Defending Against Cancer
DNA: the tiny molecule that determine what and how you are, is itself a most delicate structure.
How Tea Moderates Cancer
The body’s own and aided defense against cancers or precursors of cancers is as complex as how cancers are formed. Scientists all over the world are continuously investigating in a wide array of pertaining subjects. As to how tea protects the body against cancer, several mechanisms have been observed and hypothesized. We have tried to digest them and represent a few prominent concepts here in plain English:
Preventing and repairing DNA damage in healthy cells
Oxidative stress on the cell caused either by carcinogens or an unbalanced body condition weakens the cell and renders it receptive to mutation triggered by carcinogens. The mutation happens in the chromosomes of the cell. When the DNA that defines what the cell is mutate, the cell becomes abnormal. It is not part of the body but will pretend to be, so as to continue to grow and infiltrate other cells. EGCG is a powerful anti-oxidative agent that is able to reverse the chemistry around the cell that defines stress so that the cell can operate in a healthy environment against such mutation (14).
Causing tumor cells to die naturally
Time-lapse microscopy video showing apoptosis of prostate cancer cells. Notice how the cells breakdown and disintegrate
Our cells have a built-in mechanism to die when they are dysfunctional, no longer usable, or no longer needed. Apoptosis, as it is called, is part of our normal body function. Billions of cells die everyday in the average human body. However, when cells are caused to mutate by carcinogens, one other survival mechanism these abnormal cells develop is to cheat apoptosis so they can live on continuously to take over the immediate surrounding area. EGCG is observed to have regulated the cell chemistry such that the mutants are not able to continue to fool the apoptosis process. The body will then recognize these abnormal cells and would start to make them die or stop infiltrating (15).
Reducing blood supply to the mutated cells so as to deplete them of nutrients
Tumour cells trick the body to grow blood vessels to them so they get the nutrients for growth. They do this by changing the chemistry around them with an enzyme called MMP. EGCG inhibits the activity of the enzyme and thereby induces anti-angiogenesis — “pruning down” of the tiny blood vessels — to reduce nutrient supply to halt tumor growth (16).
Anti-inflammation
Tissues in the body get inflamed when there is an attack by bacteria, virus or other pathogens. Inflammation sets the micro-environment for crossing over to tumor growth (17). Tumors in the stomach, liver and lung are some examples of such a development. Substances in tea, most notably catechins and theaflavins, have been observed to reduce or eliminate topical inflammations or even ulcers to reduce such risks (18).
Dear Leo,
Thank you very much for your prompt reply. Yes, as you correctly point out, I am aware that many responsible traders in the tea business check their pu’erh for pesticides and even the presence of heavy metals. However, very few do it for mycotoxins like aflatoxin. I only know of a couple of vendors based in Taiwan, and they only check the ripe pu’erh not the raw one.
However, the article that I mentioned from Yunnan Agricultural University claims that raw pu’erh is also strongly contaminated, which I personally find very alarming. I believe the authors of this study should be contacted by members of the tea industry to ask them for further clarification as their results are certainly disturbing, if true.
Concerning the incidence of liver cancer in Asia, and China in particular, and its connection to Hepatitis, I fully agree that the latter is the main cause. Therefore, it is utterly important to use vaccination to prevent infection and the possibility of developping hepatic cancer.
Nevertheless, it has been found by researchers that, once a person is infected by the Hepatitis B virus, the chances of developing liver cancer in the future become substantially higher (by a factor of 30) if he or she is exposed to aflatoxins. See, for instance:
http://www.ncbi.nlm.nih.gov/pubmed/11922091
Food stuff of frequent consumption in Asia like peanuts, corn, etc, are known to be often contaminated with mycotoxins, but I wonder if (wet/traditional stored) dark teas should be also blamed and therefore avoided, in case they turn out to be contaminated with high levels of mycotoxins.
Anyway, thanks for addressing my concerns in such a forthright manner. I look forward to your email in case you need me to provide you with a copy of the article from the Yunnan researchers. Please, do not hesitate to contact me.
Sincerely,
xiaobai
@xiaobai, thank you for this very meaningful discussion. Seems I will have to really spend time to do more research about this topic now. If you have not received the previous email we sent you about the two other reports, I shall have another sent to you right away.
The high rate of hepatitis in China, according to some other reports, relates more with the hygiene concept and food habits of the Mainlanders rather than the use of peanuts and corns. These staple food items are used popularly almost everywhere else. Furthermore, puer tea has never been really popular in the Mainland until the recent couple of decades since the spread of the teashop business trend and of course the speculation craze that has never really died down even now. Puer had only been popular in Hong Kong and neighbouring parts of Guangdong previously. Yet hepatitis and liver-related death in China has stayed high all the time throughout China. This seems to me a negative evidence of the argument that puer is part of the problem. However, the existence of the reports you cited are not to be dismissed. I shall most definitely write about the topic. Give me some time to do the needed study. Pls forward the copies you have. Thanks again.
Well, the address you have used to register in this site does not exist, according to the gmail response. You must have made a typo or something.
Dear Leo,
yes, sorry, there was a typo in the email address that I entered before. Please, try again.
I really apologize for the inconvenience.
By the way, I am not arguing about the causes for the high incidence of Hepatitis B in China. The latter is also an issue in other places like Taiwan and Malaysia (although this disease can be transmitted in absence of good hygiene, the main means of contagion are via contact with blood and other bodily fluids, e.g. sex). Of course, I am well aware of the lack of hygiene and manners of many mainlanders (I spend long periods in Taiwan, where we are also very familiar with this problem).
Anyway, please, contact me. I really think someone from the tea industry who is more qualified than me should contact the authors of those studies. Either they have made some big mistakes or there are serious reasons for concern
about pu-erh consumption.
No no no, I am not saying you are arguing. What I meant was the hypothesis. It is an expression that is very popular in academic discourse when there are discussions on different view points and presumptions of a hypothesis, an argument per se. I was only presenting why I think you should not be too worried. It is an issue that we tea people should look at anyhow. I’ll have an e-mail sent to you tomorrow for the documents. Thanks again in advance.
@xiaobai, thank you for the well thought out comment, and thank you for offering the copy of the reports. I shall contact you separately through email for it. Although we subscribe to a major distributor of science and technology reports, you probably understand that any such subscriptions would not include all things going on, in particular those from the sources that you have cited.
Mycotoxins are a concern for a number of food items that are produced through fermentation; and pu’er, either sheng or shu, are no exceptions. I have been keeping an eye on that for commercial purposes.
With the exception of Taiwan, this category of contaminants is not high in priority in the importers’ radar for tests, so far as I have been aware of. However, some other compounds are. For example, Anthraquinone. We have found it in two of our candidates for launching in Europe. On further investigation, we have found that it has been the cause for the rejection of a number of major shipments of pu’er entering Europe. We suspect it has been a major reason why not more importers are buying. I have been discussing with an European client on the situation and hope to find a way to combat the issue with Yunnan producers.
Anthraquinone comes not from fertilisers or insecticides. We are trying to find where it comes from. If what we suspect is true, the production processes of many other F&B items may have to change to avoid it, not only for China, but everywhere else.
I cannot talk further on that yet since this is all speculations right now.
As for higher liver cancer rates in populations of the Chinese descent, for many decades now there is an understanding in the medical profession that it is the wide spread of hepatitis rather than anything else. For example, 100% of Chinese adults in the Chinese Mainland have found to be hepatitis positive. Sometimes I wonder why the liver cancer rate in China ( not HK ) is not higher than the official figure. That is also why I have been extremely careful when travelling in China, especially when sharing the table with my Mainland friends.
As for the link between puer tea and that, I have yet to read convincing reports about it. I am looking forward to reading those quoted by you.
Dear Leo,
I was trying to post this question in the forum section of this website, but unfortunately, I could not find the find the link to register.
I was wondering if you have been following up on the recent research results
about mycotoxins (like, for instance aflatoxins) found in Puerh. Here are two examples of recent references from two different research groups in China:
http://www.tandfonline.com/doi/abs/10.1080/10942912.2014.885043#.VL9Toy6UcZM
http://www.lifescienceglobal.com/pms/index.php/jbas/article/view/2217
For the first article, only the abstract is freely accessible, but I will be glad to provide you with a copy if you contact me by email. I find the results disturbing,
although I think that the article may contain several typos, at least.
As a tea expert and a Hongkongnese with a long experience with puerh, I would love to hear your opinion on these recent research results, which, in my modest opinion, are a good reason for concern (e.g. you may be aware that aflatoxin
is a potent carcinogen, affecting especially the liver and that liver cancer is in the top 5 most common types of cancer in places like Hong Kong, Singapore, and Taiwan, with elevated consumption per capita of post-fermented puerh teas).
Best regards,
xiaobai