By: By: Dr. Michael Greger, Director of Public Health and Animal Agriculture at the Humane Society of the United States.
Back in the 1960s, a patient isolator unit was developed for cancer patients undergoing chemotherapy. Because our immune system cells are 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, they developed this bubble boy contraption where they shave you, dip you in disinfectant, rinse you off with alcohol, antibiotic ointment in every orifice, and a rotating regimen of a dozen of the most powerful antibiotics we had. Procedures were performed through plastic sleeves and everything in and out had to be sterilized and pass through airlocks, and so, no fresh fruits and vegetables.
People went crazy cooped up in the things, with 38% of people starting to hallucinate. 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 air locks and alcohol baths were abandoned, but they continued to make sure no one got to eat a salad. Neutrophils are our front line of defense white blood cells, and when we don’t have enough, we’re called neutropenic, immunocompromised, so we’re put on a neutropenic diet, no fresh fruits and vegetables. The only thing is that there’s a striking lack of evidence that such a diet actually helps.
Ironically, the neutropenic diet is the one component that’s still practiced, yet has the least evidence supporting its use. Their rationale was like look, there’s bacteria on salads, bacteria cause infections, immunocompromised patients are at risk for infections and so no salad, and we’re glad there’s no studies on it because it could be way too risky to give a cancer patient a salad. So its continued use seems to be based on a ‘‘better safe than sorry’’ philosophy.
The problem is kids diagnosed with cancer come in already low in dietary antioxidants, the last thing you’d think you’d want to say is no fresh fruit. So in addition to the lack of clinical evidence for this diet, there may be some drawbacks—maybe restriction of fruits and vegetables may increase the risk of infection, compromise their nutritional status.
So are neutropenic diets for cancer patients reasonable prudence or clinical superstition? A resurgence of research started during the 90s, when the need to support clinical practice with, wait for it, evidence, became increasingly important—what a concept.
In other words, you don’t know until you put it to the test. Three randomized controlled trials were published, and none supported the neutropenic diet. This was the biggest—an all cooked diet versus one that allowed raw fruit 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 FDA nor the CDC support the neutropenic diet nor does the American Cancer Society. The real dangers are the pathologic food poisoning bacteria like Campylobacter, salmonella, E. coli. So you still have to keep people away from risky foods like undercooked eggs, meat, dairy and sprouts. Maybe there’s no longer even a debate, yet many institutions continue to 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 doctors may be hesitant to incorporate evidence-based medicine into the practice. They have limited time to review the literature. They’d like to dig deep into studies but they simply don’t have the time to look into the evidence. That’s what Nutritionfacts.org is for.
Bone marrow transplants are the final frontier. Sometimes it’s your immune system itself that is cancerous—leukemia, lymphoma, and so the immune system is wiped out on purpose to rebuild from scratch, and so inherent in the procedure is a profound immunodeficiency for which a neutropenic diet is often recommended, but 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 didn’t have the good bugs from fruits and vegetables crowding out the bad guys in the gut. Not only was the neutropenic diet not beneficial but there was a suggestion that it could be potentially harmful. It would not be the first time that an intervention strategy made good theoretical sense, but ultimately was ineffective when put to the test.
About Michael Greger M.D. – Michael Greger, M.D., is a physician, 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. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.
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