Weekly Health Update: green tea

Health Report:

Green Tea, Aging & Lifespan

"A critical weekly review of important new research findings for health-conscious readers..."

By, Robert A. Wascher, MD, FACS

Updated: 09/07/2009

The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.

GREEN TEA, AGING & LIFESPAN

Many health claims have been made for green tea, and as with the vast majority of over-hyped fad foods and nutritional supplements, the majority of such claims will, inevitably, turn out to be overstated or false. However, recent and ongoing clinical research continues to suggest that, at least in the laboratory environment, key chemical components of green tea (catechins) may indeed have potentially beneficial health properties. Specifically, research in the areas of cardiovascular health and cancer prevention have suggested that green tea catechins might actually be able to decrease the risk of these two top killers, although, in the interest of remaining objective, not all research in these areas has been uniformly favorable.

Now, a newly published public health study of elderly Chinese adults suggests that increased green tea intake, at least in elderly Chinese men, may be associated with a potential increase in lifespan. In this epidemiological study, just published in the British Journal of Nutrition, a total of 976 men and 1,030 women aged 65 and older were initially evaluated in 2006. In addition to daily food intake questionnaires, the blood of these research volunteers was tested for telomere length, in an effort to identify any dietary or other lifestyle factors that might be associated with lifespan-lengthening preservation of telomere length.

Telomeres can be thought of as protective “caps” at the ends of every chromosome in our body. With every division of the cells of our body, small pieces of our telomeres are lost. After a certain number of cell divisions, our cells lose their protective telomeres and die. This cumulative process of telomere loss and cell death (senescence), over the course of our lives, is thought to directly determine the potential lifespan of humans and other creatures, and has also been implicated in the process whereby many cancer cells become “immortalized.” In addition to aging (due to cumulative telomere loss with each cell division), inflammation and other biochemical stresses (including increased dietary fat intake) on our bodies can also prematurely shorten the length of telomeres in our cells, resulting in a shortened lifespan and an increased risk of developing cancer (and, perhaps, an increased risk of cardiovascular disease as well). Interestingly, the rate of telomere loss appears to be more rapid in men, and this is thought to be one of the most important biological factors underlying the generally shorter lifespan of men, compared to women.

Scientists can actually roughly estimate a person’s age by measuring the length of telomeres in their blood cells. Moreover, variations in telomere length between individuals can also be used as a rough guide to potential differences in lifespan between such individuals. In this innovative public health study, differences in telomere length among the 2,006 elderly research volunteers participating in this study were then matched to variations in the diets and lifestyles of these Chinese patients.

After adjusting for other health, lifestyle, and nutritional factors known to be associated with telomere length, the scientists conducting this study determined that a high level of green tea consumption was associated with longer telomeres in elderly Chinese men. After measuring the average difference in telomere length between men who consumed the most green tea and those who consumed the least, the researchers calculated a potential lifespan difference of 5 year between these two groups of men (the effects of green tea length on telomere length in the elderly Chinese women was less significant in this study, however). The researchers also determined that increased dietary fat and oil intake was also associated with a decrease in the length of telomeres in women (as has been noted in both men and women in previous studies, particularly in association with meat intake).

Therefore, in summary, the frequent consumption of green tea appears to be linked with longer telomere length, at least in elderly Chinese men. This finding suggests that, on average, such men may be approximately 5 years “younger,” physiologically speaking, than their same-aged counterparts who rarely drink green tea!

This study, unfortunately, did not identify the same telomere protective effect for green tea in elderly Chinese women, although this finding does not exclude the possibility that women may also derive similar benefit from regular green tea consumption. As it is already known that males lose telomere length more rapidly than females over the course of their lives, the gender-based differences in telomere length preservation observed in this study may arise from green tea catechins’ reversal of male-specific causes of increased telomere shortening, although this has not yet been scientifically confirmed. (I should also add that Vitamin D, which has recently gained a great deal of research attention in the areas of cardiovascular disease and cancer, as well, has also been associated with telomere length preservation.)

I will delve much more deeply into the potential cancer prevention roles of green tea catechins and Vitamin D in my new book, “A Cancer Prevention Guide for the Human Race,” which is due to be published in early 2010.

Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity

Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and a Surgical Oncologist at the Kaiser Permanente healthcare system in Orange County, California

Weekly Health Update

Monday, September 7, 2009

Green Tea, Aging & Lifespan

Tuesday, July 7, 2009

Prostate Cancer & Green Tea

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