Sweet potatoes, tomatoes, and the many other colorful fruits and vegetables high in carotenoids may reduce women’s risk of breast cancer, suggests a new analysis published last week.
The study was published in the Journal of the National Cancer Institute.
Carotenoids are a large group of phytochemicals that give our foods their red, orange, and yellow hues. Many dark green vegetables, such as kale and spinach, also contain plenty of these phytochemicals. Beta-carotene, lycopene, zeaxanthin and lutein are a handful of the well-studied carotenoids for their role in cancer prevention — and other health benefits, such as eye health.
Earlier research has pointed to the protective role of carotenoids but dietary intake studies have had mixed findings.
In this new analysis, the researchers focused on blood levels of carotenoids in order to overcome potential problems with dietary recall. The study pooled data together from eight population studies. Each of the studies collected blood samples from women who were initially healthy, and then tracked their health over time. At the time their blood was drawn, most of the women were postmenopausal.
Together, the studies made up over 80 percent of all the published literature on the topic, note the authors, including approximately 3,000 women who were diagnosed with breast cancer and 4,000 women who were not. The cancer-free women were matched in age and other risk factors to those diagnosed.
When comparing the women who measured the highest versus the lowest blood levels, those with the highest levels of total carotenoids linked to almost 20 percent lower breast cancer risk. Lower risk was also associated with higher levels of many individual carotenoids, including lycopene, alpha-carotene, beta-carotene, and lutein+zeaxanthin. The link was generally strongest for tumors that were estrogen–receptor (ER) negative, a tumor less common and more difficult to treat than ER-positive tumors. There was also a stronger link to carotenoid levels and reduced risk among current smokers.
This study adds to earlier research. A review this year, for example, funded as part of AICR/WCRF’s Continuous Update Project (CUP), found a strong link between higher blood levels of carotenoids and reduced breast cancer risk.
There’s plenty of other phytochemicals in fruits and vegetables that may interact with the carotenoids or play a role in the reduced risk seen, write the authors. And it’s challenging to isolate the independent effects of single carotenoids. Further research is needed, they conclude.
But there’s also numerous reasons to include a variety of colorful carotenoid-rich foods in your day, aside from the fact many are quite tasty. AICR’s expert report and its updates found that eating a diet high in carotenoids reduces the risk of mouth, pharynx, larynx and lung cancers. Eating plenty of carotenoid-filled fruits and vegetables can also help you stay at or get to a healthy weight, and that can reduce the risk for seven cancers.