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

"Don't you know that eating too many eggs can cause cancer?"

"I bought authentic free-range eggs, how could they cause cancer? I spent tens of thousands of dollars on just these 10 eggs."

In the vegetable market, Aunt Jiang was chatting with Aunt Liu after buying vegetables.

I heard that eating eggs is good for the body and can protect the heart, especially suitable for the elderly, so Aunt Jiang came to the market to buy local eggs. The more expensive the eggs are, the more nutritious they are.

However, Aunt Liu's words made Aunt Jiang feel unhappy. Eggs are good things, how can they be said to cause cancer? This is nonsense.

Eggs are a very common food in our daily life. They are not only cheap but also nutritious. Different cooking methods bring out a variety of flavors and are loved by men, women, young and old.

However, Chinese people are very concerned about food safety. There have been many studies at home and abroad on eggs, especially discussing the relationship between egg cholesterol and the risk of cardiovascular disease.

1. Eating one more egg a day may increase the risk of death from heart disease and cancer?

Previously, research from Zhejiang University has received a lot of attention and controversy.

Generally speaking, the average cholesterol in an egg is 186 mg. Most people usually eat one egg a day, but some people like to eat several.

The research team led by Professor Zhang Yu and Professor Jiao Jingjing of the School of Biosystems Engineering and Food Science at Zhejiang University, based on a study of 520,000 people, found that consuming an extra 300 mg of dietary cholesterol per day increased the risk of premature death by 19%, the risk of cardiovascular disease by 16%, and the risk of cancer by 24%. Eating half an egg a day would also increase the risk of all-cause mortality by 7%.

After seeing this research, many people are worried that they can no longer eat eggs.

In fact, this study is still an observational study, and there is no clear cause and effect relationship. Moreover, the participants in the study were Americans aged 50-71, but the dietary structure of China and the United States is very different.

In April, the latest research from the Second Xiangya Hospital of Central South University showed that Asians may enjoy "privileges". The study analyzed more than 20,000 participants in Finland and found that eating one more egg may increase cardiovascular risk, but this association was not reflected in the analysis of the Asian cohort.

So, there is no need to stop eating eggs because of this study. In fact, there are more benefits to eating eggs than you know.

2. Peking University's latest research: Uncovering the mystery of eggs protecting the heart

In fact, a recent study published by Peking University in the journal eLife found evidence that eating eggs can protect the heart.

The study included data from 4,778 Chinese people aged 30-79, of whom 3,401 had cardiovascular disease. In order to understand how eggs affect the cardiovascular system, the study focused on changes in plasma metabolites.

The researchers found 24 lipid metabolites related to egg intake, and 14 metabolite markers affect the risk of cardiovascular disease. Through analysis, it was found that eating eggs in moderation would increase the content of beneficial lipid metabolites in the blood and reduce the content of harmful lipid metabolites, thus playing a protective role in cardiovascular disease.

This study, based on the Chinese population, provides a potential explanation for the association between moderate egg consumption and prevention of heart disease, or may correct our misconceptions about eggs.

3. How many eggs is the most appropriate to eat every day?

So how do we determine the “right amount”?

A study led by Academician Dongfeng Gu from the Fuwai Hospital of the Chinese Academy of Medical Sciences found that people who eat 3-6 whole eggs a week have healthier blood lipid indicators, and the results are not affected by factors such as diabetes and high blood pressure.

According to the recommendations of my country's dietary guidelines, while ensuring normal intake of fish, meat and poultry, it is necessary to consume 280-350 grams of eggs per week, which is equivalent to one egg per day.

But the specific situation also varies from person to person. For example, people who usually eat less fish, meat and poultry, fitness enthusiasts, growing children and adolescents, as well as pregnant and lactating women, can eat more eggs at this time, 1-2 eggs a day, to supplement protein.

If you suffer from high blood pressure, high blood lipids, diabetes and other diseases and need to control your cholesterol intake, you can eat one egg every other day without discarding the egg yolk.

To eat eggs healthily, you also need to pay attention to the following:

1. Do not eat undercooked eggs

The health risk of eggs mainly comes from salmonella infection, and the risk is greater when the eggs are not fully cooked. It may cause mild symptoms such as vomiting, diarrhea and abdominal pain, or even severe symptoms such as dehydration and shock. It may also cause sepsis in children. Therefore, it is best to eat eggs cooked.

2. Boiled eggs are the best way to eat them

Boiling eggs is not easy to destroy the nutrients in eggs. The highest digestibility of nutrients in eggs is in boiled eggs, followed by scrambled eggs and fried eggs. It is recommended that the boiling time of eggs should not be too short or too long. Usually, it is enough to boil eggs for 5 minutes after boiling water.

3. Eat fresh eggs

Generally speaking, unfresh eggs are dark grey in colour, feel light to hold, have a grey-brown shadow or are opaque under light. If they feel a bit rough but have no cracks, shake gently without vibration, and appear pink when light passes through them, with a small air chamber, they are probably fresh eggs.

4. What is the difference between eggs that cost a few dollars and those that cost dozens of dollars?

There are many varieties of eggs, and their prices vary. Are the more expensive eggs better? Are red-skinned eggs more nutritious? Xiao Miao will show you the difference between eggs that cost a few yuan and those that cost dozens of yuan.

To be honest, there is not much difference between free range eggs and ordinary eggs in terms of the content of nutrients such as protein, calcium, phosphorus, and iron. In addition, chickens raised in intensive chicken farms often have more nutrients in their feed, so the content of vitamins and mineral elements in the eggs produced is higher than that of free range eggs.

As for the color of the eggshell, it is determined by a substance called eggshell porphyrin and has nothing to do with nutritional value. So when eating eggs, there is no need to choose high-priced ones. Hygiene and freshness are the criteria for selection.

In short, for most people, eating one egg a day will not harm cardiovascular health, let alone cause cancer. It is recommended to consume eggs in moderation according to your needs, and choose fresh and safe eggs, and cook them thoroughly before eating.

References:

[1] “Is eating one extra egg a day risky? Asians may enjoy a “privilege”!” China Biotechnology Network. 2022-04-19

[2] "The mystery of eggs protecting the heart has been solved! A Peking University team analyzed nearly 5,000 Chinese people and found that egg intake was associated with high levels of "good" lipid metabolites and low levels of "bad" lipid metabolites." Qidian.com. 2022-06-19

[3] "Another benefit of eggs has been discovered! But there are some rules for eating them, and many people don't know it yet." Science Popularization China. 2022-06-26