Vitamin C Isn't a Smoker's Salvation
May 23, 2000 -- People taking vitamin C to cancel out the health consequences of smoking should take note. Although some previous studies have shown that injections of vitamin C can improve smoking-related damage of the blood vessels, a new study in the May issue of the Journal of the American College of Cardiology suggests that extra vitamin C has no real benefits for smokers.
Because smoking is known to cause damage to blood vessels that can lead to heart disease and stroke, scientists have looked for ways to prevent that damage, or possibly reverse it. Research has shown that levels of vitamin C are generally lower than normal in the blood of smokers. Vitamin C, like many other vitamins, is an antioxidant, and may have beneficial effects on the heart and other organs.
It has been suggested that boosting the blood levels of vitamin C might improve function in blood vessels that have been damaged by years of smoking. Indeed, some studies have shown that injections of high doses of vitamin C can reduce the damage to some extent but have shown no evidence that long-term damage to the blood vessels can actually be reversed. Researchers who conducted those studies always questioned whether the good results seen with the vitamin C injections could be gained by taking vitamin C tablets.
The new study seems to validate those concerns. In addition, whatever benefits vitamin C may initially have do not persist over time, writes lead author Olli Raitakari, MD, PhD, of the Royal Prince Alfred Hospital in Sydney.
The study of eight male and 12 female smokers with an average age of 36 found that a single high dose of vitamin C taken by mouth significantly increased the amount of vitamin C in the bloodstream and improved blood flow in a main blood vessel in the upper arm. But Raitakari and colleagues found that daily ingestion of the vitamin at half that dose for eight weeks resulted in no significant or sustained benefit, even though levels of the vitamin remained high in the bloodstream.