Grow Youthful: How to Slow Your Aging and Enjoy Extraordinary Health
Grow Youthful: How to Slow Your Aging and Enjoy Extraordinary Health

Green tea and healthy aging

Green tea and your brain

Cellular aging

Creaking knees?

Skin care

Green tea supplements may be harmful

How to make the best cup of green tea

Buy Organic Matcha Green Tea Powder (Australia only)

References

Green tea and your brain

Turn on your kettle to lower your risk of dying from a stroke by up to 42%. In a large study of women, those who sipped at least five cups of green tea daily had a 42 percent lower risk of death due to stroke vs. those who drank less than one cup a day. Five cups per day seems a lot, but remember that it is traditionally made very weak. Another study (10) showed that three cups per day lowers the risk of a stroke by 21%.

Another study (5) showed that older people who drank at least 2 cups of antioxidant-rich green tea per day were 50 percent less likely to develop cognitive impairment vs. those who drank 3 or fewer cups per week. Other proven ways to keep your brain sharp include exercising it regularly with puzzles, learning virtually anything, and problem solving.

A large 2015 meta study showed that green tea has a significant protection effect against liver diseases. (7, 8) A 2015 meta study of 22,817 participants with 4,743 cases of depression found a 37% decrease in the risk of depression for those drinking three cups per day. (9) A meta study (11) covering more than 850,000 people found that drinking at least three cups of green tea per day lowered the risk of heart disease by 27%, fatal heart attack by 26%, stroke by 18%, and several other cardiovascular diseases by similar percentages. It also protects against diabetes (12) and prostate cancer. (13)

Cellular aging

The appearance of green tea in three different stages

The best water temperature for green tea is about 71-82 Centigrade (160-180 Fahrenheit). If you don't have a thermometer, simply boil the water then remove it from the heat source and wait for a minute.

In a Chinese study (1) of men who drank green or oolong tea, the cells of the most enthusiastic tea drinkers showed about five fewer years worth of wear and tear compared to the cells of those who drank little tea. Those who benefitted drank three or more cups of green or oolong tea each day. Those who did not benefit drank less than one cup.

This study examined the participants' telomeres to see how their cells had aged. Telomeres are the protective caps on the end of your DNA strands. Each time your cells divide the telomeres shorten a little, and eventually old cells are not able to replicate properly. The study showed that the most devoted tea drinkers had significantly longer telomeres than those who drank less than a cup a day.

The researchers think it's the antioxidants in the tea that help maintain your telomeres. Interestingly, it was only men who benefited from this effect - not women. This may be because some of the feminine hormones already provide the same protection. But there are plenty of other reasons for women to drink green and oolong tea!

Creaking knees?

Potent compounds in green tea - EGCG and ECG - can help you avoid knee pain and keep your joints healthy (2). A green-tea devotee is more likely to have youthful knees from the powerful flavonoids being sipped. The catechins EGCG and ECG found in green tea help reduce inflammation, and also cartilage and collagen destruction in arthritic joints, preventing both osteoarthritis and rheumatoid arthritis.

Other research (4) shows that just two cups per day significantly reduces the risk of dying from heart disease. The reason is not entirely clear, but it is probably because of the artery-friendly polyphenols in green tea.

A meta-study (6) showed a slight decrease in lung cancer risk for green tea drinkers.

Skin care

Use the remaining tea in your pot or cup on your skin. Dab it on with a swab or cloth. Green tea is a fantastic antioxidant moisturiser, and costs almost nothing compared to others in the shops.

Green tea supplements may be harmful

Throughout Grow Youthful I recommend that people generally do not take supplements. Supplements are only justified in rare cases where the body has a specific deficiency and consuming foods that are rich in the missing nutrient is still not enough to make up the deficiency. Green tea is yet another example of this rule in action.

Millions of people take green tea supplements safely, but at least 80 cases of liver injury linked to green tea supplements have been reported around the world. People taking green tea supplements have caused themselves symptoms ranging from lethargy, exhaustion and jaundice to severe liver and kidney injury requiring transplants. (14, 15, 16, 17)

Professor Herbert Bonkovsky, director of liver services at Wake Forest University School of Medicine in North Carolina has been tracking injuries linked to green tea supplements for nearly 20 years. He says "If you are drinking modest amounts of green tea you're very safe ... The greater risk comes in people who are taking these more concentrated extracts."

Researchers have concentrated on a potentially toxic ingredient called Epigallocatechin-3-gallate or EGCG, the most abundant of the naturally-occurring catechins with antioxidant properties in green tea.

People taking green tea extracts are often trying to lose weight, according to Professor Bonkovsky. "We know from animal studies that fasted animals absorb a much higher percentage of the catechins than do fat animals. There may well be other factors of other drugs, other chemicals, use of alcohol that are also important as modifying factors."

A recent investigation by the European Food Safety Authority into the safety of green tea concluded that the catechins in green tea brewed as a normal tea are generally safe, but when taken as supplements catechin doses at or above 800mg per day could cause problems. The EFSA did not say what a safe supplement dose is, and called for more research.

How to make the best cup of green tea

Most herbal teas and common black tea should be prepared with boiling water, but with green tea it is important not to scald the delicate phytonutrients. The best water temperature for green tea is about 71-82 degrees Centigrade (160-180 Fahrenheit). If you don't have a thermometer, simply boil the water then remove it from the heat source and wait for a minute. The steeping time is also important for the most flavorful and beneficial cup. Herbal teas need steeping for 5 to 20 minutes depending on the herb, and black teas for 2 to 6 minutes according to taste. However this is too long for delicate green tea and may affect its flavour and potency. Green tea should be steeped for only 2 to 3 minutes. Traditionally, green tea is made very weak - just a pinch in a whole pot of tea.

Buy Organic Matcha Green Tea Powder (Australia only)

References

1. Chan R, Woo J, Suen E, Leung J, Tang N. Chinese tea consumption is associated with longer telomere length in elderly Chinese men. Journal of Nutrition, May 2001. 131(5):1449-1451.Br J Nutr. 2010 Jan;103(1):107-13. Epub 2009 Aug 12.

2. Adcocks, C., Collin, P., Buttle, D. J. Catechins from green tea (Camellia sinensis) inhibit bovine and human cartilage proteoglycan and type II collagen degradation in vitro. Journal of Nutrition 2002 Mar;132(3):341-346.

3. Ahmed, S., Wang, N., Lalonde, M., Goldberg, V. M., Haqqi, T. M. Green tea polyphenol epigallocatechin-3-gallate (EGCG) differentially inhibits interleukin-1 beta-induced expression of matrix metalloproteinase-1 and -13 in human chondrocytes. Journal of Pharmacology and Experimental Therapeutics 2004 Feb;308(2):767-773.

4. Kuriyama, S. et al. Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study. Journal of the American Medical Association 2006 Sep 13;296(10):1255-1265.

5. Kuriyama, S., Hozawa, A., Ohmori, K., Shimazu, T., Matsui, T., Ebihara, S., Awata, S., Nagatomi, R., Arai, H., Tsuji, I. Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project. The American Journal of Clinical Nutrition 2006 Feb;83(2):355-361.

6. Tang N., Wu Y., Zhou B., Wang B., Yu R. Green tea, black tea consumption and risk of lung cancer: a meta-analysis. Lung Cancer. 2009 Sep;65(3):274-83.

7. Xueru Yin, Jiqiao Yang, Tony Li, Liyan Song, Tinglu Han, Mei Yang, Huihua Liao, Jianjun He, Xiaozhu Zhong. The effect of green tea intake on risk of liver disease: a meta analysis. Int J Clin Exp Med. 2015; 8(6): 8339-8346. Published online 15 Jun 2015.

8. Jin X, Zheng RH, Li YM. Green tea consumption and liver disease: a systematic review. Liver Int. 2008 Aug;28(7):990-6. doi: 10.1111/j.1478-3231.2008.01776.x. Epub 2008 May 15.

9. Dong X, Yang C, Cao S, Gan Y, Sun H, Gong Y, Yang H, Yin X, Lu Z. Tea consumption and the risk of depression: a meta-analysis of observational studies. N Z J Psychiatry. 2015 Apr;49(4):334-45. doi: 10.1177 / 0004867414567759. Epub 2015 Feb 5.

10. Lenore Arab, Weiqing Liu, David Elashoff. Green and Black Tea Consumption and Risk of Stroke. Stroke. 2009; 40: 1786-1792. Published online before print February 19, 2009, doi: 10.1161 / STROKEAHA.108.538470.

11. Chi Zhang, Ying-Yi Qin, Xin Wei, Fei-Fei Yu, Yu-Hao Zhou, Jia He. Tea consumption and risk of cardiovascular outcomes and total mortality: a systematic review and meta-analysis of prospective observational studies. European Journal of Epidemiology, February 2015, Volume 30, Issue 2, pp 103-113.

12. Yang WS, Wang WY, Fan WY, Deng Q, Wang X. Tea consumption and risk of type 2 diabetes: a dose-response meta-analysis of cohort studies. Br J Nutr. 2014 Apr 28;111(8):1329-39. doi: 10.1017 / S0007114513003887. Epub 2013 Dec 13.

13. Zheng J, Yang B, Huang T, Yu Y, Yang J, Li D. Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies. Nutr Cancer. 2011;63(5):663-72. doi: 10.1080/01635581.2011.570895. Epub 2011 Jun 11.

14. Victor J. Navarro, Herbert L. Bonkovsky, Sun-Il Hwang, Maricruz Vega, Huiman Barnhart, Jose Serrano. Catechins in Dietary Supplements and Hepatotoxicity. Digestive Diseases and Sciences, September 2013, Volume 58, Issue 9, pp 2682-2690.

15. Leonard B.Seeff, Herbert L.Bonkovsky, Victor J.Navarro, GuqiWang. Herbal Products and the Liver: A Review of Adverse Effects and Mechanisms. Gastroenterology, Volume 148, Issue 3, March 2015, Pages 517-532.

16. Naga Chalasani, Herbert L. Bonkovsky, Robert Fontana, William Lee, Andrew Stolz, Jayant Talwalkar, K. Rajendar Reddy, Paul B. Watkins, Victor Navarro, Huiman Barnhart, Jiezhun Gu, Jose Serrano. Features and Outcomes of 899 Patients With Drug-Induced Liver Injury: The DILIN Prospective Study. Gastroenterology, Volume 148, Issue 7, June 2015, Pages 1340-1352.

17. Bonkovsky, Herbert L. Hepatotoxicity Associated with Supplements Containing Chinese Green Tea (Camellia sinensis). Annals of Internal Medicine; Philadelphia Vol. 144, Iss. 1, (Jan 3, 2006): 68-71.