Part 8 in my series of posts about products which can contribute to nutrient deficiencies –
Tobacco smoke influences the nutritional status of both smokers and people who inhale other people’s tobacco smoke (also called passive smokers). Inhaling tobacco smoke removes vitamin C from the tissues and blood and increases requirements to more than 200 mg per day for this vitamin (the RDA is 60 mg). Blood levels of vitamin C decreases as cigarette consumption increases and are as much as 30 percent lower in smokers compared to nonsmokers. Smokers tend to consume less, absorb less, and use more vitamin C than do nonsmokers, while requirements are higher not only to counteract these adverse effects of tobacco but also to reduce free radical damage to tissues generated by tobacco smoke.Â
Dietary intakes and tissue levels of vitamin A and beta carotene are also low in smokers and passive smokers. In contrast, when tissue levels of vitamin A, beta carotene, and vitamin E are high, the risk of developing lung and oral cancers, and other respiratory disorders is reduced. Since tobacco smoke increases free radical damage to tissues, the reduced cancer risk associated with these vitamins is probably a result of their antioxidant abilities to destroy and deactivate free radicals.Â
B vitamins are also affected by smoking. Cigarette use alters vitamin B6 metabolism, and the residual effects might last as long as two years after cessation of smoking. One study found that blood levels of vitamin B6 were significantly lower in smokers than in nonsmokers. Although the long-term effects of this sustained decrease in vitamin B6 metabolism are unknown, increasing dietary intake of this vitamin is harmless and potentially useful.Â
Increased intake of folic acid and vitamin B12 also might help prevent some of the damage caused by tobacco use. Researchers at the University of Alabama in Birmingham reported that smokers who supplement their diets with these two B vitamins have significantly fewer precancerous cells than do other smokers.Â
The best advice is to stop smoking and avoid all forms of tobacco smoke, including cigarettes, pipes, and cigars. Since women who smoke during pregnancy have low blood zinc levels and are more likely than nonsmokers to give birth to zinc-deficient babies who are a high risk for birth defects and disease, it is even more important that women who are considering pregnancy should avoid cigarette smoke from all sources. In addition, optimal dietary intake of the anti-oxidant nutrients (that is, vitamin C, beta carotene, and vitamin E), the B vitamins, and some minerals might help counteract some of the harmful effects of tobacco smoke.