Taking vitamin E, C and other antioxidants can do more harm than
4 December 2013
Research at the University of Oslo shows that taking antioxidant
supplements, including vitamins C and E, can upset the body's
inbuilt mechanism to handle stress and prevent damage to DNA. They
have also found a key to quadrupling lifespan, at least in
Hilde Nilsen and her research group at the Biotechnology Centre,
University of Oslo studied a one millimetre-long nematode called
Caenorhabditis elegans (C. elegans), which
lives for only 25 days but has 20 000 genes, almost as many as
humans. The DNA of C. elegans can easily be altered to increase its ability to repair DNA
damage, or remove it altogether.
In C. elegans that do not have the ability to repair the
damage, the researchers observed that they had a shorter lifespan,
on average three days. These mutants do not,
however, accumulate the DNA damage that would cause ageing, but
paradoxically have less DNA damage. This happens because the
nematode releases its own antioxidant defences — other repair
proteins — to protect the DNA. They do, however, have less ability
to respond to further stress.
It is thought that the purpose of the DNA
repairs is to ensure production of healthy offspring, not
necessarily to live as long as possible. Initiating a survival response that reinforces the
antioxidant defences means that a lack of ability to repair the DNA
has less impact than it would otherwise have on reproduction. To
the species as a whole, it’s a small cost that some individuals will
be less good at handling stress and have a shorter life.
"We have found several proteins that trigger this reprogramming.
The process has the same effect as a reduction in caloric intake,
which we know helps increase the lifespan in many species. In other
words, there are two routes to a long life. When we stimulate both
of these two routes in our nematode at the same time, we can
quadruple its normal lifespan," Nilsen says.
"This is where I start worrying about the synthetic
antioxidants. The cells in our body use this fragile balance to
establish the best possible conditions for themselves, and it is
specially adapted for each of us. When we take supplements of
antioxidants, such as C and E vitamins, we may upset this balance."
"It sounds intuitively correct that intake of a substance that
may prevent accumulation of damage would benefit us, and that’s why
so many of us supplement our diet with vitamins. Our research
results indicate that at the same time, we may also cause a lot of
harm. The health authorities recommend that instead, we should seek
to have an appropriate diet. I’m all in favour of that. It’s far
safer for us to take our vitamins through the food that we eat,
rather than through pills."
The Norwegian National Research Centre in Complementary and
Alternative Medicine (NAFKAM) investigated the volume of dietary
supplements consumed in Norway in 2012 and found:
- in the previous year, 70% of the population had purchased
- in total, Norwegians spent nearly NOK3 billion on pills or
beverages intended to supplement their diet;
- many people use dietary supplements as elements of an
alternative diet or in dosages that exceed the recommendations
given in the instruction leaflet.