Protein, lipid, and hematological biomarkers in centenarians: definitions, interpretation and relationships with health.

As increasing numbers of individuals reach very advanced age, it is important to understand the influence of modifiable lifestyle factors such as diet and nutrition on both the achievement of exceptional longevity as well as the maintenance of optimal functional capacity. This includes determining the most appropriate biomarkers for monitoring changes in health and nutrition status and response to therapy in oldest old individuals. In an earlier work (Hausman et al., Maturitas 2011;68:203-9), we summarized studies of dietary intake and patterns of long-lived peoples and presented the current knowledge regarding vitamin B12, folate, 25(OH) vitamin D and other specific indicators of nutritional status in centenarians. The present review focuses on less specific biochemical indices of health and nutritional status and summarizes studies comparing protein, lipid and hematological biomarkers in centenarians and older adult controls. Such studies, from many countries worldwide, are often small, convenience samples of 'healthy' and/or community-dwelling centenarians, although a few population-based studies including participants with a broader range of physical and cognitive functioning are also presented. Though heterogeneous in design and demographic region, these studies typically show lower levels of protein and hematological indicators and improved levels of some lipid biomarkers in centenarians as compared with regionally matched older adult controls. As these biomarkers can be influenced by many factors interpretation of results must be approached with caution. Importantly, studies examining potential associations of these biomarkers with cognitive, mental and physical function must carefully control for potential confounders including genetics and chronic disease, an increasing burden at advanced age.