THE
recent heat sent many of us reaching for the sunscreen. But now, some experts
are warning this may not protect us against a potentially harmful sunray:
infrared.
Conventional
sunscreens are designed to block out ultraviolet light – UVA and UVB – the rays
that damage and burn the skin. However, these products do not block out
infrared rays.
These
rays, which were discovered in 1800, transmit heat, raise skin temperature and
are responsible for the warmth you feel when sitting in the sun.
Infrared
rays make up to half of the sun’s energy (UVA and UVB combined make up between
five per cent and seven per cent) and one type in particular, infrared A, can
penetrate the deepest layers of the skin – deeper than ultraviolet.
Recent
research in animals has suggested infrared A may play a role in skin cancer
when combined with exposure to UVB. Infrared A may also contribute to ageing of
the skin – scientists suggest it alters some of the biological processes
involved in maintaining healthy skin cells, affecting the production of
collagen, the protein that acts as scaffolding for the skin.
This
could ultimately result in wrinkles, sagging and ageing. The possible link
between infrared A and cancer was first noted in the Eighties. However, more
recent research at the University of Kiel in Germany found that mice exposed to
UVB and infrared A rays together developed faster-growing skin cancer tumours
than those exposed to UVB light alone, though those exposed to infrared A alone
did not.
So, how
can you protect yourself? Dr Lowe takes lycopene (an antioxidant found in
tomatoes and red fruit) and co-enzyme Q10 supplements, and wears UVA/ UVB sun
protection cream.
Also,
another study published last year found that just ten helpings of tomatoes a
week could help men reduce the risk of prostate cancer by almost a fifth.
Researchers
think that protection against the illness comes from a key chemical inside the
fruit known as lycopene. Tomato-based pasta sauce, tomato juice and even baked
beans and the tomato puree topping on pizza were all found to have a beneficial
effect.
Scientists
say men who doubled their intake of fruit and vegetables to the recommended
five portions a day reduced their risk by nearly a quarter.
In the
first study of its kind, researchers from the Universities of Bristol,
Cambridge and Oxford examined the diets and lifestyles of nearly 14,000 men
aged 50 to 69.
They
found that those who ate at least ten portions of tomatoes a week were 18 per
cent less likely to develop prostate cancer compared to those who had none, or
very few. One portion counted as 150g of tomatoes, half a tin of baked beans, a
portion of pizza with tomato puree, tomato-based pasta sauce or a glass of
tomato juice.
However,
the researchers urged men not to overindulge in baked beans, pizza and pasta
sauce as they can contain high levels of salt. Meanwhile, an earlier study
suggested that certain vegetables such as carrots, lettuce, spinach and
tomatoes could help improve sperm quality; sperm motility – how quickly a sperm
can swim towards an egg and sperm morphology – the size and shape of a sperm
(for the best chance of successfully conceiving, a sperm should have an oval
head and a long tail).
The study
published in the peer-reviewed medical journal Fertility and Sterility noted
that sperm quality could also be improved by quitting smoking if one smokes,
trying to achieve or maintain a healthy weight, drinking sensibly and keeping
the testicles cool.
The
researchers from Harvard School of Public Health and Universities in Canada,
Copenhagen, Murcia and New York, a study funded by a grant from the National
Institutes of Health and the European Union looked at young men’s diets and analysed
their sperm samples.
They
found that men who ate a higher amount of three antioxidants found in fruit and
vegetables had sperm with better motility and morphology.
The three
antioxidants in question were: beta-carotene – found in carrots, lettuce and
spinach; lutein – found in lettuce and spinach; lycopene – found in tomatoes.
According
to the study, men who ate higher levels of beta-carotene and lutein had a 6.5
per cent increase in sperm motility, and those who consumed higher levels of
lycopene had 1.7 per cent improved sperm morphology. However, this study
examined diet and sperm quality at the same time, so cannot prove cause and
effect.
Also, the
study involved young healthy men so the results may not apply to different
populations. “Still, increasing your intake of vegetables is unlikely to harm
you or your sperm and has many other health benefits.”
Dr. Nick
Lowe, a consultant dermatologist at London’s Cranley Clinic, says: “There’s no
conclusive link between infrared A exposure and skin cancer as there is with
UVA and UVB rays, but there is emerging evidence that they may be involved in
some way when combined with UVB.”
When it
comes to skin ageing, the evidence is stronger, according to Professor Jean
Krutmann of the Leibniz Research Institute for Environmental Medicine, in
Dusseldorf, a world authority on infrared A. “Infrared A damages the skin deep
down by interfering with enzymes that maintain healthy skin renewal,” she says.
“This means more collagen is broken down than is replenished, resulting in
premature ageing of the skin and loss of elasticity.”
Professor
Krutmann recently received a grant from the German Ministry of Science to use a
new type of lamp that can mimic the amounts of UVA, UVB and infrared A found in
natural sunlight to carry out further investigations in mice. Lowe adds: “We’ve
known since the Seventies from research on animals that infrared rays, and heat
in particular, produce changes in the skin, including increasing the size of
blood vessels and permanently affecting the elasticity of tissues. “Research
suggests repetitive exposure may lead to development of thread veins and
wrinkles more common in ageing skin.”
Crucially,
though sunscreen products usually contain protection against UVA and UVB, there
is no ingredient that has been proven to offer the same barrier protection
against infrared A. When sun creams were introduced in the Thirties, they only
helped protect against UVB rays.
It wasn’t
until the mid-Nineties that UVA rays were recognised as causing skin cancer, too,
and filters were added to sunscreens. “This may be what will happen with
infrared A rays, too, but we just don’t know yet,” says Lowe.
The one
major drawback, he says, is that there is no chemical filter that has been
proven to block the effects of infrared. “However, some antioxidants, including
vitamins C and E, and chemicals such as coenzyme Q10 may be able to help repair
or mop up damage caused by infrared A. “This is the subject of ongoing
research. The main problem is that there’s no regulation of ingredients or
equivalent to the SPF system of ratings.”
While sun
cream companies include antioxidants in their creams, in Britain only a few
brands offer specific protection against infrared A – these include Ladival and
Eriis.
Some
British dermatologists say more research is needed before it can be said that
specific protection against infrared A is needed. A spokesman for the British
Association of Dermatologists said more evidence was needed on infrared A
before it could consider changing its advice on effective sun protection.
Fiona
Osgun, health information officer at Cancer Research UK, says: “There’s no good
evidence that infrared light causes skin cancer.” Dr Bav Shergill, a consultant
dermatologist at Queen Victoria Hospital, East Grinstead, West Sussex, and a
member of the British Association of Dermatologists’ skin cancer committee, is
cautious, too. He says infrared A does appear to be linked to ‘a cascade of
reactions within the skin’, including breakdown of collagen, but adds: “It’s
too early to say whether this is clinically relevant. I am open to infrared A
having a cosmetic effect on the skin, though.”
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