Life Extension Magazine®

Issue: Sep 2003

Tea And Infections

Green tea and infections, I3C and breast cancer, calcium d-glucarate, saw palmetto and nettle root, CLA with Guarana

Scientifically reviewed by: Dr. Gary Gonzalez, MD, on January 2021.

Q I recently read an article about a component of tea being used to treat infections. Does this refer to green tea or any tea? Do you sell that extract?

A study reported in the Proceedings of the National Academy of Sciences indicated that an amino acid called L-theanine found in black, green and oolong tea can boost the body’s defense against disease. Researchers at Harvard Medical School gave 11 test subjects five to six cups of tea, equal to 230 mg of L-theanine, for four weeks. Results showed a three- to four-fold increase in interferon-gamma production. In another experiment with white blood cells from the same groups of test subjects, the researchers used killed bacterial cells of E. coli and M. morganii to see if there would be an increase in interferon-gamma production. After one week of drinking the tea, there was a two- to four-fold increase. Researches explained that L-theanine is broken down in the liver to ethylamine, a molecule that primes the response of an immune blood cell called the gamma-delta T cell. Gamma-delta T cells are the first line of defense against many types of bacteria, viral, fungal and parasitic infections. They speculate that it might be possible to further isolate and refine L-theanine from tea and use it as a drug to boost the infection defense of the body. Life Extension offers L-theanine in 100 mg capsules, for those who do not wish to drink five to six cups per day of tea.

Q How does I3C compare to tamoxifen for breast cancer prevention?

Tamoxifen is an estrogen blocking chemical used to provide short-term delay in the re-emergence of breast cancer in women who have already had breast cancer. Tamoxifen has a number of side effects that sometimes limits its use in treating breast cancer to two years. Cancer cells can become resistant to tamoxifen and the drug may begin to feed new tamoxifen dependent cancers. Researchers in France showed that tamoxifen stops the p53 gene from working. While this may sensitize cancer cells to the effects of chemotherapy, the same phenomenon in a healthy person might cripple their ability to stop cancer.

I3C is a phytochemical isolated from cruciferous vegetables (broccoli, cauliflower, brussels sprouts, turnips, kale, green cabbage, mustard seed, etc.). I3C helps to convert the strong estrogens into weaker ones. Studies done at the University of California at Berkeley showed that I3C inhibits MCF7 human breast cancer cells from growing by as much as 90% in culture. Other studies show that I3C inhibited the growth of estrogen receptor-positive breast cancer cells and stopped the synthesis of DNA for new cells in estrogen receptor-negative breast cancer by about 50%.

I3C can also protect against cancer due to exposure to carcinogens. Cancer causing chemicals can change the metabolism of estrogen by elevating 16OHE, a biologically active estrogen metabolite that sends “grow” signals, while at the same time decrease the good estrogen metabolite 2OHE.I3C can change this ratio and elevate the good estrogen. For more information on I3C and reference studies, log onto

Q Will calcium d-glucarate accelerate the removal of certain drugs in the body, thus reducing their effectiveness?

D-glucarate is a phyto-nutrient that is found and extracted from grapefruit, apples, oranges, broccoli and brussels sprouts. D-glucarate works by supporting detoxification and removal of dangerous chemicals such as pesticides, over-cooked food, alcohol, food additives, tobacco, fungal mutagens and industrial pollutants, and also by protecting against the mutating effects that these carcinogens induce on cellular DNA. It has not been shown to affect the halflife of drugs or reduce their effectiveness in the body. At the time of this writing, no evidence of drug interactions with calcium D-glucarate are substantiated in the medical literature.

Q I have been using a saw palmetto product from my local drug store but I find I still have to urinate often, especially at night. Will your Super Saw Palmetto with Nettle Root work better for me?

You did not state how much standardized saw palmetto extract your product contains or if it has other ingredients. Perhaps you are not receiving enough of the extract to derive any benefits. Studies show that when a combination of 320 milligrams of pure saw palmetto extract and 240 milligrams of nettle root extract (urtica root) was given to 2,080 patients daily for 12 weeks, they experienced an average 25.8% increase in maximum urinary flow, a 29% increase in mean urinary flow, 44.7% lower residual urine and 50.4% less nocturia (urination at night) [Journal of the American Botanical Council and the Herb Research Foundation. 34(1995)].

Q I recently purchased your CLA/Guarana. I would like to know if I should take all three pills at once or spread them out during the day.

Each CLA with Guarana softgel provides 60 milligrams of slow-release caffeine. For those who are over-sensitive to caffeine, taking all three at once may be too stimulating. If this is the case, then you can divide the dose to suit your needs. Some people find that taking one or two softgels about 1/2 hour before breakfast, lunch and an afternoon snack, suppresses their appetite.