Cigarette smoking is one of the biggest risk factors for cancer and heart disease. The more cigarettes a person smokes and the longer it's kept up, the greater the risk of dying from cancer, heart attack, or stroke. Probably less well known is that smokers are also much more likely to catch colds and other infections.

Of course, the best remedy for these risks and problems is quitting smoking , but that's not easy for many people. Because cigarette smoking poses such a public health risk, many studies have attempted to discern whether vitamin supplementation among smokers might help avert cancer and heart disease. However, the results have not been particularly promising, and one supplement, beta-carotene, may actually be dangerous for smokers.

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* Proposed Natural Treatments  

People who smoke often have deficiencies in numerous nutrients, including zinc , calcium , folate , vitamins C and E , beta-carotene , lycopene , and essential fatty acids in the omega-3 and omega-6 families. 1–15 There are many possible causes for this depletion, including free radicals in cigarette smoke that destroy natural antioxidants ; however, for some nutrients the most important single cause might be poor diet rather than smoking itself (smokers have, on average, a less well-balanced diet than non-smokers). 16

In addition, some evidence suggests that folate or vitamin C supplements may improve arterial function in smokers, thereby potentially helping to prevent heart disease . 20,21

High doses of vitamin E have not proven helpful for preventing heart disease or lung cancer in smokers. 17–19 However, vitamin E consumption has shown some promise for reducing risk of prostate cancer in smokers. 17

For all these reasons, many smokers undoubtedly benefit from general nutritional support in the form of a multivitamin/mineral tablet . However, high doses of the antioxidant vitamin beta-carotene may not be helpful for smokers, and could even cause harm (see next section).

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* Beta-Carotene: A Supplement to Avoid  

Although nutritional doses of the antioxidant nutrient beta-carotene help to supply needed vitamin A , there is evidence that smokers should avoid high doses of beta-carotene.

An enormous double-blind, placebo-controlled study called the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) enrolled 29,133 Finnish male smokers and examined the effects of vitamin E and beta-carotene supplements on lung cancer rates among them. 18 The results showed that 20 mg of beta-carotene daily for 5 to 8 years increased the risk of lung cancer by 18%.

In addition, a statistical analysis of the ATBC study, including 1,862 smokers with heart problems, found that individuals taking either beta-carotene or a beta-carotene/vitamin E combination had significantly increased risk of fatal heart attack compared to those taking placebo. 23 Another statistical review of the study analyzed the effects of beta-carotene on individuals with angina pectoris , one of the first symptoms of heart disease. 19 Results indicated that beta-carotene was associated with a slight increase in angina.

Another large double-blind, placebo-controlled trial enrolling 18,314 smokers, former smokers, and workers exposed to asbestos studied the effects of a different combination, beta-carotene and vitamin A , on lung cancer and cardiovascular disease. 22 Evidence from the trial suggests that 30 mg of beta-carotene and 25,000 IU of vitamin A taken together daily have no beneficial effects and may be harmful. Individuals taking the supplements had a 28% higher incidence of lung cancer than the placebo group; a 17% higher death rate from lung cancer; and a 26% higher death rate from cardiovascular disease. The trial was stopped 21 months early based on these findings.

The bottom line on beta-carotene: although nutritional dosages of beta-carotene (in the neighborhood of 3 mg daily for adults) are probably healthful, smokers should avoid doses of beta-carotene greater than in the range of 20 to 30 mg daily.