Challenges in dietary guidance: A US perspective

Good nutrition is essential to human health. But how do we define 'good nutrition'? Nutritional needs vary greatly through the life cycle so a diet that promotes healthy growth and development for a child may not be optimal for the elderly. Also, humans are adaptable to a wide range of dietary patterns and food intakes and their varying cultural preferences must be considered when making dietary recommendations. This paper describes the history of the development of dietary guidelines in the US and discusses some of the complexities around the development of advice for an optimal diet at a population level. The Dietary Guidelines for Americans have been published every five years since 1980. The development of the most recent Dietary Guidelines for Americans (2010) involved an evidence-based review process to evaluate the strength of the relationships between food intake and disease outcomes. Unfortunately, many accepted relationships between food patterns and disease outcomes are not strongly based on evidence-based reviews. This creates a challenge for government agencies when developing population guidelines for dietary intake, as well as for future committees charged with agreeing on the basis of an optimal diet for 'good nutrition'.