How Smokers Can 'C' Better Blood Flow

Sept. 11, 2000 -- Smoking is unhealthy for your heart -- that's a well-established fact. The bad news is that the damage smoking causes may be more extensive than previously realized. The good news is that stocking up on citrus fruits and other produce packed with vitamin C may help reverse some of the damage.

An international team of researchers has found that not only does smoking affect the large vessels of the heart, but it may also cause damage to the extensive network of tinyblood vessels that supply blood to most of the heart muscle. In a study appearing in Circulation: Journal of the American Heart Association, researchers found that smokers had a much lower blood supply to the heart during stress compared with nonsmokers.

Previous research has suggested that vitamin C and other nutrients may help decrease the risk of heart disease. Also, smoking may deplete vitamin C levels in the body, and the researchers wanted to see if giving large doses of the vitamin might improve the heart's blood flow.

The researchers used a scan to measure blood flow in the blood vessels of eight healthy male nonsmokers and 11 male smokers.

All of the subjects were given a large dose of vitamin C through the veins, and then their blood flow was measured again. The vitamin C didn't make a difference in the nonsmokers, but it had an immediate effect on the smokers. In fact, the circulation in the tiny blood vessels was almost back to normal after the smokers were treated with vitamin C.

Richard Hoffman, MD, MPH, points out that these results certainly won't change medical practice. "We already discourage tobacco smoking because we know smoking increases the risk for [heart] disease," he tells WebMD, but adds that the results of this study are very interesting, in that vitamin C reversed circulation changes caused by smoking. Hoffman, who was not involved in the study, is an associate professor of medicine at the University of New Mexico in Albuquerque.

Even though the number of people studied was very small, study author Paolo Camici, MD, feels that it did not affect the outcome and that using a larger population would not have changed their results. Camici is a professor at the Imperial College School of Medicine in London.

Hoffman points out that the vitamin C in this study was given in a controlled, experimental setting with a small number of patients receiving a large, single dose. If the research works in the real world, he says, smokers will need to take oral supplements for many years to see whether the risk of heart disease is truly reduced.

Camici agrees. "Unfortunately, I did not address this specific point in my study," he says, but adds that both blood and tissue levels of vitamin C have been previously measured in smokers and found to be lower than in nonsmokers. "Therefore, I presume that only after [long term] treatment you would achieve a lasting effect."

The researchers also speculate that vitamin C may be one of the reasons why the Mediterranean diet appears to help protect the heart, since it contains larger amounts of the vitamin than do the traditional diets eaten by northern Europeans and those in the U.S. So it is quite possible that vitamin C supplements may have the same effect.

"Oral vitamin C is absorbed very quickly because it is a water soluble vitamin," says Mohsen Meydani, PhD. Mohsen, who was not involved in the study, is a professor of nutrition and director of the Vascular Biology Laboratory at Tufts University in Boston.

For now, Meydani recommends that smokers drink fluids with a high vitamin C content when they exercise. "This may help offset the stress of exercise, and help their circulation," he says.

Camici says that he would like to repeat their study, using an oral form of vitamin C. "And only then would I be in a position to recommend the use of this vitamin in smokers."

In the meantime, experts tell WebMD that this study doesn't mean someone could continue to smoke and reverse all of the damage by taking vitamin C supplements.