In the Sacramento and Davis regional area, the University of California, Davis studies the many health benefits of green tea. For example, one study recently focused on green tea and breast cancer prevention. See the article, “New study on the effects of green tea on breast cancer prevention.”
And another study at UC Davis, “UC Davis Green TEA Academy – Andrew Hargadon,” focused on the University of California at Davis (UC Davis) Center for Entrepreneurship, back in 2008 when Amory Lovins, co-founder, chairman, and chief scientist, Rocky Mountain Institute, spoke at the second annual Green Technology Entrepreneurship Academy. UC Davis, in the Sacramento-Davis regional area, several years ago studied green tea’s effects on health.
Back then, a research group from U.C. Davis discovered how organically and sustainably grown food crops contained significantly higher concentrations of phenolic compounds and vitamin C than the same crops grown conventionally. Also check out two studies of green tea done in China, which are posted to a UC Davis site. In China green tea is a mainstay of the diet, and the latest studies resulted in promising health benefits. For more information about NCI-sponsored studies on green tea, see the document, “Yesenia Garza.” How would a consumer know whether a study done with rats can be applied to humans?
How would one find out whether the study was done with humans or animals and the results? You might go first to the primary source, the study published in a scientific journal to find out whether the study involved participants (humans) or animals. Most consumers without science backgrounds turn to news releases written to report the highlights of a current study.
Locally, there are a lot of plants to study based on what health benefits each might have, such as lowering the risk of certain diseases. Also check out another UC Davis research article published in 2003, a (PDF file) based on the study, “Comparison of the total phenolic and ascorbic acid content of freeze dried and air-dried marionberry, strawberry, and corn grown using conventional, organic, and sustainable agricultural practices,” Journal of Agric. Food Chem. 51:1237-1241, 2003. Department of Food Science and Technology, University of California, Davis.
Phenolics are potent antioxidants and are thought to have anti-cancer activity, according to the 1992 study, “Fruit, vegetables, and cancer prevention: A review of the epidemiological evidence,” Nutr. Cancer 18:1-29. (Authors are, Block, G, B. Patterson, and A. Subar. 1992.)
Another study on the health benefits of Hawaiian Spirulina® has been done at UC Davis. Check out the article, “UC Davis Research Study Indicates That Cyanotech’s Spirulina Pacifica(R) May Counter Anemia And Declining Immune Function In Persons Over Age 50.” Researchers at the University of California at Davis have determined that microalgae-based Hawaiian Spirulina Pacifica® may improve immune function and ameliorate anemia in persons over 50.
At another university, Newcastle University, in the U.K., more studies on green tea now focus on how green tea might protect the brain against possibly developing Alzheimer’s disease. A news release on the study also has been picked up by Life Extension magazine in its April 2011 issue. See the article in Life Extension magazine, April 2011, page 19, “Green Tea May Help Prevent Alzheimer’s Disease,” by J. Finkel.
According to the January 6, 2011 Newcastle University, U.K. news release, “Protective properties of green tea uncovered,” regularly drinking green tea could protect the brain against developing Alzheimer’s and other forms of dementia. The study has been published in January 2011 in the academic journal Phytomedicine, also suggests this ancient Chinese remedy could play a vital role in protecting the body against cancer.
Led by Dr Ed Okello, the Newcastle team wanted to know if the protective properties of green tea – which have previously been shown to be present in the undigested, freshly brewed form of the drink – were still active once the tea had been digested. Digestion is a vital process which provides our bodies with the nutrients we need to survive. But, says Dr Okello, according to the news release, it also means that just because the food we put into our mouths is generally accepted to contain health-boosting properties, we can’t assume these compounds will ever be absorbed by the body.
“What was really exciting about this study was that we found when green tea is digested by enzymes in the gut, the resulting chemicals are actually more effective against key triggers of Alzheimer’s development than the undigested form of the tea,” explains Dr. Okello, in the news release. Dr. Okello is based in the School of Agriculture, Food and Rural Development at Newcastle University and executive director of the university’s Medicinal Plant Research Group. “In addition to this, we also found the digested compounds had anti-cancer properties, significantly slowing down the growth of the tumour cells which we were using in our experiments.”
As part of the research, the Newcastle team worked in collaboration with Dr Gordon McDougall of the Plant Products and Food Quality Group at the Scottish Crop Research Institute in Dundee, who developed technology which simulates the human digestive system. It is this which made it possible for the team to analyse the protective properties of the products of digestion.
Two compounds are known to play a significant role in the development of Alzheimer’s disease – hydrogen peroxide and a protein known as beta-amyloid. Previous studies have shown that compounds known as polyphenols, present in black and green tea, possess neuroprotective properties, binding with the toxic compounds and protecting the brain cells.
When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the Newcastle team tested in their latest research. “It’s one of the reasons why we have to be so careful when we make claims about the health benefits of various foods and supplements,” explains Dr Okello, according to the news release. “There are certain chemicals we know to be beneficial and we can identify foods which are rich in them but what happens during the digestion process is crucial to whether these foods are actually doing us any good.”
Carrying out the experiments in the lab using a tumour cell model, they exposed the cells to varying concentrations of the different toxins and the digested green tea compounds. Dr Okello explained in the press release: “The digested chemicals protected the cells, preventing the toxins from destroying the cells.
“We also saw them affecting the cancer cells, significantly slowing down their growth. Green tea has been used in Traditional Chinese medicine for centuries and what we have here provides the scientific evidence why it may be effective against some of the key diseases we face today.”
The next step is to discover whether the beneficial compounds are produced during digestion after healthy human volunteers consume tea polyphenols. The team has already received funding from the Biotechnology and Biological Sciences Research Council (BBSRC) to take this forward. Dr Okello adds in the news release: “There are obviously many factors which together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important. But I think it’s fair to say that at least one cup of green tea every day may be good for you and I would certainly recommend it.”
For further information, read the study online, published in Phytomedicine, January 2011, as it’s the primary source for the news release. The study is “In vitro protective effects of colon-available extract of Camellia sinensis (tea) against hydrogen peroxide and beta-amyloid (A(1-42)) induced cytotoxicity in differentiated PC12 cells.” E J Okello, G J McDougall, S Kumar and C J Seal. Phytomedicine. DOI: 10.1016/j.phymed.2010.11.004.
Studies are ongoing on numerous plant extracts, for example olive leaf extract’s health benefits. Also check out the study, “The neuroprotective effect of olive leaf extract is related to improved blood–brain barrier permeability and brain edema in rat with experimental focal cerebral ischemia,” 23 December 2010. The question now is whether these studies can be applied to possible health benefits for humans?