Vitamin C’s surprising tonic for arteries
BHF scientists in Cardiff have lifted the lid on an unusual way in which vitamin C acts on arteries.
Although vitamin C is a well-known antioxidant, in this instance it works as a ‘pro-oxidant’ – a revelation that could help to treat several heart and circulatory conditions.
The discovery is surprising to scientists since pro-oxidant activities are usually seen as bad for health, while antioxidants are credited with many of the healthy effects of fruit and vegetables.
Research has shown that taking vitamin C supplements doesn’t reduce the chances of suffering a heart attack or stroke, but injections of vitamin C are known to help arteries to relax in people with high blood pressure, high cholesterol, diabetes and heart failure.
In people with these conditions, the arteries often stay tightly constricted, placing strain on the heart. Vitamin C can help the arteries relax and widen, but until now it wasn’t fully understood how this process worked.
The new research, from the School of Medicine at the University of Cardiff, has revealed that the effect is partly due to vitamin C acting as a pro-oxidant. It generates a potentially harmful chemical called hydrogen peroxide, which boosts signals telling the artery to relax.
“The reactive chemicals targeted by antioxidants can be damaging if we have too many of them, but we’re now finding out that they’re not always bad,” said Professor Tudor Griffith, who led the research.
Professor Jeremy Pearson, Associate Medical Director at the BHF, said the research opened up new possibilities for the treatment of conditions in which the artery lining is faulty, such as diabetes and heart failure.
“It suggests that pro-oxidant strategies might be effective at helping arteries to relax and reducing strain on the heart.”
Prof Griffith warned that although vitamin C is a vital part of our diet, the results do not suggest that dietary vitamin C can lower blood pressure.
“Taking vitamin C orally probably can’t achieve the high blood concentrations necessary to have these beneficial effects on arteries because it quickly gets filtered out by the kidneys,” he said. “But we’re hoping that other pro-oxidants might be effective orally to lower blood pressure.”
Further media enquiries
For more information please call the BHF press office on 020 7554 0164 or 07764 290381 (out of office hours) or email newsdesk@bhf.org.uk
The full study is: Garry et al. 'Ascorbic acid and tetrahydrobiopterin potentiate the EDHF phenomenon by generating hydrogen peroxide', Cardiovascular Research, vol. 84 no. 2 (November 2009), pp. 218-226. doi:10.1093/cvr/cvp235.
