Full interpretation of the eight hottest food rumors of 2014
Editor's note: Life has never lacked rumors, and especially in today's information age, rumors are generated and spread far more fiercely than they are debunked. Fueled by new mobile media, the food world has become the area most likely to attract attention and also the area where rumors are most easily produced. As 2014 draws to a close, this page has specially invited authoritative food experts to select the hottest food rumors of the year and interpret them one by one.
1. Small-molecule collagen fights aging
Rumor trace: At the beginning of the year, entertainer Lin Zhiying became a hot topic of discussion thanks to his “reverse aging.” Among the products launched by his company was a collagen drink whose main ingredient was “small-molecule collagen,” and Lin Zhiying said the secret to his agelessness lay in it.
Expert interpretation: Yun Wuxin, PhD in food engineering from the Department of Agricultural and Biological Engineering at Purdue University in the United States, said that hydrolyzed collagen (or the advertised “small-molecule collagen”) has no evidence supporting beauty and skin-care benefits. Hydrolyzed collagen is equivalent to carrying out part of the human digestive process outside the body, so it is digested and absorbed faster after being eaten. In addition, many dipeptides and tripeptides in hydrolyzed collagen are directly absorbed into the bloodstream, but they cannot enter cells to serve as raw materials for protein synthesis. In other words, they are indeed absorbed into the blood, but they cannot be put to use, and in the end they are excreted from the body.
2. Oxygen-enriched water can “replenish oxygen”
Rumor trace: You can “replenish oxygen” just by drinking water, with dissolved oxygen content 6 to 10 times that of ordinary drinking water…… At the end of February, Hangzhou Wahaha Group launched an oxygen-enriched weak alkaline water billed as a “revolutionary beverage,” claiming that drinking one bottle of oxygen-enriched water allows the high-concentration oxygen in the water to be absorbed through the mucosal penetration of the digestive tract.
Expert interpretation: Yun Wuxin said that, first, oxygen-enriched water is not magical, and it releases oxygen as soon as the bottle is opened. Second, absorbing oxygen by drinking water is not very realistic. When water is drunk, it enters the digestive system. Although some “scientists” have proposed the theory of “absorbing the high-concentration oxygen in water through the mucosal penetration of the digestive tract,” it has not been recognized by the scientific community. Supplementing oxygen by drinking water is theoretically untenable. Finally, compared with breathing, the oxygen content in water is too low. Even if all the oxygen in oxygen-enriched water could be fully absorbed by the human body, the amount would still be negligible compared with breathing.
3. Genetically modified food is harmful
Rumor trace: In early March, many websites posted an investigative documentary on genetically modified organisms filmed in the United States by television host Cui Yongyuan, which received a large number of views and shares. At a CPPCC meeting, he put forward a proposal demanding a ban on the commercialization of genetically modified staple grains and the immediate termination of seed companies' genetically modified projects.
Expert interpretation: Luo Yunbo, dean of the College of Food Science and Nutritional Engineering at China Agricultural University, pointed out that so far no adverse effects on human health have been found from approved genetically modified foods. Genetic modification only changes the genes of crops. When these altered genes are eaten, they are digested along with other genes and will not change human genes. Genetically modified foods must undergo strict safety evaluation before entering the market. It should be said that the genetically modified foods we can buy are safe and can be eaten with confidence.
4. Fruit and milk cannot be eaten together
Rumor trace: Various taboos about drinking milk are widely circulated among the public. On a television program this year, an expert used an experiment showing that “pouring orange juice into milk produces flocculent precipitation” to tell everyone that sour fruits should not be eaten within 1 hour before or after drinking milk.
Expert interpretation: In response, Hu Changli, PhD from the Key Laboratory of Functional Dairy at China Agricultural University, said that precipitation upon contact with acid is a basic property of “casein” in milk. Even if it is not drunk with fruit juice, milk will still precipitate in the stomach. This is because there is a large amount of gastric acid in the stomach, whose main component is hydrochloric acid, which is much more acidic than the fruit acids in fruit. After milk enters the gastrointestinal tract, it also first comes into contact with gastric acid and flocculates, and only then undergoes further digestion and absorption. From another perspective, fruit and milk are still good partners, and their nutrition can be called a perfect match.
5. Heating in a microwave oven causes cancer
Rumor trace: The claim that microwave ovens cause cancer has a long history. This summer, a post titled “Stop Using Microwave Ovens Right Now, They Cause Cancer!” was wildly reposted on WeChat. The article claimed that food heated in a microwave oven produces carcinogens, once again arousing people's concerns.
Expert interpretation: Fan Zhihong, associate professor at the College of Food Science and Nutritional Engineering at China Agricultural University, pointed out that microwaves only heat the water molecules in food, and the food itself does not undergo chemical changes, so no carcinogens are produced. Lu Jianguo, director of the Comprehensive Inspection Department of the National Household Electrical Appliance Quality Supervision and Inspection Center, also said that microwave ovens of qualified quality have all undergone strict testing and repeated experiments, and their microwave leakage and generated radiation are within the standards stipulated by the state. Under normal use, they will not harm the human body, let alone bring harm through the food they heat.
6. Mushrooms are rich in heavy metals
Rumor trace: In October this year, an article titled “Better Eat Less Mushrooms” circulated in WeChat circles. The article said that a PhD from the University of Zurich in Switzerland who studies fungi said that although mushrooms are good, they have a strong ability to accumulate heavy metals such as lead and mercury, by as much as more than 100 times.
Expert interpretation: Professor Lin Xinying of the Institute of Nutrition and Food Hygiene at Shandong University told reporters that compared with certain foods, mushrooms do have a high ability to accumulate heavy metals. However, whether mushrooms exceed heavy metal limits is mainly related to their growing environment. Most mushrooms sold on the market today are grown in culture media prepared from agricultural and forestry by-products such as cottonseed hulls and wheat bran, so their opportunities to contact heavy metals are especially small, let alone exceed heavy metal limits. In addition, mushrooms contain polysaccharides, and this component can inhibit the dissociation of heavy metals, making it impossible for them to become ions in the body, so they are difficult for the intestinal tract to absorb. Therefore, even if people eat mushrooms, the impact on the human body is relatively small.
7. “Jicao” has miraculous effects
Rumor trace: Jicao 5X Cordyceps sinensis, a product advertised as something that can be “dissolved in the mouth” and that has effects such as boosting human immunity and fighting tumors, became well known to everyone because of its high price and frequent advertisements. In November this year, well-known anti-counterfeiting activist Wang Hai sent Jicao 5X Cordyceps sinensis classic lozenges for testing, and the results showed that the lozenges contained no cordycepin.
Expert interpretation: Yun Wuxin said that Cordyceps has long been “decoded” by science———it is simply a fungus that attaches to an insect, kills it, and then grows fruiting bodies on its corpse. There is also no evidence in Western research supporting the miraculous effects of Cordyceps; instead, research conclusions tend toward “denial.” In the scientific literature, most research on Cordyceps has been done by Chinese people, and the research level is basically at the stage of “component identification.” It can be said that Cordyceps research still has a long road to travel before human trials show effectiveness. At present, there are also no scientific test results showing that Cordyceps sinensis lozenges are more conducive to absorption or work better.
8. Brewing tea in a stainless steel cup is toxic
Rumor trace: After the beginning of winter, some media filmed a video claiming that after brewing tea in a stainless steel cup for 72 hours, the cup showed “corrosion.” This was because stainless steel contains the toxic heavy metal chromium, which would be released into the tea.
Expert interpretation: Yun Wuxin said that corroding stainless steel is not easy. Only under strongly corrosive conditions and after soaking for a sufficiently long time can visible corrosion results appear in stainless steel. Tea is close to neutral, and its ionic strength is also very low, so it is almost non-corrosive, and it is even less possible for visible corrosion to occur within dozens of hours. The most likely possibility is that tea scale deposited on the cup was mistaken for “corrosion.” In addition, stainless steel is corroded only under certain conditions, and some chromium dissolves out, but the amount is extremely small. For daily use, there is no need to worry about stainless steel tableware that meets national standards.