Vitamin C and Chemotherapy: Bad Combo?
Supplementing With Vitamin C May Reduce Effectiveness of Chemotherapy Drugs, Study Shows
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Vitamin C, Chemotherapy: Another Opinion
Applying the findings to people "is impossible," says Balz Frei, PhD, director and endowed chair at the Linus Pauling Institute at Oregon State University in Corvallis, who reviewed the study for WebMD.
He took issue with several aspects of the study. "The dose was very large," he says. But Heaney says the concentrations inside the cells were similar to what you would see in people who took vitamin C supplements.
The researchers only used two types of cancer cells, leukemia and lymphoma, he says. So the results may not apply to other cancers.
Other research has found beneficial effects of vitamin C supplements during cancer chemotherapy, especially in increasing survival times and decreasing side effects, Frei tells WebMD. But he concedes that "vitamin C could be contraindicated during some types of [chemo] drug therapy" and that larger clinical studies are needed to see if vitamin C and chemotherapy are a good combination.
Patients should be monitored by their physician if they do take vitamin C during chemo, he says.
Vitamin C, Chemotherapy: Researchers' Advice for Patients
"I think that patients should probably refrain from taking supplemental vitamin C during chemotherapy," Heaney says.
"If you take an oral dose even as low as 100 milligrams a day you can get concentrations of vitamin C inside your white blood cells that are close to the concentrations that we used experimentally, and that could be harmful," he says.
The recommended intake of vitamin C for healthy people is 75 milligrams daily for women and 90 milligrams daily for men.
Although a multivitamin with vitamin C "would probably be OK,'' taking larger amounts should be avoided while on chemo, Heaney says.