Autism correlated with guthealth. More evidence links gut bacteria to developmental disorders.
There is mounting evidence of a relationship between the microbiome and autism. Taken in isolation one study that challenges conventional thinking about any condition such as autism should be treated with suspicion. However, increasing scientific research into gut health and wellbeing is starting to shift the thinking about human health in a completely new direction.
A number of studies have observed abnormal gut microbiota correlated with a range of conditions including autism. However the issue of causality is still uncertain. So what does this mean? In short that the bacteria in the human gut demonstrates a different profile in people with autism than people without autism. The scientific term for a balance and blend of gut bacteria that falls outside of the ‘normal’ range is known as dysbiosis. Exactly how gut dysbiosis is linked to autism is still far from clear. There is the possibility that dysbiosis is the effect of a condition rather than the cause of it, although we know there is a two-way relationship between the gut and the brain through the gut-brain access.
A recent overview of research into gut microbiota and dysbiosis in autism found that gut microbiota probably has a mediating role in ASD. By logical deduction, we can be confident that diet at some level is likely to be connected to the development of ASD or the maintenance of its symptoms.
So while we are waiting for science to deliver ‘conclusive’ findings that will help us understand more about autism, what shall we do?
Clearly, we should attempt to establish a healthy gut. The list of health problems linked to dysbiosis grows almost every day, they currently include a range of cancers, heart disease and even dementia! Amongst the simple measures every person can engage with immediately to keep a healthy gut, are to avoid processed meats and eat more fermented foods.
It’s far too early to draw firm conclusions about diet and complex developmental conditions such as ASD. But a picture is starting to emerge were just as diet influences gut health, gut health influences physical and mental wellbeing, there was never a greater case for embracing the maxim ‘we are what we eat’.
Fibre is an essential part of the human diet, strategic reviews indicate that consuming just 30g of fibre a day is correlated to reduced risk of colon cancer, type-2 diabetes, heart attacks and strokes.
For most of us there is a simple thing we can do to improve our short and long-term health, eat more fibre! The role of fibre in regulating digestion has been understood by humans for hundreds of years. But the full benefits linked to fibre (also known as roughage) are only just starting to be understood. A recent study published in The Lancet1 analysed a wide range of research and found that a shortage of fibre in our diets is linked to greater risks of type-2 diabetes, bowel cancer, heart attacks and strokes. In addition people that eat more fibre tend to have lower weight, lower blood pressure and reduced cholesterol levels. Amazingly the research suggested that consuming a mere 30g (1oz) of fibre a day was sufficient to deliver the full range of health benefits. To put this into some kind of perspective the 30g target can be reached by consuming four slices of brown bread, eating a handful of nuts and seeds in addition to the regulation five portions of fruit and veg a day. In essence it is available to most of us with only a few small changes to our eating habits.
Fibre consumed through our diet can be divided into two types, soluble and insoluble. Soluble fiber is generally though of as a prebiotic, which means it supports communities of helpful bacteria in the gut microbiome. Insoluble fibre does not dissolve in water and typically passes through the digestive system aiding bowel movements. Most fibre rich foods contain soluble and insoluble elements, today food science is more concerned with the total amount of fibre rather than the different forms (cellulose, pectins and beta glucans) we eat.
In summary; fibre is an essential part of the human diet, strategic reviews of the available evidence strongly suggest that consuming 30g of fibre a day is correlated to reduced risk of colon cancer, type-2 diabetes, heart attacks and strokes. There is a growing body of evidence that fibre also plays an important role in maintaining helpful bacteria in the gut microbiome.
The importance of the microbiome to human health is just starting to emerge, but our attitude to gut health hasn’t always been this enlightened.
Just a heads up for anyone interested in learning more about the changing relationship between humans and gut health. A short series The Gut Instinct: A Social History has been broadcast on BBC Radio 4 this week over five 15 minute episodes. At the time of writing the transmissions were still available on the BBC iPlayer here.
The concept was to explore how humans related to digestive processes and gut health across culture and time. There’s a lot of general information linked to the microbiome, some directly relevant to us today. The programme was written and presented by restaurant owner Tim Hayward and it seeks to offer an account relevant to a general audience, setting out major historical landmarks as well as important contemporary issues. Unusually for a British show we actually hear adults talking about bowel movements and human waste in a practical and informative manner. The five episode titles reflect the general content of the series (Gut Culture, A Window into the Gut, The Language of the Gut, The Disease of Civilisation and The Gut Speaks). Don’t expect much detailed science but I’d imagine anyone who tunes in to pick up some new morsels of gut knowledge, total listening time is just 75 minutes.
Do probiotics work? Research from 2018 suggests that some probiotic strains might struggle to find a home in our gut, being quickly forced out by the established microbes.
Do probiotics work?
Research into the human microbiome is demonstrating that gut health is both complex and nuanced. Complex because of the sheer quality and quantity of microbes that we humans host. For example according to the Human Genome Project each of us has around 22,500 human genes, however it’s estimated that we also carry 100 times that number in microbial genes! Understanding the colonies of microbes (predominantly bacteria) inside our gut is further complicated because no two people have exactly the same gut flora. So therefore each of us has a unique bacterial ecosystem.
A research paper published in the journal Cell in September 2018 and highlighted by the BBC website, has made the claim that “Humans feature a person-specific gut mucosal colonization resistance to probiotics”. The study found that an 11-strain probiotic mix, administered for a month had almost no impact on the long term gut health of 25 participants. Either passing straight through the digestive tract or lingering for a short time before being forced out by the well established resident bacteria. Although provisional, the results are highly suggestive that the gut has a defence mechanism designed to protect itself from rapid colonization by new visitors. This is kind of intuitive, if any new bacteria that we ingested could quickly establish a foothold in our body then we would be much more vulnerable to harmful microbes.
Although this initial study hasn’t been replicated and is based on a relatively small number of people it suggests that probiotics might work best if they are tailored to each of us individually. That probiotics might offer the greatest benefit if they are designed to coexist with our unique resident populations. From a consumer’s point of view I am left thinking how might I be able to tell if the probiotics I consume are having a lasting effect without going down the road of expensive lab based testing? Hopefully further studies offering greater insight will follow.
Evidence is mounting that there is a relationship between what we eat and 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.
Cabbage offers vital support in resistance to cancer. New research suggests new molecular evidence.
This blog reflects a growing interest in the benefits of consuming fermented food as a way of improving health and wellbeing. Cabbage is a popular vegetable in Europe, and it is one of the simplest things to start fermenting at home. Most parents would have urged their children to ‘eat up your greens’ at some point, but the real value of this advice is only just starting to emerge. Cabbage is part of the cruciferous family (brassicas) which includes lots of vegetables long associated with a healthy diet such as kale and broccoli (wasabi and horseradish too incidentally). Including them in your diet has long been recognised as a good idea. With a growing understanding of the link between lactic acid fermentation and good gut health, cabbage is being thought of as a superfood, able to increase protection against a wide range of health problems.
News published today on the BBC website adds yet another dimension to the benefits of eating cabbage. Scientists at the Francis Crick Institute have identified anti-cancer chemicals created in the process of digesting brassicas, including cabbages. It is supposed that a chemical (indole-3-carbinol) created when cabbage is broken down in the body, encourages the healthy renewal of the bowel lining. The cited research was not carried using fermented cabbage, however the long standing association between sauerkraut consumption and healthy bowels suggests to me that fermentation may have a favorable link with indole-3-carbinol production.
This research was carried out on mice so how it translates to humans is as yet uncertain (is the use of mice really necessary?). And as already mentioned this wasn’t a study on fermented cabbage.
Finally I just want to remind everyone of the importance of eating organically whenever possible. In a recent court case in the US, a man was awarded £226m in damages after claiming that his cancer was caused by a weedkiller that included the compound glyphosate. Despite being developed by a powerful chemical company (Monsanto), glyphosate has been attracting health concerns for some considerable time. France plans to ban it’s use within three years and at least one study by the UN argued it is probably carcinogenic in humans. While washing vegetables before consumption is always good practice, many chemicals used in agriculture like glyphosate are absorbed through foliage and roots. I’m uncertain of the extent to which glyphosate is present in the production of brassicas, but going organic is the only way to be sure.
Although it’s often a subject shunned by polite society, what happens in your bowels is becoming increasingly an object of open discussion. The growth of interest in fermentation and gut bacteria is linked to an awareness of a relationship between improved health and how what we eat is processed in our gut. It goes without saying that we are what we eat. This maxim reflects the traditional understanding that the quality of the food we consume is a factor in our health. But science is increasingly demonstrating that the nutrients contained in our meals rely on a range of microbes to extract the maximum benefit from them.
While a discussion centered on healthy eating is normally something that can be sanitized, with the microbiome (the human microbial population), sooner or later human waste has to be discussed. What happens all through the intestinal tract including the colon has a key part to play in human health. Often the state of your own faecal matter (poo) can be a good indicator of what’s going on inside you. If you have a healthy diet and your food is being digested properly, the chances are you that you have a good quality and quantity of helpful bacteria in your system. There are a number of conditions that lead to the loss of a significant proportion of useful gut bacteria, these include the overuse of antibiotics.
Faecal Microbial Transplant (FMT) is a treatment used in a limited number of clinical cases, but its application demonstrates just how crucial gut bacteria is. As its name suggests, FMT is the transplanting of bacteria and yeasts from a person with a healthy digestive function into a person that has a significant lack of the necessary microbes. When one of the world’s best triathletes, Lesley Paterson contracted Lyme Disease, she turned to FMT as an alternative solution. Lyme Disease often leads to tiredness and low energy in those infected, and antibiotics are often prescribed as part of the treatment. Antibiotics have a number of possible side effects including massive reduction in gut bacteria, often further lowering the body’s natural resistance further. In some cases FMT is thought to offer an effective yet inexpensive solution with few negative side effects. Lesley Paterson’s story can be found on the BBC website.