The Myth: Ingesting acidic foods or beverages makes urine more acidic, irritating the bladder and flaring symptoms.
The Truth: While some acidic foods are common triggers for IC, the body is extremely complex and 'acid in' doesn't equal 'acid out.' Many foods that contain acid are considered entirely 'IC-safe,' while some basic (meaning non-acidic) foods and drinks can also be major triggers. Furthermore, acidic urine has been proven to be no more painful than neutral urine for patients with IC.
Myth Origin: This myth originated as a simplified shorthand to explain certain trigger foods. Citrus fruits and juices, containing citric acid, are common trigger foods for many patients. From there, the assumption was made that these foods were triggers because they 'acidified' the urine and that all acidic foods should be avoided.
Debunking the Myth: There are two parts of this myth that need to be debunked: 1) 'acid in' results in 'acid out' within the body, and 2) that acidic urine actually causes an increase in symptoms.
While it may seem that acidic foods would 'acidify' the body, the acidity of a food or drink when you put it into your body has almost no relationship to what it does while inside. Many acidic foods are metabolized and actually become basic when they go through the body. Take the lemon - one of the most acidic foods we can tolerate eating, but after it's ingested the lemon actually turns basic within the body, and drinking lemon juice actually raises the pH of the urine in the bladder!
"We don't have any proof that it's the acid or the alkaline that makes a difference in the bladder."
- Dr. Barbara Shorter, ICA Medical Advisory Board
The other part of the myth is that acidic urine causes increases symptoms. When researchers from the University of British Columbia tested this theory, they found acidic urine didn't have any impact on symptoms.
In one study, they actually put a patient's urine back into their bladder. These brave volunteers with IC either had their own highly acidic urine re-inserted into the bladder, or a neutralized solution that wasn't acidic at all. Researchers were surprised to find that the acidity of the urine didn't seem to matter at all.
These results were confirmed in a recent study published in the International Pelvic Pain Society. In that research from St. Louis University, researchers actually found that IC symptoms were more correlated with neutral or basic urine than acidic urine.
"The symptoms of urgency, burning, and bladder spasm occur more often in urine with neutral or alkaline pH when compared to acidic pH."
- Marcu I et al, IPPS 2017
Impact of the Myth: While the idea of avoiding acidic foods can be a helpful simplification for some patients with IC, it's important to remember that "acid in" doesn't equal "acid out." Patients need to find their specific trigger foods, and not try and avoid an entire category of foods just because they happen to be acidic.
In fact, there are many different types of acid which often occur in both 'IC-safe' and trigger foods. Malic acid is in bananas, but also tomatoes. Oxalic acid is in leafy green vegetables like spinach. Lactic acid is in mild, cheese, and sour cream. Ascorbic acid (also known as Vitamin C) is found in many fruits and vegetables - some of them might be trigger foods, and others that aren't at all. While it may seem that acidic foods are common triggers, the truth is that many 'safe' foods also contain acid, and some trigger foods don't contain acid at all.
The two rules of diet changes with IC are simple: avoid your personal trigger foods and eat healthy. It doesn't have to be any more complicated than that.
Read on to find out the truth about these myths, and feel free to join the online Facebook community Finding Pelvic Sanity for support and resources!
Dr. Nicole Cozean is the founder of PelvicSanity physical therapy, Orange County's premier pelvic floor physical therapy clinic. Nicole was named the 2017 IC Physical Therapist of the Year, was the first PT to serve on the ICA Board of Directors, and is the author of the award-winning book The Interstitial Cystitis Solution (2016). She is an adjunct professor at her alma mater, Chapman University.