Overview of Evidence for High-Dose Vitamin C
Vitamin C is widely known as a treatment for colds and for enhancing immunity; however, what could it do to cure cancers? For more than forty years, vitamin C has been attracting increasing attention as a possible and yet controversial agent against cancer. Some of these researchers have gone as far as to claim that it has been proven to work, if only for the terminally ill, using mostly high-dose protocols. Evidence against the claims only presents a lack of evidence, according to others.
What is the untruth in this regard?
The reader here follows thus, everything above topics, from history and clinical observation to recent research and possible mechanisms through which vitamin C acts in cancer therapy, with perhaps most important-a-what for chemotherapy and radiation patients-methods, namely, oral versus intravenous (IV) administration.
A Brief Historical Glance: Home of High-Dose Vitamin C Cancer Treatment
Going back to the 1970s, speculations were made about the possible use of vitamin C as a cure for cancer. Indeed, even Linus Pauling, co-winner of the Nobel Prize twice, and Scottish surgeon Ewan Cameron, published a paper saying high doses of vitamin C could extend the quality of life and life in terminal cancer patients.
Such patients did include those studies wherein they took up orally at least 10 grams of vitamin C daily or more by suspension; those who had their treatment through the intravenous route lived a significant time longer with nonmedicated control. Such an exciting result ignited enthusiasm and money to investigate vitamin C-as an anti-cancer agent.
However, all of these postulates had too short an idyllic time.
The Moertel Study: A Great Obstruction
In the 1980s, a group of researchers at the Mayo Clinic led by Dr. Charles Moertel decided to put these hopeful findings to the acid test in a rigorously double-blind placebo-controlled trial. Patients with advanced colorectal cancers were given oral vitamin C, 10 grams a day. Well, it turned out disappointing; vitamin C patients were no different than placebo patients.
This study became the so-called gold standard and led many in medicine to sweep high-dose vitamin C under the rug, labeling it an ineffective treatment in managing cancer. A review in 2003 reiterated that no mortal benefits were seen in patients with advanced cancer taking vitamin C.
So, what went wrong? Were the original hopes misplaced, or were there things these trials failed to see?
Route of Administration: Oral Versus Intravenous
An important detail, by and large, not controlled in this debate is how vitamin C has been given.
The Moertel trial legitimately used oral administration only; Pauling and Cameron's original studies combined oral with intravenous (IV) administration. This difference is unfortunately not as trivial as it sounds.
Here's the reason:
The absorption of oral vitamin C is limited by the body. Even doses pushed to extremes have plasma concentrations rarely exceeding 220 μmol/L.
IV vitamin C circulation: No absorption problem, straight to plasma, and a maximum plasma level of 26000 μmol/L—more than 100 times higher than oral.
So what is the big deal?
How high plasma concentrations can induce toxicity against cancer cells are measured.
Experimental studies have shown such high concentrations to be pharmacological ones for vitamin C that can be achieved solely through intravenous infusion, allowing the compound to:
- Induce death in cancer cells while protecting healthy tissues.
- Act like a powerful oxidant and source hydrogen peroxide in that environment which goes to the tumor site - a toxin to cancer cells".
- Induce apoptosis in malignant cells.
- Prevent tumor growth in clinical animals, particularly in cancer types that are generally difficult to treat.
- Intravenous vitamin C has been reported to reduce tumor volume in mice with different cancers, which shows that it might help humans react positively to this type of intervention.
Some case histories detail patients with rapidly aggressive, late-stage cancers experiencing unusually long survival periods fueled by high bolus dose IV treatment of vitamin C.
As a result of such promising findings, vitamin C was once again refueled with interest for adjuvant cancer treatment and set up heated debate regarding its reevaluation in possible applications in modern oncology.
No stand-alone treatment: Evidence Says
High-dose therapeutic infusion of vitamin C does not in itself furnish a gleam of hope for curing cancer.
Existing evidence is scanty and mostly derived from:
cell and animal research
small human studies
anecdotal case reports.
However, there is a lack of large, adequately controlled trials that would enable an evidence-based conclusion to be drawn.
But existing evidence will indicate that vitamin C probably makes the quality of life better and reduces the toxicity of considering chemotherapy, or perhaps modifies the effect of specific drug regimens against cancer therapy.
Vitamin C activity in cancer therapy is pro-oxidant
The most surprising aspect is that vitamin C itself becomes a prooxidant to the cancer when administered in very high doses via the intravenous route.
POV-ANT iopenASP-textHere, it would directly work against cancer by generating oxidative stress. However, chemotherapy and radiotherapy have expected toxic effects through oxidative stress, and, therefore, the concern is that vitamin C, being an antioxidant, may lessen the effect of these treatments.
Contrary to this view, studies show mixed results. Some evidence demonstrates that antioxidants provide enough protection to normal tissues from therapy-induced damage without impeding effectiveness, while others suggest that the timing and, more importantly, the dosage of vitamin C may actually reduce treatment effectiveness.
For the reasons mentioned above, it is advisable for anyone undergoing chemotherapy and radiotherapy to consult their treating oncologist before taking vitamin C or antioxidant supplementation, especially in high doses.
Prospect of Vitamin C in Cancer Therapy
There is a resurgence in very serious investigations on the therapeutic potentialities of IV vitamin C. Many clinical trials are ongoing to evaluate:
The use of vitamin C in supplementary treatment with standard chemotherapeutic agents.
The outcome of tumorigenesis and inflammation progression and on quality of life.
Whether it will enhance treatment response in pancreatic, ovarian, and glioblastoma cancers.
The positive outcome of future studies may put IV vitamin C into the mainstream of integrative oncology protocol.
Would You Consider High-Dose Vitamin C for Cancer?
If you or a loved one may potentially be diagnosed with cancer, you might want to find out whether this is a therapy worth considering.
Things to Consider:
Potential Benefits
It may promote immune function and lessen inflammation.
It may decrease or prevent fatigue and nausea that can arise from chemotherapy.
Preclinical studies document selective toxicity toward malignant cells.
May enhance the quality of life for some cancer patients.
Limitations and Risks
Does not replace standard treatment.
Large-scale human data lacking.
Potential interactions with chemotherapy and/or radiation.
Requires infusion under trained personnel-not so accessible in many locations.
It needs an oncologist or integrative medicine specialist to supervise.
Conclusion: Optimistic Yet Cautious Perspective
Vitamin C has had a long and controversial history as an antitumor agent. From early euphoria for this treatment to disappointing results in clinical trials and renewed interest in IV treatment today, vitamin C is not finished yet.
What we know is:
There are absolutely no anticancer effects of oral vitamin C alone.
With IV vitamin C, pharmacologic concentrations that may be rendered therapeutic are obtained.
Promising early work, particularly as an adjuvant to conventional treatment.
Much more research is warranted for an assessment of safety, efficacy, and best practice.
Until that time, vitamin C will be seen as a potentially valuable adjunct but will not cure. Patients wishing to pursue this avenue should discuss it with their health-care team and consider joining clinical trials that will study it under expert supervision.
As science unfolds, likewise, will the understanding of the role of this simple vitamin in the intricate puzzle of cancer treatment.
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