It has been suggested that protective factors might explain the differential incidence of lung cancer within a given population. Changes in diet, for example, might modulate neoplastic cell formation, since food contains many modifiers of carcinogenesis. The number of studies carried out so far does not permit to draw final conclusions yet. Interesting topics to be discussed include substances which doubtlessly play no role whatsoever for the prevention of lung cancer, like vitamin C, and those which seemingly do, like selenium. Still others consist in cholesterol, vitamins A and E, for which data are either controversial or, at present, still scanty. Moreover, the paper reviews the importance of interactions among nutrients for their effects on cancer risk. Considering major studies in this field, the review puts into evidence the principal results of research carried out so far.