The effect of sodium acetate on energy metabolism in humans
Research type
Research Study
Full title
The effect of sodium acetate on energy metabolism in humans
IRAS ID
262300
Contact name
Edward Chambers
Contact email
Sponsor organisation
Imperial College London
Duration of Study in the UK
2 years, 8 months, 1 days
Research summary
Ageing is associated with a loss of skeletal muscle mass and function often referred to as sarcopenia. This is accompanied by a change in the gut microbiota, suggesting a possible link between the gut microbiota and skeletal muscle. An important feature of the gut microbiota is its capacity to produce bioactive metabolites from ingested foods, such as short-chain fatty acids. These metabolites can enter the bloodstream and have the potential to influence peripheral tissue metabolism, including skeletal muscle. There is evidence to suggest that an individual’s ability to produce short-chain fatty acids diminishes as they age, and therefore may play a role in age-induced loss of skeletal muscle mass and function. Acetate is the most abundant short-chain fatty acid in the circulation and is a key energy source for skeletal muscle. However, the effect of acetate supplementation on skeletal muscle metabolism in humans remains largely unknown.
Therefore, the aim of the present study is to investigate the influence of acute oral supplementation with sodium acetate on markers of protein metabolism in both young and elderly individuals, and during the postprandial and postabsorptive state.
Healthy volunteers will be asked to complete two experimental visits:
1. Sodium acetate ingestion
2. Sodium chloride ingestionBlood samples and subjective appetite responses would be collected at regular intervals throughout the 6 hour experimental visits. A mixed meal tolerance test will be given halfway through each study visit to look at postprandial effects. Urine and stool samples will also be collected.
Lay summary of study results: As people age, they commonly experience a gradual loss of muscle strength and bone density. These changes can increase the risk of falls, fractures, loss of independence, and reduced quality of life. Researchers are increasingly interested in understanding whether the bacteria that naturally live in the gut (the gut microbiome) can influence muscle and bone health. One way the gut microbiome may affect the body is through the production of substances called short-chain fatty acids, which are created when gut bacteria break down dietary fibre.
Acetate is the most abundant short-chain fatty acid found in the bloodstream. Previous studies in animals have suggested that acetate may help maintain healthy bones and muscles, but this had not been investigated in older adults. The aim of this study was therefore to determine whether increasing acetate levels through oral supplementation could affect markers of bone and muscle health in healthy older adults.
Twelve healthy volunteers aged between 65 and 80 years took part in the study. Each participant attended two study visits and received both treatments in a random order: sodium acetate capsules and sodium chloride capsules (used as a control). Neither the participants nor the researchers knew which treatment was being given at each visit until the study had been completed. Blood samples were collected throughout the study visits to measure acetate levels and markers related to bone and muscle health. Participants also reported any symptoms, including nausea, to assess whether the supplements were well tolerated.
The study found that sodium acetate supplementation successfully increased acetate levels in the blood. Importantly, acetate supplementation reduced levels of CTX-1, a marker of bone breakdown. Lower CTX-1 levels suggest that bone resorption (the process by which bone is broken down) was reduced. This finding is encouraging because excessive bone resorption contributes to age-related bone loss and osteoporosis.The researchers also investigated whether acetate increased the availability of amino acids in the bloodstream, which could potentially support muscle growth and maintenance. However, no significant changes were observed in amino acid levels, suggesting that acetate did not have an immediate effect on this measure of muscle health.
In addition, acetate supplementation increased levels of insulin-like growth factor-1 (IGF-1), a hormone that plays an important role in maintaining healthy bones and muscles. The increase in IGF-1 was associated with higher acetate levels in the blood, suggesting that IGF-1 may help explain the beneficial effects of acetate on bone metabolism.
No intervention-related adverse events occurred during the study. Participants tolerated the supplementation well, with no increase in nausea and only a small, non-significant reduction in appetite.
In summary, this study demonstrated that acute oral acetate supplementation is safe and well tolerated in healthy older adults and may reduce bone breakdown. While no immediate benefits for muscle amino acid availability were observed, the findings suggest that acetate could represent a promising new approach to supporting bone health during ageing. Larger and longer-term studies are now needed to determine whether these short-term improvements lead to meaningful benefits for bone density, fracture prevention, and overall musculoskeletal health.
REC name
London - South East Research Ethics Committee
REC reference
19/LO/1470
Date of REC Opinion
24 Oct 2019
REC opinion
Further Information Favourable Opinion