Cutting back on steak, sausages and salami could help prolong your life, according to the most comprehensive study done on meat and mortality.
A team of researchers tracked half a million Americans over a decade and found those who ate more red and processed meats appear to have a "modestly increased" risk of dying from all causes, and specifically from cancer or heart disease.
In contrast, those who ate more white meat have a decreased risk of dying, and in particular of dying from cancer.
"The results complement the recommendations by the American Institute for Cancer Research and the World Cancer Research Fund to reduce red and processed meat intake to decrease cancer incidence," said Rashmi Sinha, a specialist in nutritional epidemiology at the National Cancer Institute in Bethesda, Md. The lead author of the study, published yesterday in the Archives of Internal Medicine, added that she is personally not a vegetarian.
Red meat is associated with death in several ways. Cancer-causing compounds are formed when meat is cooked at a high temperature. Meat is also a major source of saturated fat and contributes to risk factors for heart disease, including higher blood pressure and elevated cholesterol levels. Processed meats have a high level of sodium nitrate, considered by many to be carcinogenic.
Of the half million people in the study, 47,976 men and 23,276 women died over the 10-year period. They ranged in age from 50 to 71.
The study found that eating the equivalent of a four-ounce (quarter-pound) hamburger daily gave men and women a much higher risk of dying over all, and of dying of heart disease and cancer, compared with those who ate less than an ounce of red meat a day.
Eleven per cent of deaths in men and 16 per cent of deaths in women could have been prevented if they had decreased their meat consumption to the equivalent of a quarter of a small hamburger a day. The chance of men dying of cardiovascular disease would have decreased 11 per cent - and 21 per cent for women.
A similar trend was found in the consumption of processed meats. People whose diets contained more white meat had lower risks of death.
Study participants were recruited from AARP, formerly the American Association of Retired Persons and now a lobby group for people aged 50 and older. At the beginning of the study, participants filled in surveys about their eating habits, and then researchers monitored their health for a decade.
As with other nutritional epidemiology studies, the results are subject to potential error because the initial food surveys relied upon people's memories, which can be faulty. As well, the study cohort is better educated and healthier than the general population.
Red meat includes all kinds of beef and pork, bacon, cold cuts, hot dogs, sausage, liver and meats in pizza and stew. White meat includes chicken, turkey, fish and poultry cold cuts, tuna and chicken dogs.
The study comes at a time when levels of obesity, heart disease and certain cancers are reaching new highs, food prices are escalating and the world is experiencing an energy shortage.
An accompanying editorial in the Archives of Internal Medicine argues that people should not shun meat altogether because there are some nutritional benefits and its consumption has played an important role in the evolution of our species.
"The consensus is not that we should all become vegans or vegetarians," writes Barry Popkin, a nutrition professor at the University of North Carolina. "Rather the need is for a major reduction in total meat intake, [and]an even larger reduction in processed meat and other highly processed and salted animal-source food products."
Reducing our consumption of meat would also combat the rising global demand for animal foods, which has caused food prices to rise, according to the editorial. Raising livestock uses up valuable resources and increases greenhouse gas emissions. Two to five times the amount of water is needed to raise livestock, compared with that needed to grow legumes and grains.
To prevent cancer and heart disease, it is recommended people limit the intake of saturated fats and shift to a leaner diet, Dr. Popkin says. "Excessive consumption [of meat]is found only in the West and is generally far below norms in the low- and middle-income world," he concludes.