Should Cancer Patients Avoid Raw Fruits and Vegetables?

Image Credit: Sally Plank

Should Cancer Patients Avoid Raw Fruits and Vegetables?

Back in the 1960s, a patient isolator unit was developed for cancer patients undergoing chemotherapy. Because our immune system cells were often caught in the friendly fire, up to 50% of cancer patients died of infections before they could even complete the chemo because their immune systems had become so compromised. So, a bubble boy-like contraption was developed. The patient was shaved, dipped in disinfectant, rinsed off with alcohol, rubbed with antibiotic ointment into every orifice, and placed on a rotating regimen of a dozen of the most powerful antibiotics they had. Procedures were performed through plastic sleeves on the sides of the unit, and everything in and out had to be sterilized and passed through airlocks. So, the patient wasn’t allowed any fresh fruits or vegetables.

People went crazy cooped up in these bubble-like units, with 38% even experiencing hallucinations. Fifteen years later, the results were in: it simply didn’t work. People were still dying at the same rate; so, the whole thing was scrapped—except the diet. The airlocks and alcohol baths were abandoned, but they continued to make sure no one got to eat a salad.

Neutrophils are white blood cells that serve as our front line of defense. When we’re immunocompromised and don’t have enough neutrophils, we’re called “neutropenic.” So, the chemotherapy patients were put on a so-called neutropenic diet without any fresh fruits and vegetables. The problem is there’s a glaring lack of evidence that such a neutropenic diet actually helps (see my video Is a Neutropenic Diet Necessary for Cancer Patients?).

Ironically, the neutropenic diet is the one remaining component of those patient isolator unit protocols that’s still practiced; yet, it has the least evidence supporting its use. Why? The rationale is: there are bacteria in salads, bacteria cause infections, immunocompromised patients are at increased risk for infections, and therefore, no salad. What’s more, they are actually glad there aren’t any studies on this because it could be way too risky to give a cancer patient an apple or something. So, its continued use seems to be based on a ‘‘better safe than sorry’’ philosophy.

The problem is that kids diagnosed with cancer are already low in dietary antioxidants; so, the last thing we should do is tell them they can’t have any fresh fruit or veggies. In addition to the lack of clinical evidence for this neutropenic diet, there may be some drawbacks. Restricting fruits and vegetables may even increase the risk of infection and compromise their nutritional status.

So, are neutropenic diets for cancer patients “reasonable prudence” or “clinical superstition”? Starting in the 1990s, there was a resurgence of research when greater importance was placed on the need to “support clinical practice with evidence.”

What a concept!

Three randomized controlled trials were published, and not one supported the neutropenic diet. In the biggest study, an all-cooked diet was compared to one that allowed raw fruits and veggies, and there was no difference in infection and death rates. As a result of the study, the principal investigator at the MD Anderson Cancer Center described how their practice has changed, and now everyone is allowed to eat their vegetables—a far cry from “please don’t eat the salads” 31 years earlier. 

Today, neither the Food and Drug Administration, the Centers for Disease Control and Prevention, nor the American Cancer Society support the neutropenic diet. The real danger comes from pathogenic food-poisoning bacteria like Campylobacter, Salmonella, and E. coli. So, we still have to keep patients away from risky foods like undercooked eggs, meat, dairy, and sprouts. At this point, though, there really shouldn’t be a debate about whether cancer patients should be on a neutropenic diet. Nevertheless, many institutions still tell cancer patients they shouldn’t eat fresh fruits and veggies. According to the latest survey, more than half of pediatric cancer doctors continue to prescribe these diets, though it’s quite variable even among those at the same institution.

Why are doctors still reluctant to move away from the neutropenic diet? There are several reasons why physicians may be hesitant to incorporate evidence-based medicine into their practices. They may have limited time to review the literature. They’d like to dig deep into studies, but simply don’t have the time to look at the evidence. Hmm, if only there was a website… :)

Bone marrow transplants are the final frontier. Sometimes, it’s our immune system itself that is cancerous, such as in leukemia or lymphoma. In these cases, the immune system is wiped out on purpose to rebuild it from scratch. So, inherent in the procedure is a profound immunodeficiency for which a neutropenic diet is often recommended. This also had never been tested—until now.

Not only did it not work, a strict neutropenic diet was actually associated with an increased risk for infection, maybe because you don’t get the good bugs from fruits and vegetables crowding out the bad guys in the gut. So, not only was the neutropenic diet found to be unbeneficial; there was a suggestion that it has the potential to be harmful. This wouldn’t be the first time an intervention strategy made good sense theoretically, but, when put to the test, was ultimately ineffective.

Unfortunately, there’s an inertia in medicine that can result in medical practice that is at odds with the available evidence. Sometimes this disconnect can have devastating consequences. See, for example, Evidence-Based Medicine or Evidence-Biased? and The Tomato Effect.

The reason it is so important to straighten out the neutropenic diet myth is that fruits and vegetables may actually improve cancer survival:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

23 responses to “Should Cancer Patients Avoid Raw Fruits and Vegetables?

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  1. Oh I cringe at that kind of news and then I say, “Wow, now there is!

    As a health professional I am faced with the long procession of facts of the way things were and how they are now- and so much better. Thank goodness that ultimately nothing is static.

    Food heals and I am so grateful to UNLEARN the ideas that I was taught so that people, who trust in my role and its attendant duty to stay current, can be encouraged along their healing journey with evidence based nutrition.

    Thank Dr. Greger and team! And my husband is a Cardiologist and he has transformed his approach to cardiology nutrition education to his patients thanks to this website- we recently made a new brochure all about a WFPBD for the patients with consultation with me for free.

  2. What about those that love cooked veggies, and eat them in abundance, but just don’t like raw veggies and very little of them? Do they still get the benefits?

  3. Hi there,

    This question is only tangentially-related, but I have a family member that has recently been diagnosed with Stage 4 lung cancer, and he’s been following advice from a non-expert about getting and maintaining his body in a ketogenic state. The rationale has been that cancer cells need to be starved, and that by continuing to eat a diet where his body burns glucose for fuel, he’s feeding not only his healthy cells but his cancer ones as well. If his body is burning fat for energy, the cancer cells will starve.

    I’m cringing while I watch him focus his dinner around a steak and pick away at a few vegetables. Luckily, his targeted treatment is giving us signs of optimism. Can anyone share some research to help me better acquaint him with facts?

    1. You have valid concern and it irks me to see this head in the sand plant based attitude. There is evidence to be looked at for sure and some fruits, for example, have been manipulated to be very sweet through hybridization (not GMO) so why make blanket statements and lump all fruits and veggies together? Yes some are cancer destroyers but maybe others are cancers favourite food; remember, viruses evolved before humans so they must dine on the same basic building blocks off all organic substances. As such, what is the best fuel for them? Why not look into this deeply to see if we can connect some dots? That Gregor ignores progressive information is beyond me, sure some things are almost conceptual but wasn’t it that same intuition that Pritikin followed when he tried to beat his cancer and inspired the likes of Gregor to be a doctor, le sigh.

      1. Hello Marcello,
        Thank you for your comment. I am a family doctor with a private practice in lifestyle medicine and also am a volunteer moderator for this website. I don’t know to whom you addressed your comment that “You have valid concern….”, so I don’t know what that concern is.

        I don’t think that Dr. Greger has a “head in the sand” approach to nutrition, nor do I think that he ignores progressive information. If you look at a good cross-section of his videos, you will see that very often, when discussing a correlation that implies a benefit to plant based nutrition, he takes the “devil’s advocate” position, and tries to consider alternative explanations for the data, which would negate the correlation.

        Your main concern seems to be that it is not wise to lump all vegetables and all fruits together as being beneficial. That is a good point. However, using inductive reasoning to draw general conclusions from various specific data is what science is about.

        I do appreciate your concern, though. There are many examples of scientists clinging to a theory despite evidence to the contrary. I’m sure that lots of people who follow this website have already made up their minds that all whole plant foods are good, and that no animal products are good, and whose first impulse is to discount/disregard data that contradicts this view.

        Rather than disparaging Dr. Greger’s work in general, your argument would be much more powerful if you would provide specific examples of studies which show harm from eating a whole foods plant based diet. There are, of course, specific instances of harm: e.g. people who are allergic to peanuts, or diabetics who would be wise not to eat huge amounts of sugary fruits, etc.

        Dr. Jon
        Volunteer moderator for

    2. I am looking for an answer to this debatable topic as well. My mother has been diagnosed with stage 4 lung cancer. While people following naturopathy and vegan diets are advising to shift to a raw uncooked diet, doctors in family and friends don’t believe so. One point is that cooking food kills the bacteria and hence is very important, while the latter focus on starving the cells by eating uncooked food.

      I’m trying to read and figure but both sides have ample articles.

  4. It seems so counter-intuitive that a science based discipline like medicine would cling to virtually pointless paradigms like this when “cutting edge” is so often the buzzword.

  5. Dr. Greger –

    Are the hyperlinks the only sources you are referencing? Do you have any further articles you’ve written or references on this topic? I am in the process of beginning research in an effort to at least decrease the restrictions for neutropenic patients at our facility or discontinue the use of the low bacteria diet. Any further references would be great! Thanks for all your great work!

  6. My mom was in the hospital with pneumonia after chemotherapy. They put her on a neutropenic diet and blasted her every antibiotic known to man. The processed food they served her was awful. She already had a poor appetite and was craving fruit and vegetables. I spoke with the Nurse and her Doctor about it. Despite that fact that I’m a Registered and Licensed Dietitian and brought several good resources I found about the lack of evidence for the neutropenic diet, the Doctor wouldn’t budge. So I started sneaking in yogurt, salads, and fresh fruit for her to eat.

    1. Good on you, looking out for your mom!
      Had it been your child, social services would have been called.

      Getting the attending of the hook by having the patient acknowledge her/his advice is not followed -in writing if necessary- does the trick. Insurance however could deny coverage if complications point back to patient non-compliance.
      I have refused to follow sooo many orders.
      Nice being an adult with freedom to choose.

  7. I was fortunate with the radiation treatment for my cancer.The facility I attended had a nutritionist specializing in specific diets and supplementation for various cancers and treatments. My diet included:raw organic fruits and veggies, where possible oriental crucifers, bok choy, napa cabbage, chinese broccoli, all mushrooms especially asian, raw nuts and seeds etc.
    All fruits and veggies allowed during treatment even high anti-oxident one. Emphasis on anti-inflammatory foods, ginger , tumeric etc during and after treatment.Even supplementation during treatment with anti-inflammatories ( curcurmin, boswella etc) but not anti-oxidents.
    My first day, when I walked in and saw the big sunflower poster with the listing of what to eat ,put a smile on my face and really raised my confidence

  8. Hi Dr. Greger,

    You probably won’t reply to this, so if anybody else has insight, it would be greatly appreciated. Would this advice be complicated by someone suffering from an original diagnosis a grade 3 GVHD of the gut? It seems that this diagnosis makes my stomach even more prone to bacteria and possibly presenting it with something that contained even good bacteri may be hazardous.

    Thank you

  9. Thanks for this great article. I pity those patients whose doctors continue to insist on these myths. The patients puts his full trust in the doctors under the premise that they are the best resource having gone thru intensive medical training. Between a layman like me & a doctor i stand no chance of convincing a patient not to follow doctors orders. Personally i have not followed many of the doctors orders & i have never felt much better. Its really time for patients to be equally involved in their healing process.

  10. Diagnosed with cancer in 2008, I was given paperwork instructing no raw fruits or vegetables at the start of treatment. I went completely raw diet for the first year of treatment, and fortunately my oncologist supported my choice and agreed that the standard direction was nonsense (yet the paperwork had not been changed to reflect his attitude). He actually said, after all treatment was complete, that the best I could do for myself was to maintain a vegan (not raw) lifestyle. He went on to say that eating in restaurants was a much bigger risk than raw fruits and vegetables. And then admitted he was vegetarian.

  11. What else can I expect from an 18th medical treatments for cancer. I have Stage IIIA breast cancer and refused all traditional medical treatments, no chemo, no radiation, no surgery, no hormone therapy, etc. If we are what we eat, I plan to survive. To thine own health be true!

  12. What bothers me most about this study is this line: “In the biggest study, an all-cooked diet was compared to one that allowed raw fruits and veggies, and there was no difference in infection and death rates.” Why didn’t eating the better diet make a difference for the better?

  13. My nephew (10 y/o, recently turned 11) has burketts lymphoma and is on week 4 of chemo. It was in all his organs and pressing against his diaphragm. he has been hospitalized at Children’s since the beginning, for about 2.5 months now. He eats garbage from their menu and when he can eat something else his mother takes him cheeseburgers with french fries, hot cheetos, you get the picture.

    Are there any studies on this specific cancer in children, or does anyone have any advice? I supplied the WHO study that shows deli meats and processed meats are class one carcinogens and they literally do not care one bit.

  14. Okay so I was diagnosed with stage 1 B cell lymphoma and have done one chemo treatment so far. I was Neutropenic after. My wbc counts got to 0.7 at the lowest. I read this article because before I was diagnosed my diet consisted heavily of high fiber vegetables and seafood. Now I’m kind of at a loss for what I should eat. I’ve heard many people say not to eat fruits and vegetables but that’s the opposite of my whole eating regimen. Could I simply wash them better???

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