Can the body’s hunger hormones be manipulated to promote weight loss?
- Hunger is presumably one of the earliest sensations we experience. The sensations of hunger and fullness (or satiety), are complex and occur in response to neural, hormonal, habitual and social cues. Researchers at the Institute of Metabolic Science in the University of Cambridge are particularly interested in the hormonal regulation of hunger and fullness, especially regarding the role of the hormone glucagon-like peptide 1 (GLP-1). GLP-1 is made in the lower small intestine and promotes a feeling of fullness. It is produced by specialised gut cells in response to nutrients in the gut, such as might occur after a meal. Concentrations of GLP-1 increase markedly after bariatric surgery and this increase may be in part responsible for the weight loss and improved blood sugar control seen in people after bariatric surgery.
- Full4Health partners Fiona Gribble, Claire Meek and colleagues at the University of Cambridge carried out a study to identify if they could promote fullness using a nutritional product to increase levels of GLP-1, to help people lose weight without the need for surgery. The nutritional product was delivered in a specialised capsule which was designed to release its contents close to the gut cells where GLP-1 is produced. They used three different types of nutritional products containing either protein, fat or a cholesterol derivative (bile acid). Healthy volunteers and people with type 2 diabetes were invited to attend the Clinical Research Facility at Addenbrooke’s hospital to ingest the capsules and have blood taken. They also assessed the effects of the capsules upon hunger, blood glucose levels and meal size.
What did they find?
- The protein and fat supplements did not appear to work well and did not increase the level of GLP-1 in the blood or affect hunger or satiety. However, the cholesterol derivative showed some initially promising results. Unfortunately, this substance was relatively unstable inside the capsules and had a short shelf life which limited the amount of testing they could perform. They are now thinking of other ways to use bile acids to stimulate GLP-1 production.
- Obesity is a global problem: tackling obesity with cost-effective and non-invasive measures remains a priority. The aim of this study was to test a potential option for promoting fullness and reducing hunger to help people attain a healthy weight – a potential alternative to bariatric surgery. Although none of these capsules were suitable for further testing, it was discovered that it is safe, feasible and convenient to deliver nutrients in this way to human volunteers. The research also suggested that the bile acids deserve more investigation in the future, although an alternative delivery method may be needed to increase the product’s stability.
The effect of encapsulated glutamine on gut peptide secretion in human volunteers
Claire L. Meek, Hannah B. Lewis, Bensi Vergese, Adrian Park, Frank Reimann, Fiona Gribble
Peptides 77: 38-46