Interactions between people's diet and their smoking habits: the dietary and nutritional survey of British adults.

OBJECTIVE: To compare diet, nutrient intakes, and biochemical measures between smokers and non-smokers. DESIGN: Analysis of data collected in cross sectional survey conducted in 1986 and 1987. Subjects were recruited from electoral wards in England, Wales, and Scotland to reflect the regional distribution of the population. SUBJECTS: 2197 subjects (70% of those asked) aged between 16 and 64 undertook dietary assessment. Of these, 1842 subjects were considered to have kept a record typical of their usual dietary intake and had given data on smoking, and their results were analysed: 1224 non-smokers (631 men), 359 light smokers (166 men), and 259 heavy smokers (153 men). MAIN OUTCOME MEASURES: Differences in dietary, nutrient, and biochemical measures between nonsmokers and smokers. RESULTS: Smokers ate more white bread, sugar, cooked meat dishes, butter, and whole milk and less wholemeal bread, high fibre breakfast cereals, fruit, and carrots. Smokers had lower intakes of polyunsaturated fat, protein, carbohydrate, fibre, iron, carotene, and ascorbic acid. Adjusting for other covariates did not substantially alter the pattern of intakes. At the same dietary intake of carotenoids smokers were more likely to have lower circulating serum beta carotene concentrations than non-smokers. CONCLUSIONS: The diet and nutrient intakes and circulating levels of nutrients of smokers were different from those of non-smokers. Smokers were more likely to have an imbalance between the dietary intake of antioxidant nutrients and the metabolic demand for antioxidant protection. This imbalance is likely to make smokers more susceptible to oxidative damage. Smokers are at increased risk of chronic disease because their diets are different and because smoking creates an altered pattern of demand for specific nutrients. The diets of smokers not only fail to meet the unusual requirements for specific nutrients to satisfy the altered pattern of demand but are likely to exacerbate the damage caused by smoking.