The study, which was just published in a professional journal, Proceedings of the National Academy of Sciences, also contradicts the conclusions of some research that was widely publicized three years ago. It had suggested that this essential nutrient might actually have toxic effects.
The new OSU study confirmed the results of that earlier laboratory study, which had found vitamin C to be involved in the formation of compounds potentially damaging to DNA.
But that research, the scientists say, only provided part of the story about what actually happens in the human body. The newest findings explain for the first time how vitamin C can react with and neutralize the toxic byproducts of human fat metabolism.
"This is a previously unrecognized function for vitamin C in the human body," said Fred Stevens, an assistant professor in the Linus Pauling Institute. "We knew that vitamin C is an antioxidant that can help neutralize free radicals. But the new discovery indicates it has a complex protective role against toxic compounds formed from oxidized lipids, preventing the genetic damage or inflammation they can cause."
Some earlier studies done in another laboratory had exposed oxidized lipids which essentially are rancid fats to vitamin C, and found some reaction products that can cause DNA damage. These test tube studies suggested that vitamin C could actually form "genotoxins" which damage genes and DNA, the types of biological mutations that can precede cancer.
But that study, while valid, does not tell the whole story, the OSU researchers say.
"It's true that vitamin C does react with oxidized lipids to form potential genotoxins," said Balz Frei, professor a
Contact: Balz Frei
Oregon State University