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.

 

Help for migraine sufferers from bacteria

People suffering from migraines tend to have particular profile of bacteria linked to nitrate processing.

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I am keen not to overstate the potential of any individual scientific study. However this story highlights exciting news about a potential relationship between bacteria and migraines. In 2016 The Guardian featured a study that appeared to demonstrate a link  between the efficient break down of nitrates in humans and the occurrence of migraines. As I understand the research,  migraineurs (people that suffer from migraine) tend to have more nitrate reductase genes in both the mouth and in stool samples, than the wider population.

Nitrate reductase genes are responsible for processing nitrates in food and drinks, point being the greater their abundance the more efficient the nitrate processing. So getting more nitrates from food (compared to non migraineurs) may be linked to triggers for migraines. Obviously further research will be needed but the link between nitrates and headaches is not new. What this study is demonstrating is that the key might rest with the microorganisms in the mouth and gut.

Many migraine sufferers are aware of a relationship between certain foods and increased risks of attacks, through chocolate and wine for example. It is also known that certain drugs high in nitrates can provoke severe headaches. When broken down, nitrates lead to increased blood circulation in the cardio vascular system, this increase may be a key factor in migraines. The complexity of the human microbiome, particularly the gut-brain axis, makes demonstrating causality between food and health challenging. However this seems like a promising area of research. Controlling  the intake of foods high in nitrates might be a short term solution. But given that fruit and vegetables are rich sources of nitrates, cutting down on them could present a range of risks and benefits. For more information visit the Migraine Action or Migraine Trust websites.

We always welcome your feedback, comments in the text box below. Thanks for Peter for suggesting the subject and as always please read our disclaimer.

How your food directly affects your brain

There is a two way communication system between the gut and brain, this is one way that gut microbiota mediate our health.

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bacteria – crucial to your health

The growing excitement over the role of gut bacteria is being fuelled, in part, by the realisation of the potential role of the gut – brain axis. The gut-brain axis is the hard wiring between the digestive tract and the brain. That is to say a direct communication link passing information between neural, hormonal and immune systems. A key point to make is that the communication is bi-directional, that means the brain talks to the gut and that the gut talks to the brain. Thus the microbiota (gut bacteria) and metaboloites (small molecules that are the product of metabolism) may be in reciprocal communication with different parts of the brain. While this has a direct and obvious impact on processes related to eating and digesting, there is rising evidence that our gut flora may be significant factors in physical and mental health.

The relationship between emotions and  the digestive system is one of which we are intuitively aware. For example, feelings of love often manifest as ‘butterflies’ in the stomach. Engaging in team sports enables you to observe pre-match nerves in both yourself and others; the digestive system often plays an obvious role in how some people deal with tension! There is evidence that stress is a mediating component in gut microbiota, perhaps through increasing or decreasing the optimal conditions for certain types of bacteria to flourish.

New studies are suggesting that individual microbiota may be influential in functions as apparently disparate as memory and fear. It is not known what the basis of the relationship is, where the causality can be found. But that there is a correlation between what is in our gut and how we experience life in terms of mental and physical well being. The take home point is that many of the things we eat and drink are able to positively and negatively influence our health. By taking more interest in what goes into your stomach you might do yourself a power of good.