Uncovering the mechanisms through which krill oil increases muscle function in older adults

As we age, unfortunately, we lose muscle strength and this frequently results in older people not being able to carry out everyday tasks, such as getting up from a chair or stepping on to a bus. This results in a reduced quality of life and an increased risk of having a fall that can result in hospitalisation. Low muscle strength is also a risk factor for many conditions such as diabetes, cancer and cardiovascular disease and makes recovery from any illness slower. These negative consequences translate to large economic costs with the most recent study in 2016 showing that the excess health and social care cost of muscle weakness in the UK was £2.5 billion/year. Currently we do not have any medicines that are effective in reversing muscle weakness and although resistance (weightlifting) exercise works, very few people do this, and any gains are readily lost after stopping training. Excitingly, in a study of around 100 people, we have recently shown that krill (small crustaceans) oil supplementation for 6 months results in a 10% increase in muscle strength, equivalent to the loss of muscle strength seen from 55 to 65 years of age. Whilst this is exciting, we need to understand the mechanisms underlying these effects to optimise treatment. Our data indicates that the increases in strength may be due to more effective transmission of the signal from the brain to the muscle, via the nerves, but exactly where is not clear. Furthermore, we need to investigate whether the increases in muscle strength and mass result in improvements in how older people perform daily activities like walking and getting up from a chair. The aim of the current study, therefore, is to determine the mechanisms via which krill oil supplementation increases muscle strength, and to determine whether it results in improvements in daily activities. In the proposed study we will recruit 80 older adults and supplement them for 6 months with placebo or krill oil and compare the effects of this on muscle size and strength, the brain-nerve-muscle interactions and its effects on daily activities. Together, this series of experiments will provide a comprehensive understanding of the effects of krill oil supplementation on muscle function, performance of daily activities and provide an in-depth characterisation of the mechanisms underlying these effects. Such information is crucial to optimise strategies to prevent and/or treat the age-related decline in muscle function.

Ageing is accompanied by a decline in muscle function causing a reduced quality of life and an increased risk of falls and subsequent hospitalisation, with excess health and social care costs of £2.5 billion/year in the UK. There are currently no effective strategies to combat muscle weakness in old age, lifestyle or pharmaceutical, but our pilot data has demonstrated that krill oil may be effective. In around one hundred healthy older adults we found that 6 months of krill oil supplementation resulted in a 10% increase in muscle strength - which is both statistically and clinically/physiologically significant. Indeed, this increase is equivalent to the decline in muscle strength seen from 55 to 65 years of age. We also found that this increase was associated with an increase in the M-wave, a measure of muscle membrane excitability, possibly reflecting greater neuromuscular junction (NMJ) stability but this remains to be investigated. Whether the benefits of krill oil on muscle translate to functional changes during normal daily activities also remains unknown. In the proposed study we will recruit 80 healthy older adults and supplement them for 6 months with placebo or krill oil, with study visits at baseline, 6 weeks and 6 months. We will compare the effects of krill oil on muscle structure and function, neuromuscular and central nervous system control/function and gait/functional characteristics. Together, this series of experiments will provide a comprehensive understanding of the effects of supplementation with krill oil on muscle mass, function and functional abilities whilst importantly elucidating the mechanisms underlying these effects. Such information is crucial to optimise strategies to prevent and/or treat the age-related decline in muscle function.