Defending Against Cancer
Bioavailability: the key
These may all sound rosy and hopeful for the worried, but there is a catch. While most reports have been promising and positive, some scientists point out that results can be inconsistent. “In spite of the strong evidence for the cancer preventive activity of tea polyphenols in animal models, such an activity has not been consistently observed in studies on humans…” write Dr Yang’s team in their well-studied report on the subject (19). Yang and Dr Lambert have been teamed up for years in the pursuit of understanding more about tea and its health nature.
Some conclude that the salutary contents of tea, in particular the unstable EGCG, may have been excreted or deteriorated before reaching the part of the body needing its rescue (20). Bioavailability, as it is often called, still need to be understood for the salutary contents of tea, as are the mechanism and the constituents themselves.
Dr William Li’s (Anti-)Angiogenesis Blend
Dr William Li’s very own anti-angiogenesis blend: jasmine pearl + sencha
One advocate who promotes natural food in the diet to fight cancer is Dr William Li of the Angiogenesis Foundation. In his studies of natural food products that aid anti-angiogenesis in the human body, he found out that ordinary quality tea is very good, and that by combining jasmine pearls with sencha, the effect is much better than each tea alone, and the best in his range, which is quite very limited. I guess what Dr Li said was ordinary from his neighbourhood in Cambridge Massachusetts would be quite, well, ordinary.
We were interested to find out what it would taste like anyway so we made a blend of the most ordinary quality sencha and jasmine pearls from our sample cabinet.
None in the team are quite fond of either tea but we were surprised. The result, in term of taste, is actually better than either tea alone. Not a bad idea. That’s credit to Dr Li.
The first impulse I got was to try to hypothesize on why, but then I think it’s pretty premature to establish anything yet. One good thing is obvious, however. Since this is your own blend, you can adjust the proportion of the taste from the sencha to the proportion of taste and jasmine aroma from the jasmine pearls.
For my own drinking, I’ll stick to my own repertoire of selections for better taste afterall. At the back of my mind, I know all of them will give me great health support incomparable by any other drinks anyway.
Others emphasize the need to establish a clue to the dosage of tea constituents needed for the human body in order for them to be effective (21).
Yet repeatedly scientists found out that even when they composed tea extract drinks using accurate dosages of various tea extracts, the effects were still not as good as with real tea infusions (22).
Well, some people look very closely to examine at molecular level how things work, or at the individual subject of study, but others look at it in a macro scale.
In the long run, macro scale
A group of Spanish scientists studied the epidemiologics (study of a disease pattern in a large group of people) of cancers and tea conducted in various countries conclude that the occurrence of breast cancer, ovarian cancer, prostate cancer, stomach cancer and lung cancer is inversely proportional to quantity of tea consumption, i.e. those who drink more tea are less likely to have these cancers (23).
There have been quite a few such large scale studies. For example, in an US study following 35,369 post-menopause women for 8 years (the Iowa Cohort) (24) late last century, scientists found out that those who drank 2 cups of tea a day were 30 to 60% less likely to contract cancers in the digestive tract, and various degrees of lower risks of cancers in the pancreas, cervix, uterus, urinary tract, and even the dreadful leukemia. Remember that in those years in Midwest USA, it was mostly only teabags.
Let’s look east to Asia, where more people drink leaf teas, such as the famous Oshaki Cohort Study “Green Tea Consumption and Mortality Due to Cardiovascular Disease, Cancer, and All Causes in Japan” (25) where Dr Shinichi Kuriyama and his colleagues conclude — after following 40,530 randomly selected matured adults for 11 years, including smokers and alcohol drinkers — those who drank tea regularly were 16% to 26% less likely to die early of ALL causes.
Tea does not do miracles, but it helps.
Tea does not do miracles, but it helps
Dr. Siro Trevisanato of Banting and Best Institute of Medical Research sums it well, “They (tea flavonoids) act as antioxidants and prevent tissues from being damaged by free radicals. Within cells, flavonoids block effects of known carcinogens. Flavonoids also appear to protect genes from mutagenic effects of environmental factors. All of these effects may contribute to the maintenance of the healthy state of cells…” (26)
Cancer is a huge topic and to many people, a real pain and extreme trauma. It is often life-threatening. We have no intention of simplifying its concern by saying tea is a miracle alternative for all, but wouldn’t it be unwise not to develop a habit for it simply for a better chance? Quality of life needs to be maintained before bad things happen. Make yourself a fine cup of tea.
As for Charlene, she quitted job and works full time as a volunteer in an alternative cancer therapy support group, and enjoying life.
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