In the past two weeks, two great papers have been published on ageing and the microbiome in the medical literature. I included these new research insights in the microbiome seminar I taught for a group of Reflexologists and Physiotherapists as part of their study day on ageing last week. I discuss these new papers and cover some more material from that seminar in this blog, looking at ways we can support our own healthy ageing.
The art and science of working with microbes to mature cheeses is known as affinaging!
Our gut microbiome changes dramatically in the first thousand days of life. It then continues to evolve as it responds to – and meets – our changing needs as a growing child. By adulthood, the overall composition tends to be fairly stable if there are no major medical interventions or dietary changes. But researchers have observed significant microbiome changes as we age, with many of these shifts associated with changes in health. For clients who come to microbiome analysis in midlife, attending to the health of their microbiome is a great investment in a healthy ageing process.
Microbiome researchers have observed that the diversity of bacterial species in our microbiome declines as we age. We also tend to see a decrease in some bacteria, and an increase in others. Researchers studying the gut bacteria of thousands of people around the world found the gut microbiome is a surprisingly accurate biological clock (Galkin 2018). Using machine learning, they were able to predict the age of most people within 4 years!
The microbiome plays such an important role in the healthy functioning of every bodily system – including our heart and blood vessels, musculoskeletal system and of course our digestive system. Several changes in the balance of the microbiome have now been directly linked to age-related health conditions.
Does the microbiome age us, or do we age the microbiome?
We can’t separate out age-related changes in the microbiome from other life changes that happen as we age. We may see changes in:
Activity levels – especially following illness, injury or reduced mobility, but also reducing work hours can mean a reduction in physical activity.
Diet – older people also find their sense of taste changing, often favouring sweet foods. They may also rely more on ready-made meals, or find their diet is restricted due to changes in appetite, shopping or cooking abilities, or catering in long-term residential care.
Sleep – people commonly find they get less sleep as they get older. Severe insomnia is a common peri-menopausal symptom that can result in a very disrupted sleep/wake cycle longer-term.
Medication – including antibiotics, but also oral HRT and PPIs. These could have a cumulative effect on our microbiome over many years from younger adulthood.
These changes are all reciprocal – they affect the microbiome, but the microbiome also affects them. For example, we know changes in diet alter the microbiome, but also our microbiome influences the activity of our tastebuds and this can cause us to change what we eat. Circadian rhythms (our sleep/wake cycles) heavily influence the composition and activity of our gut microbiome, and we are also learning how the microbiome influences circadian rhythms (Murakami & Tognini 2020).
Changes in the gut microbiome are associated with age-related illnesses
The association between disruptions in the gut microbiome with both Parkinson’s Disease and Alzheimer’s have been a focus for medical research for a number of years now. Research also shows us that certain species protect against athleroscerosis (the build-up of plaque in our arteries) and osteoarthritis. Other bacteria have been identified that increase the risk of developing these conditions. Do some people lose this protective capacity of their microbiome as they age, and can this be prevented – or even reversed?
After menopause, a reduced level of estrogen leads to changes to the vaginal environment. A well-known menopausal symptom is vaginal dryness, but less well known is that less estrogen means fewer protective lactic acid bacteria. The vaginal microbiome protects the health of the entire urogenitary tract, and UTIs become more common in older women. Repeated use of antibiotics in treating these UTIs may well have a cumulative impact on the gut microbiome too. Improving the health of both the gut and vaginal microbiome can be an important route to explore if this is the case.
The concept of “inflammaging” has become more popular as the role of inflammation in health and disease is becoming better understood. There are species bacteria in our microbiome that protect against inflammation – and these support us in healthy ageing. There are also certain kinds of bacteria that contribute to inflammation (in the gut and throughout the body). It’s really important to make sure what we eat is nourishing the anti-inflammatory species in our microbiome.
The Mediterranean diet is rich in vegetables and prebiotic-foods, like this broad bean pesto and braised chicory.
Research shows the microbiome can protect us from age-related illnesses
Researchers have discovered that a poor or restrictive diet helps speed up the onset of frailty in older people. Two weeks ago, the same researchers published their latest research showing that eating a Mediterranean diet promotes gut bacteria linked to healthy ageing, and protects against frailty and cognitive decline (Ghosh 2020). They had analysed the gut microbiomes of more than 600 people, aged 65–79, living in five different countries, before and after 12 months of either eating their usual diet or a Mediterranean diet – rich in fruits, vegetables, nuts, legumes, olive oil and fish, and low in red meat and saturated fats. Those eating the Mediterranean diet better maintained bacterial diversity and saw an increase in the types of bacteria associated with several indicators of reduced frailty, such as walking speed and hand grip strength, and improved brain function, such as memory. They also had fewer markers of inflammation.
A fantastic review has been published today that explores a range of dietary interventions to delay the ageing process and to increase health and life span (Ross & Carrascosa 2020). The authors look at how some of these dietary changes alter the microbiome, and review a number of clinical trials and animal studies where prebiotics and probiotics have demonstrated health benefits in older populations. They also discuss the importance of the anti-inflammatory capacity of the microbiome.
How our microbiome forms in our first thousand days of life has a life-long effect on our health, as does how we care for our microbiome in adulthood. As the research into the microbiome and ageing continues, it becomes clearer that supporting microbiome balance can not only prevent but also treat age-related conditions. This could include diet changes, tailored to your unique microbiome, and the use of targeted prebiotics and probiotics, as well as lifestyle interventions. Investing in your microbiome health is an empowering and even delicious way to invest in an enjoyable, healthy older age.
Book a session to find out how you can support your microbiome health.
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Ros & Carrascosa (1 March 2020) Current nutritional and pharmacological anti-aging interventions. Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. Volume 1866, Issue 3
Ghosh et al (17 February 2020) Mediterranean diet intervention alters the gut microbiome in older people reducing frailty and improving health status: the NU-AGE 1-year dietary intervention across five European countries. Gut.
Galkin (December 2018) Human microbiome aging clocks based on deep learning and tandem of permutation feature importance and accumulated local effects. BioRxiv
Murakami & Tognini (January 2020) The Circadian Clock as an Essential Molecular Link Between Host Physiology and Microorganisms. Frontiers in Cell. Infect. Microbiology.