Vitamin C may fight cancer — but not the way scientists once thought

Linus Pauling, a brilliant scientist from the 20th century, gained fame for his belief in the potential of high doses of vitamin C in treating cancer. Although many doctors dismissed him, recent research is reevaluating vitamin C's role in cancer treatment. Pauling's ideas began in the 1970s when he collaborated with Ewan Cameron to administer large amounts of vitamin C to patients with advanced, incurable cancer.

Initial results showed longer lifespans and improved well-being in the vitamin-treated group, but subsequent large trials conducted by the Mayo Clinic found no benefit. The discrepancy arose from the method of vitamin C administration. Pauling and Cameron used intravenous vitamin C, which could reach much higher levels in the blood compared to oral tablets used in the trials.

At high doses, vitamin C can behave differently inside the body. While acting as an antioxidant at normal levels, it can generate hydrogen peroxide at extreme levels, which can damage cancer cells that are already under stress due to rapid growth and poor blood supply. However, this effect cannot be achieved with oral tablets. The evidence from small trials suggests that intravenous vitamin C infusions may have some benefits for patients with hard-to-treat cancers, but serious side effects can occur, particularly in those with poor kidney function or rare inherited conditions.

Some studies indicate that adding vitamin C infusions to chemotherapy might help certain patients live longer or alleviate side effects, although other studies show no clear benefit. Quality of life improvements, such as reduced fatigue, pain, and nausea, have been noted in some patients given vitamin C alongside chemotherapy. Additionally, lab research suggests that high vitamin C levels may influence cancer cell behavior, making them less aggressive and more sensitive to treatment.

However, large, definitive randomized trials are still pending to confirm whether high-dose intravenous vitamin C clearly prolongs life for most cancer patients. For now, vitamin C should be seen as experimental, promising enough to study but not proven enough to replace standard cancer therapies. The use of vitamin C in cancer treatment should be confined to clinical trials or carefully supervised medical settings, not sold as a universal cure on the market.

The story of vitamin C and cancer treatment continues to evolve, and further research is needed to clarify its role.