The darker the egg yolk, the more nutritious it is? Does sweating when you move mean you are weak? Here comes the July science rumor list →

1.The darker the egg yolk, the more nutritious it is?

Rumor content: The yolk is the essence of the egg. Nutrients will be reflected through the yolk. The darker the color, the higher the nutritional value.

Truth: This is not the case. The color of the yolk is affected by many factors, such as the age, breed, health status of the hen, feed ingredients and pigment content. For example, the older the hen is, the darker the yolk color of the egg it lays. The higher the carotenoid and fat content in the feed, the yellower the yolk color (note that this does not represent the nutritional level). In addition to the above factors, anti-nutritional factors in the feed, drugs, and environmental control of the chicken house will also affect the color of the yolk. The nutritional value of eggs mainly depends on their protein, fat, vitamin and mineral content, and the content of these ingredients does not have a big effect on the color of the yolk. Therefore, from a nutritional point of view, you really don’t need to worry too much about the color of the yolk. Eggs purchased through formal channels and properly stored are very nutritious.

Source: Science Refutes Rumors

2. Can getting more sun exposure prevent osteoporosis?

Rumor: Getting more sun exposure helps synthesize vitamin D and promotes calcium absorption, so getting more sun exposure can prevent osteoporosis.

Truth Interpretation: This statement is not rigorous. Sunbathing can help the body synthesize vitamin D and make up for the deficiency of vitamin D in the diet, but it cannot guarantee the prevention of osteoporosis. Because osteoporosis is a symptom caused by multiple factors, calcium and vitamin D are possible influencing factors. But according to research data in recent years, there is no single influencing factor that can prevent the occurrence of osteoporosis. In addition, sunbathing also has its harms - ultraviolet rays increase the risk of skin cancer. Long-term accumulation of ultraviolet radiation can also cause dry skin and aging. There is no consensus in the scientific community on how much sun exposure is appropriate. The Dietary Supplement Office of the NIH in the United States recommends: "Sun exposure between 10 am and 3 pm, twice a week (without sunscreen), 5 to 30 minutes each time." In addition to sunbathing, you can also supplement calcium-rich foods and vitamin D to reduce the risk of osteoporosis.

Source: Tencent

3. Are people who sweat when they move physically weak?

Rumor content: Some people sweat a lot when exercising, while others sweat less. People who sweat when they move are weak and need supplements.

Truth interpretation: This statement is not correct. Sweating is a common physiological phenomenon. One of the functions of sweating is to regulate body temperature and balance body fluids. Generally speaking, when the environment changes, the sympathetic nerves of the thalamus will cause the sweat glands to discharge sweat from the pores. The environment here refers not only to the external environment of the human body, but also to the internal environment - people will sweat when they are under the control of emotions such as mental tension, fright or fear. There may be many reasons for a large amount of sweating, such as well-developed sweat glands, frequent muscle exercise, and vigorous metabolism. Mental tension may also lead to excessive sweating, and even spicy or high-salt foods may stimulate sweating. Therefore, for ordinary healthy people, there are many factors that affect sweating, and you don’t need to worry about sweating more or less.

Source: Science Refutes Rumors

4. Overnight watermelon cannot be eaten, and putting plastic wrap on it is useless?

Rumor: Overnight watermelons will breed a lot of bacteria and cannot be eaten, even if you put plastic wrap on them.

Truth interpretation: In fact, whether the watermelon is left overnight is not the main issue, the key is whether there are pathogenic bacteria. Watermelon is indeed easy to breed bacteria, and various bacteria are hidden in the refrigerator, so don't keep it for too long after cutting, it's best to eat it as soon as possible. But if you use a clean knife and cutting board to cut the melon, wrap it with a clean plastic wrap in time and put it in the refrigerator, you can eat it even if it is left overnight. As for the use of plastic wrap, first check whether the plastic wrap used is qualified? If the plastic wrap is unqualified, it will be difficult to play the role of preservation, and bacteria will naturally multiply more if it is left for a long time. Secondly, it depends on the condition of the food before the plastic wrap is used. If the watermelon is not handled properly before the film is applied, it has been contaminated with more microorganisms and bacteria, and the film will hardly play a role in preservation. Therefore, it is best to use qualified and regular plastic wrap, and the food that needs to be preserved should be covered with plastic wrap as soon as possible and refrigerated in time.

Source: Tencent News

5. My mouth feels astringent after eating cucumbers. Is it pesticide residue?

Rumor content: Many pesticides can affect our sense of taste and mouthfeel. Cucumbers need to be sprayed with pesticides frequently. The reason your mouth feels astringent after eating cucumbers is because of the pesticide residues.

Truth: This is not the case. The bitterness of cucumbers is caused by the ingredients of the cucumbers themselves. The main phenolic substances in cucumbers are tannins and catechins. Tannins are also called tannins, which are found in many plants and fruits. For example, persimmons will feel astringent and numb when eaten, and the oral mucosa will also feel wrinkled. This is the tannins "playing tricks". Cucumber peels contain more tannins, and the darker the green color of the skin, the more tannins it may contain. So it tastes astringent, and the cucumber peel will be more astringent. Catechins are more common in tea. When we usually drink tea, we will feel a little astringent. In fact, it is because of the effect of catechins. There are many catechins in cucumber peels, so it will feel astringent when eaten. In addition, cucumbers also contain a small amount of bitter substances. Generally speaking, the closer to the tail of the cucumber, the more bitter substances there are, and the taste will feel bitter when eaten.

Source: Science Refutes Rumors

6. Will you avoid getting tanned if you use a parasol?

Rumor: If you don’t apply sunscreen in the summer, you can just use a parasol to avoid getting tanned.

Truth Interpretation: Using a parasol can block most of the ultraviolet rays, but this is not enough. Because the ground or other mirrored objects reflect sunlight, there are also ultraviolet rays in the reflected light. Therefore, even if you choose a parasol with good ultraviolet protection, it cannot guarantee that you will not get darker. In addition, different people have different skin colors, and the amount of melanin produced by melanocytes in the basal layer of the skin is different, and the degree of absorption of ultraviolet radiation is also different. Therefore, even with the same physical sunscreen, the actual effect varies from person to person. Parasols are textiles, and relevant standards (such as "Evaluation of the Ultraviolet Protection Performance of Textiles") have made clear requirements for their sun protection performance. You can buy parasols that meet the standards. On the other hand, when we hold an umbrella, don't forget to apply sunscreen and wear sunglasses, so that we can fully protect ourselves from the sun.

Source: Tencent

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

Supported platforms: Weibo rumor refutation, Toutiao rumor refutation, Tencent Jiuzhen, NetEase Health, Toutiao Health, Baidu Knows, Douyin

Scientific rumor debunking: Sponsored by the China Association for Science and Technology, the National Health Commission, the Ministry of Emergency Management, the State Administration for Market Regulation and other ministries and commissions, guided by the Central Cyberspace Affairs Commission, and jointly created by national societies, authoritative media, social organizations and scientific and technological workers, it aims to effectively improve the dissemination, guidance and influence of rumor debunking information, so that rumors can stop at the wise and let science outrun rumors.

List of review experts

(In order of the number of strokes of surname)

Song Shuang, Associate Researcher, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention

Zhang Yu, researcher at the Chinese Center for Disease Control and Prevention/PhD, national health science expert

Zhang Jie, Chief Engineer of China Textile Construction Planning Institute

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

Meng Fengxia, researcher at the Institute of Infectious Diseases, Chinese Center for Disease Control and Prevention

This article is produced by "Science Facts" (ID: Science_Facts). Please indicate the source when reprinting.