Bananas are very low in saturated fat, cholesterol and sodium and are a good source of dietary fiber, vitamins C and B-6 and the minerals potassium and manganese. They are great sources of energy that can be eaten in many ways, including mixed with other fruit to make a fruit salad, sliced on cereal or yogurt, combined in a sandwich with peanut butter or blended into a smoothie. A banana makes a convenient snack for those on the go -- all wrapped up in its very own package.

A medium-sized banana has about 105 calories. Of those calories, 97.4 percent come from carbohydrates, 3.3 come from fat and 4.3 from protein. A banana contains 27 grams of total carbohydrates, with 3.1 grams representing fiber, 6.3 grams starch and 14.4 grams naturally present sugars. A banana has only 0.4 grams of fat in a single serving, with almost twice as much omega-6 fatty acids compared to omega-3 fatty acids.

A single banana contains 75.5 IU of vitamin A, 10.3 milligrams of vitamin C,11.6 milligrams choline and trace amounts of vitamin E, vitamin K, riboflavin, niacin, vitamin B-6, folate, pantothenic acid and betaine. Additionally, a medium-sized banana contains 5 milligrams of calcium, 31 milligrams of magnesium, 422 milligrams of potassium and trace amounts of sodium, zinc, iron, copper and selenium.

Bananas offer several health benefits because they are considered potassium-rich foods. Potassium is an important mineral in the regulation of blood pressure, organ health and muscle integrity. Potassium deficiency symptoms can range from cramped and tired muscles to high blood pressure and headaches. Bananas help maintain cellular function, electrolyte balance and a healthy cardio-vascular system. They also offer a quick, convenient and bio-available source of immediate and long-term energy.

Bananas can reduce depression because they contain tryptophan, which converts to serotonin, known to improve mood. Because bananas contain the prebiotic compound fructooligosaccharide, they provide nourishment to the probiotic flora, or good bacteria, present in the gut. Prebiotics are insoluble fiber components present in food that stimulate the growth of bacteria in the digestive system and help produce digestive enzymes. A strong showing of healthy prebiotics and probiotics in the intestinal tract is beneficial to the immune system and overall digestive health.