Featured Research

from universities, journals, and other organizations

Vitamin C Produces Gene-Damaging Compounds, Test-Tube Study In Science Reports

Date:
June 15, 2001
Source:
American Association For The Advancement Of Science
Summary:
Vitamin C, known to be a DNA-protecting "antioxidant," is a switch hitter, also capable of inducing the production of DNA-damaging compounds, suggests a study in the 15 June issue of the international journal, Science. Mutations caused by these compounds have been found in a variety of tumors.

Vitamin C, known to be a DNA-protecting "antioxidant," is a switch hitter, also capable of inducing the production of DNA-damaging compounds, suggests a study in the 15 June issue of the international journal, Science. Mutations caused by these compounds have been found in a variety of tumors.

Such mutations can be repaired, however, and lead author Ian Blair of the Center for Cancer Pharmacology, at the University of Pennsylvania, cautioned that the study shouldn't be interpreted as a claim that vitamin C causes cancer. Nor does it question the wisdom of eating a balanced diet rich in fruits, vegetables, and whole grains, he said.

The findings, which come from test-tube experiments (in vitro), may help explain why vitamin C has thus far shown little effectiveness at preventing cancer in clinical trials, according to the Science authors.

"It's possible that vitamin C isn't working in cancer prevention studies because it's causing as much damage as it's preventing, but that's really speculation at this point. What we can say is that vitamin C clearly doesn't work when you expect it to, and now we're in a position to see if that's what's happening in vivo, [or, in living cells]" Blair said.

Some scientists have long recommended dietary supplements of vitamin C, particularly for treating and preventing cancer. But the supplements' effectiveness has been hotly debated, with critics saying they either have no effect or that they may be harmful.

"The logic being used [for vitamin C supplements] is that 'fruits, vegetables, etc. contain vitamin C; these foods prevent cancer; thus vitamin C prevents cancer," Blair said. "But our message is that it's the total diet that's important, not just one antioxidant in isolation."

Vitamin C is known to do beneficial work in the body, including acting as an antioxidant that "disarms" free radicals. These highly reactive ions are produced by the breakdown of oxygen, which occurs constantly in cells.

In addition to damaging DNA directly, free radicals can also act indirectly. They begin by converting linoleic acid, the major polyunsaturated fatty acid in sunflower, grape, and safflower cooking oils, as well as the major polyunsaturated fatty acid in human plasma, into another compound called a lipid hydroperoxide. When certain metal ions are present to act as catalysts, the lipid hydroperoxides degrade further, into DNA-damaging agents called "genotoxins."

These compounds react with DNA, switching one base for another in mutations that have been found in human tumors.

Scientists, including Blair and his colleagues, have suspected that vitamin C might also be capable of making lipid hydroperoxides degrade into genotoxins, in place of the transition metal ions.

To investigate, the Science authors added vitamin C to solutions of lipid hydroperoxides in the lab. They used concentrations comparable to those found in the human body, assuming a person would take 200 milligrams a day.

The vitamin was more than twice as efficient as transition metal ions at inducing the formation of genotoxins, including a particularly potent variety.

The researchers' next step is to see whether vitamin C produces significant amounts of genotoxins in intact cells, and whether they generate cancer-causing mutations.

The other members of the research team are Seon Hwa Lee and Tomoyuki Oe, of the Center for Cancer Pharmacology, at the University of Pennsylvania. Funding for this research was provided by the National Cancer Institute and the University of Pennsylvania Cancer Center.


Story Source:

The above story is based on materials provided by American Association For The Advancement Of Science. Note: Materials may be edited for content and length.


Cite This Page:

American Association For The Advancement Of Science. "Vitamin C Produces Gene-Damaging Compounds, Test-Tube Study In Science Reports." ScienceDaily. ScienceDaily, 15 June 2001. <www.sciencedaily.com/releases/2001/06/010615072358.htm>.
American Association For The Advancement Of Science. (2001, June 15). Vitamin C Produces Gene-Damaging Compounds, Test-Tube Study In Science Reports. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2001/06/010615072358.htm
American Association For The Advancement Of Science. "Vitamin C Produces Gene-Damaging Compounds, Test-Tube Study In Science Reports." ScienceDaily. www.sciencedaily.com/releases/2001/06/010615072358.htm (accessed September 23, 2014).

Share This



More Health & Medicine News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Costs Keep Mounting

Ebola Costs Keep Mounting

Reuters - Business Video Online (Sep. 23, 2014) The WHO has warned up to 20,000 people could be infected with Ebola over the next few weeks. As Sonia Legg reports, the implications for the West African countries suffering from the disease are huge. Video provided by Reuters
Powered by NewsLook.com
Ebola Cases Could Reach 1.4 Million Within 4 Months

Ebola Cases Could Reach 1.4 Million Within 4 Months

Newsy (Sep. 23, 2014) Health officials warn that without further intervention, the number of Ebola cases in Liberia and Sierra Leone could reach 1.4 million by January. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Cases to Triple in Weeks Without Drastic Action

WHO: Ebola Cases to Triple in Weeks Without Drastic Action

AFP (Sep. 23, 2014) The number of Ebola infections will triple to 20,000 by November, soaring by thousands every week if efforts to stop the outbreak are not stepped up radically, the WHO warned in a study on Tuesday. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
5 Ways Men Can Prevent Most Heart Attacks

5 Ways Men Can Prevent Most Heart Attacks

Newsy (Sep. 23, 2014) No surprise here: A recent study says men can reduce their risk of heart attack by maintaining a healthy lifestyle, which includes daily exercise. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins