Omega-3 Linked To Younger Biological
High blood levels of omega-3 fatty acids may slow cellular aging
in people with coronary heart disease, suggests a new study.
Researchers from the University of California, San Francisco
looked at the length of telomeres, DNA sequences at the end of
chromosomes that shorten as cells replicate and age.
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. Elizabeth Blackburn,
a telomere pioneer at the University of California San Francisco,
likened telomeres to the ends of shoelaces, without which the
lace would unravel.
With each replication the telomeres shorten, and when the telomeres
are totally consumed, the cells are destroyed (apoptosis). Previous
studies have also reported that telomeres are highly susceptible
to oxidative stress. Some experts have noted that telomere length
may be a marker of biological aging.
Among patients with stable coronary artery disease, there
was an inverse relationship between baseline blood levels of marine
omega-3 fatty acids and the rate of telomere shortening over 5
years, wrote the researchers, led by Ramin Farzaneh-Far.
These findings raise the possibility that omega-3 fatty
acids may protect against cellular aging in patients with coronary
heart disease, they added.
The research adds to a large body of science supporting the potential
health benefits of omega-3 fatty acids, particularly in relation
to heart health.
Several studies have shown increased survival rates among individuals
with high dietary intake of marine omega-3 fatty acids and established
cardiovascular disease. The mechanisms underlying this protective
effect are not well understood, according to background information
in the article.
The UCSF researchers looked at telomere length in blood cells
of 608 outpatients with stable coronary artery disease. The length
of telomeres was measured in leukocytes at the start of the study
and again after 5 years.
Comparing levels of omega-3 fatty acids, EPA (eicosapentaenoic
acid) and DHA (docosahexaenoic acid) with subsequent change in
telomere length, the researchers found that individuals with the
lowest average levels of DHA and EPA experienced the most rapid
rate of telomere shortening, while people with the highest average
blood levels experienced the slowest rate of telomere shortening.
Each 1-standard deviation increase in DHA plus EPA levels
was associated with a 32 per cent reduction in the odds of telomere
shortening, wrote the authors.
Commenting on the potential mechanism, Dr Farzaneh-Far and his
co-workers noted that this may be linked to oxidative stress,
known to drive telomere shortening. Omega-3 fatty acids have been
shown to reduce levels of F2-isoprostanes, a marker of systemic
oxidative stress, as well as increasing levels of the antioxidant
enzymes catalase and superoxide dismutase, thereby reducing oxidative
Another possible mechanism may involve the enzyme telomerase.
The enzyme works to maintain telomere length, and omega-3 may
increase its activity.
The researchers added that a double-blind, randomized, placebo-controlled
trial would be necessary to definitively confirm the link between
omega-3 fatty acids and cellular aging.
Multivitamins and green tea, too?
The work of the UCSF scientists was limited to people with CHD,
thereby limiting how general the results may be. Other studies
in healthy people have already linked specific nutrients to telomere
length, and subsequently a younger biological age.
Recently, researchers from the US National Institute of Environmental
Health Sciences reported that telomere length was longer in regular
multivitamin users in their cohort of 586 women aged between 35
and 74. The subjects did not have coronary heart disease.
Writing in the American Journal of Clinical Nutrition, the US-based
researchers noted that theirs was the first epidemiologic
study of multivitamin use and telomere length.
Regular multivitamin users tend to follow a healthy lifestyle
and have a higher intake of micronutrients, which sometimes makes
it difficult to interpret epidemiologic observations on multivitamin
use, they said.
An association between green tea drinkers and telomere length
was also reported by scientists from the Chinese University of
Hong Kong last year. The telomeres of people who drank an average
of three cups of tea per day were about 4.6 kilobases longer than
people who drank an average of a quarter of a cup a day, reported
the researchers in the British Journal of Nutrition..
This average difference in the telomere length corresponds to
approximately a difference of 5 years of life, wrote
the researchers, led by Ruth Chan.
Dr Chan told NutraIngredients in August 2009 that "Chinese
tea" in their study refers to both black and green tea, but
added: "Our data showed that majority of Chinese tea consumed
by our subjects were of green tea".
Source: Journal of the American Medical Association
January 22, 2010