Does Vitamin C Help With Terminal Cancer?

Studies in the 1970s showed an extraordinary survival gain in terminal cancer patients with vitamin C, a “simple and relatively nontoxic therapy.” It’s no wonder it got a lot of attention, especially when reported by a world-renowned scientist, Linus Pauling. But studies in the 1980s found no such benefit, so scientists were “left with the inevitable conclusion that the apparent positive results [in the original study] were the product of case-selection bias rather than treatment effectiveness.” In the 1990s, though, an alternative explanation arose: The disappointing ’80s research only used oral vitamin C, whereas the apparently successful ’70s experiments also gave vitamin C intravenously, and we didn’t realize until the ’90s that the same dose given intravenously can lead to dramatically higher levels in the bloodstream than when taken orally. So maybe high dose vitamin C does help in terminal cancer, but maybe only when given intravenously. This is the topic of discussion in my video The Role of Vitamin C in the Treatment of Terminal Cancer.

Encouraging case reports continued to be published. Regression, remission, and cure had been documented in individual cases of advanced kidney cancer, bladder cancer, and lymphoma, but that was three success stories out of how many? If it was three out of a hundred, or even three out of a thousand, then okay, if the treatment is sufficiently nontoxic. But there is evidence that IV vitamin C is widely used in the alternative medicine world, as in 86 percent of 172 practitioners surveyed. Just those 172 practitioners alone treated about 10,000 patients a year, and manufacturers are selling hundreds of thousands of vials of this stuff in the United States. It’s not all being used for cancer, but, presumably, at least thousands of cancer patients are being treated every year with IV vitamin C, making the publication of three remarkable case reports seem less impressive. So no matter how amazing these cases seemed, it’s possible the cancers just spontaneously regressed all on their own, and it was just a coincidence that it happened after the patients were given vitamin C. To know for sure, you have to put it to the test.

To date, there have been some small pilot studies, and the results so far have been disappointing. The good news is that even insane doses of IV vitamin C seem remarkably safe, but failed in a study of two dozen patients “to demonstrate anticancer activity.” Similar small studies have been published, all the way through to the present, with results that are tantalizing but inconclusive. What we do know is that the present state of cancer chemotherapy is “unsatisfactory.” People have a perception that chemotherapy “will significantly enhance their chances of cure,” but if you put all our cancer-killing chemo together, the overall contribution to five-year survival is on the order of 2 percent—all those side effects for a 2.1 percent survival rate bump, at a cost of maybe $100,000 per patient per year. So, it may be worth looking deeper into therapies like IV vitamin C. However, the lack of financial reward (since vitamin C can’t be patented and sold for $100,000) and bias against alternative medicine “could dissuade conventional investigators and funding agencies from seriously considering this approach.”

So, decades later, what can we conclude? “After trials which have included at least 1,609 patients over 33 years, we have to conclude that we still do not know whether Vitamin C has any clinically significant antitumor activity.” Although “there is currently no definitive evidence” of benefit, the Mayo Clinic’s randomized controlled trials “do not negate the potential benefit” based on what we now know about oral-versus-IV routes of administration. So, we’re kind of back at square one: Does it work or not? There are highly polarized views on both sides, but everyone’s working off the same incomplete data. What we need are carefully controlled clinical trials. The question, though, is what do we do until then?

If it was completely nontoxic, one could argue, “Well, what have you got to lose?” But it is not—it’s only relatively nontoxic. For example, there have been rare but serious cases of kidney injury reported. After all, if it’s so safe, why did our bodies evolve to so tightly control against excess absorption? It can also be expensive and time-consuming. Each infusion can cost $100 to $200 out of pocket since insurance doesn’t pay for it, which can be quite a boon for alternative medicine practitioners. About 90 percent of the millions of doses of vitamin C being dispensed are in for-profit arrangements, so there are financial pressures pushing in both directions, for and against this treatment.

Given the relative safety and expense, though, if controlled studies even find a small benefit, it would be considered worthwhile. And if they don’t, the vitamin C question can be put to rest once and for all. But “[i]n cancer treatment we currently do not have the luxury of jettisoning possibly effective and nontoxic treatments. We should revisit promising avenues, without prejudice and with open minds…”


This video is the third installment in a three-part series. For the complete saga, watch the other two videos Intravenous Vitamin C for Terminal Cancer Patients and Vitamin C Supplements for Terminal Cancer Patients.

I discuss the conundrum of what do to about funding research of non-patentable natural treatments in Plants as Intellectual Property: Patently Wrong?.

Additional videos of interest include:

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:

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 were 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 has 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:

What Are the Benefits of Organic?

The medical literature has been historically hostile to organic foods, blaming in part erroneous information supplied by the health food movement for our ignorance of nutrition. But until just a few generations ago, all food was organic. It’s kind of ironic that what we now call conventional food really isn’t very conventional for our species.

By eating organic, we can reduce our exposure to pesticides, but it remains unclear whether such a reduction in exposure is clinically relevant. In my video, Are Organic Foods Safer?, I talked about some of the test tube studies comparing health-related properties of organic versus conventional foods. Organic produce was found to have higher antioxidant and antimutagenic activity combined with better inhibition of cancer cell proliferation, but in terms of studies on actual people rather than petri dishes, there isn’t much science either way.

Why can’t you just compare the health of those who buy organic to those who don’t? Organic consumers do report being significantly healthier than conventional consumers, but they also tend to eat more plant foods in general and less soda and alcohol, processed meat, or milk, and just eat healthier in general. No wonder they feel so much better!

Therefore, there is an urgent need for interventional trials, or studies following cohorts of people eating organic over time like the Million Women Study in the UK, which was the first to examine the association between the consumption of organic food and subsequent risk of cancer. The only significant risk reduction they found, though, was for non-Hodgkin’s lymphoma. This is consistent with data showing a higher risk of developing lymphoma in those who have higher levels of pesticides stored in their butt fat, a study undertaken because farmworkers have been found to have higher rates of lymphoma.

Parental farmworker exposure is also associated with a birth defect of the penis called hypospadias; and so, researchers decided to see if moms who failed to choose organic were at increased risk. Indeed, they found that frequent consumption of conventional high-fat dairy products was associated with about double the odds of the birth defect. This could just be because those that choose organic have other related healthy behaviors, or it could be that high-fat foods, like dairy products, bioamplify the fat-soluble toxins in our environment.

In my video, Are Organic Foods Healthier?, you can see two other general population pesticide studies that have raised concerns. One study found about a 50 to 70% increase in the odds of ADHD among children with pesticide levels in their urine, and another that found triple the odds of testicular cancer among men with higher levels of organochlorine pesticides in their blood. 90% of such pollutants come from fish, meat, and dairy, which may help explain rising testicular cancer rates in many Western countries since World War II. 

What about interventional trials? All we have in the medical literature so far are studies showing organically grown food provides health benefits to fruit flies raised on diets of conventional versus organic produce when subjected to a variety of tests designed to assess overall fly health. And what do you know—flies raised on diets made from organically grown produce lived longer. Hmm, insects eating insecticides don’t do as well. Not exactly much of a breakthrough!


For how to best get pesticides off of conventional produce, see my video How to Make Your Own Fruit and Vegetable Wash.                                                                                                  

Pesticides are one thing, but Are Organic Foods More Nutritious?

Overall, Are the Benefits of Organic Food Underrated or Overrated?

For more on the impact of food contaminants during pregnancy, see:

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: