People who eat a lot of red meat and processed meats have a higher risk of
several types of cancer, including lung cancer and colorectal cancer, US
researchers say.
The work is the first big study to show a link between meat and lung cancer.
It also shows that people who eat a lot of meat have a higher risk of liver
and esophageal cancer and that men raise their risk of pancreatic cancer by
eating red meat.
"A decrease in the consumption of red and processed meat could reduce the
incidence of cancer at multiple sites," Dr Amanda Cross and colleagues at
the US National Cancer Institute wrote in their report, published in the
Public Library of Science journal PLoS Medicine.
The researchers studied 500,000 people aged 50 to 71 who took part in a diet
and health study done in conjunction with the AARP, formerly the American
Association for Retired Persons.
After eight years, 53,396 cases of cancer were diagnosed.
"Statistically significant elevated risks [ranging from 20 per cent to 60
per cent] were evident for esophageal, colorectal, liver, and lung cancer,
comparing individuals in the highest with those in the lowest quintile of
red meat intake," the researchers wrote.
The people in the top 20 per cent of eating processed meat had a 20 per cent
higher risk of colorectal cancer – mostly rectal cancer – and a 16 per cent
higher risk for lung cancer.
"Furthermore, red meat intake was associated with an elevated risk for
cancers of the esophagus and liver," the researchers wrote.
These differences held even when smoking was accounted for.
"Red meat intake was not associated with gastric or bladder cancer,
leukemia, lymphoma, or melanoma," added the researchers.
Red meat was defined as all types of beef, pork and lamb.
Processed meat included bacon, red meat sausage, poultry sausage, luncheon
meats, cold cuts, ham and most types of hot dogs including turkey dogs.
Meats can cause cancer by several routes, the researchers wrote.
"For example, they are both sources of saturated fat and iron, which have
independently been associated with carcinogenesis," the researchers wrote.
Meat is also a source of several chemicals known to cause DNA mutations,
including N-nitroso compounds (NOCs), heterocyclic amines (HCAs) and
polycyclic aromatic hydrocarbons (PAHs).
Jeanine Genkinger of Georgetown University in Washington, DC, and Anita
Koushik of the University of Montreal in Canada said the findings fitted in
with other research.
"Meat consumption in relation to cancer risk has been reported in over a
hundred epidemiological studies from many countries with diverse diets,"
they wrote in a commentary.
# – Prahladananda Swami – 13/1/08