Feeding pregnant female mice a diet high in fat derived from common corn oil resulted in genetic changes that substantially increased breast cancer susceptibility in three generations of female offspring, reports a team of researchers led by scientists at Georgetown Lombardi Comprehensive Cancer Center.
“It is believed that environmental and life-style factors, such as diet, plays a critical role in increasing human breast cancer risk, and so we use animal models to reveal the biological mechanisms responsible for the increase in risk in women and their female progeny,” says Hilakivi-Clarke.
A high-fat diet is linked to excess inflammation, and a number of epidemiological studies have made the connection between inflammation and risk of cancer, she says.
Hilakivi-Clarke has found in earlier studies that mice that eat a high fat diet when they are pregnant have “daughters” that are at excess risk of the cancer. This study, however, found that if pregnant mice were switched to a high fat diet during their second trimester when the germ line mediating genetic information from one generation to another forms in the fetus, an increase in breast cancer risk is also seen in “great granddaughters.
A gene screen revealed a number of genetic changes in the first (daughter) and third (great granddaughter) high-fat mice generations, including several genes linked in women to increased breast cancer risk, increased resistance to cancer treatment, poor cancer prognosis and impaired anti-cancer immunity. The researchers also found three times as many genetic changes in third generation than first generation mammary tissue between high-fat diet progeny and the control group’s offspring
Dr. Stegall’s Comments: As with most other issues surrounding cancer risk, details matter. Based on existing research, it seems that the type of fat is of paramount importance here. Healthy fats, such as those found in coconut oil, avocados, grass fed meat, eggs, nuts, and seeds, confer a health benefit due to their anti-inflammatory effect. These healthy fats should reduce cancer risk, not raise it. In contrast, unhealthy fats such as trans fats and other man-made fats, especially in conjunction with a high sugar diet, are likely to increase cancer risk.