Diet in Adolescence Linked to Breast Cancer Risk Factor
The types of fats that girls consume during adolescence could influence their breast density, a risk factor for breast cancer, in young adulthood.
Adolescent girls who consumed high amounts of saturated fats – such as those found in dairy products and meat – or low amounts of mono- and polyunsaturated fats – such as those found in olive oil, fish, nuts, and seeds – were found to have higher breast density in young adulthood.
Breast density is a risk factor for breast cancer. So, the study, which was published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research (AACR), suggests that diet consumed in early life may influence risk for breast cancer later in life.
Breast cancer is the most commonly diagnosed cancer among women in the United States, with 246,660 new cases expected to be diagnosed in 2016, according to the National Cancer Institute. Risk factors include age at starting menstruation (menarche), age at first birth, taking hormones for symptoms of menopause, and obesity.
The new results are particularly interesting because diet during adolescence is modifiable, whereas most of the well-known risk factors for breast cancer, such as age at menarche and number and timing of pregnancies, offer little chance for intervention, according to the senior author of the study, Joanne Dorgan, PhD, MPH, professor in the Department of Epidemiology and Public Health at the University of Maryland School of Medicine. Adult alcohol consumption is the only adult dietary factor consistently associated with breast cancer risk, she noted.
In the study, Dr. Dorgan and her colleagues, including Seungyoun Jung, ScD, a fellow in the same department at the University of Maryland School of Medicine, used percent dense breast volume (DBV), which they calculated by magnetic resonance imaging (MRI), as a measure of breast density.
The researchers found that after adjusting for multiple variables, including race, education, adulthood fatness, number of live births, and total energy and protein intakes, women who had consumed the highest amount of saturated fat in adolescence had a mean percent DBV of 21.5 percent compared with 16.4 percent for those who consumed the least. A similar difference in percent DBV was found for those in the lowest versus the highest quartile of monounsaturated fat intake.
“The 5 to 6 percentage point difference in percent DBV is relatively modest, compared to the overall distribution of percent DBV observed in our study participants,” said Dr. Jung. “There is no clinical cut-point to define high versus low percent DBV to indicate women at increased risk of breast cancer. However, because there is a gradient of increasing breast cancer risk with increasing breast density, the differences in percent DBV we observed across extreme quartiles in our study, if confirmed, could potentially be of interest with regards to later breast cancer risk.”
Dr. Jung noted that if the study results are confirmed, the take-home message should be that diet consumed in early life is important and may confer chronic disease risk or protective benefits later in life. In particular, the timing of dietary exposures might be important and appropriate dietary modifications during adolescence may potentially contribute to lowering breast density and consequently breast cancer risk as well as preventing obesity, diabetes, and cardiovascular disease, she said.
According to Dr. Jung, one of the main limitations of the study is that the researchers were unable to rule out whether the significant associations observed for fat consumption during adolescence were attributable to other components in foods that are good sources of different types of fat. They also could not evaluate whether the results are independent of other possible unknown factors associated with breast density. Finally, the study was based on a relatively small number of participants, most of whom were Caucasian, so Jung said that a large prospective study of a racially and ethnically diverse population is needed to replicate the findings.