Vitamin C in Alternative Cancer Treatments
Alternative cancer treatments are treatment approaches or cures that are not a part of the old model of cancer treatment which includes chemotherapy, radiation therapy, surgical procedures, etc. These treatments include acupuncture, aromatherapy, hypnosis, dietary treatments, use of vitamins and minerals, exercise, massage and meditation, music therapy, relaxation techniques, Tai chi, yoga, etc. The use of high dose vitamin C is one such treatment.[1, 2]
Vitamin C is a vital nutrient for the human body found in food, such as grapefruit, oranges, papaya, and peppers, or dietary supplements. It is a cofactor for many enzymes, has redox functions, and plays a key role in the production of collagen. A lack of vitamin C leads to scurvy, a disease linked to lethargy, malaise, easy bruising, and spontaneous bleeding.
The use of high dose vitamin C as an anticancer agent was first propagated in the 1970s when it was discovered that vitamin C is toxic to cancer cells. However, subsequent studies revealed that vitamin C pills had no beneficial effect on people suffering from cancer.
In recent times, pharmacokinetic experiments have shown that intravenous administration of vitamin C helps to achieve much higher levels than when taken through the oral route.[3] This has renewed interest in the use of vitamin C in cancer treatment as additional research reveals that high concentrations such as those attained by intravenous administration are sufficient to cause cell death in cancer cells.[4]
Various mechanisms of action of vitamin C on cancerous cells have been investigated. Some studies show that it exerts its effects by generating hydrogen peroxide. The use of vitamin C in colon cancer treatment leads to iron metabolism disruption, downregulation of specificity protein (Sp) transcription factors, and Sp-regulated genes implicated in cancer progression. It kills cancer cells by activation of an autophagy pathway.
Another in vitro investigation reveals that vitamin C kills colorectal cancer cells having KRAS and BRAF mutations by inhibiting the enzyme glyceraldehyde 3-phosphate dehydrogenase.[5] Also, it augments the effects of arsenic trioxide on ovarian cancer cells.
The use of vitamin C enhances the quality of life for cancer patients by reducing pain and safeguarding normal tissues from toxicity caused by chemotherapy. Furthermore, vitamin C has demonstrated synergistic effects when used in combination with radiation and standard chemotherapies.
High dose intravenous vitamin C shows very few side effects in experimental trials. However, it may be dangerous in patients with certain risk factors. People suffering from glucose 6 phosphate dehydrogenase (G6PD) deficiency develop hemolytic anemia when high doses of vitamin C are administered.
Metabolism of high amounts of vitamin C produces excessive oxalic acid resulting in hyperoxaluria and thereby, the chances of kidney stones and kidney failure are increased. Vitamin C aids in the absorption of iron therefore it is not recommended patients suffering from hemochromatosis. Also, it interacts with other drugs thereby interfering with their effects such as it reduces bortezomib’s growth inhibitory effect on multiple myeloma cells.[6]
The use of high dose intravenous vitamin C as an anticancer agent is far from proven. But some initial studies do favor its use in conjunction with traditional cancer treatments. Until scientific trials are concluded, it is early to ascertain what part vitamin C may play in the cure of cancer.[7]
References
1. Roa, F.J., et al., Therapeutic Use of Vitamin C in Cancer: Physiological Considerations. Front Pharmacol, 2020. 11: p. 211.
2. Padayatty, S.J., et al., Vitamin C: intravenous use by complementary and alternative medicine practitioners and adverse effects. PLoS One, 2010. 5(7): p. e11414.
3. Padayatty, S.J., et al., Vitamin C pharmacokinetics: implications for oral and intravenous use. Ann Intern Med, 2004. 140(7): p. 533-7.
4. Verrax, J. and P.B. Calderon, Pharmacologic concentrations of ascorbate are achieved by parenteral administration and exhibit antitumoral effects. Free Radic Biol Med, 2009. 47(1): p. 32-40.
5. Yun, J., et al., Vitamin C selectively kills KRAS and BRAF mutant colorectal cancer cells by targeting GAPDH. Science, 2015. 350(6266): p. 1391-6.
6. Perrone, G., et al., Ascorbic acid inhibits antitumor activity of bortezomib in vivo. Leukemia, 2009. 23(9): p. 1679-86.
7. Carr, A.C. and J. Cook, Intravenous Vitamin C for Cancer Therapy – Identifying the Current Gaps in Our Knowledge. Front Physiol, 2018. 9: p. 1182.