48 | New Scientist | 20 February 2021
admittedly, both can be good for you. Even
the much-vaunted effects of exercise are
equivocal: only half of studies show positive
links with telomere length, most of them weak.
In fact, there is a lot of conflicting research.
For example, one study may say that physically
active people have longer telomeres for their
age, but another will find no effects. The same
goes for sleep quality and meditation. Even a
healthy diet doesn’t always come out as good
for your telomeres, despite some studies
revealing a robust connection. In 2019,
for instance, Finnish researchers showed
that a Mediterranean diet has little effect on
telomeres, while another study in Australia
found that antioxidant intake isn’t associated
with their length.
One reason for such inconsistencies is that
telomere research has been the victim of its
own success, with lots of the studies done by
scientists who specialise in other areas. “They
are just kind of excited about it, so they maybe
publish one or two papers and then move on,”
says Belinda Needham at the University of
Michigan. The result has been that not all
of the studies are of the highest standard.
There is another possible reason why
lifestyle interventions often seem to have little
effect on telomere length. In 2018, researchers
studying European starlings were surprised
to discover that birds with shorter telomeres
tended to engage in more risky behaviours
than those with longer telomeres. This
prompted a provocative idea: that people with
short telomeres may be more likely to adopt
some unhealthy behaviours. A meta-analysis
of smoking and telomere length published last
year seems to back this up. Smokers do have
shorter telomeres than non-smokers, but
smoking itself has little impact on how fast
your telomeres shorten. The researchers
calculated that it would take 167 years of
smoking to account for the telomere length
differences between smokers and non-
smokers. In other words, it looks like
smokers have shorter telomeres in the
first place, hinting that this might make
them more prone to adopting the risky habit.
So, perhaps when it comes to telomere
length and behaviour, we are getting causeand effect the wrong way around. Elissa Epel at
the University of California, San Francisco, who
co-authored a book called The Telomere Effect
with Blackburn, believes researchers must
explore this possibility. Causation could go
in both directions, she says, and be far from
simple. For example, there could be factors
that drive both telomere shortening and a
penchant for poor lifestyle choices, such as
exposure to childhood adversity.
All this suggests that we shouldn’t
necessarily base our lifestyle choices on the
results from telomere research. And there is
another reason we should be sceptical about
these studies. Many use a method called qPCR
to estimate telomere length. It is cheap and
easy to use, but prone to measurement errors,RE
UTER
S/ANUSH
RE
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ADNAVIS“ People with shorter
telomeres might be
more likely to adopt
risky behaviours”
Anti-ageing activity?
Yoga on a smoggy day
in New Delhi, India