Apples are slightly acidic. Acidity has actually been shown to prevent urinary tract infection by changing the pH to help prevent bacteria infections including urinary tract infections. I believe your friend may be referring to a condition called interstitial cystitis. Interstitial cystitis is a chronic condition characterized by a combination of uncomfortable bladder pressure, bladder pain and sometimes pain in your pelvis, which can range from mild burning or discomfort to severe pain. Although there’s no scientific evidence that points to diet as the cause of interstitial cystitis, many people with the condition find that eliminating or reducing their intake of potential bladder irritants may help to relieve their discomfort. Some of the most irritating foods can be summarized as the “four Cs.” The four Cs include carbonated beverages, caffeine in all forms (including chocolate), citrus products and food containing high concentrations of vitamin C. All in all, if you notice a pattern of certain foods that irritate your body functioning, omit these from your diet and try the over 200 varieties of fruits and vegetables. Continue to eat lots of fruits and vegetables to promote lifelong health!