OSU scientists unlock vitamin C's ability to neutralize body toxins.

Byline: Greg Bolt The Register-Guard

CORVALLIS - Researchers at Oregon State University say a new study suggests that vitamin C might help people fight off heart disease and possibly even cancer through a previously unknown biological process.

The findings not only support the possibility of significant health benefits from vitamin C, they also contradict research published three years ago that found potentially toxic side-effects from the body's use of the vitamin. The new research, conducted at OSU's Linus Pauling Institute, was released today in a scientific journal, the Proceedings of the National Academy of Sciences.

Scientists have long known that vitamin C is a powerful antioxidant, something that neutralizes the DNA-damaging molecules known as free radicals produced from the breakdown of oxygen in cells. But a 2001 study at the University of Pennsylvania suggested that the vitamin also contributed to the production of different fat-derived toxins that attack DNA, sometimes called genotoxins, which are implicated in cancer.

That happens when vitamin C interacts with oxidized lipids - essentially, rancid fat - creating genotoxins. However, that research was conducted using test-tube samples where the fat level was much higher than in the human body.

Chemistry professor Fred Stevens, co-author of the OSU article with institute director Balz Frei, said that study was correct only as far as it went.

"We have confirmed that reaction, but it's not the end of the story," he said. "Vitamin C can react again with the breakdown products that it makes and detoxify them so they cannot react with DNA anymore."

What the OSU scientists found was that vitamin C neutralizes whatever toxins that it and other substances create during fat metabolism. It does that by reacting with harmful molecules produced by fat metabolism, forming a harmless product and preventing the toxin from damaging DNA.

Stevens and Frei found very high levels of these protective molecules in human blood samples, suggesting that vitamin C is actively neutralizing toxins. And Stevens said the level of vitamin C in human cells is orders of magnitude higher than the level of these genotoxins, providing more than enough protection.

What's more, the researchers said, the same process could help prevent the buildup of artery-clogging plaque, the source of atherosclerosis, or hardening of the arteries. Reactions with oxidized lipids also play a role in allowing the proteins in low-density lipoproteins, the so-called "bad cholesterol," to accumulate in artery walls.

Stevens said that the protective molecules produced by vitamin C when it reacts with oxidized lipids might also keep the LDL from building up in the arteries.

"These rancid lipids, when they get broken down, can initiate and be responsible for the progress of atherosclerosis," he said. "So, obviously, if you can take those products out of circulation, then that would slow down the process of atherosclerosis."

And by neutralizing toxins that damage DNA, vitamin C could play a role in preventing cancer as well as other age-related diseases. Lipid oxidation has been a hot topic among researchers looking for new ways of treating Alzheimer's disease and immune systems disorders as well as cancer and heart disease.

Stevens said the next step is to study the blood chemistry of patients who have diagnosed coronary artery disease and compare that to healthy people. He cautioned that vitamin C isn't seen as a treatment for those who already have heart disease or cancer but may be important in preventing them.

"I would certainly put it in the category of preventive medicine," Stevens said. "It could slow down the early processes of (heart) disease, so it would be most relevant for people at risk but who do not yet have the disease."