Is breast milk no longer nutritious after 10 months? Can smoking prolong your life? Here are the scientific rumors for March

1. Alcohol and hand sanitizer can inactivate norovirus

Rumor content: Norovirus is not scary, it can be killed by wiping with alcohol or no-rinse hand sanitizer.

Truth interpretation: This statement is unscientific. Alcohol, disinfectant wipes, and hand sanitizer are ineffective against norovirus.

The "Health Tips for Campus Prevention and Control during the High-Incidence Season of Norovirus Infectious Diarrhea" issued by the National Health Commission clearly states that the norovirus has strong environmental resistance and can survive in a temperature range of 0℃-60℃, can survive on the surface of objects for 2 weeks, and can survive in water for more than 2 months. In fact, alcohol, disinfectant wipes and hand sanitizers cannot disinfect norovirus.

To prevent norovirus infection, the main measures are to ensure food hygiene, drinking water hygiene and management of infected people's excrement, keep hands clean by using ordinary hand sanitizer and soap, and clean and disinfect the environment.

Source: Toutiao refutes rumors

2. Hangnails next to the nails indicate a lack of vitamins

Rumor content: Hangnails are caused by a lack of vitamin B2, vitamin A, vitamin E, etc.

Truth interpretation: Hangnails on fingers are a common phenomenon and have nothing to do with vitamin deficiency. They are caused by physical friction or excessive hand washing.

Hangnails are called reverse peeling in medicine, which is a common skin problem around the nails. There is a very thin stratum corneum on the outermost layer of our skin, which is commonly known as "dead skin". There is a layer of oil on its surface, which can ensure the moisture content of the stratum corneum and make it fit tightly with the skin below. But if soap and hand sanitizer are used frequently or clothes are washed by hand frequently, the oil on the surface of the stratum corneum will be washed away, and the stratum corneum without protection will become dry and peel off.

In other words, hangnails are simply the peeling of dead skin and have nothing to do with vitamin deficiency.

Source: Science Popularization China

3. Breast milk has no nutritional value after 10 months

Rumor content: Babies can be weaned at 10 months old because breast milk has no nutrition and it is better not to drink it.

Truth interpretation: *This statement is too exaggerated. A thin layer of breast milk does not mean it has no nutrition at all.

Breast milk is divided into colostrum, transitional milk, mature milk, and late milk according to different ages. Colostrum is breast milk produced 4-5 days or within one week after delivery. The amount of colostrum is relatively small, but the immunoglobulin content is the highest; transitional milk is breast milk produced from one week to 14 days after delivery, and the fat content of milk in this period is high; breast milk from 14 days to 10 months is mature milk, and the protein content in breast milk at this stage will gradually decrease with the increase of age; breast milk after 10 months is late milk, and the protein content of breast milk at this stage is even lower.

However, the lower protein content does not mean that breast milk has no nutrition. Instead, the composition of breast milk changes with the baby's physical maturity. At this time, breast milk is still the most suitable natural food for babies.

Source: Douyin (recommended by Toutiao to refute rumors)

4. Take collagen supplements and your skin will improve

Rumor content: Collagen can protect the skin and increase elasticity, and eating more of it can beautify the skin.

Truth interpretation: The collagen you eat will not directly affect the skin. After reaching the body, collagen will first be digested and broken down into amino acid molecules, but the body will not synthesize more collagen just because of the increase of amino acids in the body.

Moreover, the body's process of synthesizing collagen is not controlled by the will, and it is impossible to automatically generate collagen where needed.

Source: Tencent

5. Smoking can prolong your life because nicotine can resist aging

Rumor content: Li Xiang's team at the Shenzhen Institute of Advanced Technology of the Chinese Academy of Sciences found that chronic low-dose nicotine can improve energy metabolism and delay systemic aging by activating the NAD+ salvage pathway. Therefore, some netizens believe that nicotine can prevent aging and smoking is good for health.

Truth interpretation: Smoking is certainly harmful to health, let alone prolonging life.

The idea that nicotine slows down aging has only been confirmed in mouse experiments. Without human experimental results, we must be cautious about the "effects" shown in animal experiments. Therefore, it is a bit unrealistic to talk about smoking improving the symptoms of aging.

In addition, smoking significantly accelerates skin aging, and smokers are more likely to have dry skin, wrinkles, and spots. Studies have shown that the degree of skin aging is also related to the number of cigarettes smoked per day and the length of time smokers smoke. A 40-year-old heavy smoker has the same degree of facial skin aging and wrinkles as a 60-year-old non-smoker.

Source: Tencent

6. The higher the HPV vaccine price, the better the prevention effect

Rumor content: The nine-valent vaccine is the best for preventing cervical cancer because it has the highest “price”.

Truth interpretation: "Valence" refers to the type of HPV. The bivalent, quadrivalent and nonavalent vaccines are equally effective in preventing cervical cancer.

The bivalent vaccine prevents HPV16 and 18-related cervical cancer and precancerous lesions. The quadrivalent vaccine adds two low-risk types, 6 and 11, on the basis of HPV16 and 18. The nine-valent vaccine can effectively prevent HPV6, 11, 16, 18, 31, 33, 45, 52, and 58-related cervical cancer and precancerous lesions, warts, vaginal cancer and precancerous lesions, and anal cancer and precancerous lesions.

Although the bivalent vaccine only targets HPV types 16 and 18, current research shows that 70% of cervical cancer is related to these two viruses.

Therefore, the protection provided by the bivalent vaccine against cervical cancer is in no way inferior to that of the quadrivalent and nine-valent vaccines.

Women who plan to receive the HPV vaccine can choose according to their age group. As long as they meet the age requirements, they can get whichever HPV vaccine they can get an appointment for.

Source: Science Refutes Rumors

About the Science Rumors List

Released by the China Association for Science and Technology, the list is reviewed by experts every month. Based on criteria such as timeliness and harmfulness, hot rumors are selected for special interpretation and pushed across the entire network.

Jointly published: Scientific rumor-busting platform, China Internet Joint Rumor-busting Platform, "Study to Strengthen the Country" learning platform

Platform support: Tencent Jiuzhen, Weibo Rumor Refutation, Toutiao Rumor Refutation, Douyin, Dad Review, NetEase Health

List of review experts

(In order of the number of strokes of surname)

Zhang Yu, Deputy Director of the Office of the Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention

Chen Peng, Associate Professor, Department of Communication, Nankai University

Jia Changkai, deputy chief physician, Xiamen Eye Center affiliated to Xiamen University

Tang Qin, Chief Researcher, Department of Science Popularization, Chinese Medical Association

Han Hongwei, Researcher, National Food Safety Risk Assessment Center