A life course perspective on diet quality and healthy ageing
It is generally known that eating healthy can benefit your health, but how is the healthfulness of the diet measured, and how does it influence healthy ageing over the life course? This thesis describes the development of the Lifelines Diet Score, a score to measure the quality of a diet based on the scientific evidence underlying the 2015 Dutch Dietary Guidelines. In subsequent studies, this diet score was beneficially associated with various outcomes that are part of healthy ageing. For example, a better diet quality was helpful to prevent weight gain, especially in children and young adults. This emphasizes that dietary interventions for weight gain prevention should focus on these younger generations. Later in adulthood a better diet quality was relevantly associated with a lower risk to develop Type 2 Diabetes. However, this benefit of a healthy diet was smaller for individuals from a lower socio-economic background. This was possibly due to the remaining presence of other risk factors for Type 2 Diabetes. Furthermore, for the majority of the adult population, a better diet quality was associated with a lower risk of premature death. Only for elderly individuals with multiple morbidities such as Diabetes and cardiovascular diseases, this association was unclear. In this subgroup of the population dietary needs may be altered, requiring more specialized dietary guidelines. In conclusion, it is never too late to start eating a healthy diet to promote healthy ageing, but the health outcomes most dominantly influenced by diet will differ throughout the life course.