“The association between consumption of red and processed meats and cancer, particularly colorectal cancer, is very consistent,” says Marji McCullough, PhD, a nutritional epidemiologist with the American Cancer Society.
After a systemic review of scientific studies, an expert panel of the World Cancer Research Fund and the American Institute for Cancer Research concluded in 2007 that “red or processed meats are convincing or probable sources of some cancers.” Their report says evidence is convincing for a link between red meat, processed meat, and colorectal cancer, and limited but suggestive for links to lung, esophageal, stomach, pancreatic, and endometrial cancers.
Rashmi Sinha, PhD, the lead author of the National Cancer Institute study, points to a large number of studies that link red meat consumption with chronic diseases.
“The level of evidence is what people look at,” Sinha says. “If there are 20 studies that say one thing and two studies that say the other thing, you believe the 20 studies.”
2. If eating red meat does increase the risk of cancer, what’s the cause?
A: That’s not clear, but there are several areas that researchers are studying, including:
- Saturated fat, which has been linked to cancers of the colon and breast as well as to heart disease
- Carcinogens formed when meat is cooked
- Heme iron, the type of iron found in meat, that may produce compounds that can damage cells, leading to cancer.
3. Are there nutritional benefits from eating red meat?
A: Red meat is high in iron, something many teenage girls and women in their childbearing years are lacking. The heme iron in red meat is easily absorbed by the body. Red meat also supplies vitamin B12, which helps make DNA and keeps nerve and red blood cells healthy, and zinc, which keeps the immune system working properly.
Red meat provides protein, which helps build bones and muscles.
“Calorie for calorie, beef is one of the most nutrient-rich foods,” says Shalene McNeil, PhD, executive director of nutrition research for the National Cattlemen’s Beef Association. “One 3-ounce serving of lean beef contributes only 180 calories, but you get 10 essential nutrients.”