High-Fat Diet May Boost Breast Cancer Risk
Study found women who ate the most saturated fat were more likely to develop tumors
By Kathleen Doheny
WEDNESDAY, April 9, 2014 (HealthDay News) -- For more than three decades, experts have debated whether eating a high-fat diet increases breast cancer risk.
Now, new research suggests it might boost the chances of three common types of breast cancer.
In a large European study evaluating more than 337,000 women in 10 countries over 11 years, researchers found that women who ate the most saturated fat were about 30 percent more likely to develop breast cancer than those who ate the least.
While the study showed an association between a high-fat diet and breast cancer risk, it didn't prove cause-and-effect.
"The results of this large study provide support for the hypothesis that breast cancer development is related to dietary fat," said study author Sabina Sieri, a researcher from the department of preventive & predictive medicine at the Fondazione IRCCS Istituto Naziolale dei Tumori in Milan.
The study is published April 9 in the Journal of the National Cancer Institute.
Sieri and her team found that a high intake of total fat and saturated fat was linked to an increased risk of breast cancer subtypes known as estrogen receptor-positive (ER-positive) and progesterone receptor-positive (PR-positive). High-fat diets also were tied to a raised risk of developing HER2-negative breast cancer, the investigators noted.
Cancers that are ER- or PR-positive grow in response to those hormones. Cancers that are HER2-negative have tested negative for the presence of a protein, HER2, which promotes cancer cell growth.
One strength of the new study is its large numbers, said Mia Gaudet, director of genetic epidemiology at the American Cancer Society. The breast cancer subtypes linked with fat intake are common, she said. "The majority of breast cancers in the U.S. and Europe are ER-positive, PR-positive, HER2-negative," she noted.
In the new study, women answered questions about their fat intake and other habits that could affect risk, including smoking, age at first period, pregnancy history, use of hormone therapy and their body mass index (a measurement of body fat based on height and weight).