the activity of pigment cells is weak. Proper sunbathing is necessary for human skin. By sunbathing, a layer of pigment can be formed in the skin, which can prevent harmful ultraviolet rays from harming the human skin and protect the skin. Simply put, the whiter the skin, the more fragile it is. Acid rain, ozone layer destruction and other air pollution make our living environment worse and worse. On the other hand, influenced by the wrong one-sided propaganda of some cosmetics companies, we lack correct knowledge of ultraviolet rays and rely too much on cosmetics, which makes our skin gradually fragile. At the same time, in the fast-paced modern urban life, we have fewer and fewer opportunities to enjoy sunbathing. This paper puts forward the necessity of artificial sunbathing by machine to form pigment layer, strengthen and beautify our skin.
Sweating effect is similar to sauna.
Not only in summer, but also in winter, the radiation from all directions in the tanning bed can raise the temperature in the machine in a short time and cause a lot of sweating. The physiological function of sweating can not only promote the metabolism of the skin, but also achieve the function of moderate exercise. Play a comprehensive effect of fitness, weight loss and body shaping. Especially in autumn and winter when sweating is not easy, the excess water retained in the body can be forcibly discharged after sweating by the machine, so as to relieve muscle soreness, eliminate edema of lower limbs, improve blood circulation and relieve the troubles of cold limbs and cold hands and feet.
For those who feel pain or resist entering the sauna, using a sunbed is a quick and comfortable way to sunbathe and sweat. In addition, ultraviolet rays have a bactericidal effect and can keep the skin surface clean and hygienic.
Don't ask men and women, make it radiant.
Besides its many advantages in health, we also emphasize its role in beauty. By sweating, you can get rid of the accumulated water in the body, eliminate edema, make the skin look firm and elastic, and make the figure look slender. Dark skin itself will give people a thin feeling visually, especially in today's advocating nature and emphasizing physical beauty. Moderate sunbathing will make handsome men and beautiful women look more beautiful.
Any clothes assembled on the healthy and beautiful wheat skin color will look more beautiful and decorative. Nowadays, people who have spare capacity in leisure and consumption in Europe, America and Japan will go to the day bath fashion salon regularly, and sunbathing has long been a part of modern life. Whether it's formal clothes or casual clothes, when you go out against the sun with wheat-colored skin every day, that moment is the beginning of fashion life.
The origin of the birth of sunbeds
In northern Europe, tanning beds are actually the sun in winter. Because of the high latitude and less sunshine time in northern Europe, ultraviolet sunlight in the sun is extremely precious and an important means to keep healthy. Therefore, in a few sunny days, people sunbathing all over the park can be seen everywhere. In medicine, sunbathing has been proved to prevent diseases and neuralgia. In the long winter in northern Europe, the sunshine time is very short, so it is almost impossible to sunbathe naturally. In order to keep healthy, machines instead of the sun naturally appeared to keep healthy, and machines instead of sunbeds naturally appeared.
Medical effect of sunbathing
Ultraviolet rays are the source of health.
1. The sun is omnipotent.
Generally speaking, ultraviolet rays can regulate the function of human skin, promote blood circulation and metabolism, and make nutrition. When ultraviolet rays are irradiated on the skin, vitamin D can be formed on the skin surface and absorbed by the human body to treat and prevent various diseases. As we all know, sunbathing has been used to treat diseases and tuberculosis except tuberculosis for a long time. It is widely used to treat modern urban diseases unique to living in big cities, such as improving the resistance to bacteria and strengthening bones.
2. "Phototherapy", Sun is a doctor.
The sun is essentially a doctor, just like the technical term "phototherapy". For skin diseases such as acne and eczema, too much sunlight, especially ultraviolet radiation, is a natural therapy.
3. Spiritual effects caused by ultraviolet rays
Sunlight is found to make people feel happy, which is not only caused by the obvious role of ultraviolet rays in skin diseases, but also a secondary role in promoting blood circulation and relieving mental stress. Affected by mental relaxation, it is extremely beneficial to hair growth.
Safer than sunshine?
The darkening of the skin after sunbathing is actually the result of the natural protective function of the skin after ultraviolet irradiation.
According to the wavelength from long to short, the sunlight we irradiate every day can be divided into three types: infrared, visible and ultraviolet, and among the ultraviolet rays, there are three types: UVA, UVB and UVC. Due to the destruction of the ozone layer in the atmosphere, there used to be three kinds of UVC. Due to the destruction of the ozone layer in the atmosphere, harmful and carcinogenic harmful ultraviolet rays (UVC) that could not reach the surface completely in the past have also reached the surface. The tanning bed is "safer than the sun" because it contains no harmful UVC waves, mainly UVA waves and moderate UVB waves.
Why is tanning important?
Tanning the skin is the most natural way to protect the skin. Moreover, ultraviolet rays can promote the formation of vitamin D which is difficult to be ingested through food, and vitamin D plays a very important role in the regulation of human immune system.
Sunlight and tanning
Solar rays are a mixture of several kinds of light, some of which directly illuminate the surface, and some of which illuminate the surface through atmospheric diffusion; In the invisible line, infrared light can be felt by heat, and visible light can be formed into light sensation in the inner eye, which we can see. The darkening of skin color after sunbathing is the result of skin reaction to invisible light and ultraviolet light.
The principle of skin tanning
Skin is composed of epidermis, dermis and subcutaneous tissue, which is a physiological phenomenon of tanning and only exists in epidermis. Sunlight can reach the whole epidermis. At the bottom of the epidermis, there is a kind of pigment cell, and light tanning is the result of pigment cell activity. When the sun's rays (mainly UVA) penetrate the epidermis and irradiate the bottom layer of epidermis, the pigment cells in the bottom layer cells begin to move after being stimulated by UVA, producing melanin, and the skin color turns black. This is a physiological phenomenon of human physiological self-defense function. ) The tanning phenomenon we see is caused by the influence of oxygen and UVA. When oxygen combines with melanin in skin, melanin becomes thicker, which is called oxidation.
The difference between sunshine and sunbeds.
Suntanning with a tanning bed will turn the skin red. Sunbathing is different. Generally speaking, the skin is red, and it feels painful and itchy, and even blisters in severe cases. However, sunbathing with a sunbed can avoid this situation. Using tanning bed is a way to get the ideal skin color of wheat without causing discomfort such as redness and itching, because its principle is not to simulate natural sunlight, but to scientifically adjust different wavelengths, not to mention pain and ultraviolet rays, to remove harmful ultraviolet rays and retain ultraviolet rays beneficial to human body. If your skin turns red because of the tanning bed, it is only possible that you did not use the tanning bed correctly according to the instructions. As long as it is used correctly, there will be no redness or sunburn, and beautiful wheat-colored bronze skin will be obtained. With tanning beds, you can not only get the popular wheat-colored skin, but also warm your skin and prepare for your skin before going to the seaside or going up the mountain for vacation, which can minimize the impact of harmful rays from the sun on the human body.
Heat and tanning
The process of skin tanning has nothing to do with "heat", but "heat" has a bad effect on the skin. In summer, the heat (infrared ray) and UVB of the sun's rays are the causes of skin inflammation. Indoor sunbathing solves this problem with tanning bed machine. First of all, the ultraviolet rays in the tanning bed are mainly UVA and a small amount of UVB, thus avoiding the direct damage to the skin caused by a large amount of UVB radiation. Secondly, the sun bed is equipped with air conditioning and ventilation equipment, and the temperature is always controlled within a suitable range to avoid thermal burns; High-end models are also equipped with spray, fragrance and sound, so that you can get beautiful skin while resting in a warm, comfortable and relaxed environment.
In a warm environment with moderate temperature, you can sunbathe and sunbathe your skin, and at the same time promote metabolism, relax your spirit and relieve stress. When sunbathing indoors, the indoor temperature should be controlled below 23 degrees (especially in summer), and it is generally best to have a thin layer of sweat on your body after sunbathing. When exposed to the sun, it is best to have a thin layer of sweat on the body surface after exposure. When exposed to the sun, the body feels that the temperature change is caused by infrared rays, not UVA. UVA can't be felt or seen by human body, so it can't be used as heat.