Smoking out B-vitamins' role in lungs.

Smoking out B-vitamins' role in lungs

Research by Carlos Krumdieck and his colleagues at the University of Alabama at Birmingham (UAB) has shown that several components of cigarette smoke can affect vitamins. Nitrous oxide, for example, can break down vitamin B12; other smoky pollutants can inactivate folic acid, another B vitamin. Such findings led Krumdieck to suspect that smoking might generate localized areas of B-vitamin deficiency in the lungs of persons who are otherwise vitamin sufficient.

To test this, he gave longtime smokers--people who had puffed at least a pack a day for 20 years--high-dose supplements of these vitamins. His just-completed double-blind study involving 88 men not only indicates that cigarette smoke affects B-vitamin levels in the lung, but also suggests a link between this localized vitamin deficiency and lung cancer in smokers. The results were reported in Washington, D.C., last week at a Bristol-Myers Co. briefing.

The study focused on sputum, coughed up respiratory secretions that contain cells sloughed off from deep in the lung. Initially, each smoker "had abnormal sputum smears,' explains Charles E. Butterworth, chairman of UAB's nutrition sciences department. In them, he says, "you [could] see the premalignant cells that are known to be correlated with early cancer.'

Roughly half the participants were then randomly selected to receive large daily B-vitamin supplements--roughly 100 times the recommended daily allowance of B12 and 20 times that of folic acid. After four months, there was a noticeable improvement in both the number and degree of abnormal and precancerous cells in the sputum of those taking the supplements. However, "there was a worsening or no change in those who got the placebo,' Butterworth says.

He says this research may ultimately "provide a medical treatment for an early lesion in the form of a vitamin capsule.' However, he adds, such pills "would be a poor substitute to stopping smoking.' For now, the real benefit of these findings, he says, is the insight they offer into the way cells are genetically altered into early, noninvasive cancers. For example, he says, the folic acid found in yeast, liver and green leafy vegetables may limit the lung's ability to repair damaged DNA.