A review of research trends in dietary supplements is reported, and the applicability of research methodology of health psychology to contemporary research on dietary supplements is explored. First, an outline was provided of food for specified health conditions, as well as functional food and potential issues related to them. Then, a field survey was conducted, which indicated that a majority of dietary supplement users expect direct benefits on their health and nutrition, whereas they were skeptical about their substantial effects. The need to investigate the function of dietary supplements in human health and lifestyle by applying research methods typically used in health psychology is proposed as a new trend in dietary supplements and health psychology research in Japan. Examining the effects supplements on variations in mental and physical health under naturalistic conditions, such as in daily life would be significant. Finally, we have discussed the applicability of practical interventions based on methodology established in health psychology to examine the benefits of dietary supplements to buffer against stress and maintaining health.