NEW YORK - Teenage girls who eat more colorful fruits and vegetables are less likely to develop benign breast disease as young adults, according to a new study.
Benign breast disease, or a group of lumps that can develop during adolescence or young adulthood, is not in itself dangerous. But benign breast disease does increase the risk of breast cancer later in life, the authors of the new study write.
Seeing the same association between certain antioxidants and benign breast disease among teen girls as has been seen for breast cancer among adults is exciting, Caroline E. Boeke said. She worked on the study at Brigham and Women's Hospital in Boston.
"Consumption of these vegetables might be a way to prevent benign breast disease," Boeke said. However, she noted that this is an observational study, and can't prove veggies ward off the disease.
So-called carotenoids give red, yellow and orange fruits and vegetables their colour. Some previous studies have found that women who eat a lot of them have a lower risk of breast cancer.
This study sought to "connect the dots" between eating colorful veggies as a teenager, when breast tissue is still developing, and having benign breast disease a decade later, which itself increases the risk for breast cancer in middle age, Boeke said.
Women who have benign breast disease are between one and a half and two times more likely to develop breast cancer than women without it, she told Reuters Health.
For the study, 6,500 girls filled out dietary questionnaires once a year for three years, starting when they were about 12 years old. Between nine and 14 years later, the young women filled out questionnaires about whether they had been diagnosed with benign breast disease.
The researchers divided the girls into four groups based on how many carotenoid-rich foods they ate as teens. They found the group that ate the least amount of beta-carotene - a common type of carotenoid - was almost twice as likely to be diagnosed with benign breast disease as girls who ate the most, according to results published in Pediatrics.
"If there were a 50 per cent reduction it would be impressive," Cynthia Thomson told Reuters Health in an email. "But I am cautious not to over interpret these results."
In total only 122 women in the study developed benign breast disease.
Thomson, from the University of Arizona Cancer Center in Tucson, studies diet and cancer prevention but was not involved in the new study.
"What it does suggest is that this is a hypothesis worth exploring further," she said.
"Carotenoids absorb free radicals and protect cells from oxidative damage," Dagfinn Aune, who researches cancer and nutrition at Imperial College London, told Reuters Health by email. "They also inhibit cell growth and the ability of cancer tumours to form blood vessels that can feed the tumours."
Aune was not involved in the new study.
It can be difficult to determine how much of an effect eating certain vegetables has on cancer risk, since people who eat more vegetables tend to be healthier overall, Boeke said.
"We adjusted for body mass index (a measure of weight in relation to height), alcohol consumption, smoking, most of the known risk factors for benign breast disease and breast cancer," she said. "So it does make us more confident that the association is real."
Thomson wouldn't recommend teens start eating more fruits and vegetables based on this study alone. But overall, young people do need to get more of these foods in their diets, she said.
"Eating carotenoid-rich fruits and vegetables like carrots and sweet potato, pumpkin, kale and spinach may be protective against breast disease and certainly has many other health benefits," Boeke said. "Encouraging consumption of these foods is a great thing."