Oral microbiome linked to Alzheimer’s dementia

The notion that bacteria in our mouth might mediate neurodegeration, stresses the importance of attending to what we we eat and the pollutants in our environment.

Could the oral microbiome be linked to neurodegeneration?
Could the oral microbiome be linked to neurodegeneration?

Gut well soon originally started life as a cheerleader for traditional fermented products such as kefir and sauerkraut. Simple fermented foods, easy to make at home, with a long association to health and wellbeing. Over time we have edged a lot closer to the wider discussion about the human microbiome more generally. Exactly why do fermented foods, containing large amounts of helpful bacteria, appear to boost human health quite so dramatically?

As part of this growing understanding, I want to highlight and link to a new scientific study that suggests a potential relationship between gum disease and Alzheimer’s dementia.  There is not yet sufficient evidence to claim that the oral microbiome has a causal role in dementia1, but this paper offers more support for the notion that our bacterial populations (good and bad) have a crucial role in our physical and mental health.

pain armchair dentist suffering

The general idea that many of our most challenging health problems can be mediated by the bacteria we carry in and on our bodies is still highly controversial. Not least because our healthcare systems are often based on a treatment rather than prevention paradigm. If some of these treatments, such as antibiotics, can cause other problems in the short and long term what then? It is estimated that lifestyle choices (including diet), are connected to 80% of health problems seen by GPs in the NHS. And yet UK medical schools offer almost no nutritional education to their students. It can be argued that our doctors have been taught for decades, to engage with treatment opportunities rather than prevention strategies.

Returning to the cited study discussed in New Scientist. It has been hypothesised that a gum disease bacterium (Porphyromonas gingivalis), may get into the brain and cause inflammation which could be a factor in neurodegeneration. People with Alzheimer’s dementia tend to have higher levels of this bacterium in their brains. A company has created an oral medicine that is intended to block the activity of the toxins established by the bacterium. An initial small trial has seen some positive preliminary results.

A second question arising from this new approach to Alzheimer’s dementia is what lifestyle and dietary choices are likely to improve the mouth microbiome and reduce harmful bacteria that attack the gums?

Notes:

1 https://www.newscientist.com

Alzheimer’s disease linked to gut bacteria

Evidence is mounting that there is a relationship between what we eat and dementia.

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Could prebiotics and probiotics have a role in the reduction of the risks of dementia?

I trained as a cognitive scientist/neuroscientist originally because I wanted to know more about how people could lower their risks of developing dementia in general and Alzheimer’s disease (AD) in particular. My interest in fermentation comes from exposure to research indicating that gut bacteria is correlated to a range of physical and mental health conditions. That if you have too many or two few of certain types of microbes within your digestive tract, then you are more likely to experience better or worse health.

Imagine my interest then when I receive details of research that stated,

“All the results suggest that AD may begin in the gut.”

This conclusion from Hu, Wang and Jin appeared in their 2016 study Alzheimer’s disease and gut microbiota. Clearly if the results stand up and can be replicated this will change much of what we know about AD, and how it might be treated. There is a growing body of research that has linked AD to diet, it is widely discussed in the vegan and vegetarian communities. But Hu, Wang and Jin take the current thinking further; that AD is not just linked to what we eat per se’ but the prebiotic and probiotic effects of our diet. This research suggests that future treatments for AD are likely to come in the form of dietary or microbiotial interventions. The investigation covers a wide range of evidence, the scientists also draw attention to known links between gastrointestinal diseases and reduced cognitive function as well as Parkinson’s Disease and abnormal levels of gut microbes. If you’re puzzled as to how the gut influences the brain, look into the gut- brain axis.

As a general rule I’m cautious about the findings of academic studies dealing with complex areas of human health like AD. There are such a wide range of factors able to influence wellbeing that to isolate and demonstrate causality is not a simple matter. There is also evidence linking a number of other behaviours (meditation, mindfulness) to reduced risks of neurodegeneration. So that if there is a correlation between both meditation and gut bacteria with lower risks of developing AD, we need to think about how it might work.

Anyone who has been around the meditation community for a while may have noticed a few things about regular meditators. They tend to be relatively calm and their diet and lifestyle tends to be a little different from the mainstream. For example I’ve observed that meditators appear to smoke tobacco and drink alcohol less than the general population. Anecdotally I have found more vegans and vegetarians in the meditation community than my non-meditating friends. You can see from these speculative ideas that the relationship between gut bacteria and AD could hold up even given the evidence linking meditation to lower risks of neurodegeneration.

Whilst this study in isolation does not prove that AD begins in the gut, it signposts further areas of potential research. We now need to look for more specific evidence and ‘joined up’ explanations. It seems that there has never been a better time to think about the benefits of bringing fermented food into your diet and protecting your gut health as far as possible.