Preston A M
Department of Biochemistry and Nutrition, University of Puerto Rico, School of Medicine, San Juan 00936-5067.
Prog Food Nutr Sci. 1991;15(4):183-217.
Although the effects of cigarette smoking on a variety of diseases, from cancer through emphysema and cardiovascular illness are well documented, direct effects on the levels of macro- and micronutrients in the body are reported less frequently. In fact, imbalances in these nutrients may have a role in many of the pathological conditions attributed to smoking. Tobacco smoke contains numerous compounds emitted as gases and condensed tar particles, many of them being oxidants and prooxidants, capable of producing free radicals thus enhancing lipid peroxidation in biological membranes. Vitamin E, vitamin C, B-carotene and selenium are involved in the overall cellular anti-oxidant defense against deleterious effects of reactive oxygen species. Smoking has been shown to lower the level of vitamin C and B-carotene in plasma. Cadmium, naturally found in tobacco, decreases the bioavailability of selenium and acts antagonistically to zinc, a cofactor for the antioxidant enzyme, superoxide dismutase. Vitamin E, the principle lipid-soluble antioxidant, may be at suboptimal levels in tissues of smokers. In addition, tobacco constituents have been shown to reduce levels of several vitamins of the B-complex. Nutritional status in smokers may be further compromised by an inadequate diet. Data from the Second National Health and Nutrition Examination Survey indicates that smokers are less likely to consume fruits and vegetables, particularly those high in vitamin C and carotenes. Cessation of smoking is the obvious solution to ending cigarette-related problems. In the world as it is, however, the medical community should be responsible for making recommendations to lower the risk in smokers to tobacco related diseases. Nutritionists could have a role in this process. There exists a lively debate as to where levels of nutrients should be set. Additional vitamin C has already been recommended for smokers. Should other antioxidants also be increased? Arguments for the against are considered.
尽管吸烟对从癌症到肺气肿和心血管疾病等多种疾病的影响已有充分记录，但关于吸烟对人体常量和微量营养素水平的直接影响的报道却较少。事实上，这些营养素的失衡可能在许多归因于吸烟的病理状况中起作用。烟草烟雾包含许多以气体和冷凝焦油颗粒形式排放的化合物，其中许多是氧化剂和促氧化剂，能够产生自由基，从而增强生物膜中的脂质过氧化作用。维生素E、维生素C、β-胡萝卜素和硒参与了细胞整体抗氧化防御，以抵御活性氧的有害影响。吸烟已被证明会降低血浆中维生素C和β-胡萝卜素的水平。烟草中天然存在的镉会降低硒的生物利用度，并与抗氧化酶超氧化物歧化酶的辅助因子锌产生拮抗作用。维生素E是主要的脂溶性抗氧化剂，在吸烟者的组织中可能处于次优水平。此外，烟草成分已被证明会降低几种B族维生素的水平。吸烟者的营养状况可能会因饮食不足而进一步受损。第二次全国健康和营养检查调查的数据表明，吸烟者食用水果和蔬菜的可能性较小，尤其是那些富含维生素C和胡萝卜素的水果和蔬菜。戒烟显然是解决与吸烟相关问题的办法。然而，在当今世界，医学界应该负责提出建议，以降低吸烟者患烟草相关疾病的风险。营养学家可以在这个过程中发挥作用。关于应该设定何种营养素水平存在激烈的争论。已经建议为吸烟者额外补充维生素C。是否也应该增加其他抗氧化剂呢？支持和反对的观点都被考虑在内。
