The short answer
The alkaline diet claims that eating certain foods changes your body's acidity and fights cancer. A 2016 systematic review found almost no research and no trials, and said promoting it for cancer prevention or treatment is not justified. There is no good evidence that an alkaline diet cures or prevents cancer, though eating more vegetables and fruit is healthy for other reasons.
The alkaline diet claims to fight cancer by changing body pH.
A 2016 systematic review found only one eligible study and no trials of an alkaline diet or water.
There is no good evidence an alkaline diet cures or prevents cancer.
Eating more vegetables and fruit is still healthy for other reasons.
Watch: The alkaline diet claim
45 sec · Captioned · Food can't change your blood pH — and no evidence the diet treats cancer.
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This page is for anyone who has heard that an alkaline diet can prevent or cure cancer. It explains how the body controls pH and what the research found.
The claim
The alkaline diet rests on one idea. It says cancer thrives in an acidic body, and that eating alkaline foods and avoiding acidic ones can change your body's pH (how acidic or alkaline it is) to prevent or cure it. The idea is widely promoted online and in books.
Why the science does not support it
MedlinePlus says the kidneys and lungs maintain the balance of acids and bases in the body. The sources we opened do not address how diet affects blood or urine pH, so this page makes no claim about that.
If the balance goes off, it is a medical problem in itself. Doctors call it acidosis or alkalosis. See a doctor if you are worried about it.
What the research actually found
A 2016 systematic review in BMJ Open searched the literature through April 2015. Out of 8,278 citations, only one study met the standard, and it found no link between dietary acid load and bladder cancer. The review found no randomized trials testing an alkaline diet or alkaline water as a cancer treatment.
The authors found almost no actual research and concluded that promoting the alkaline diet or alkaline water to the public for cancer prevention or treatment is not justified. The review is from 2016, so newer studies may exist.
The bottom line
An alkaline diet is not a proven way to cure or prevent cancer. There is a catch, though. Many alkaline diets lean on vegetables and fruit and cut processed food, which is healthy for other reasons.
The harm comes when a diet is used to delay or replace real cancer treatment. Delaying treatment that works can let a cancer grow. Talk to your care team before you make big diet changes during treatment, and keep to the treatment plan you agreed on.
Sources
Common questions
Can an alkaline diet cure cancer?
There is no good evidence it can. A 2016 systematic review found no trials and called public promotion of it for cancer treatment not justified.
Can food change my body's pH?
MedlinePlus says the kidneys and lungs keep the body's acid-base balance. The sources we opened do not say how diet affects it.
Is the alkaline diet harmful?
Its emphasis on vegetables and fruit is healthy, but it can cause harm if used to delay or replace proven cancer treatment.
So why do people feel better on it?
Alkaline diets often mean more vegetables and less processed food, which is generally healthy — but that is not the same as curing cancer.
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Sources last checked: 2026-08-11 what this meansLast updated: 2026-10-02Next planned review: 2027-01-12
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Editorial review complete — This page completed Cancer Explained's editorial checks (sources, safety, plain language, duplication). It has not been reviewed by a physician or other healthcare professional.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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