August "Science" Rumors List: Can intravenous infusion prevent stroke? Can using an air fryer cause cancer?

The August "Science" Rumor List is here! Can intravenous infusion prevent stroke? Can using an air fryer cause cancer? Can eating celery lower blood pressure? The truth is revealed.

The monthly "science" rumor list is guided by the Beijing Association for Science and Technology, Beijing Municipal Cyberspace Administration, and the Capital Internet Association, and jointly released by the Beijing Science and Technology Journalists and Editors Association and the Beijing Regional Website Joint Rumor-Refuting Platform, and supported by the Science Communication Professional Committee of the China Science Writers Association, the China Evening News Science Editors and Journalists Association, the Shanghai Science Communication Association, and the Beijing Institute of Scientific and Technological Information.

1. Infusion can prevent stroke

gossip:

As the seasons cool down in autumn, intravenous infusion can dilate blood vessels and effectively prevent cerebral stroke.

the truth:

This practice is unscientific, and there is currently insufficient evidence to prove that regular infusion can prevent stroke. Infusions generally use Chinese medicine injections that promote blood circulation and remove blood stasis, or vasodilators in Western medicine. Its mechanism of action is to temporarily dilate blood vessels, reduce blood viscosity, increase circulating blood volume, and improve cerebral perfusion, which only has a short-term therapeutic effect. This type of drug generally acts for 6 to 8 hours, and it is impossible to permanently dredge blood vessels and prevent stroke. Moreover, these drugs act on blood vessels, which is equivalent to overdrawing the expansion capacity of blood vessels in advance. When symptoms such as cerebral infarction actually occur and require infusion, drug tolerance often occurs, resulting in poor treatment effects, and even missing the real opportunity for rescue and treatment.

In addition, "infusion to dilate blood vessels" is not as simple as most people imagine. Intravenous infusion of thrombolytic drugs is a rescue method for acute stroke, which has very strict restrictions. For example, thrombolysis should not be performed more than 4-5 hours after onset. In addition, patients with a history of bleeding and surgical trauma cannot receive thrombolysis.

The pathogenesis of stroke is very complex. The causes of stroke and recurrence include age, heredity, hypertension, atherosclerosis, heart disease, diabetes, hyperlipidemia, smoking, alcohol, obesity, drugs, diet and other factors. Any intervention behavior that is not combined with the above-mentioned pathogenic factors will hardly play a preventive role. It is obviously unscientific to use infusion alone to prevent stroke.

2. The radiation from hospital security scanners is very strong and will affect the health of the fetus

gossip:

The radiation from the security scanners installed in hospitals is very strong, and if pregnant women pass through them, it will seriously affect the health of the fetus.

the truth:

Whether it is a security gate for "people" or a security scanner for "objects", the radiation dose to the human body is very small, especially the security scanner, the radiation dose is not as good as that of a mobile phone.

The country has clear standards for the radiation dose of various electromagnetic equipment. Security inspection equipment from regular manufacturers can fully meet human health requirements. Generally speaking, the greater the power of the equipment, the greater the intensity of electromagnetic radiation. The power of millimeter wave security inspection instruments generally does not exceed 0.1 watts, while the maximum power of mobile phones during calls can reach 2 watts. The power of security inspection instruments is less than 1/20 of that of mobile phones, and the intensity of citizens using security inspection instruments is far less than that of mobile phones. The distance when passing through security inspection instruments is also much greater than the contact distance with mobile phones, so there is no need to worry about the electromagnetic radiation of security inspection instruments affecting health.

X-ray security scanners are commonly seen in daily life. All the internal radiation is sealed inside the machine. Lead curtains are used at the entrance and exit, and the four internal walls are also lead walls. Under normal circumstances, they can effectively block X-rays from entering the external environment. During use, the machine will only emit radiation for detection when luggage items pass through the X-ray security scanner. People just pass by it quickly, and the radiation is extremely small. Therefore, pregnant mothers can go through baggage security checks normally without worrying about affecting the health of themselves and their babies.

3. Seedless watermelon and seedless grapes are harmful to the human body if they are used with contraceptives

gossip:

Seedless watermelons and seedless grapes are treated with contraceptives and contain large amounts of hormones. Frequent consumption is harmful to the human body.

the truth:

Seedless watermelons are bred by hybridization, and have nothing to do with contraceptives. People treated watermelons with colchicine to obtain tetraploid watermelons, which were then hybridized with ordinary diploid watermelons to form triploid watermelons. Triploid watermelons have no reproductive ability, so they cannot produce seeds and therefore have no seeds.

In addition to triploid grape varieties cultivated through hybridization and vegetative propagation, some seedless grapes do rely on "contraceptives" to grow and mature, but this contraceptive is very different from the contraceptives we humans use. This is a plant growth regulator called gibberellin that inhibits seed development.

Grape growers artificially apply gibberellins to grapes to replace the endogenous hormones produced by the grapes themselves, so that they bear fruit without pollination, thus forming seedless grapes. For example, Kyoho grapes have seeds by themselves. After gibberellins treatment, not only can seedless Kyoho grapes be obtained, but the fruit can also be expanded. The weight of a single grape can be increased by about 30%, the size is uniform, and the taste is better.

Gibberellic acid is a natural plant growth regulator, with more than 100 kinds, and has a history of more than 60 years of agricultural application. In addition, gibberellins are used before and after the flowering period of grapes. When the grapes are fruiting, they are basically undetectable. The results of the grape quality and safety risk assessment of the Ministry of Agriculture over the years show that gibberellins are rarely detected in grapes, and the residue in the detected samples does not exceed 0.1 mg/kg. According to the internationally accepted safety limit conversion, an adult would have to eat 1,800 kg of grapes a day to ingest 180 mg of gibberellins, which is a level that would cause harm to the body. This is obviously impossible to achieve.

4. Using an air fryer can cause cancer

gossip:

The high temperature heating of the air fryer will cause the food to produce the "carcinogen" acrylamide. At the same time, under the action of the "high-speed air circulation technology" of the air fryer, the volatilized oil will stick to the heat pipe and fan. The next time it works, the oil will be heated again and enter the circulation, thus becoming "thousand-boiled oil" with more carcinogens.

the truth:

The working principle of the air fryer is "high-speed air circulation technology". It generates hot air by heating the heat pipe inside the machine at high temperature, and then uses a fan to blow the hot air into the pot to heat the food, so that the hot air circulates in a closed space, and uses the fat of the food itself to fry the food, thereby dehydrating the food and making the surface golden and crispy, achieving the effect of frying. Therefore, the air fryer is actually a simple oven with a fan.

Acrylamide is produced by "reducing sugars" (such as glucose, fructose, etc.) and certain amino acids (mainly aspartic acid) during frying, baking and roasting. As long as there are carbohydrates and proteins in the food, acrylamide will inevitably be produced during high-temperature heating. Compared with ordinary frying, the main feature of frying in an air fryer is "less oil" or "no oil", but this cannot prevent the production of acrylamide. Therefore, the production of acrylamide really cannot be blamed on the air fryer.

There is another view about "air fryers can cause cancer", that is, it is believed that the "thousand-boiled oil" produced by air fryers can produce carcinogens. In fact, this worry is unnecessary. There are indeed some volatile fatty acids in food, such as in various meat foods. These volatile fatty acids will have a strong aroma, which is why we think meat smells good. However, the total content of volatile fatty acids in food is not high. Most fatty acids are not easy to evaporate, and will not evaporate with the air into the air circulation of the air fryer. The proportion of volatile fatty acids in food is relatively small. For example, a study found that the total volatile fatty acids in the fat tissue of sheep, cattle and pigs accounted for 0.6 g/kg, 0.45 g/kg and 0.2g/kg respectively. Moreover, these volatile fatty acids will evaporate quickly in the air and will not always exist in the air fryer. Therefore, you don't have to worry too much about these volatile fatty acids causing harm to the human body.

5. Eating celery can lower blood pressure

gossip:

The apigenin contained in celery can dilate blood vessels, so eating celery can lower blood pressure.

the truth:

Scientific experiments have shown that apigenin contained in celery can act on the vascular endothelium, thereby dilating blood vessels. Dilating blood vessels is indeed good for lowering blood pressure.

Scholars from the Chinese Center for Disease Control and Prevention have conducted a quantitative study: It takes about 0.026 grams of apigenin per kilogram to lower the blood pressure of mice. That is, a one-kilogram mouse needs to eat 0.026 grams of apigenin at a time to lower its blood pressure. According to this estimate, a person weighing 60 kilograms needs to eat 1.56 grams at a time.

The content of apigenin varies in different varieties of celery and different parts of celery, ranging roughly from 0.003% to 0.088%; and it is higher in the leaves, while it is lower in the celery stalks that we love to eat.

According to the highest content of 0.088%, one kilogram of celery contains 0.88 grams of apigenin. In other words, if you want to achieve the effect of lowering blood pressure by eating celery, you must first learn to choose the variety with the highest apigenin content, secondly, throw away the celery stems and eat more celery leaves, and finally, eat more than 1.7 kilograms at a time, which is obviously unrealistic.

6. Drinking milk can cause fibroadenoma

gossip:

Milk contains hormones. Excessive intake can cause breast lumps in girls to grow rapidly and form fibroadenomas.

the truth:

Fibroadenomas are the most common benign breast lesions in adolescents, accounting for 30%-50% of adolescent breast masses and prevalence in the general female population in their teens or twenties.

As for the causes of fibroadenomas, the medical community has not yet given a definitive answer. Some studies have shown that it may be related to genetics; others believe that it may be related to hormones, because it has been observed that the lumps persist during the childbearing years, increase in size during pregnancy or the use of estrogen, and usually disappear after menopause. Therefore, it is speculated that sex hormones may be related to the occurrence and development of fibroadenomas.

The occurrence and development of breast fibroadenomas may indeed be related to hormones, and for adolescent girls, the largest source of hormones is normal sexual development. The content of natural estrogen in milk is not high. According to data published by the state, the average content of estradiol hormone in boxed liquid milk sold in my country is 0.117-0.199±0.0425 micrograms/liter. Foreign data show that the estrogen content in raw milk and commercially available cow milk in the United States, South Korea, the Netherlands, etc. is between 0.16-4.4 micrograms/kilogram. In other words, the estrogen content in meat and aquatic products is higher than that in milk.

In fact, there is no standard range for the content of natural estrogen in milk at home and abroad. There is no unified standard for the amount of hormones in milk that may affect the human body, and there is no evidence that the hormones in milk can cause breast fibroadenomas. Generally speaking, as long as you buy dairy products from regular channels and match your diet reasonably, you don’t need to worry about the direct impact of the hormones on the human body. Of course, for the sake of dietary balance, drinking too much milk is not recommended. The Chinese Residents’ Dietary Guidelines recommend that adults consume 300ml of dairy products per day. Even in major milk-consuming countries such as the United States and Australia, the recommended upper limit of daily milk intake is no more than 750ml. Excessive intake of milk may lead to obesity, and adipose tissue will produce excessive estrogen, which will increase the incidence of breast tumors. In addition, consuming too much milk will occupy the stomach capacity, reduce the intake of other foods, lead to unbalanced diet, and even iron deficiency. Therefore, it is important to master a reasonable milk intake.

(Source: Beijing Evening News, WeChat public account of "All People Are Serious - Tencent News", Tadpole Musical Notation)

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