Some people believe that bananas are good for the bones because they contain lots of calcium. It is true that bananas are beneficial for bones but just because bananas are white, they cannot be assumed to be rich in calcium
Calcium content of banana is only 5 mg / 100g so it cannot be considered as a source of calcium at all.
Rather, bananas contain a type of indigestible starch called fructo oligosaccharides (FOS). FOS have been shown to enhance absorption of calcium by facilitating proliferation of gut friendly bacteria and production of organic acids. Calcium requires an acidic medium for absorption into body cells.Therefore banana consumption can be helpful in improving bone calcification.
Green bananas contain higher quantity of insoluble and soluble fiber which can have more benefits on overall nutrient absorption !