The Acute Effect of Propionate on Energy Homeostasis

Dietary fibres have long been recognised for their important role in a healthy diet due to their negative association with, and even management of, chronic diseases such as obesity, diabetes, metabolic syndrome, cardiovascular disease and inflammatory-bowel disease among others.Emerging evidence has suggested that these benefits could largely be attributed to short chain fatty acids (SCFA) (acetate, propionate and butyrate), the main by-products of fibre fermentation in the gut. Previous research has demonstrated that a long-term elevation in the SCFA propionate significantly reduced body weight gain in overweight adults and reduced liver fat storage. The current project will examine potential mechanisms for the positive effect of propionate on energy homeostasis and metabolic profile.The effects of propionate on circulating glucose, insulin, gut hormones and lipid levels at rest, following moderate-intensity exercise and mixed meal tolerance test will be examined. To acutely increase propionate absorption from the gut the present project will use a simple nutritional supplement: sodium propionate in a hydroxypropylmethyl cellulose (HPMC) capsule. This capsule is coated with an enteric film which prevents gastric digestion until the capsule reaches the intestine. This nutritional supplement has been used in human volunteers in a previously approved ethics application (12/LO/1769: Oral propionate and glucose homeostasis). A 5g acute dose of sodium propionate had previously been tested and reported no adverse effects . The MHRA have confirmed that encapsulated sodium propionate is not classed as an investigative medicinal product.