High-Fat Diet Linked to Increased Risk of Breast Cancer Across Generations

New findings may improve the understanding of how breast cancer develops, and help people learn how to work towards prevention.

When a person is told that they have breast cancer, it is common for them and their loved ones to want to know what caused the disease. Unfortunately, nobody knows the exact cause of breast cancer. The medical community doesn't have enough information to understand exactly why one woman may develop breast cancer, while another will not. The one thing that doctors do know is that breast cancer is always caused by some sort of damage to a cell's DNA. The job of the cancer research community is try and figure out which factors may increase the risk of this damage.

In breast cancer, cancer cells form inside the tissues of the breast. One out of every eight women in the U.S. will be diagnosed with breast cancer and it is the most commonly diagnosed cancer in women. The National Breast Cancer Foundation, Inc. estimates that more than 246,660 women in the U.S. will be diagnosed with breast cancer and over 40,000 will die, making breast cancer the second leading cause of cancer death among women. While breast cancer in men is rare, it is not impossible. The National Breast Cancer Foundation, Inc. estimates that around 2,600 men are diagnosed with breast cancer each year in the U.S. and that about 440 will die from it. A huge goal in breast cancer research is to determine which factors can increase the risk of breast cancer so that eventually there may be a preventative medical solution or a cure.

A high-fat diet: The study

One study that was conducted on pregnant mice shows that when the pregnant mother eats a diet high in fat, it can increase the chance of breast cancer across generations.

The new study was conducted by the Georgetown Lombardi Comprehensive Cancer Institute in Washington, D.C., and suggests that when women eat foods that are high in fat during their pregnancy, they may be inadvertently increasing the risk of breast cancer in their offspring across future generations. The senior study author, Leena Hilakivi-Clarke, Ph.D., a professor of oncology at Georgetown Lombardi, and colleagues recently published their research findings in the Breast Cancer Research journal (Cohut, 2017).

In order to study the impact of intergenerational diet, the mouse specimens were bred in two different phases. In the first experimental phase, the pregnant females were divided randomly into two groups just after breeding. The pregnant females in the first group were fed a high-fat diet while the females in the other group were fed a diet with normal fat intake (Cohut, 2017).

The pregnant females in the normal fat intake diet group were fed a diet with only 16 percent of their calories taken from fat, while the pregnant females in the high-fat intake diet group were fed a diet with a little over 41 percent of their calories from fat (just 39 percent of those calories came from corn oil, while around 2 percent of the calories came from soybean oil) (Cohut, 2017).

The research group wanted to study how the dietary effects would be similar in human pregnant females who eat a diet high in fat. Because the gestation period in mice is only around 19 to 21 days, the researchers began the controlled feed phase of the high-diet group around the 10th day of their pregnancy, which is considered a mouse's second trimester. In humans, the second trimester is especially critical to the study because that is the phase in which a female fetus begins to experience the development of her ovaries. After this initial controlled feeding phase, the offspring and later generations that were created from this phase of the experiment were then placed on normal diets consisting of normal fat intake (Cohut, 2017).

During the second phase of the experiment, the females that were directly born from the original phase groups were bred with males that were fed a diet high in fat, and all of the females that were mated to the high-fat diet males were fed normal diets.

The researchers discovered that the female offspring born of the first and third generations (daughters and great-granddaughters), whose mothers had been fed diets high in fat during their second trimester, had an increased risk of developing breast cancer and their malignant tumors had become established earlier during the course of their cancer.

The researchers also noticed some differences in the genetic structure of the offspring that fell in the first and third generations and laboratory tests showed that the female mice born of the third generation revealed at least three times more changes in the genetic makeup of their mammary glands when compared with the female mice born of the first generation.

Hilakivi-Clarke said, "The soil in the breast, so to speak, remained fertile for breast cancer development in our high-fat experimental mice."

The findings of this research study imply that the risk of breast cancer development over generations may be increased with the direct exposure (while in the womb) to a genetic makeup that is already more susceptible to an increased threat of malignant tumors (Cohut, 2017).

"Studies have shown that pregnant women consume more fats than non-pregnant women, and the increase takes place between the first and second trimester," added Hilakivi-Clarke.

This new information, along with the results of the study, suggests that women and the medical community should pay more attention to the fatty foods that a woman eats during her pregnancy, due to the links shown between the intake of a pregnant female's intake of a diet high in fat and the risk of breast cancer presented to offspring and future generations of women.

Other risks of breast cancer

While attention is currently being paid to the link between pregnant females consuming diets high in fat and the risk of breast cancer to their offspring and future generations, past studies have also presented a number of other risk factors.

Other risks include hormone therapy, breast-feeding, certain contraceptives, obesity, alcohol consumption, and lack of physical exercise (coined "sitting disease" by the medical community).

Another recent study shows that there may be a link between certain hair products, such as relaxers and hair dyes, and a woman’s increased risk of developing breast cancer. This study revealed that there is a significant link between a woman's use of chemical relaxers (or straighteners) and certain hair dyes and an increased risk of developing breast cancer, although the results differed slightly between black women and white women. For black women, the research showed that when using darker shades of hair dye, the risk of developing breast cancer increased. Whereas for white women, the risk of developing breast cancer increased with the use of relaxers (or straighteners), both alone and along with hair dyes.

The key to preventing breast cancer (and other cancers) is to understand which factors may increase a person’s chance of being born with genetic traits that increase the odds of developing breast cancer or making certain choices in diet or lifestyle that may increase the chance of getting breast cancer. By understanding direct links between diet or lifestyle choices, women and their medical care teams can start learning which choices they should make to decrease their own chance of developing breast cancer, as well as decreasing the chance of their offspring or future generations developing breast cancer.

References

Breast Cancer Foundation, Inc. (n.d.). About Breast Cancer. [Web]. Retrieved on 7/13/17 from: http://www.nationalbreastcancer.org/breast-cancer-facts

Cohut, M. (2017). Breast cancer: Maternal high-fat diet raises risk across generations. [Web]. In Medical News Today. Retrieved from: http://www.medicalnewstoday.com/articles/318270.php