A Nutritionist's Perspective on Behavioral Assessment

The perspective shared here is that of a nutritionist who has been collaborating with a behavioral scientist for 20 years. Examples will be related to long-chain polyunsaturated fatty acids, the subject of our collaboration. While it is well accepted that nutrition is key to optimal human health and development, nutrition intervention trials in populations and randomized controlled trials of specific nutrients that have measured these outcomes have occurred relatively recently. Studies of nutrition and behavior are even less common - the first appears to have been a protein intervention that began in 1969 in Guatemala that involved developmental follow-up to adulthood. When results of multiple trials are available, findings of individual trials frequently range from no effect to benefit, making it difficult to make decisions about policy and practice. A meta-analysis that combines the results of all randomized trials of a nutrient is considered the highest level of evidence for drug trials. For studies of nutrient supplementation, however, meta-analyses can err on the side of no effect and lead to assumptions that a nutrient is adequate in populations with deficient or marginal status. In studies that assess behavior, collaboration with a behavioral scientist is necessary to determine the behavioral outcome(s) to assess, ensure the proper administration of the outcome, and analyze and interpret the results. The goal of the paper is to offer insight into issues common to all nutrition research, but especially issues unique to studies that assess behavior. As noted, industry, governments, health organizations, journals, as well as scientists have roles to play.