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 fall 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 fibre is generally thought 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 a 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.
Latest study links processed meat to increased risks of breast cancer.
Latest research confirms processed meat increases breast cancer risk
I generally have mixed feelings writing about lifestyle choices correlated with increased risks of cancer. I don’t think provoking people’s fear is usually beneficial and I don’t see my role as pushing people towards or away from things that I feel are important. Even as a vegetarian and now a non-strict vegan I have never found that scare tactics draw people into thinking about their own wellbeing or that of others. I do retain however a genuine sense of gratitude to the people that educated me about the relationship between diet, gut bacteria and mental and physical health. So if I highlight the latest research reviewing the dangers of eating processed meats it does reflect my own thoughts but I hope that it offers readers the opportunity to make an informed choice about what they eat.
An understanding of the health risks of eating animal products has been around for decades, and the scientific evidence of potential dangers linked to meat consumption increase week to week. The latest study to hit the media, reports that women who eat processed meat products such as bacon and sausages, have a 9% increased risk of breast cancer compared to women eating low levels of those products. This is not the first (nor the last I’ll bet) study that links meat with increased risks of developing cancer. But once you look into this issue further you realize that eating processed meat is a triple whammy! Firstly you have the statistically evidenced increased risk of breast cancer, secondly there are also greater risks of a wide range of other health problems. But also that while you’re eating potentially harmful animal products you are not consuming health supporting fresh fruit and vegetables.
As a society we know that the mass, unthinking consumption of animals and animal products isn’t helping us individually or benefiting the wider society. I’m an advocate of a healthy diet based primarily on plants, including fermented products. The indications are that even if you eat fresh fruit and vegetables alongside your processed meats, the benefits to your gut health are going to be limited. A final point to consider is that if we know that the type and quality of the food we eat affects our own health, what is the impact on us of the diet of the animals we consume? If animals are being reared in harsh unsanitary conditions, dependent on antibiotics for their survival and with poor quality fodder, should we be surprised if eating them increases our risks of poor health?
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.
Your diet can play a significant role in your chances of becoming obese, suffering from asthma or a range of other illnesses.
Discovery, a general science programme from the BBC World Service, has put together a helpful three part guide to the human microbiome. It is made for the wider World Service audience so it presents the issues in an interesting but accessible way. The discussion of the subject matter is engaging, and important contributions are made by leading scientists in the field such as Prof Rob Knight, from the University of California and Prof Tim Spector from Kings.
The show provides a general outline broken down into three parts; Manipulating Our Hidden Half, Dirt and Development and Gateway to the Mind. The idea that humans (in common with other animals) have not one but two genomes is central to this mini series. Our human genome is the one handed down to us through our parents, set in stone at conception. The so called second genome is made up of a vast pool of genetic diversity present in the microbes found throughout and within our bodies. The Human Microbiome Project has begun the process of analyzing the large number of microbes present in us. Two key issues that have started to excite scientists in recent years are,
the extent to which microbes can influence human health and experience.
the ability of individuals to alter their own microbial profile.
For example, it is generally observed that increased diversity of different kinds of helpful bacteria in the gut, is correlated with improved wellness. Studies in obesity, allergies, asthma and auto immunity suggest that gut bacteria may have a crucial role in meditating our health. This opens up the prospect that lifestyles remedies such as changes to diet may offer us significant potential benefits. It also raises the question about the long term benefits of medication known to have a detrimental affect on gut bacteria such as antibiotics.
This then takes us back to the discussion of probiotic and prebiotic food and drinks. When you consume products rich in helpful bacteria (probiotics) or the soluble fibre known to support microbial diversity in the large intestine (prebiotics), you are likely to be improving your health in a number of ways. It cannot yet be said that there is a direct causal relationship between your diet and certain illnesses. However the scientists are starting to think of gut bacteria as increasing or decreasing the chances of suffering from particular health problems.
At the time of writing all three programmes were freely available online or to download here.
There may be a relationship between kefir and obesity.
I’m becoming increasingly convinced of the benefit of fermentation, that enriching beneficial gut bacteria has widespread effects on wellbeing and health. I’m still near the beginning of this journey and learning all the time. I’ve posted a series of articles linked to kefir, not because I’m an expert, but based of the apparent benefits accrued over the last two months from a small glass of kefir each day. I should also say that Maggie has lost a lot of weight over the time she has been drinking kefir, but, she has also been exercising. However weight loss isn’t my only reason for writing about this subject. A few months ago I felt obliged to take a course of antibiotics, I think it was a mistake ( I am aware of the downsides of this kind of medication) but it’s water under the bridge now. The subsequent decline in my overall health was striking. I started to have trouble concentrating and sleeping, I got a cold, suffered from reflux and saw an augmentation in weight.
I didn’t really connect these things with the antibiotics until I noticed that my bowel movements changed significantly. If you are new to the gut bacteria scene you might feel a little uncomfortable around talk about bowel movements, don’t be. A regular healthy bowel movement is one of the signs of a healthy balance in gut bacteria. So when I noticed I wasn’t going to the toilet regularly I though about the possible impact of antibiotics on my gut. I started to take kefir more regularly whilst keeping my usual prebiotic and probiotic consumption at the same level. The difference was gradual but pretty much everything started to improve after about five days. Two months later things are back where there were before the antibiotics. I’m much healthier, bowels are back to normal and……..I’ve lost weight without any exercise.
This isn’t a morality narrative about the harm of antibiotics. I believe antibiotics represent a life saving technology, and in the right place and time are essential. It’s their inappropriate overuse which I think is harmful.
My own anecdote is that I think it took two months to return the state of my gut bacteria to somewhere like normal, and I am a daily consumer of natural prebiotics and probiotics. In all of this story things pretty much fitted my modest understanding of the underlying science except the weight loss. I know that lack of diversity in gut bacteria is correlated with obesity generally but I hadn’t come across any research papers linking kefir to weight loss. If you can improve your gut health and pull your body weight closer to its optimum level this has to be a win-win. So I started to look through the scientific literature. The most recent research is featured here.
Are their differences in traditional and commercial kefir?
This is the second part of the feature, you’ll find part one here.
Despite my scientific training, regular followers of my blogs will have realized I have an established scepticism for extravagant scientific claims. I am a fan of science generally but feel the need to maintain a discriminating eye and treat each scientific claim on its merits. However a recent study into the relationship between kefir and obesity has been worth a closer look.
In a research paper titled Traditional kefir reduces weight gain and improves plasma and liver lipid profiles more successfully than a commercial equivalent in a mouse model of obesity, Bourrie, Cotter and Willing found that kefir appeared able to meditate metabolic health. This study compared the ability of traditional with commercially produced kefir to mediate mouse weight gain, plasma cholesterol, and liver triglycerides. Four traditional and one commercially available kefirs were used in the experiment. Commercial kefir was shown to have no beneficial effect whilst two of the traditional kefirs demonstrated a reduction in the rate of weight gain and increase in blood cholesterol. This was (as far as I know) the first ever study comparing mass produced with traditionally produced kefir, so the research must be regarded as preliminary. It was a study with mice so the extent to which results can be generalised to humans is uncertain.
The research concluded that when also considered in relation to the modulation of the gut microbiome, traditional kefir has the potential to mediate obesity through the improvement to metabolic dysfunction.
The report also explained that different forms of traditional kefir do not generate identical microbial populations. It is assumed that this could be linked to variable health benefits. Further that whilst Lactobacillus, Lactococcus, and Leuconostoc would be expected to be found in most forms of kefir, acetic acid bacteria was not found in a majority of commercial products. Research has also suggested that traditional kefir possesses highly complex fungal communities (including, S. cerevisiae, Pichia fermentans, Kazachastania unispora, and Kluyveromyces marxianus and lactis) not always found in commercial products.
In conclusion, three take home points:
This is preliminary research, it’s early days!
Traditional kefir may support improved cholesterol and fatty acid metabolism.
Traditional kefir appear to offer a much greater microbial diversity to the host than commercially produced kefir.