Hamburgers and hot dogs are getting even more grilling.
A new study indicates that eating unprocessed red meat (hamburger, pork, roast beef, lamb) and processed meats (bacon, hot dogs, bologna, sausage) may increase a person's risk of premature death and raise their risk of death from heart disease and cancer.
Conversely, substituting other foods such as fish, poultry, nuts and beans for red meat may lower their risk of premature death, the analysis suggests.
Other studies have linked eating red meat and processed meat to an increased risk of Type 2 diabetes, heart disease, some types of cancer, particularly colorectal cancer, and premature death.
"This new study provides further compelling evidence that high amounts of red meat may boost the risk of premature death," says the study's lead author, An Pan of the Harvard School of Public Health. But, he adds, this type of study shows association, which doesn't necessarily mean causation.
Pan and colleagues analyzed the diet, health and death data on 37,698 men and 83,644 women. Participants completed questionnaires about their diets every four years. During the study followup period of more than two decades, almost 24,000 of the participants died, including 5,910 from heart disease and 9,464 from cancer.
To determine the risk of eating unprocessed red meat or processed meat, the researchers factored out other lifestyle factors, including age, weight, physical activity and family history of heart disease, and dietary factors, such as intake of whole grains, fruit and vegetables, nuts, legumes, dairy products, fish and poultry.
Among the findings published online Monday in the Archives of Internal Medicine: Eating one serving a day of unprocessed red meat (about the size of a deck of cards) was associated with a 13 per cent increased risk in premature death; eating one serving a day of processed red meat (one hot dog or two slices of bacon) was associated with a 20 per cent increased risk of premature death.
Using a statistic model, the researchers estimated that replacing one serving a day of red meat with one serving of fish would decrease premature death by seven per cent; replacing it with poultry would decrease the risk by 14 per cent; nuts, 19 per cent; beans, 10 per cent; low-fat dairy, 10 per cent; whole grains, 14 per cent.
"The message we want to communicate is it would be great if you could reduce your intake of red meat consumption to half a serving a day or two to three servings a week, and severely limit processed red meat intake," Pan says.
He says the sodium and nitrites in processed red meat might explain the relatively higher risk found in processed compared with unprocessed red meat.
But the beef industry says this study doesn't prove red meat is the dietary villain. "Once again, what we are seeing here is an observational study that's limited because it can't establish cause and effect," says registered dietitian Shalene McNeill, executive director of human nutrition research for the National Cattlemen's Beef Association. "The most striking thing about this study is those who were eating higher intakes of red meat also were eating more calories, were less physically active, were more likely to smoke and ate fewer fruits, vegetables and whole grains."
Pan says those factors were taken into consideration in the statistical analysis to try to eliminate their impact, "but certainly, it is possible that other unmeasured or residual confounding effects from lifestyle exist."
McNeill says, "We have a recent randomized controlled trial that showed eating four to five ounces of lean beef daily as a part of a heart-healthy diet improved heart health, including lowering bad (LDL) cholesterol levels, as effectively as several other heart-healthy diets. There are many ways to build a healthy diet with lean beef that also includes fruits, vegetables, whole grains and legumes."
Robert Eckel, a past president of the American Heart Association, says the group does not set a limit on consumption of lean red meat but promotes an overall heart-healthy diet. "A small serving (about three ounces) of lean red meat several times a week can be added to an overall heart-healthy dietary pattern without concern. This amount is substantially below the level of risk reported by the Harvard group."
— USA Today