By lettuce (Lactuca sativa), we mean iceberg, romaine, red leaf, or butterhead (Boston, bibb) lettuce. Not included in the lettuce category is arugula, which is a cruciferous vegetable. Lettuce is a good dietary source of vitamin A (from its relatively high beta-carotene content), lutein, and vitamin K. Generally speaking, romaine lettuce is far more nutritious than iceberg lettuce, with higher levels of these micronutrients. Bibb lettuce and red leaf lettuce fall in between. Lettuce has been shown to have antioxidant properties (but lower than most other vegetables) and to improve cholesterol profile. Lettuce consumption has been found to be associated with lower risks of lung, gastric, bladder and colorectal cancer.
Breast cancer-related effects of eating lettuce
A Japanese study found that frequent lettuce consumption was associated with lower risk of breast cancer. One Mexican study found that consumption of lettuce was associated with lower risk of breast cancer in premenopausal women. A Greek study found that women with breast cancer consumed significantly less lettuce than those without breast cancer.
Lutein consumption and circulating lutein levels have been found to be associated with reduced risk of breast cancer in several epidemiological studies. Lutein has been shown to inhibit the progression of both ER+ and ER+ breast cancer cells under hypoxia, a low-oxygen condition in which solid breast tumors can thrive. Lutein has also been shown to potentiate the effect of taxane chemotherapy drugs (Taxol and Taxotere) in breast cancer cells.
Non-organic lettuce must be washed very thoroughly to remove pesticide residue as much as possible. Outbreaks of E. coli, salmonella, and shigellosis infections linked to lettuce occur from time to time. Consumers should stay aware of and act upon any such reports.
Below are links to recent studies concerning this food. For a more complete list of studies, please click on lettuce.