Posted 06/05/2007

Longtime diet of smoked, grilled meat puts older women at increased risk of breast cancer

A longtime diet of grilled, barbecued and smoked meat puts older women at increased risk of developing breast cancer, according to a new study led by a researcher at USC’s Arnold School of Public Health. 

Dr. Susan E. Steck and colleagues found that postmenopausal women who consumed the most grilled, barbecued or smoked meat over their lifetimes have a 47 percent increased risk of breast cancer compared to women consuming these meats less often. 

The risk of breast cancer was elevated by 74 percent in those postmenopausal women who ate the cooked meats and also consumed fewer fruit and vegetables.  

The findings are published in the May 2007 issue of Epidemiology, the official journal of the International Society of Environmental Epidemiology. 

Steck, a research assistant professor in the Department of Epidemiology and Biostatistics and the Statewide Cancer Prevention and Control Program, said, “Our research supports guidelines that are currently recommended by the American Cancer Society and the American Institute for Cancer Research to limit red meat and processed meat intake and to increase intake of fruits and vegetables.” 

The study found a close association with but didn't actually show that cooked meats caused breast cancer. Other related factors could be at work, she explained, such as high fat content in the diet of women who consume these types of meat products. 

The study noted that polycyclic aromatic hydrocarbons and heterocyclic amines are known carcinogens produced by cooking meat at high temperatures. Polycyclic aromatic hydrocarbons are found in grilled, barbecued and smoked meat (as well as many other foods), while pan-fried and grilled meat have particularly high heterocyclic amine content. 

Steck said the study compared the lifetime and recent intake of cooked meat among 1,508 women with breast cancer and 1,556 healthy women.  The data were drawn from the Long Island Breast Cancer Study Project done in 1996-1997. 

Postmenopausal women in the highest two thirds for lifetime consumption of smoked, grilled or barbecued meats -- more than once a week -- had a 47 percent greater risk of the disease compared with women who ate the least amount of meat -- once a week or less.
 
Significantly, post-menopausal women who ate plenty of barbecued or smoked meat but few fruits and vegetables (less than five servings per day) were at a 74 percent increased risk of breast cancer.

However, risk was not elevated substantially in women consuming high amounts of meat and more than five servings of fruits and vegetables per day.  This supports laboratory data which suggests that phytochemicals in fruits and vegetables may protect against carcinogens found in cooked meat. 

At the same time, smoked, grilled or barbecued poultry or fish did not increase breast cancer risk when examined independently of red meat, the study reported.  

The investigators found no significant association between long- or short-term meat intake and breast cancer in pre-menopausal women.