Girls eating more fruits and vegetables during their teenage years are significantly lowering their risk of developing breast cancer later on in life. According to a study published today by BMJ, dietary choices made during adolescence may be very important when it comes to avoiding breast cancer. Consuming more fruits is especially found to be associated with lowering the risk of breast cancer. Girls need to gorge more on fruits which are rich in α-carotene, such as apples, bananas and grapes in adolescence, along with oranges and kale in early adulthood, since these may lessen the pathogenesis of breast cancer in them. The study also highlighted the role of fiber in preventing the synthesis of cancerous neoplasms in the breast tissues.
In 2010, the Centers for Disease Control and Prevention (CDC) found that only 16.8% of high school students ate fruits four times a day, while 28.5% consumed one serving of fruits per day. Similarly, only 11.2% of students going to high school ate vegetables four times a day, while 33.2% of students only ate one serving of vegetables every day. The report concluded that the rate of fruit and vegetable consumption had gradually decreased in the US in recent years. On the other hand, 1 in 8 women in the US is at the risk of developing breast cancer, which is equal to 12% of the women from the total population. It is estimated that in 2016, more than 246,660 new cases of invasive breast cancer will be diagnosed.
Maryam Farvid, PhD, at the Harvard School of Public Health, was the lead author of the study. The aim of the study was to find if an association does exist between breast cancer rates and fruit and vegetable intake. The cohort study design was based on data generated from the ‘Nurses’ Health Study II’ of premenopausal nurses from all over the country. The mean age of the women participating in the study was 27 to 44 years.
The study was carried out on a total of 116,430 registered female nurses, with 90,476 of the participants first completing a Food Frequency Questionnaire (FFQ) back in 1991, while the rest of the 44,223 participants filled the questionnaire in 1998.
A follow-up in 2013, after 20 years, found that a total of 3,235 participants had developed invasive breast cancer. The incidence of breast cancer was confirmed by their pathology reports. Five groups were made on the basis of their fruit consumption, ranging from the highest fifth to the lowest fifth.
It was concluded that women who had consumed 2 to 3 servings of fruits every day during their teenage years had a 25% less risk of developing breast cancer later in life, as compared to women who had only consumed half a serving of fruit every day. If the risk reduction rate by eating fruits is applied to an entire lifetime, then breast cancer may be even completely prevented throughout life by frequently eating more fruits.
“This prospective study provides evidence that greater consumption of fruits during adolescence is associated with lower risk of breast cancer,” said Farvid.
According to the researchers, their study results have ‘several strengths’ which back up their authenticity. The team evaluated the association during different life periods, such as adolescence, early adulthood and the premenopausal period. In the same way, gathering a large number of participants ensured that modest differences in risk were also documented.
The researchers also found that adolescent fruit intake influenced the levels of estrogen and progesterone in women. “We also observed that the associations between adolescent fruit intake and breast cancer differed by hormone receptor status, with a stronger inverse association for both estrogen and progesterone receptor negative cancer,” said Farvid.
The study concluded that its findings are in line with ‘cancer prevention recommendations’ which preach consumption of more fruits and vegetables in early life. The study also called for more research on diet in early life and risk of breast cancer.
However, there is conflict of interest, since fruit and vegetable consumption is not only necessary in early life but also in later life. This is because women are more prone to developing carcinomas i.e., tumors in their breast during later years, when breast tissue is more defenseless against carcinogenic effects.
An additional finding of the research was that fruit juice is not as effective in preventing breast cancer as eating whole fruit. It is possible that the consumption of essential fibers present in whole fruits, which promote health and prevent disturbances in the metabolism, are responsible for the cancer eliminating effect. Fruits and vegetables are known to be rich in biologically positive nutrients and these active substances may favor the inhibition of the breast cancer pathogenesis.
Bioactive compounds present in fruits and vegetables include carotenoids, vitamin C, flavonoids, fiber, calcium, magnesium, potassium, iron and so on. All of these compounds act through several mechanisms to inhibit the generation of cancerous cells.