Acidic foods can sometimes be just as troublesome as they are delicious. Foods such as tomatoes, citrus fruits, bell peppers, and spices are often the biggest culprits for causing stomach discomfort or heartburn. It may seem logical that this acidity can be felt “burning” other areas of the body, such as the bladder, but this is not the case.
The bladder is an end organ of excretion. It receives urine, which is a compilation of wastes filtered and secreted from the kidneys. It passes the urine through the urethra to the outside of the body. Urine’s pH is usually neutral to slightly acidic, but this can vary with different diets and disease states. Urine is normally sterile, but the presence of bacteria and the byproducts of their digestion can cause the bladder wall to become irritated and make it painful to pass urine. Your doctor can do a test called a urinalysis to assess the color and pH of urine and detect the presence of bacteria and inflammatory cells.
Diets high in meats, fish and cheese can lower the pH of urine, making it more acidic. Conversely, vegetables and some fruits, like bananas, can increase the pH of urine, making it more basic. Additionally, many bacteria produce enzymes that release ammonia into the urine. Ammonia increases the pH of urine, making it more basic. Metabolic disorders, in which patients lack or have a defective form of an enzyme, can lead to acidic urine as well. However, these disorders are usually diagnosed early in life through neonatal screening tests and cause neurological symptoms, not bladder pain.
Many things can cause bladder pain. Among the most common causes is an infection in the urine. Chronic inflammation of the bladder wall, often referred to as interstitial cystitis, can also be painful. Bladder outlet obstruction, commonly found in adult men with enlarged prostates, is another possible source of bladder discomfort. Most bacterial urinary tract infections are caused by organisms such as Escheria coli, which make ammonia as a metabolic byproduct and cause an increase in pH, if any change at all. Also, no data suggest that interstitial cystitis or bladder outlet obstruction directly influence urinary pH. So, some of the most common causes of bladder pain have no effect on the acidity of urine.
Between Stomach and Bladder
Although acidic foods are well known to cause upper gastrointestinal discomfort, no evidence supports their ability to cause pain in the bladder. Once food passes through the stomach and is churned into an acidic mixture called chyme, it stimulates the small intestine and pancreas to secrete alkaline, or basic, juices, which help to neutralize the chyme’s acidity. By the time food passes the first part of the small intestine, the acidity is greatly diminished, and the acidic foods that may exacerbate heartburn are significantly neutralized by the time they arrive at the kidneys to be made into urine. Even if urine remains acidic at this point, altered urinary pH is not among the likely causes of bladder pain.
- "American Family Physician"; Urinalysis: A Comprehensive Review; Jeff A. Simerville et al.; March 2005
- "American Family Physician"; Evaluation of Dysuria in Adults; Judy D. Bremnor et al.; April 2002
- “Journal of the American Dietetic Association”; Potential Renal Acid Load of Foods and Its Influence on Urine pH; T Remer, F Manz; July 1995
- “Disease of the Kidney and Urinary Tract”; Robert W. Schreier; 2007
- "Journal of Inherited Metabolic Diseases"; Classical Organic Aciduria, Methylmalonic Aciduria and Isovaleric Aciduria; C Diomisi-Vici et al.; November 2005
- “Understanding Normal and Clinical Nutrition”; Sharon Rady Rolfes, et al.; 2009