Health
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Anil AnanthaswamyLonger telomere length will become one ingredient in a recipe for successful mental and bodily ageing.A SIGN of a cell's age could help predict the onset of dementia. Elderly people are more likely to develop cognitive problems if their telomeres - the stretches of DNA that cap the ends of chromosomes - are shorter than those of their peers.
The shortening of telomeres is linked to reduced lifespan, heart disease and osteoarthritis. Telomeres naturally shorten with age as cells divide, but also contract when cells experience oxidative damage linked to metabolism. Such damage is associated with cognitive problems like dementia. Thomas von Zglinicki at Newcastle University, UK, showed in 2000 that people with dementia not caused by Alzheimer's tended to have shorter telomeres than people without dementia.
To see if healthy individuals with short telomeres are at risk of developing dementia, Kristine Yaffe at the University of California, San Francisco, and colleagues, followed 2734 physically fit adults with an average age of 74.
Yaffe's team tracked them for seven years and periodically assessed memory, language, concentration, attention, motor and other skills. At the start, the researchers measured the length of telomeres in blood cells and grouped each person according to short, medium or long telomeres.
After accounting for differences in age, race, sex and education, the researchers found that those with long telomeres experienced less cognitive decline compared to those with short or medium-length telomeres (Neurobiology of Aging, DOI: 10.1016/j.neurobiolaging.2009.12.006).
Von Zglinicki calls the work a "carefully done, large study", but notes that short telomeres by themselves are not enough to predict whether an individual will get dementia.
The key, says Ian Deary at the University of Edinburgh, UK, will be to combine telomere length with other biomarkers. "Most likely, longer telomere length will become one ingredient in a recipe for successful mental and bodily ageing."
Longer telomere length will become one ingredient in a recipe for successful mental and bodily ageing.
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A study conducted by researchers at the National Institutes of Health has provided the first epidemiologic evidence that the use of multivitamins by women is associated with longer telomeres: the protective caps at the ends of chromosomes that shorten with the aging of a cell. The study was reported online on March 11, 2009 in the American Journal of Clinical Nutrition.
Telomere length has been proposed as a marker of biological aging. Shorter telomeres have been linked with higher mortality within a given period of time and an increased risk of some chronic diseases.
For the current research, Honglei Chen and colleagues evaluated 586 participants aged 35 to 74 in the Sister Study, an ongoing prospective cohort of healthy sisters of breast cancer patients. Dietary questionnaires completed upon enrollment collected information concerning food and nutritional supplement intake. Stored blood samples were analyzed for leukocyte (white blood cell) DNA telomere length.
Sixty-five percent of the participants reported using multivitamin supplements at least once per month, and 74 percent consumed them daily. Eighty-nine percent of all multivitamin users consumed one a day multivitamin formulas, 21 percent consumed antioxidant combinations, and 17 percent were users of "stress-tabs" or B complex vitamins.
The researchers found 5.1 percent longer telomeres on average in daily users of multivitamins compared with nonusers. Increased telomere length was associated with one a day and antioxidant formula use, but not with stress-tabs or B complex. Individual vitamin B12 supplements were associated with increased telomere length and iron supplements with shorter telomeres. When nutrients from food were analyzed, vitamins C and E emerged as protective against telomere loss.
In their discussion of the findings, the authors explain that telomeres are particularly vulnerable to oxidative stress. Additionally, inflammation induces oxidative stress and lowers the activity of telomerase, the enzyme that that is responsible for maintaining telomeres. Because dietary antioxidants, B vitamins, and specific minerals can help reduce oxidative stress and inflammation, they may be useful for the maintenance of telomere length. In fact, vitamins C and E have been shown in cell cultures to retard telomere shortening and increase cellular life span.
"Our study provides preliminary evidence linking multivitamin use to longer leukocyte telomeres," the authors conclude. "This finding should be further evaluated in future epidemiologic studies and its implications concerning aging the etiology of chronic diseases should be carefully evaluated."
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