World Food Safety Day | Will you get "lychee disease" if you eat lychees on an empty stomach? Will you get a "beer belly" if you drink beer regularly? The truth is...

There are many popular myths about food health, and many people believe them after hearing them many times. However, many of these myths just "sound reasonable" but are not actually in line with scientific facts.

June 7th is World Food Safety Day. We have compiled 8 food safety rumors that you often hear and analyzed them one by one.

1. Eating lychees on an empty stomach can cause "lychee disease"

"Lychee disease" does exist, and its symptom is "hypoglycemia after eating a large number of lychees on an empty stomach." At present, medical research has not fully understood the pathogenesis of lychee disease and the cause of lychee disease, but through the summary of a large number of disease processes, eating a large number of lychees on an empty stomach is a key factor in causing the disease.
Therefore, it is actually safe to eat lychees, just know when to eat and don't eat too much at one time. It is also okay to eat some carbohydrate-containing foods before and after eating lychees.

2. People with high uric acid and gout should not eat tofu

The source of this statement is that "soybeans contain a lot of purine", which is converted into uric acid after consumption.

The purine content of dried soybeans is indeed not low, but people rarely eat dried soybeans directly. The "soy products" such as tofu that we usually eat are made by making soybeans into soy milk, and then further processing the soy milk into tofu and other foods.

During these processing steps, a considerable amount of purine will dissolve into the water and be discarded. For example, the purine content of tofu is often less than 70 mg/100 g, and the purine content of cooked soybeans is less than 50 mg/100 g. These contents are similar to those of vegetables and fruits such as broccoli, peas, spinach, green peppers, and bananas.

Some studies have explored the relationship between soy product intake and gout, and found no correlation between soy product consumption and high uric acid or gout. Some studies even show that people who consume more soy milk and soy products further processed from soy milk have a lower risk of high uric acid.

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3. Drinking beer frequently will cause a "beer belly"

Many people who like to drink beer have developed a "beer belly", so everyone believes that "the 'beer belly' is caused by drinking beer."

The beer is a bit unfair.

Beer is fermented from malt juice, which contains a lot of sugar. The sugar content of malt juice varies greatly from one beer to another, usually between 6% and 20%. The indicators such as "wort concentration", "original wort concentration" and "malt degree" on the beer label refer to the sugar content of the malt juice. Most of these sugars are fermented into alcohol, which has calories but cannot be absorbed and utilized by the human body.

So, beer does have higher calories than liquor, but overall the calories absorbed are not that much.

However, drinking beer is often accompanied by eating grilled skewers or cold dishes, and the food consumed is large, and that part of the calories is the bulk. Drinking beer frequently can easily increase weight, especially abdominal fat, and form the so-called "beer belly".

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4. Hormones in fried chicken can cause early puberty in children

There are many rumors online saying: "Today's chicken contains hormones that will cause precocious puberty."

In fact, this statement is completely taken for granted. Fast-growing chickens grow fast because they are excellent breeds that can efficiently convert feed into meat. Coupled with a nutritionally comprehensive and balanced formula feed, as well as the most suitable temperature, humidity, and light environment for chicken growth, they can grow from chicks to market in 5 to 6 weeks. This has nothing to do with hormones, and regulations do not allow the use of any hormones in chicken farming.

Fried chicken absorbs a lot of oil, and the "high-protein, low-fat" chicken becomes a "high-fat, high-calorie" food. From this perspective, the frequency and amount of fried chicken should be controlled. However, neither the chicken itself nor the fried chicken food contains hormones, and it has nothing to do with precocious puberty.

5. Crayfish grow in sewage, so they are dirty

Crayfish have strong survival ability and can survive in harsh environments, but this does not mean that they do not like clean environments, nor does it mean that they will not grow well in clean environments. Currently, crayfish on the market are basically farmed, and the core of farming is to provide the cleanest environment possible and good feed so that they can grow fast and big.

In 2016, Associate Professor Huang Cheng of Nanjing University led his students to conduct two experiments. The first experiment was to put 100 crayfish in a cave with normal river water. In another cave, one side had clean water and the other side had sewage. As a result, about 80 of them ran into the clean water, 20 ran into the sewage, and then 5 retreated and ran into the clean water. After multiple experiments, the results were roughly the same. The second experiment was to feed the crayfish with fresh meat and rotten meat. As a result, most of the crayfish chose to eat fresh meat.

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6. The fact that noodles can ignite indicates that glue has been added

First of all, noodles are made of protein and starch. They are both organic substances, and as long as they reach the ignition point and are in full contact with air, they can burn. Usually, the surface area of ​​noodles is limited, and it is difficult to fully burn when burning, so carbon black is left. Especially if the noodles are not dry enough, they are not easy to ignite. But as long as they continue to contact with fire, the noodles will dehydrate and dry, and eventually they will ignite. Glue is an organic substance and can also burn. In other words, noodles can be ignited regardless of whether glue is added or not.

Secondly, some flour products do contain modified ingredients, such as some glue. Food glue is a legal food additive, and from a nutritional point of view, it is usually dietary fiber. Their addition has no adverse effects on safety and health, but only improves the taste of flour products.

7. Moderate drinking is good for your health

"Moderate drinking is good for health" is something the alcohol industry and drinkers often say, but this distorts scientific evidence and dietary guidelines.

According to epidemiological survey data, people who "drink moderately" have a lower incidence of cardiovascular disease than those who "do not drink at all" and "drink heavily". However, human health is not just about cardiovascular health. A large amount of data shows that as long as you drink, you will increase the risk of many cancers. There is no such thing as "moderate drinking".

According to the "Dietary Guidelines for Chinese Residents (2022)", based on the amount of alcohol, the maximum amount of alcohol that adults drink per day is recommended not to exceed 15 g. Any form of alcohol is not beneficial to human health.

8. Drinking alcohol in winter can keep you warm

"Drinking to keep warm" is an illusion.

In a cold environment, the human body surface temperature will drop. When it drops to about 20°C, the capillaries on the surface of the body will be closed to ensure that blood is adequately supplied to the heart and other core organs. In other words, stopping the body surface heat production and feeling "cold" is an automatic protection of the human body against the cold.

After drinking, capillaries expand and more blood flows to the body surface, making people feel "warm". However, this causes the body to dissipate heat faster and gives the brain the wrong message that the body needs to "dissipate heat" instead of "reduce heat loss". This wrong message speeds up the flow of blood to the body surface and even causes sweating to increase heat dissipation. If rescue measures are not taken in time, it may lead to hypothermia and death.

Planning and production

Author: Yun Wuxin, PhD in Food Engineering, Science Writer

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

Planning丨Zhong Yanping

Editor: Zhong Yanping

Proofread by Xu Lailinlin