Thinking Nutrition
Thinking Nutrition is all about presenting the latest nutrition research in plain language and then translating this into what it means for your health. Dr Tim Crowe is a career nutrition research scientist and an Advanced Accredited Practising Dietitian. Tim has over 30 years of research and teaching experience in the university and public health sectors, covering areas of basic laboratory research, clinical nutrition trials and public health nutrition. He now works chiefly as a freelance health and medical writer and science communicator.
Thinking Nutrition
Can probiotics help fight age-related muscle loss?
Some aspects of ageing may be inevitable, but when it happens together with an accelerated loss of weight, muscle mass and strength it makes an older person much more susceptible to disability, poor quality of life and earlier death. The condition is called sarcopenia and it is underpinned by chronic inflammation. Diet and lifestyle changes can go a long way in preventing and treating sarcopenia and inflammation. And now research is adding to this by looking at the role of probiotics as a way to influence the gut microbiome and with that, the muscle loss and inflammation seen in sarcopenia. That’s what I’ll be exploring in this podcast.
Links referred to in the podcast
- Systematic review of probiotics in adults with markers of sarcopenia https://pubmed.ncbi.nlm.nih.gov/38370462
Episode transcript
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Some aspects of ageing may be inevitable, but when it happens together with an accelerated loss of weight, muscle mass and strength it makes an older person much more susceptible to disability, poor quality of life and earlier death. The condition is called sarcopenia and it is underpinned by chronic inflammation. Diet and lifestyle changes can go a long way in preventing and treating sarcopenia and inflammation. And now research is adding to this by looking at the role of probiotics as a way to influence the gut microbiome and with that, the muscle loss and inflammation seen in sarcopenia. That’s what I’ll be exploring in this podcast.
The world’s population is ageing. We’re living longer and with that comes a host of potential health problems. One such issue is that of nutrition frailty. It is a state commonly seen in older adults and is characterised by significant loss of weight, loss of muscle mass and loss of strength – making the person susceptible to disability. This is all made worse by chronic undernutrition, the presence of disease, hormonal changes and decreased physical activity. Which then leads to sarcopenia.
What is sarcopenia? Sarcopenia is a syndrome characterised by progressive and generalised loss of muscle mass and strength. It is tightly correlated with physical disability, poor quality of life and earlier death. Ageing is a major cause of sarcopenia.
Sarcopenia is compounded by a decline in physical activity, a decrease in motor neuron recruitment needed to make muscles work, and a drop in anabolic hormones. This is all underpinned by chronic inflammation because ageing commonly occurs hand-in-hand with chronic low-grade inflammation.
The combination of chronic disease, inflammation and sarcopenia in older age gives rise to a unique descriptor of the underlying problem: and that’s a term called inflammageing.
There is now growing evidence linking a dietary pattern ranking high in its proinflammatory potential (and here, think of a typical Western diet high in highly processed foods and low in fibre) and a greater risk of the presence of inflammation, low muscle mass, low muscle function and sarcopenia.
Diet and lifestyle choices can go a long way to treating inflammation. And for diet, what is widely considered an ‘anti-inflammatory diet’ is one high in fruits, vegetables, healthy fats, legumes, and wholegrains. A Mediterranean-style diet would be one such variation of this, especially when you add in fish and olive oil.
But it doesn’t stop there. Exercise is also a potent force against chronic inflammation with a negative association between physical activity levels and CRP which is a blood marker for inflammation. So exercise in older age not only helps fight sarcopenia but aids in blunting inflammation – it’s all related.
And then we have dietary fibre. Fibre is a top-rated fuel for our gut microbiome which is a big player in chronic inflammation, especially when you consider our gut is the home to most of our immune activity. When certain beneficial bacteria ferment fibre, they produce butyric acid. Butyric acid helps mediate the immune response, lower circulating inflammatory markers and improve the integrity of the gut barrier. Beneficial microbes also help fight off more inflammatory, gut-damaging microbes by suppressing their growth. Simply put: the more fibre (which means more plant foods) a person eats in their diet, the lower their blood markers of inflammation are likely to be.
So with that last mention of the gut microbiome, it opens up the next avenue to explore and that’s how probiotics could interact with our host microbiome and potentially address some of the undercurrent issues of age-related sarcopenia, inflammation and muscle loss.
To help study this further, a recent systematic review and meta-analysis of randomised controlled trials using a supplemental probiotic or placebo in older adults who had frailty and some indication of sarcopenia has just been published. In all, 7 trials involving 733 adults were included with studies running from 8 weeks up to 6 months with the main outcomes of interest being muscle mass and muscle strength. And I’ll link to the review in the show notes. https://pubmed.ncbi.nlm.nih.gov/38370462
The types and forms of probiotics used were quite variable. It included both single-strain probiotics and multistrain mixtures. Some of the clinical trials combined probiotics with nutritional supplements. Two of the studies also included resistance training and physical activity as part of the program for people taking probiotics as well as those taking a placebo.
So, what did the review uncover? The results looked favourable with probiotic supplementation found to have a large effect on muscle mass and muscle strength in older adults compared to the placebo control groups. However, a caution that there was a lot of variability between the studies in what they found yet this was in the face of all of the studies considered to be at low risk of being biased. And a positive going into the study is that animal studies at least have also shown the potential for probiotics to improve muscle mass so the findings from these human studies are not out of the blue.
How could probiotics help in situations of muscle loss from sarcopenia? Several reasons have been put forward including reducing chronic inflammation which would be expected to have favourable benefits on muscle growth and repair. Links have also been seen between the gut microbiome and the production of insulin-like growth factor which promotes muscle protein synthesis. Gut microbes are also known to stimulate protein digestion and the uptake of nutrients in the muscle – all pathways that could result in a state of positive protein synthesis.
So, let’s wrap all this up. Nutrition becomes even more important in older age when you consider how many barriers can arise to eating well. Some aspects of ageing may be inevitable, but the risk of specific age-related diseases and disability may, in part, be mediated by dietary intervention.
What is novel about the research I presented here is that even though the research base is small in terms of the number of clinical trials even with the issues of study variability, study design and range of probiotics used, it is the first study to provide some evidence that signposts towards probiotics being a beneficial adjunct treatment in older adults with sarcopenia.
It is resistance exercise and a high-protein diet that form the base in the management and prevention of sarcopenia. But to build on that, good nutrition and positive factors that can influence the gut microbiome like plenty of plant fibre prebiotics and potentially probiotics can all help to preserve and build vital muscle in the later stages of life.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.
