|
Millions of people are
at risk of getting cancer unless they slash levels of alcohol and red meat in their diets,
medical experts have warned in a landmark study.
The most comprehensive
review of the evidence linking obesity, diet and physical activity to the chances of
developing cancer recommends sweeping changes to our lifestyles if we are to combat rising
cancer rates.
Current guidelines on
the intake of alcohol and red meat should be nearly halved while people should try to be at
the slimmer end of the recommended weight limits in order to lower their risk of developing
the disease.
People must be leaner,
take more exercise, eat more whole foods, virtually cut out alcohol, consume less red meat
and eat no bacon or ham at all.
Mothers should
breastfeed their children in order to reduce their own risk of developing cancer and that of
their children, the 500-page report from the World Cancer Research Fund
said.
A panel of 21 world
experts spent five years evaluating what increases the risk of cancer and what decreases it
based on an in-depth analysis of 7,000 cancer studies from around the world dating back to
the 1960s.
After smoking, obesity
is the most important risk for developing cancer and it is thought one third of the 300,000
cases of cancer in the UK every year are linked to diet.
Excess body fat can
cause six different types of common cancers, including those affecting the breast, bowel and
pancreas.
Prof Sir Michael Marmot,
from University College London, who chaired the panel, said the strength of the link between
body fat and cancer was 'the most striking thing to emerge from the
report'.
He said: "Not only
should we avoid obesity and being overweight but the healthiest thing is to be as lean as
possible within the healthy range. Young adults should try not to put on weight through their
adult life and to stay as lean as possible."
But he added that for
people who are already overweight there is limited evidence on whether losing weight will
decrease the risk of developing cancer. He said it is thought the risk would gradually reduce
over time with weight loss.
Sir Michael said: "I was
a bit shocked at the idea that we were saying be as be as lean as possible. A Body Mass Index
of 23 is fine but it would be finer if it were lower - that is what the evidence shows, so
important is the link between weight and cancer."
The recommendations on
avoiding sugary drinks and high calorie foods is related to maintaining a healthy body weight
along with encouraging more physical activity, although exercise as been shown independently
to reduce the risk of colorectal cancer.
There are no such things
as superfoods as far as cancer risk goes as single vegetables, berries or fruits cannot be
taken in isolation as having a significant protective effect, the panel said. Foods like
broccoli, garlic, chocolate and red wine have been singled out because they contain compounds
which seem to have an effect on cancer, they said.
Sir Michael said the
evidence that fruit and vegetables protect against cancer is not as overwhelming as it was
but there was 'probably' still an effect.
He said the evidence on
colorectal cancer and red meat is now 'convincing' and the safe limit of 500g was chosen
because above that level cancer risk clearly rises. Previous guidance had said 900g a week
was safe.
Sir Michael added that
the evidence on processed meat is even stronger, so any meat that has been cured, salted,
preserved or smoked should be avoided altogether.
Alcohol consumption is
clearly linked with several cancers including breast so should be avoided but this is in
conflict with recommendations from the British Heart Foundation which found that moderate
drinking can protect against heart disease.
So, in order to be
consistent but also limit cancer risk, alcohol should be limited to one unit a day for women
and two for men- this is half the current safe recommended limits issued by the Department of
Health.
The report was welcomed
by scientists and cancer patient groups.
Pamela Goldberg, Chief
Executive Breast Cancer Campaign said "A recent survey carried out for Breast Cancer Campaign
by Ipsos MORI showed that less than ten per cent of women knew that a diet high in saturated
fat and high alcohol consumption increased the chances of developing breast cancer, which was
their biggest health fear.
"The advice to lead a
healthy lifestyle, maintain a healthy body weight and adopt general good health has never
been more relevant. Although breast cancer survival rates are increasing, the disease can be
prevented or the risk reduced."
Dr Lesley Walker, Cancer
Research UK's director of cancer information, said: "We know that lifestyle choices can
affect cancer risk. After smoking, obesity is the biggest risk factor for cancer and the
evidence showing the link continues to strengthen.
"We have been
disappointed with the Government's response to the problem of
obesity.
"We need to make the
healthy choice the easy choice in all aspects of our lives. The obesity epidemic is being
referred to as a health time bomb with significant problems for individuals as well as a
nation. We must take action to defuse this bomb while we still can."
Recommendations to
reduce the risk of developing cancer
• A body mass index
(weight divided by height squared) of between 18.5 and 23.
• One hour of moderate
exercise, such as swimming or housework, a day or 30 minutes of vigorous exercise, such as
jogging or football.
• Avoid sugary drinks
and processed food.
• Eat wholegrains and
beans at every meal and at least five portions of fruit and vegetables daily. Limit
starch.
• Only 500g of red meat
a week, ie two 8oz steaks. Avoid processed meat, ie bacon, ham, burgers,
salami.
• Less than one unit of
alcohol a day for women; two units a day for men.
• No more than six grams
of salt a day.
• Avoid supplements to
protect against cancer.
• Mothers should
breastfeed for six months.
|
