Psychoimmunology of nutrition.

The relationships between behavior and immune responses have been studied for a long time. It is well recognized that persons under psychological stresses, such as depression, marital problems, bereavement or alcoholism, are more susceptible to infections. Nevertheless only a few studies were conducted before the 1970s. Since then, progress in knowledge of the immune system, improvement in questionnaires assessing the characterization and quantification of different moods, and very recently the link between a psychological approach and brain neuron cell functions (neuroimmunology) have pushed to extend research in this new field, called psychoneuroimmunology. This review will briefly describe the immune system and its roles. Thereafter the most important findings linking psychological stresses and immune responses will be discussed. Recent research at the neuron cell level is reported in order to present the current hypotheses being investigated.