Apple - 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.
Scientists have recently shown that important health benefits of apples may stem from their impact on bacteria in the digestive tract. In studies on laboratory animals, intake of apples is now known to significantly alter amounts of two bacteria (Clostridiales and Bacteriodes) in the large intestine. As a result of these bacterial changes, metabolism in the large intestine is also changed, and many of these changes appear to provide health benefits. For example, due to bacterial changes in the large intestine, there appears to be more fuel available to the large intestine cells (in the form of butyric acid) after apple is consumed. We expect to see future studies confirming these results in humans, and we are excited to think about potential health benefits of apple that will be related to its impact on bacterial balance in our digestive tract.