Eating Red and Processed Meats May Increase Risk of Death

This health effect does not extend to consumption of poultry. Researchers found that a higher intake of white meat results in a slightly decreased risk for overall death and cancer death.

Rashmi Sinha, PhD, and colleagues at the National Cancer Institute at Rockville studied the association between meat intake and risk of death among more than 500,000 people who were part of the National Institutes of Health-AARP Diet and Health Study.

Participants were recruited from six states - California, Florida, Louisiana, New Jersey, North Carolina, and Pennsylvania - and from metropolitan areas - Atlanta, Georgia, and Detroit, Michigan. Questionnaires on demographic and lifestyle characteristics, including dietary habits, were mailed to 3.5 million members of AARP [The American Association of Retired Persons] in 1995.

Grilled meats at the Los Angeles County Fair (Photo by Chris Cho)

The approximately 500,000 participants were then followed for 10 years through Social Security Administration Death Master File and National Death Index databases. Participants filled out questionnaires at the five year mark and the 10 year mark. During the follow-up period, 47,976 men and 23,276 women died.

The one-fifth of men and women who ate the most red meat, such as steaks and burgers, - a median or midpoint of 62.5 grams (2.2 ounces) per 1,000 calories per day - had a higher risk for overall death, death from heart disease and death from cancer than the one-fifth of men and women who ate the least red meat - a median of 9.8 grams (.34 ounces) per 1,000 calories per day.

The one-fifth of men and women who ate the most processed meat, such as cured bacon and sausages - a median of 22.6 grams per 1,000 calories per day - had a higher risk of death than those who ate the least amount of processed meat - 1.6 grams per 1,000 calories per day.

"For overall mortality, 11 percent of deaths in men and 16 percent of deaths in women could be prevented" if people decreased their red meat consumption to the lowest level, write the authors in their study, published in the Journal of the American Medical Association's Archives of Internal Medicine on Monday.

Death from cardiovascular disease dropped 11 percent in men and a 21 percent in women if the red meat intake was decreased to the amount consumed by people in the lowest one-fifth of the study group, the authors write.

For women eating processed meat at the lowest level, the decrease in cardiovascular disease mortality was about 20 percent, compared to women eating the most processed meat, the study found.

Processed meats on display (Photo credit unknown)

In general, the researchers found that those with the highest red meat intake tended to be married, more likely of non-Hispanic white ethnicity, more likely a current smoker, have a higher body mass index, and have a higher daily intake of energy, total fat, and saturated fat than those consuming the lowest amount of red meat. They also tended to have lower education and physical activity levels and lower fruit, vegetable, fiber, and vitamin supplement intakes, the study shows.

These may be "conservative estimates," the authors caution, because the study participants "were predominantly non-Hispanic white, more educated, consumed less fat and red meat and more fiber and fruits and vegetables, and had fewer current smokers than similarly aged adults in the U.S. population."

Still, they write, "it is unlikely that the mechanisms relating meat to mortality differ quantitatively between our study population and other white populations older than 50 years."

The American Meat Institute, a trade association of companies that process 95 percent of red meat and 70 percent of turkey in the United States, faulted the study for "relying on notoriously unreliable self reporting about what was eaten in the preceding five years."

"No doubt many participants guessed extensively in an effort to recall five years of habits and answer 35 pages of questions. Health conclusions and public policy recommendations should not be based on mere guesses," said AMI Executive Vice President James Hodges.

"This imprecise approach is like relying on consumers' personal characterization of their driving habits in prior years in determining their likelihood of having an accident in the future," he said.

But the authors point out that in relation to cancer, meat is a source of several multi-site carcinogens, including heterocyclic amines and polycyclic aromatic hydrocarbons, which are both formed during high-temperature cooking of meat, as well as N-nitroso compounds.

"Iron in red meat may increase oxidative damage and increase the formation of N-nitroso compounds. Furthermore, meat is a major source of saturated fat, which has been positively associated with breast and colorectal cancer," they write.

In relation to cardiovascular disease, they write, "elevated blood pressure has been shown to be positively associated with higher intakes of red and processed meat, even though the mechanism is unclear, except that possibly meat may substitute for other beneficial foods such as grains, fruits, or vegetables."

Reducing meat consumption also will have beneficial effects on the environment, writes Barry Popkin, PhD, of the University of North Carolina, Chapel Hill in an editorial accompanying the study. "There is a global tsunami brewing, namely, we are seeing the confluence of growing constraints on water, energy and food supplies combined with the rapid shift toward greater consumption of all animal source foods," he says.

"Not only are components of the animal-source foods linked to cancer, as shown by Sinha et al, but many other researchers have linked saturated fat and these same foods to higher rates of cardiovascular disease," Dr. Popkin writes.

Because there are health benefits to eating some red and white meats, although not processed meats, the consensus is not for a complete shift to vegan or vegetarian diets, Dr. Popkin concludes. "Rather, the need is for a major reduction in total meat intake, an even larger reduction in processed meat and other highly processed and salted animal source food products and a reduction in total saturated fat."

Click here to read the full study results.

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