Zhejiang University study: Eating one more egg a day may increase the risk of death from heart disease and cancer? credible

Ah Qiang came back from overtime, his stomach was growling with hunger. He happened to see that there was leftover rice in the rice cooker, so he went to the refrigerator to get an egg and made a plate of egg fried rice to satisfy his hunger.

However, around two o'clock in the middle of the night, A Qiang felt a strong nausea, vomited continuously, and was completely weak. When he took a thermometer to check it, he had a high fever of 40 degrees Celsius. Seeing that A Qiang's face was dull and his lips were purple, A Qiang's mother immediately called 120 and sent A Qiang to the hospital for emergency treatment.

After examination, the doctor judged that it was caused by food poisoning. Further investigation found that the eggs used by Ah Qiang had deteriorated.

According to Ah Qiang's mother's retelling, at that time the eggs were local eggs brought back from their hometown. Seeing that the eggs were covered with a lot of chicken excrement , I was worried that bacteria would breed in the refrigerator, so I cleaned all the eggs and put them in the refrigerator. storage.

But in fact, if you wash the egg, the original protective film of the eggshell will be washed away, and the bacteria will directly drill into the inside of the eggshell through the small hole, causing the whole egg to deteriorate .

1. Is an egg a day good or bad?

A small egg contains most of the nutrients the human body needs. Published in the journal "Heart", a study by Li Liming, a teacher from Peking University School of Public Health, found that an egg a day can reduce the risk of cardiovascular death by 18% and reduce the risk of hemorrhagic stroke death by 28%.

But some studies have found that eating one more egg a day will greatly increase the risk of cardiovascular disease and cancer death. Is it true?

In February 2021, a research team led by Professor Zhang Yu and Professor Jiao Jingjing from the School of Biosystems Engineering and Food Science of Zhejiang University conducted a related study on the association of egg and cholesterol intake and cardiovascular health, and the study was published in "PLOS Medicine" superior.

The study used data from 521,120 participants in the NIH-AARP Diet and Health Study in the United States. After an average follow-up of 16 years, the researchers found that whole egg intake was significantly associated with all-cause mortality.

An extra 300 mg of dietary cholesterol per day (about one and a half egg) was associated with a 19% increased risk of premature death, a 16% risk of cardiovascular disease, and a 24% increased risk of cancer; The risk of all-cause mortality increased by 7%.

Eating more eggs actually increases the risk of death? The researchers analyzed that cholesterol in egg yolks can accumulate in arteries, form blood clots, and lead to atherosclerosis.

In addition, the flora in the human gut can convert the nutritional choline in eggs into a toxic compound - trimethylamine oxide . This metabolite can flow through the body along the bloodstream and cause cancers in the digestive system and reproductive system. happened.

Coincidentally, in a new study published in Circulation, researchers followed 27,000 participants for 31 years.

The final finding: Consuming one more egg per day was associated with an increased risk of death from all causes and cardiovascular disease. However, in the geographic analysis, the researchers found no association with cardiovascular disease risk in the Asian cohort.

How much is the healthiest to eat? According to the "Dietary Guidelines for Chinese Residents 2021", the weekly egg intake is 280-350 grams, which is the amount of one egg .

However, it should be noted that people who suffer from hyperlipidemia, cholecystitis, and egg allergy are best to avoid eating foods with high cholesterol during the onset period. When eating eggs, they should control the intake, or only eat protein, not egg yolk.

2. Why are there no feces on the eggs sold in the supermarket?

Friends who have raised chickens at home may know that after the hen lays eggs, the eggs are usually stained with chicken excrement, but when we go to the supermarket, we can find that the eggs sold in the supermarket are white and clean. Why is this?

Eggs are usually stained with feces when they are just out of the nest. This is because the end of the chicken's genitals and the end of the intestines are a passageway, so it is easy to get feces when laying eggs.

But these fecal-stained eggs are generally born from chickens living in "rural areas", commonly known as farm eggs.

Most of the eggs sold in supermarkets are eggs produced on a large scale from modern chicken farms. All chickens produced will live in luxury "large factories", and the bottom of the bed is a specially designed inclined grid, and the end of the grid is grooved. egg trough.

When a chicken lays an egg, the egg will ride the slide into the egg trough, and the chicken excrement will fall into the manure ditch through the grid, thereby separating the chicken excrement from the egg .

Some manufacturers will also send the eggs to be cleaned by professional machines to wash off the surface eggshells. Then it goes through ultraviolet sterilization to completely eliminate Salmonella and Escherichia coli on the surface of eggshells.

Afterwards, the eggs will be graded, generally classified as AA, A, or B. After the eggs are rated, they can be printed with logos and spray codes to become an egg with identity and sent to the supermarket. sell. After this set of processes, it is a rest assured egg that everyone can eat.

3. The dirtiest thing on eggs is not "chicken shit", but it

More than 90% of Salmonella poisoning food in China comes from livestock and poultry products, especially egg products. A survey shows that the detection rate of Salmonella in eggs and their products is 3.9%-43.7%.

Salmonella is widely distributed in nature, and its viability is strong in nature. It can multiply in large numbers at 20 °C, and can survive for up to 2 years in feces, soil, food, and water.

However, Salmonella is less resistant to heat and can be killed in about 15 minutes at a temperature of 60°C.

Chickens are the main host of Salmonella. There are generally two ways for the bacteria to enter eggs. One is to infect hens into eggs, and the other is to enter eggs from feces and soil.

Therefore, it is not recommended to store eggs in the refrigerator after washing. Therefore, there are many dense small holes on the surface of the eggshell. In order to protect the inside of the eggshell, an invisible film will be attached to the outside of the eggshell to block the small holes. If washed with water, the protective film will be washed away, allowing bacteria and microorganisms to take advantage.

So what are the ways to prevent it?

• Eggs are best cooked thoroughly before eating;
• It is best to buy eggs that have passed the quarantine. Farm eggs do not have a set of procedures, and there may be food risks;
• Properly store eggs, bought eggs can be put into clean packaging bags, and then put in the egg layer of the refrigerator;
• Pay attention to kitchen hygiene, use raw and cooked cutting boards separately to avoid cross infection.

Finally, I need to remind that many people like to eat soft-hearted eggs, thinking that they are the most nutritious. In fact, the nutrition of raw eggs is not as good as that of cooked eggs, and the temperature of soft-hearted eggs is not enough to kill germs, which can easily lead to disease from the mouth.

If you really like to eat soft-hearted eggs, it is recommended to choose sterilized eggs that you can buy raw.

References:

[1] "Zhejiang University Zhang Yu/Jiao Jingjing team provides the latest evidence: Eating one more egg a day will greatly increase the risk of cardiovascular disease and cancer death". China Biotechnology Network. 2021-02-10

[2] "Why are there no feces on the eggs sold in the supermarket? 》.Inspur Studio.2020-05-20

[3] "Attention! Salmonella, this "killer" is not far from you! 》.Guangxi Disease Control.2021-08-17

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