[Part 2 of 2]

At her public lecture, “Intravenous Vitamin C: Does it Work?” delivered at the Linus Pauling Institute’s Diet and Optimum Health Conference in September 2017, Dr. Jeanne Drisko of the University of Kansas Medical Center, Kansas City, provided an overview of current research on the potential impact of intravenous vitamin C in treating disease.

She began this portion of her talk by reflecting on the factors that have continued to propel her own scientific interest in the topic, despite the headwinds generated by critics of the work. For one, Drisko has taken heart in the fact that intravenous vitamin C is used in many clinics around the world. Indeed, at a 2006 integrative medicine conference, Drisko and colleague Mark Levine took a survey of participants and found that some 8,000 patients had received intravenous vitamin C from doctors attending the meeting. Because Drisko maintains contacts in both conventional and alternative medical circles, she knows that naturopaths have been using intravenous vitamin C as well.

Drisko then pointed out that one barrier to more widespread acceptance of vitamin C as a cancer treatment is that, conventionally, it does not make sense to administer it in tandem with chemotherapy, since vitamin C is known to be an antioxidant and chemotherapy is a prooxidant. That said, Levine and Drisko’s colleague in Kansas, Qi Chen, have found that when vitamin C is given intravenously, it actually works as a prooxidant because it produces hydrogen peroxide. As such, it actually becomes a very good compliment to chemotherapy. Moreover, studies conducted by Drisko and others have found no evidence of conflict arising as a result of vitamin C dosages given alongside chemotherapy. On the contrary, researchers have reported a synergistic relationship in many cases.

In explaining why this is so, Drisko noted that when vitamin C is injected into a vein, it takes on the form of an ascorbyl radical, which she described as a “very promiscuous and active molecule that likes to interact with transition metals” like copper and iron. These interactions lead to the formation of hydrogen peroxide, which is quickly turned into water and oxygen by the enzymes glutathione peroxidase and catalase, such that levels of hydrogen peroxide in the bloodstream are promptly rendered as unmeasurable.

However, when vitamin C gets into the extracellular fluid it also becomes hydrogen peroxide. The difference in this case is that glutathione peroxidase and catalase do not intervene and the hydrogen peroxide is not broken down into water and oxygen. Instead, the hydrogen peroxide diffuses throughout the extracellular fluid, bathing the cells.

While the presence of hydrogen peroxide in the cells might seem unsafe, Levine’s cell culture tests have found that hydrogen peroxide caused harm only to cancer cells. In reporting his results, Levine explained that the glutathione peroxidase and catalase enzymes are not as efficient in attacking cancer cells because they direct their activity towards reproduction rather than other processes. The fact that glutathione peroxidase and catalase are not active in the extracellular fluid renders vitamin C as a pro-drug and hydrogen peroxide as an actual drug.

Drisko’s research portfolio on the use of intravenous vitamin C includes the first randomized controlled trial involving ovarian cancer patients, work that was published in 2014. The trial studied two groups of patients: one group received standard care, which included carboplatin and paclitaxel chemotherapy for six cycles. The other group received this same care along with 75 to 100 gram doses of intravenous vitamin C.

The trial made clear that this form and dosage of vitamin C therapy is safe to administer. It also yielded a statistically significant improvement in how certain types of patients felt during their cancer treatment. Drisko called this a “feel good effect” which she believes is neurological. This same impact, however, was not observed in patients suffering from more advanced stage three and stage four cancers. Drisko is currently following up on these results by looking at the role that vitamin C might play in brain chemistry.

While her work has generated positive results, Drisko is also aware that vitamin C should not be used in all cases. Importantly, vitamin C is known to be potentially harmful when given in large doses under certain conditions. One such case is in individuals suffering from a deficiency of Glucose-6-Phosphate Dehydrogenase, or G6PD. On its own, G6PD can cause anemia, but when combined with high levels of vitamin C it leads to hemolysis, or the destruction of red blood cells. As a matter of standard protocol, Drisko checks her own patients for G6PD deficiencies, but she knows of others who have been unaware of this biological conflict and who have had to send patients to the emergency room.

Drisko will likewise opt against administering intravenous vitamin C when a patient reports a history of oxalate kidney stones, which can form as a result of excessive vitamin C intake. For individuals who have gone ten years or more since their last instance of oxalate kidney stones, Drisko administers vitamin C, but she does so cautiously, monitoring kidney functions and liver enzymes throughout the process.

Another barrier to studying intravenous vitamin C is that it is a difficult substance to measure since it is processed by the body so quickly. To get around this difficulty, Drisko developed a finger stick method that emerged from her interactions with a diabetic ovarian cancer patient. Over the course of these interactions, Drisko found cause to contact a glucometer manufacturer who told her that, because vitamin C and glucose molecules are so similar, the glucometer would indicate levels of both. Making use of this similarity, Drisko started taking finger stick glucose readings both before and right after her patients received their doses, and using this process she is now able to ascertain a rough estimate of how much vitamin C has been absorbed by the body.

In attempting to achieve greater certainty about appropriate dosage levels of vitamin C to administer, Qi Chen and Mark Levine have conducted experiments wherein they give intravenous vitamin C to mice and rats with tumors. This work is a follow-up to Levine’s original studies in the 1990s, which showed that vitamin C given orally could not be absorbed above a 10 millimolar concentration. In their more recent invesigations, Levine and Chen have found that blood concentration levels of 20 to 30 millimolar can be achieved as a result of intravenous application. They also found that the tumors in their mice studies would take up the vitamin C and that hydrogen peroxide formed in the tumors and subcutaneous tissue, but not in the blood.

Drisko gives her patients two to three infusions of vitamin C per week in advanced cases. Ideally, the vitamin C would be administered as the fluid loading dose for chemotherapeutic drugs, but it is often difficult to carry out both vitamin C and chemotherapy treatments on the same day because patients are already burdened by a busy treatment schedule and the facilities providing the two types of treatments are often not in the same location. (A new dosing device that attaches to the hip, developed by Channing J. Paller at Johns Hopkins, could help to get around some of these barriers.) Drisko’s treatment schedule uses a “stair-step” methodology wherein doses ranging from 0 to 100 grams are able to achieve 20 millimolar blood concentrations.

The appropriate duration of vitamin C treatment for cancer is still an open question. What is known is that it takes at least a couple of months before effects start to show. This stands in stark contrast to chemotherapy, which makes a much quicker impact.

Drisko concluded her talk by sharing the hopeful story of a woman who had participated in her ovarian cancer trial. This patient had been part of the group that had received the standard chemotherapy treatment only. She had subsequently relapsed very quickly and was believed to have only months to live. In her conversations with Drisko, the patient expressed a strong desire to live long enough to give her grandson a present at Christmas, and she requested that Drisko give her vitamin C in addition to her chemotherapy, since she was no longer part of the trial.

Initial CT-PET images showed that the woman was suffering from an accumulation of fluid, or ascites, full of cancer cells that were pushing against her organs. At the start of her intravenous vitamin C treatment in 2004, a second CT-PET scan showed both the malignant ascites as well as a residual tumor that could not be removed surgically.

Subsequent scans after Drisko began her treatment showed gradual improvement. In 2007, the pictures included fewer ascites and the tumor was somewhat smaller, trends that continued to be seen in 2012. By 2014, calcification appeared in the tumor and around the fluid, with further calcification showing in 2015. In essence, what the scans were revealing was an eight-year process of “turning her cancer into a scar.” While this is only a single example, it is a powerful one, and may prove to be harbinger of medical breakthroughs to come.