Researchers from Harvard Medical School examined records from The Nurses' Health Study -- which includes data on more than 90,000 women who were questioned on their dietary habits in 1991, 1995 and 1999 -- and found that red meat consumption is linked with a higher risk of breast cancer.
The researchers found that women who tend to eat more red meat are also more likely to be overweight and smoke cigarettes, which have both been linked with increased breast cancer rates. However, when the researchers took those factors into account, the women who ate more red meat still ran an increased risk of breast cancer.
"Our study may give another motivation to reduce red meat intake," said co-author Eunyoung Cho, whose study appeared in Monday's edition of the journal Archives of Internal Medicine.
However, according to Dr. Anne McTiernan of the Fred Hutchinson Cancer Research Center in Seattle, women who eat red meat occasionally should not go vegetarian based on Cho's study alone. McTiernan questioned the study participants' ability to accurately recall the amount of red meat they ate.
"A 16-ounce steak and a three-ounce piece of meat are counted the same," said McTiernan, author of "Breast Fitness." "People are horrible at determining what is a real serving."
Consumer advocate Mike Adams, author of "Grocery Warning," says Cho's findings indicate consumers should stop eating red meat entirely, and the risk applies to both fresh red meat and processed, packaged meats.
"These research findings come as no surprise, given what we know about the cancer-causing chemicals added to processed meats," Adams said. "Previous research on red meat reveals strong correlations with prostate cancer, colorectal cancer, pancreatic cancer and breast cancer, among other health problems.
"People who wish to avoid cancer are strongly advised to stop eating red meat for life and switch to a primarily plant-based diet," he said.