The Optimal Fruit for Building Better Digestion and Cardiac Health

Creamy, rich, and sweet, bananas are a favorite food for everyone from infants to elders. Sports enthusiasts appreciate the potassium-power delivered by this high energy fruit. Bananas are one of our best sources of potassium, an essential mineral for maintaining normal blood pressure and heart function. Since the average banana contains a whopping 467 mg of potassium and 1 mg of sodium, a banana a day may help to prevent high blood pressure and protect against atherosclerosis. 

The effectiveness of potassium-rich foods such as bananas in lowering blood pressure has been demonstrated by a number of studies. For example, researchers tracked over 40,000 American male health professionals over four years to determine the effects of diet on blood pressure. Men who ate diets higher in potassium-rich foods, as well as foods high in magnesium and cereal fiber, had a substantially reduced risk of stroke. 

A study published in the Archives of Internal Medicine also confirms that eating high fiber foods, such as bananas, helps prevent heart disease. Almost 10,000 American adults participated in this study and were followed for 19 years. People eating the most fiber, 21 grams per day, had 12% less coronary heart disease (CHD) and 11% less cardiovascular disease (CVD) compared to those eating the least, 5 grams daily. Those eating the most water-soluble dietary fiber fared even better with a 15% reduction in risk of CHD and a 10% risk reduction in CVD. In addition to these cardiovascular benefits, the potassium found in bananas may also help to promote bone health. Potassium may counteract the increased urinary calcium loss caused by the high-salt diets typical of most Americans, thus helping to prevent bones from thinning out at a fast rate.  Bananas have long been recognized for their antacid effects that protect against stomach ulcers and ulcer damage. In one study, a simple mixture of banana and milk significantly suppressed acid secretion. In an animal study, researchers found that fresh bananas protected the animals' stomachs from wounds. Bananas work their protective magic in two ways: First, substances in bananas help activate the cells that compose the stomach lining, so they produce a thicker protective mucus barrier against stomach acids. Second, other compounds in bananas called protease inhibitors help eliminate bacteria in the stomach that have been pinpointed as a primary cause of stomach ulcers. 

Bananas are a smart move if you suffer from elimination problems. A bout of diarrhea can quickly deplete your body of important electrolytes. Bananas can replenish your stores of potassium, one of the most important electrolytes, which helps regulate heart function as well as fluid balance. In addition, bananas contain pectin, a soluble fiber (called a hydrocolloid) that can help normalize movement through the digestive tract and ease constipation. Bananas also contain resistant starch, but this amount varies depending on their degree of ripeness. In their lesser ripe stages, bananas score as low as 30 on the glycemic index (below 50 would be considered low). In their riper stages, this number usually rises to a moderate level in the 60's. All of the above features help place banana in a more favorable digestive light than might otherwise be expected for a sugary fruit. 

Your mother may have told you carrots would keep your eyes bright as a child, but as an adult, it looks like fruit is even more important for keeping your sight. Data reported in a study published in the Archives of Ophthalmology indicates that eating 3 or more servings of fruit per day may lower your risk of age-related macular degeneration (ARMD), the primary cause of vision loss in older adults, by 36%, compared to persons who consume less than 1.5 servings of fruit daily. In this study, which involved over over 100,000 women and men, researchers evaluated the effect of study participants' consumption of fruits; vegetables; the antioxidant vitamins A, C, and E; and carotenoids on the development of early ARMD or neovascular ARMD, a more severe form of the illness associated with vision loss. Food intake information was collected periodically for up to 18 years for women and 12 years for men. 

While, surprisingly, intakes of vegetables, antioxidant vitamins and carotenoids were not strongly related to incidence of either form of ARMD, fruit intake was definitely protective against the severe form of this vision-destroying disease. Three servings of fruit may sound like a lot to eat each day, but by simply tossing a banana into your morning smoothie or slicing it over your cereal, topping off a cup of yogurt or green salad with a half cup of berries, and snacking on an apple, plum, nectarine or pear, you've reached this goal. 
Build better bones by eating bananas? Yes, enjoying bananas frequently as part of your healthy way of eating can help improve your body's ability to absorb calcium via several mechanisms. Bananas are an exceptionally rich source of fructooligosaccharide, a compound called a prebiotic because it nourishes probiotic (friendly) bacteria in the colon. These beneficial bacteria produce vitamins and digestive enzymes that improve our ability to absorb nutrients, plus compounds that protect us against unfriendly microorganisms. When fructooligosaccharides are fermented by these friendly bacteria, not only do numbers of probiotic bacteria increase, but so does the body's ability to absorb calcium. In addition, gastrointestinal transit time is lessened, decreasing the risk of colon cancer. 

Green bananas contain indigestible (to humans) short chain fatty acids (SCFAs) that are a favorite food of the cells that make up the lining of the intestines. When these cells are well-nourished and healthy, the body's ability to absorb nutrients such as calcium can increase dramatically. Research published in Digestive Diseases and Sciences underscores just how much bananas can improve nutrient absorption. In this study, 57 male babies (5-12 months) with persistent diarrhea of at least 14 days duration were given a week's treatment with a rice-based diet containing either green banana, apple pectin or the rice diet alone. Treatment with both green banana and apple pectin resulted in a 50% reduction in stool weights, indicating that the babies were absorbing significantly more nutrients. 

Also, to check how well their intestines were able to absorb nutrients, the babies were given a drink containing lactulose and mannitol. Lactulose is a compound that should be absorbed, while mannitol is one that should not be. When the intestines are too permeable, a condition clinicians call "leaky gut," too little lactulose and too much mannitol are absorbed. After just one week of being given the green banana-rice diet, the babies' were absorbing much more lactulose and little mannitol, showing that their intestines were now functioning properly.  Some banana cultivars are also rich in provitamin A carotenoids, which have been shown to protect against chronic disease, including certain cancers, cardiovascular disease, and diabetes. How to identify which bananas contain the most carotenoids? Check the color of their edible flesh. Bananas whose flesh is more golden contain the most carotenoids. 

About 190,000 cases of kidney cancer are diagnosed each year. Risk factors include smoking, high blood pressure, obesity, and exposure to toxic chemicals such as asbestos and cadmium.  Dietary factors can be related to kidney disease in a preventive way. Research published in the International Journal of Cancer suggests that regular, moderated consumption of whole fruits and vegetables, especially bananas, can be protective. The results of this large population based prospective study (13.4 years) of 61,000 women aged 40-76, show that women eating more than 75 servings of fruits and vegetables per month (which translates into 2.5 per day) cut their risk of kidney cancer 40%. Among the fruits, bananas were especially protective. Women eating bananas four to six times a week halved their risk of developing the disease compared to those who did not eat this fruit. Salads, eaten at least once a day, were associated with a 40% decreased risk. Among vegetables, frequent consumption of root vegetables and white cabbage offered the most protection, providing a 50-65% decrease in risk. The conclusion drawn by the researchers: routine and moderated consumption of fruits and vegetables, especially bananas, cabbage and root vegetables, may reduce risk of kidney cancer. Why these foods? Bananas and many root vegetables contain especially high amounts of antioxidant phenolic compounds. Cabbage is rich in sulfur compounds necessary for efficient and effective detoxification of potential carcinogens. This mixture of phytonutrients may have been particularly helpful in protecting kidney function. 

The benefits of regular and moderated fruit intake need to be contrasted, however, with the increased risks that stem from very high consumption of fruit juices. In several studies examining diet and renal (kidney) cancer, very high consumption of fruit juices is associated with increased cancer risk. Since most fruit juice consumption involves highly processed fruits and stands in sharp contrast to consumption of whole, natural foods, this finding is not surprising. The reasons for avoiding high intake of fruit juice are not limited to increased risk of kidney disease, but also to problems involved with excessive sugar intake and excessive calorie intake from non-whole foods. Moderate amounts of fruit juice - especially juice containing as much of the whole fruit as possible, for example, pulp or skin - are still recommended, since these limited amounts in a balanced diet appear to be protective against kidney cancer. *As noted in the world’s healthiest foods.