Bananas are a good source of fiber, which improves the quality of bowel movements, feeds our beneficial gut bacteria and facilitates the absorbance of some dietary components, including calcium. The vitamin B6 found in bananas may support eye health and alleviate dry eye symptoms. These widely consumed fruits are also rich in serotonin, the neurotransmitter responsible for regulating mood, and may prove capable of modulating or preventing depression symptoms. A study performed in vitro showed liver cancer cells growth rate decreasing 40% after exposure to bananas. However, increased intake of bananas was not associated with a decreased risk of developing breast cancer in a study of African American women. Long-term, regular consumption of bananas does, however, appear to help stabilize blood sugar levels.
Compared to other fruits, bananas are poor sources of phytonutrients, like the eye-protecting zeaxanthin, which may be why they do not appear to be protective against glaucoma. They are also relatively low in antioxidants, and even elicit significantly smaller decreases in inflammatory markers after ingestion, compared to other fruits (see also here).
While bananas do contain potassium, they appear relatively low on the list of best sources of this essential mineral, coming in in 86th place, behind fast food milk shakes. The actual best sources: leafy greens, beans and dates. These statistics should not discourage you from eating bananas; as part of a balanced, varied diet, consuming bananas is healthy (but berries and most other fruits may be healthier).
Topic summary contributed by Miranda.