Abstract
Trends in vitamin A research were analyzed by PubMed, based on the publication date (DP) and medical subject headings (MeSH). The number of papers concerning retinoids was declined in recent 20 years. Especially, the number of retinoid papers related to nuclear receptors and neoplasm was drastically reduced. The number of retinoid papers related to chemistry was also decreased, implying that the pharmacological research of retinoids and subsequent drug discovery are difficult. On the other hand, the number of retinoid papers related to eye, immune system and metabolic diseases was relatively constant and even slightly increased recently. Future perspective deduced from these analyses is that we should pay attention to nutritional, visual, immunological and metabolic aspects of retinoids in order to solve social problems such as “hypovitaminosis”, which is still the main problem in developing countries. Furthermore, continuous effort will be needed to achieve retinoid drug discovery in the future.
