Pu'er is a 'moldy tea', there are 500 million molds in one gram? Can drinking too much cause cancer? the truth is coming
"Are you still drinking 'moldy' Pu'er tea? I suggest tea lovers start today and try to quit Pu'er tea!
As early as a few years ago, Fang Zhouzi, a well-known popular science writer, pointed out that ' Pu'er tea contains aflatoxin, drinking too much can cause cancer ' ... ”
Brother Zhang usually pays great attention to health preservation, and is especially keen on drinking tea to maintain health. He has a lot of precious tea leaves in his family, including Pu'er. He also followed many health science bloggers on the short video platform, and the above video content was released by the bloggers he followed the most.
But Brother Zhang thinks this content looks very unreliable. Pu-erh tea, which has been passed down for thousands of years, has been drunk by people in the past, and there is no such thing as "carcinogenic" . What discomfort, so he did not believe this statement.
But after all, I was still a little uneasy in my heart, so I sent a private message to Xiaojiu, asking if there was any scientific basis for this statement.
In fact, in recent years, there are not uncommon "black pots" about Pu'er tea, such as:
"Pu'er is moldy tea, one gram of Pu'er contains 500 million molds"
"Puer bacteria exploded, drinking Puer is equivalent to drinking dirty water"
"Pu'er contains aflatoxin, drinking too much is not only poisonous but also carcinogenic"
“……”
Is drinking Pu-erh tea health-preserving or cancer-preserving? Today, Xiao Jiu will explain it clearly to everyone.
1. Bacteria explosion in Puer tea? Many are "good bacteria"
To understand whether Pu-erh tea is harmful, let's first understand how it is made.
At the beginning, tea makers will sprinkle water on the pile of tea and cover it with a layer of sackcloth, and then use the heat and humidity to ferment the tea.
During the fermentation process, various molds in the tea leaves, mainly Aspergillus niger, will start to play a role , and finally give Pu-erh tea a unique aroma and taste.
Indeed, during the fermentation process 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 kind of "good bacteria". Not only is it non-toxic and harmless, but it can also inhibit the growth of Aspergillus flavus, produce toxins, and degrade 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 aflatoxin in Pu'er tea, it may not necessarily produce aflatoxin. It is understood that only 10% of the Aspergillus flavus strains isolated from nature can produce toxins.
2. Pu-erh tea causes cancer? "Wet warehouse Pu'er" ≠ normal Pu'er
Fang Zhouzi pointed out in the article that "aflatoxin was detected in the experiment", in fact, the sample used in the experiment was wet warehouse Pu'er , which is different from normal Pu'er.
Put simply, a wet warehouse for Pu’er tea 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 you still have doubts, we can look at an experiment.
In order to know whether Pu'er tea is carcinogenic, the Guangdong Provincial Center for Disease Control and Prevention took samples of 40 brands of Pu'er tea to detect the content of aflatoxin in them, and the inspection method was determined by tandem mass spectrometry.
Finally, it was found that aflatoxin B1 was detected in only 3 samples of Pu’er tea, with a maximum value of 0.56 μg/kg, which was similar to the minimum limit of 0.5 μg/kg of aflatoxin B1 in formula foods for infants and young children stipulated in the national standard, but lower than Limits of 5 μg/kg for wheat and 10 μg/kg for rice are much lower.
It can be seen that the risk of cancer caused by Pu'er tea is very low, so you don't have to worry too much.
3. Is drinking tea good or bad for the heart?
There used to be a saying that "drinking tea is not good for the heart and can lead to heart disease." In fact, drinking tea regularly may be good for the heart.
Tea is a nutritious food material, which is rich in flavonoid antioxidant substances, such as tea polyphenols, catechins, etc. These substances can remove free radicals in the human body to a certain extent, which is beneficial to health. In addition, tea also contains nutrients such as amino acids and vitamins.
Numerous studies have found that drinking tea also has positive effects 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 insisted on drinking tea for a long time, the level of LDL-C in the body decreased more slowly, and the risk of cardiovascular disease 8% reduction .
As for the caffeine that everyone is more worried about, some people report that drinking too much can 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 organizations in the world believe that drinking coffee and caffeine in moderation (about 1-2 cups of coffee per day, caffeine about 200mg) will not be harmful to the heart.
4. Green tea VS black tea, which one is healthier?
Pu-erh tea is 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 the potassium ion channel protein on the blood vessel wall To relax blood vessels, thereby helping lower blood pressure.
In addition, many studies have shown that whether it is black tea, green tea or other teas, it has positive effects on health .
But among them, the research on green tea is more extensive. A number of in vivo and in vitro studies have shown that green tea extract can help reduce the risk of high blood pressure and heart disease to a certain extent . So, everyone can drink according to their own preferences.
However, there are several types of tea that are not recommended, especially the following three types:
1. Strong tea
The content of caffeine and theophylline in this kind of tea is relatively high. If you drink too much, it is easy to 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 raw green gas, which is easy to irritate the gastric mucosa and cause stomach pain and other discomforts, so it is best not to brew it directly, you can first stir-fry it slowly, remove the raw green gas first, and then taste it.
3. Overheated tea
If the temperature is too high for a long time, especially hot tea over 65°C, it can burn the esophageal mucosa and cause inflammation, which will increase the risk of esophageal cancer.
Drinking Pu'er tea in moderation does not cause cancer, but is good for heart health. Therefore, friends who like to drink Pu'er tea can drink it in moderation, but pay attention to the method, such as avoiding drinking tea with too high temperature, so as not to endanger health.
References:
[1] "Can Pu'er Cause Cancer? Oh, drink... ". Shenzhen Market Supervision. 2017-09-08
[2] "Puer Tea Causes Cancer? Laboratory results let you know the truth in seconds." Guangdong CDC. 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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