RESUMEN
Age-related changes in gut hormones may play a role in anorexia of ageing. The aim of this study was to determine concentrations of ghrelin, PYY, and GLP-1 in older adults exhibiting an anorexia of ageing phenotype. Thirteen older adults with healthy appetite (OA-HA; 8f, 75±7 years, 26.0±3.2 kg·m-2), fifteen older adults with low appetite (OA-LA; 10f, 72±7 years, 23.6±3.1 kg·m-2), and twelve young adults (YA; 6f, 22±2 years, 24.4±2.0 kg·m-2) completed the study. Healthy appetite and low appetite were determined based on BMI, habitual energy intake, self-reported appetite, and laboratory-assessed ad libitum lunch intake. Participants provided a fasted measure of subjective appetite and blood sample (0 minutes) before consuming a standardised breakfast (450 kcal). Appetite was measured and blood samples were drawn throughout a 240-minute rest period. At 240 minutes, an ad libitum lunch meal was consumed. Relative intake at lunch (expressed as percentage of estimated total energy requirement) was lower for OA-LA (19.8±7.7%) than YA (41.5±9.2%, p<0.001) and OA-HA (37.3±10.0%, p<0.001). Ghrelin suppression was greater for OA-LA (net AUC, -78719±74788 pg·mL-1·240min-1) than both YA (-23899±27733 pg·mL-1·240min-1, p=0.016) and OA-HA (-21144±31161 pg·mL-1·240min-1, p=0.009). There were trends for higher GLP-1 concentrations in OA-LA compared with YA at 90 minutes (8.85±10.4 pM vs. 1.88±4.63 pM, p=0.073) and 180 minutes (5.00±4.71 pM vs. 1.07±2.83 pM, p=0.065). There was a trend for a greater PYY response for OA-LA compared with OA-HA (net AUC p=0.062). "Anorexigenic response score" - a composite score of gut hormone responses to feeding - showed greater anorexigenic response in OA-LA, compared with YA and OA-HA. No differences were seen in subjective appetite. These observations suggest augmented anorexigenic responses of gut hormones to feeding may be causal mechanisms of anorexia of ageing.
RESUMEN
The 'double burden of malnutrition' is a global health challenge that increasingly affects populations in both low- and middle-income countries (LMICs). This phenomenon refers to the coexistence of undernutrition and overweight or obesity, as well as other diet-related non-communicable diseases, in the same population, household or even individual. While noteworthy progress has been made in reducing undernutrition in some parts of the world, in many of these areas, the prevalence of overweight and obesity is increasing, particularly in urban areas, resulting in greater numbers of people who were undernourished in childhood and have overweight or obesity in adulthood. This creates a complex and challenging situation for research experts and policymakers who must simultaneously address the public health burdens of undernutrition and overweight/obesity. This review identifies key challenges and limitations in the current research on the double burden of malnutrition in individuals, including the need for a more comprehensive and nuanced understanding of the drivers of malnutrition, the importance of context-specific interventions and the need for greater attention to the food environment and food systems. We advocate for the re-evaluation of research strategies and focus, with a greater emphasis on multidisciplinary and systems approaches and greater attention to the synergistic relationship between the biological, environmental, commercial and socio-economic determinants of malnutrition. Addressing these key challenges can enable us to better comprehend and tackle the multifaceted and dynamic issues of the double burden of malnutrition, particularly in individuals and work towards more effective and sustainable solutions.
RESUMEN
Introduction: A major component of the digesta reaching the colon from the distal ileum is carbohydrate. This carbohydrate is subject to microbial fermentation and can radically change bacterial populations in the colon and the metabolites they produce, particularly short-chain fatty acids (SCFA). However, very little is currently known about the forms and levels of carbohydrate in the ileum and the composition of the ileal microbiota in humans. Most of our current understanding of carbohydrate that is not absorbed by the small intestine comes from ileostomy models, which may not reflect the physiology of an intact gastrointestinal tract. Methods: We will investigate how ileal content changes depending on diet using a randomised crossover study in healthy humans. Participants will be inpatients at the research facility for three separate 4-day visits. During each visit, participants will consume one of three diets, which differ in carbohydrate quality: 1) low-fibre refined diet; 2) high-fibre diet with intact cellular structures; 3) high-fibre diet where the cellular structures have been disrupted (e.g. milling, blending). On day 1, a nasoenteric tube will be placed into the distal ileum and its position confirmed under fluoroscopy. Ileal samples will be collected via the nasoenteric tube and metabolically profiled, which will determine the amount and type of carbohydrate present, and the composition of the ileal microbiota will be measured. Blood samples will be collected to assess circulating hormones and metabolites. Stool samples will be collected to assess faecal microbiota composition. Subjective appetite measures will be collected using visual analogue scales. Breath hydrogen will be measured in real-time as a marker of intestinal fermentation. Finally, an in vitro continuous fermentation model will be inoculated with ileal fluid in order to understand the shift in microbial composition and SCFA produced in the colon following the different diets. Registration: ISRCTN11327221.
