The saying that "overnight tea is poisonous, causing diarrhea at the least and harming the body at the worst" is widely circulated in the health preservation community. Is the "power" of overnight tea really that great? The truth is far less exaggerated. The latest "scientific" rumor list is revealed! Will ovarian function decline lead to "cliff-like aging"? Seasonal allergies will go away by "holding on"? Snail noodles with "odor enhancers" cannot be eaten? Can atropine reverse myopia? Today, I will package the truth for you to see for yourself.

The monthly "scientific" rumor list is guided by the Beijing Association for Science and Technology, the Beijing Municipal Party Committee's Cyberspace Administration, and the Capital Internet Association, and is jointly released by the Beijing Science and Technology Journalists and Editors Association and the Beijing Regional Website Joint Rumor Refuting Platform.

Rumor: Spinach that is so green that it is black cannot be eaten

Truth: Some people think that the spinach that is so green that it is black on the market is the product of too much fertilizer. In fact, on the contrary, the darker the green color of green leafy vegetables such as spinach, the more chlorophyll it contains, the more nutrients it synthesizes, and the higher the nutritional value.

Spinach is a vegetable that can be grown all year round. It is cold-resistant and is divided into spring spinach, summer spinach, autumn spinach and winter spinach. Winter spinach is sown before winter, hibernates in winter, and is harvested in spring. In order to improve the frost resistance of winter spinach, it is indeed necessary to fertilize and supplement nutrients before dormancy, but this is a necessary measure to help spinach survive the winter. The effect is to increase the chlorophyll content, fully enlarge the leaves, and strengthen photosynthesis so that spinach can accumulate nutrients.

In fact, the content of folic acid, vitamin K, lutein and magnesium in green leafy vegetables is proportional to the chlorophyll content. The darker the color of spinach, the more nutrients it synthesizes and the higher the nutritional value. Relatively speaking, greenhouse vegetables and hydroponic vegetables often have light leaves because of insufficient light and insufficient chlorophyll.

Rumor: Overnight tea contains toxins and drinking it will cause poisoning

The truth is that some people think that overnight tea is poisonous because they think that the nutrients contained in tea can become a breeding ground for bacteria and fungi. If it is left standing for a long time, it may breed other harmful microorganisms. After drinking, symptoms of gastrointestinal infection such as vomiting and diarrhea may occur.

In fact, there is no strict definition of overnight tea. It is mainly for tea that has been brewed for too long. Usually, the water temperature for people to brew tea is 90¡æ-100¡æ, and general bacteria will be killed, and some substances in the tea itself have certain antibacterial effects. When tea is left open indoors, a small amount of bacteria in the air will enter, but the bacteria in the tea grow very slowly, and the impact is minimal.

In addition, tea that has been brewed for too long will not produce toxic substances except that the color is easy to darken and the taste is bitter. The reason why the color becomes darker is caused by the oxidation of tea polyphenols.

So you can drink tea that has been brewed for a long time, but there is no need to drink it if it is too bitter.

Rumor: Snail noodles cannot be eaten because of the addition of "odor enhancers"

Truth "Odor enhancers" are actually a term commonly used by the media. They refer to the base material packets and stinky sauces used in snail noodles. These products are compound seasonings, among which compound food additives - flavors and spices are used. The main function is to give the product a specific smell or taste. All legal "odor enhancers" are allowed to be used, and they have also been evaluated and approved by the national safety and are safe when used reasonably.

Some people may worry whether there will be harm if they are used in excess? This worry is unnecessary. Because in actual application, it is impossible to use too much flavor. One of the characteristics of flavors is "self-limiting", which means that a small amount will smell very fragrant, but too much will smell very bad, and it is possible to feel nauseous and cough. This is also the reason why the market supervision and management personnel in the news were coughed and smoked out of the "pain mask" by the "odor enhancers" of the snail noodle shop.

Although the snail noodle soup base contains some seasonings and spices, as long as it is a regular product, the food manufacturer follows the relevant food safety standards and regulations, and uses it reasonably, there will be no food safety problems. In addition, when you dine out, try to choose a regular restaurant with good hygiene conditions.

Rumor: Black takeaway spoons made from recycled plastic are toxic

Truth: Regarding the question of whether the black spoon is hygienic, the researchers referred to the relevant national standards and added coliform bacteria and salmonella tests. The integration of all test results is within the national standard limit, and it should be said that they are all safe.

In fact, there is no necessary connection between the color of plastic and its safety. For consumers, the daily judgment of the safety of plastic products for food mainly depends on the labels on the plastic products. For example, PP is resistant to high temperatures and is stable to acids, alkalis, alcohol and oils. It is often used in plastic tableware and is also the most widely used in takeaway tableware. PET is mostly used for beverage bottle packaging. Its material is relatively stable at room temperature, but harmful substances will migrate out when overheated food is contained. PE and PVC materials commonly used for plastic wrap will also precipitate toxic substances after high temperatures... In other words, under high temperature conditions, transparent PE materials are not necessarily safer than black PP materials.

Why do some people smell a pungent "smell" when opening a takeaway tableware package? After inspection, it was found that this was from the disposable chopsticks in the packaging bag. In order to prevent corrosion and bleach, during the production process of disposable chopsticks, manufacturers will soak bamboo chopsticks with sulfites. The treated chopsticks have sulfur dioxide residues and therefore have a little irritating smell. As long as they are within the limit of the national standard, they are all compliant operations.

Although disposable tableware is non-toxic, for environmental and health reasons, it is recommended to use as little as possible when ordering takeaways, whether it is a black spoon or other plastic tableware.

Rumor: Declining ovarian function will lead to "cliff-like aging"

The truth: Women's ovarian function begins to decline at the age of 25, and will experience a significant decline between the ages of 35 and 37. This is a normal physiological phenomenon. Aging is a decline in overall function. The main effects of declining ovarian function are osteoporosis, hot flashes, night sweats, and increased risk of cardiovascular disease. A decline in ovarian function within the normal range will not cause a sudden change in facial appearance.

As for the so-called "maintenance package" of Internet celebrities, it has little effect on delaying the decline of ovarian function. Women produce about 400 follicles in their lifetime. As the follicles are consumed, the secretion of estrogen gradually decreases. This is an unchangeable natural law. Nutritional supplements that claim to maintain the ovaries are not drugs. They have a slow and trace effect on the human body.

Other drugs that claim to contain estrogen or promote estrogen secretion should not be used without following a doctor's advice, otherwise they may cause hormone secretion disorders and even cancer risks.

Rumor: Seasonal allergies will go away if you just "bear it"

Truth: If it's not serious, you don't need to take medicine. It's wrong to just bear it. If allergic diseases are allowed to recur, they may develop in a serious direction.

Some severe allergic reactions occur suddenly for unknown reasons, while others are caused by repeated exposure to allergens for a long time, leading to acute attacks. Once an attack occurs, the symptoms often spread rapidly throughout the body. Therefore, allergic diseases must be taken seriously to prevent them from progressing from mild to severe.

Compared with other types of allergens, the eye symptoms of spring pollen allergy are more prominent. Eyes often have symptoms such as itching, conjunctival edema, redness and swelling, and tearing. In severe cases, even bilateral eyelids will be red and swollen, secretions will increase, and you will not be able to open your eyes in the morning. The most effective way to prevent pollen allergies is to stay away from allergens. Outdoor activities should be reduced as much as possible during the high incidence of pollen. When going out, it is recommended to be fully armed, and long clothes, long sleeves, masks, protective glasses, etc. should also be equipped as much as possible. You can also use pollen blockers before going out, apply them on the surface of the nasal cavity, and play a role of physical isolation.

For those who have a history of pollen allergy, it is recommended to take oral antihistamines 1-2 weeks before the allergy season. If you know in advance that the pollen concentration in the place you are going to is high, you can take anti-allergic drugs in advance, or use the drugs under the guidance of a doctor. During the allergy season, you should regularly use nasal glucocorticoid sprays or antihistamine eye drops until the end of the pollen season. It is not recommended to stop taking the drugs on your own.

Rumor "magic drug" atropine can reverse myopia

Truth Atropine sulfate eye drops are called "myopia magic drugs" and are the "life-saving straw" in the minds of many parents to save their children's vision. However, the main function of atropine is to "prevent" and "control" myopia. It does not have the ability to reverse the treatment of myopia and is not a "one-time use" myopia magic drug.

As a prescription drug, it has corresponding indications and contraindications. Parents should not buy it on their own or use it blindly. Children who need to use atropine are those whose eye axes grow too fast. It is recommended that children who have just discovered myopia should have their axial length checked at least once every three months on the basis of optical correction (glasses) and improved eye habits, and the change in the axial length should be used to determine whether atropine should be used.

At present, myopia cannot be reversed by drugs. Children and adolescents should protect their eyes by developing good reading and writing habits, reducing dependence on electronic products, and letting their eyes rest.

Rumor: Eating lard can prevent cardiovascular disease

Truth: Most people who think lard is healthier hold the view that Chinese people have been using lard for generations, and have always lived in peace. Now people dare not eat fatty meat, but the incidence of heart disease has increased significantly. It can be seen that lard is a must-have for diet therapy and can prevent cardiovascular disease.

However, lard really cannot be eaten too much. Lard is an animal oil, and its main component is fat. Since each gram of fat can produce 9 kilocalories of energy, eating more oil means more energy intake. Excessive energy accumulation will cause overweight or even obesity. Obesity is a risk factor for chronic diseases such as hyperlipidemia, hypertension, diabetes, atherosclerosis, coronary heart disease, and stroke.

In the fat composition of lard, the saturated fat content can be as high as 40% or more, and it is the main fatty acid that increases our serum cholesterol. Relevant guidelines recommend that the intake of saturated fatty acids should be less than 10% of the total dietary energy.

When choosing oils, we can replace foods rich in saturated fat with oils rich in monounsaturated fats (such as tea seed oil, olive oil) and oils rich in polyunsaturated fats (such as sunflower oil, corn oil). In addition, while reducing fat, a certain energy demand can be met by appropriately increasing the amount of protein and carbohydrates. For example, choose foods that are rich in protein and relatively low in fat, such as fish, shrimp, lean meat, milk, eggs, and soy products, as well as starchy foods such as millet, sweet potatoes, and oatmeal for supplementation. Therefore, if you want to prevent heart disease, it is recommended to eat less lard.

Text/Li Jie, a reporter of this newspaper

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