By Barbara Broggelwirth, RDN, CDN

There is a lot of hype lately regarding alkaline diets. The claim is that by following a diet high in alkaline foods and low in acidic foods you can neutralize your body’s pH and subsequently prevent chronic inflammation and disease. According to “Cure Today”, a non-evidence based website promoting alkaline diets,” cancer cells thrive in acidity but not in alkalinity”.  The truth is, cancer cells can’t live in an overly alkaline environment, but neither can any of the other cells in your body (1). 

Changing your body’s pH is biologically impossible.  The fact is that cell and blood pH must stay tightly controlled (at about 7.4) to sustain life. However, the pH of urine does vary, and it is true that different foods can affect urine acidity. For instance, based on urine pH, meat, poultry, fish, dairy, caffeine, sugar, and salt are the most acid forming, and fruits and vegetables are the most alkaline forming.

What does the evidence say? When we consume an excess of acid-forming foods, the body works harder to neutralize the pH by releasing minerals (from our bones) into the blood to reduce the acid. Alternatively, alkaline-forming foods (fruits and vegetables) have a positive effect on bone health (2).

Another point of contention is that protein foods are “bad” because high-protein foods tend to be the most acidic. However, studies have suggested that protein is not necessarily a major contributor to acid load, and it can be balanced by an alkali load.  More important is the type of protein; plant proteins appear to be more protective than animal proteins.

So, what about alkaline water? While there is some evidence to support consuming a more “alkaline diet” (aka fruits and vegetables) it is a complex concept that is difficult to measure and cannot be oversimplified by drinking an alkaline product.

Bottom line: Consuming a diet with plenty of fruits and vegetables has been linked to improved health. They are low in calories and contain an abundance of vitamins, minerals, fiber, and antioxidants; all of which have been shown to protect against chronic diseases such as heart disease and cancer.


  1. “Don’t believe the hype – 10 persistent cancer myths debunked.” Cancer Research UK – Science blog,
  2. Ellis, Esther. “Alkaline and Plant Waters — What’s Behind the Trend?” Today’s Dietitian, Sept. 2017, pp. 46–46.

Barbara Broggelwirth is a Registered Dietitian Nutritionist who is currently working with Bariatric and Medical Weight Management patients.  She works with patients to help them achieve their health and weight loss goals.