The Western Dietary Pattern and Respiratory Health

The Western dietary pattern, rich in energy-dense, nutrient-poor, and highly processed foods, provides a unique combination of nutrients that have been suggested to increase the risk of chronic respiratory diseases, as well as acute respiratory tract infections. This pattern of eating is characterised by higher intakes of total and saturated fatty acids, and refined carbohydrates, which activate inflammatory, metabolic and immunomodulatory pathways, shown to be detrimental in respiratory disease. The potential anti-inflammatory benefits of omega-3 fatty acids, antioxidants and dietary fibre are reduced, owing to lower contributions of fatty fish, fruit, vegetables and wholegrains in a Western diet. Further, chronic nutrient surplus, typical in a Western dietary pattern, and resultant obesity also drive pathological mechanisms associated with increased adiposity, systemic inflammation and mechanical, metabolic and gut microbiome alterations. This chapter describes the nutrient and obesity-mediated mechanisms associated with consumption of a Western dietary pattern, and their impact on asthma, COPD and respiratory infections. In addition, a summary of the evidence from both epidemiological and intervention studies that investigate the relationship between dietary patterns in asthma, COPD and respiratory infections is provided.