Fruits and vegetables
Findings from individual studies on fruits and vegetables and breast cancer risk have been mixed [91-95]. Recent, large pooled and meta-analyses have provided better data.
Studies now show that eating vegetables may slightly lower the risk of some breast cancers. A pooled analysis that combined data from 20 studies found that eating vegetables lowered the risk of estrogen receptor-negative breast cancers, but not estrogen receptor-positive breast cancers .
Eating fruits may also help lower breast cancer risk. A meta-analysis that combined the results of 15 studies found that women who ate the most fruit had a slightly lower risk of breast cancer compared to women who ate the least fruit .
Although the effects on breast cancer risk are modest, eating a diet high in fruits and vegetables may lower the risk of heart disease, stroke and other chronic diseases [519-521]. Learn more about healthy behaviors and breast cancer risk.
Carotenoids are natural orange-red food pigments found in fruits and vegetables (like melons, carrots, sweet potatoes and squash). Many carotenoids, such as beta-carotene, are antioxidants and can be converted into vitamin A in the body. Researchers can study carotenoids by measuring levels of carotenoids in the blood or through a person’s diet.
A pooled analysis of data from eight studies found that women with higher blood levels of carotenoids had a reduced risk of breast cancer compared to women with lower levels .
Although most studies have found no link between eating a diet high in foods that contain carotenoids and overall breast cancer risk, carotenoids now appear to lower the risk of certain breast cancers [91,94,97-101]. A pooled analysis of data from over one million women in 18 studies found that a diet high in carotenoids lowered the risk of estrogen receptor-negative breast cancers . However, there was no benefit for estrogen receptor-positive breast cancers .
Note of caution on carotenoid supplements
Carotenoid supplements (such as beta-carotene supplements) may have some health risks. A few studies have found that taking a daily beta-carotene supplement (in pill form) may increase the risk of lung cancer and premature death in smokers [102-104].
In general, fruits and vegetables are the best sources of carotenoids (rather than supplements) and are part of a healthy diet.