Alkaline diet

Why an alkaline diet may sound compelling.

1. When eating something acidic, you may experience an acidic burning sensation so it appears to make sense that eating alkaline foods will prevent that. However, that is wrong.

As the chapter on heartburn explains, although some acidic foods my trigger pain, they are not the cause of the problem.

2. If stomach acid refluxing is the problem, we can neutralise it by choosing alkaline foods. Again, that is wrong.

When any food lands in the stomach, it immediately becomes acidic. Foods we consume may vary from very acidic, like lemon at around pH2, to least acidic, like coconut milk at around pH6, but stomach acid can be around pH1.

The pH scale is logarythmic. pH1 is ten times as acidic as pH2 which is 10 times as acidic as pH3 etc. pH7 is neutral.

No foods are actually alkaline though some charts issued by promoters of an alkaline diet publish lists that attempt to show they are.

This clip from a screenshot of a popular chart highlights the deception:

Meats have low acidity whilst fruits and vegetables are usually high but alkaline diet promotors suggest it's the other way round claiming once metabolised their pHs change. 

The chart from which the above image was taken, claims meat to be around pH3 and pure water at pH5, although it is defined as pH7!

One can understand that anyone with an interest in diet would wish to promote healthy choices like fruit and vegetables but they are misleading us with pseudoscience.

3. Other claims for alkaline diet suggest they reduce cancer risk by increasing the blood's pH. It may be true that tumours thrive in an acidic environment as this 2019 paper from Massachusetts Institute of Technology, How tumors behave on acid states: "Acidic environment triggers genes that help cancer cells metastasize" but the blood's pH of between 7.35 and 7.45 is strictly controlled by the body through respiration and urination. If we were able to change that by a small fraction, we'd become very ill and probably die.

This 2022 paper from Nebraska Medicine, Science and the alkaline diet: Can acidic foods cause cancer? concluded: The bottom line: According to evidence-based science, a diet focused on specific alkaline foods can't change your blood's pH. Thus, the alkaline diet can't prevent or treat cancer.  

This paper from the MD Anderson Cancer Center, "The alkaline diet: What you need to know" provides much helpful information including the following:
"Our bodies are designed to maintain a very specific pH of the blood, organs and tissues. Normal blood pH is 7.35-7.45. In the rare occasion that somebody’s blood pH is outside of that normal range, it's typically associated with severe illness and is life-threatening.
"As the body digests food and processes medications, different elements that are more acidic or alkaline are released into the blood. In response, the lungs and kidneys rapidly filter our blood to take out these extra acid or alkaline components. This constant filtering creates waste products which are removed from the body in fluids such as urine, saliva and sweat. The pH of these waste products varies depending on what is being processed."
"Another tenant of an alkaline diet is testing urine pH. While this may make the effects of an alkaline diet seem more tangible, it is important to remember that the pH of urine (or saliva or sweat) doesn’t reflect a change in the blood’s pH level. Instead, this is simply a sign that your body is working to keep the blood’s pH level stable."

An alklane diet can cause harm.

On 11 December 2025, an article about a young couple in Arkansas whose baby died because the child had been fed an alkaline diet prompted this article from Prof, Edzard Ernst: "Alkaline diet: A diet to die for," highlighting the dangers of the pseudoscience surrounding the nonsensical practice.

“Misinformation isn’t a point of view; it does actual harm,” commented Brian Castrucci, president of the de Beaumont Foundation. “It’s hurting physicians. It’s hurting medical practice. And it’s hurting the American public.” 

Page updated 30 March 2026