by Craig Weatherby
Last month, we reported on a study showing that people who take multivitamins have “younger” cells.
In that research, scientists looked at the length of DNA sequences at the end of chromosomes—called “telomeres”—that shorten as cells replicate and age.
(See “Vitamin Studies Paint a More Positive Prevention Picture”)
Now, a study from China suggests that the telomeres of men—but oddly, not women—who drink three cups of tea daily people are about five years “younger” that the telomeres of those who drink less tea (Chan R et al. 2009).
There is already growing evidence that daily tea drinking is associated with reduced risks for cancer, cardiovascular disease, and tooth decay.
And the new findings may add anti-aging effects to tea's potential benefits.
Details of the tea-telomere study
Hong Kong-based researchers measured the telomere lengths of 976 Chinese men and 1,030 Chinese women aged over 65, whose dietary habits were collected using a diet questionnaire.
After they adjusted the results for demographic and lifestyle factors that affect telomere length, the researchers found that, compared with drinking a quarter of a cup a day, drinking three cups of tea daily was associated with longer telomere length.
Oddly, this link was only seen in men. And only tea—no other foods or beverages—was associated with longer telomere lengths.
Although the study included people who drank either black or green tea, most of the subjects drank green tea.
The Chinese team, led by Dr. Ruth Chan proposed that the antioxidant properties of tea may protect telomeres.
Green tea is rich in potent polyphenol antioxidants called catechins, including epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin. (This is even more true of white tea.)
Raw cocoa and the rare chocolate made from it—such as Vital Choice 80% Extra Dark—is another good source of catechins, as well as other beneficial polyphenols.
Can tea and cocoa lenghten lives as well as the length of telomeres? Only more research can tell, and we got some intriguing indications from a study published two years ago.
Telomeres, antioxidants, and aging
A recent study in Amish people found that having longer telomeres is associated with living longer, and that the length of people's telomeres may be partly an inherited trait.
As the University of California, San Francisco researchers wrote, “Our data, which are based on one of the largest family studies of human telomere length, support a link between telomere length and aging and lifespan and suggest a strong genetic influence...” (Shuldiner AR et al 2007).
Telomere length is considered a marker of aging, and antioxidants may help preserve telomere length by reducing oxidative stress from free radicals, and related chronic inflammation.
The aging and lifespan of normal, healthy cells are linked to the so-called “telomerase shortening mechanism,” which limits cells to a fixed number of divisions.
During cell replication, the telomeres function by ensuring the cell's chromosomes do not fuse with each other or rearrange, which can lead to cancer.
With each replication of a cell the telomeres shorten, and when the telomeres are totally consumed, the cells are destroyed in a sort of programmed suicide call apoptosis.
Researchers compare telomeres to the caps on shoelaces, without which they'd unravel. Previous studies have shown that telomeres fray in response to oxidative stress exerted by free radicals.
So it makes sense that antioxidants would help protect telomeres and lengthen the life-spans of cells, with possible implications for the life-spans of people.
- Chan R, Woo J, Suen E, Leung J, Tang N. Chinese tea consumption is associated with longer telomere length in elderly Chinese men. Br J Nutr. 2009 Aug 12:1-7. [Epub ahead of print]
- Njajou OT, Cawthon RM, Damcott CM, Wu SH, Ott S, Garant MJ, Blackburn EH, Mitchell BD, Shuldiner AR, Hsueh WC. Telomere length is paternally inherited and is associated with parental lifespan. Proc Natl Acad Sci U S A. 2007 Jul 17;104(29):12135-9. Epub 2007 Jul 10.