Pu'er is 'mold tea', there are 500 million molds in one gram? Does drinking too much cause cancer? Here comes the truth

"Are you still drinking 'mold' Pu'er tea? I suggest that tea lovers try to quit Pu'er from today!

As early as a few years ago, Fang Zhouzi, a well-known popular science author, pointed out that ' Pu-erh tea contains aflatoxin, and drinking too much is easy to cause cancer ' ... "

Brother Zhang usually pays great attention to health preservation, and is especially keen on drinking tea for health preservation. He has collected many precious tea leaves at home, including Pu'er. He also followed a lot of health science bloggers on the short video platform, and the video content above was published by the bloggers he followed the most.

But Brother Zhang thinks this content looks very unreliable. Pu'er tea has been circulated for thousands of years. People have been drinking it before, and there has never been any "carcinogenic" claim . After drinking it for so many years, the body has not appeared. What's wrong, so he doesn't believe this statement.

But in the end, I was still a little uneasy, so I sent a private letter to Xiaojiu, asking if there was any scientific basis for this statement.

In fact, in recent years, the "black pot" about Pu'er tea is not uncommon, such as:

"Pu-erh is moldy tea, one gram of Pu-erh contains 500 million molds"

"Pu-erh bacteria explodes on the table, drinking Pu-erh is equivalent to drinking dirty water"

"Pu'er contains aflatoxin, drinking too much is not only toxic but also carcinogenic"

“……”

Is drinking Pu'er tea healthy or cancer? Today, Xiao Jiu will explain it to everyone in detail.

1. Pu-erh tea bacteria burst the table? Many are "good bacteria"

To understand whether Pu-erh tea is harmful, let's first understand how it is made.

In the beginning, the tea makers will sprinkle water on the tea pile and cover it with a linen cloth, and then use the moist heat to ferment the tea leaves.

During the fermentation process, various molds, mainly Aspergillus niger, in the tea will start to play their role , and finally give Pu-erh tea its unique aroma and taste.

Indeed, during the fermentation of Pu-erh tea , various microbial groups such as Aspergillus niger, Penicillium, Rhizopus, and yeast will be produced , among which Aspergillus niger accounts for the largest proportion, accounting for about 80%.

But Aspergillus niger is actually a "good bacteria", not only non-toxic and harmless, but also inhibits the growth of Aspergillus flavus, produces toxins, and degrades aflatoxin B1 during the fermentation process of Pu'er tea . Moreover, the fermentation temperature of Pu-erh tea is relatively high, and Aspergillus flavus is often unable to tolerate it.

In addition, even if there is Aspergillus flavus in Pu-erh tea, it does not necessarily produce aflatoxin. It is understood that only 10% of Aspergillus flavus strains isolated from nature can produce toxins.

2. Pu-erh tea causes cancer? "Wet warehouse Pu'er" ≠ normal Pu'er

In Fang Zhouzi's article, "aflatoxin was detected in the experiment". In fact, the sample used in the experiment is wet warehouse Pu'er , which is different from normal Pu'er.

Wet warehouse Pu'er, simply put, is a relatively high-temperature and high-humidity storage environment artificially created to promote the fermentation and aging of Pu'er tea. In this "wet warehouse" environment, aflatoxins are easily produced .

If still in doubt, we can look at an experiment.

In order to find out whether Pu-erh tea is carcinogenic, the Guangdong Provincial Center for Disease Control and Prevention sampled 40 brands of Pu-erh tea samples, and tested the content of aflatoxin in them by tandem mass spectrometry.

Finally, it was found that aflatoxin B1 was detected in only 3 Pu-erh tea samples, and the maximum value was 0.56μg/kg , which was similar to the minimum limit of aflatoxin B1 in infant formula food stipulated by the national standard of 0.5μg/kg, but higher than that of aflatoxin B1. The limit of 5 μg/kg for wheat and 10 μg/kg for rice is much lower.

It can be seen that the risk of cancer caused by Pu-erh tea is very low, and you don't have to worry too much.

3. Is drinking tea beneficial or harmful to the heart?

There was a saying that "drinking tea is not good for the heart and will lead to heart disease", in fact, drinking tea regularly may be good for the heart.

Tea is a nutrient-rich ingredient, which is rich in flavonoid antioxidant substances, such as tea polyphenols, catechins, etc. These substances can scavenge free radicals in the human body to a certain extent, which is beneficial to health. In addition, tea also contains amino acids, vitamins and other nutrients.

Numerous studies have found that drinking tea also has a positive effect on the heart.

For example, a study involving more than 80,000 Chinese people published in the "Journal of the American Heart Association" (JAHA) found that people who drink tea for a long time have a slower decrease in LDL-C levels in the body, and the risk of cardiovascular disease. 8% lower .

As for the problem of caffeine that everyone is more worried about, some people report that drinking too much will cause discomfort such as heart palpitations, so they are worried that it is not good for heart health. In fact, this situation is very normal, and the folks call it "tea drunk".

At present, authoritative health agencies in the world believe that moderate coffee consumption and caffeine intake (about 1-2 cups of coffee per day, caffeine about 200mg) are not harmful to the heart.

4. Green tea VS black tea, which is healthier?

Pu-erh tea can be divided into black tea and green tea. Which of these two kinds of tea is better?

Previously, a study published in "Cellular Physiology & Biochemistry" showed that whether it is green tea or black tea, the catechin compounds (such as ECG, EGCG) can activate potassium channel proteins on the blood vessel wall. to relax blood vessels, thereby helping to lower blood pressure.

In addition, there are many studies showing that black tea, green tea, and other teas have positive effects on health .

Among them, the research on green tea is more extensive, and many in vitro and in vivo studies have shown that green tea extract can help reduce the risk of high blood pressure and heart disease to some extent . So, everyone can drink according to their own preferences.

However, there are several kinds of teas that are not recommended to drink, especially the following three:

1. Strong tea

The content of caffeine and theophylline in this kind of tea is relatively high. Drinking too much can easily cause heart discomfort; and the tannic acid contained in it may also react with iron in food, thereby affecting the absorption of iron, which is not good for health. So drink less.

2. Raw tea

This kind of tea has serious green qi, which can easily irritate the gastric mucosa and cause stomach pain and other discomfort, so it is best not to brew it directly.

3. Over-hot tea

If the temperature is too high for a long time, especially the hot tea above 65°C, it can scald the esophageal mucosa and cause inflammation, thereby increasing the risk of esophageal cancer.

Drinking Pu'er tea in moderation will not cause cancer, but it is good for heart health, so friends who like to drink Pu'er tea can usually drink it in moderation, but pay attention to methods, such as avoiding drinking tea that is too hot, so as not to endanger health.

References:

[1] "Can Pu'er cause cancer? Oh drink...". Shenzhen Market Supervision. 2017-09-08

[2] "Pu-erh tea causes cancer? Laboratory results let you know the truth in seconds". Guangdong Disease Control and Prevention. 2018-03-19

[3] "Drinking tea is bad for the heart? In fact, you are not drinking right! 》. Ruan Guangfeng Nutritionist. 2019-02-16

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