Insomnia in the elderly: are gut microbiota to blame?
Show me your microbiota, I’ll tell you if you sleep well (and cogitate). This is, roughly speaking, the conclusion of a study that has demonstrated an interrelationship between sleep disorders, cognition and gut microbiota in the insomniac elderly.
About this article
It’s hard to sleep like a baby when you’ve already celebrated your 65th birthday. At this age, one person in two suffers from chronic (sidenote: Insomnia Difficulty falling asleep or maintaining sleep, waking up early or feeling unrefreshed on waking. Severity is measured in terms of frequency of occurrence and daytime impact on everyday activities and on social and cognitive performance. Insomnia can be acute if it lasts less than a month, or chronic if it lasts more than 6 months. Amatéis, C., Büla, C., Insomnies chez les personnes âgées : quelle approche ?, Rev Med Suisse, 2007/132 (Vol.-7), p. 2537–2541. ) , which aggravates age-related (sidenote: Cognition All the mental processes related to knowledge that involve attention, learning, intelligence, language, memory, perception, decision-making, problem-solving, reasoning, etc. Cognition_National Cancer Institute ) disorders. But rest assured: researchers are working hard to decipher the underlying mechanisms, about which we still know little. One team decided to study gut microbiota, revealed several years ago as being capable of influencing brain function1.
50% Insomnia affects approximately 50% of the adult population over the age of 65.
1 in 2 seniors Insomnia affects 1 in 2 seniors, compared to 1 in 3 or even 1 in 6 in the general population.
(sidenote: https://www.revmed.ch/revue-medicale-suisse/2007/revue-medicale-suisse-132/insomnies-chez-les-personnes-agees-quelle-approche )
As we get older, our dentition, salivary function, digestion and intestinal transit come under strain, affecting gut microbiota and causing an imbalance (dysbiosis): the composition and diversity of this mixed flora of bacteria, fungi, viruses and other small (sidenote: Microorganisms Living organisms that are too small to be seen with the naked eye. They include bacteria, viruses, fungi, archaea and protozoa, and are commonly referred to as “microbes”. What is microbiology? Microbiology Society. ) evolve over the years, to the point where the elderly progressively develop a microbiota that is very different to that of younger adults.
Changes in gut microbiota linked to insomnia
In elderly people suffering from insomnia, the researchers found that one bacterial phylum (Bacteroidetes) occupies the lion’s share, while there are fewer Firmicutes and Proteobacteria compared with healthy patients. More importantly, they discovered that in elderly people with insomnia, sleep and cognition alone explain 7.5 to 7.9% of the variation in gut microbiota composition, which has a significant impact, comparable according to a previous study2 to that exerted by medication, blood parameters, digestive transit, diet, health status, weight and height!
Typical bacteria in insomniacs
They also found that elderly people with insomnia having high levels of Lachnoclostridium bacteria in their guts have high-quality sleep and better cognitive performance. Conversely, lower cognitive performance is associated with more Blautia.
There is no point attempting to deduce causal relationships; it would be impossible at this stage. On the other hand, gut microbiota may one day help in the diagnosis of elderly people with insomnia and cognitive decline. If a causal relationship is ever proven, it could also become a new therapeutic target in the field of aging... and sleep. But by then the sandman will have come and gone multiple times...
The gut microbiota
1. Haimov I, Magzal F, Tamir S et al. Variation in Gut Microbiota Composition is Associated with Sleep Quality and Cognitive Performance in Older Adults with Insomnia. Nat Sci Sleep. 2022 Oct 6;14:1753-1767.
2. G, Joossens M, Vieira-Silva S, et al. Population-level analysis of gut microbiome variation. Science. 2016;352(6285):560–564.