Challenges in conducting clinical nutrition research.

Clinical nutrition research has played a pivotal role in establishing causality between diet or nutrient intake and health outcome measures and in the determination of dietary requirements and levels of supplementation to achieve specific outcomes. Because the studies are performed with humans, clinical nutrition research can be readily translated into public health messages. However, there are many challenges and considerations unique to the field, such as the baseline nutritional status of study participants, defining appropriate control groups, effective blinding of participants and investigators, the evolving ethics of randomized control trials, and a tension in a priori decisions regarding inclusion of nutritionally vulnerable participants versus representative samples of general populations. Regulatory approvals that place increasing burdens on the ability of investigators to carry out and complete research protocols have grown dramatically in recent years. There is much room for improved efficiency in the approval and reporting processes aimed at protecting volunteers and providing transparency to the public. Decreased redundancy would have a direct benefit to clinical nutrition research and investigators. Despite these challenges, the information to be gained and the rewards of clinical nutrition research remain high.