Publication trends of vegetarian nutrition articles in biomedical literature, 1966-1995.

We documented publication trends of vegetarian nutrition articles in biomedical literature between 1966 and 1995 using the National Institutes of Health MEDLINE bibliographic database. The publication rate of vegetarian articles increased steadily during the 3 decades, from an average of <10/y in the late 1960s to 76/y in the early 1990s. After adjusting for the total number of articles indexed in MEDLINE annually, we found that publication of vegetarian nutrition articles increased dramatically, by 4-fold, during the 1970s and reached an oscillating plateau during the 1980s. In the early 1990s, the proportion of vegetarian nutrition articles 8 articles per 1000 vegetarian nutrition articles and approximately 20 per 100000 articles indexed by MEDLINE. Non-nutrition journals have progressively published a larger share of all vegetarian articles in the biomedical literature during the period studied. The nature and study design of published vegetarian research has changed over the years as well. The proportion of original research and review articles increased whereas case series and letters to the editor decreased. Reports of epidemiologic studies of vegetarians with longitudinal designs have superseded cross-sectional designs in number and proportion. In 40% of all publications, preventive and therapeutic applications of vegetarian diets constituted the major themes of vegetarian articles in the decade of 1986-1995. However, 20 y earlier the main focus was on the nutritional adequacy of vegetarian diets. The progressive change in the themes of vegetarian nutrition publications is interpreted as a shift in the role of vegetarian diets in human nutrition.