The bacteria in your gut affect blood insulin levels and may influence your chances of developing type 2 diabetes

Developing type 2 diabetes is for a large part influenced by your diet but also genes. However, a recent study has now shown that your gut microorganisms might also play an important role in the risk of developing type 2 diabetes (T2D). The article published in Nature Genetics entitled “Causal relationships among the gut microbiome, short-chain fatty acids (SCFA’s) and metabolic diseases”, claims evidence that bacterial metabolites such as SCFA’s are able to influence insulin levels and increase the risk of getting T2D.

Various studies have suggested that increased SCFA production benefits the host by exerting anti-obesity and antidiabetic effects, however, results of different studies are not always in agreement. Moreover, there is also evidence that increased production of SCFAs in the gut might be related to obesity, due to energy accumulation. Resolving these conflicting findings requires a detailed understanding of the causal relationships between the gut-microbiome and host energy metabolism, and the present study contributes to this.

The authors analyzed data from a large population study based in Groningen (The Netherlands), comprising 952 individuals with known genetic data, as well as information on parameters associated with metabolic traits such as BMI and insulin sensitivity. In addition, data were acquired for the type and the function of the bacteria which were present in the gut of the study participants. Combining this data, the authors tried to answer the question of whether changes in microbiome features causally affect metabolic traits or vice versa?

A technique called Mendelian randomization (MR) which is increasingly accepted to establish cause-effect relationships in the onset of diseases was applied. The primary outcome of the analysis was that host genes influence the production of the SCFA butyrate in the gut, which is associated with improved insulin response in the blood after an oral glucose tolerance test. In addition, abnormalities in the production or absorption of propionate, another SCFA, were causally related to an increased risk of T2D.

So far available data suggest that overweight humans or those with type 2 diabetes may have different microorganisms in their gut compared to healthy people. These microorganisms which are commonly found in healthy people are absent from the T2D patients. Whether the differences in the microbiota between healthy and T2D patients are an effect of the disease development or account for causality is challenging to be answered. With the data from the present study, authors are able to go one step further and demonstrate potential routes by which microorganisms are able to regulate our metabolic status underlying their importance for our wellbeing.

Collectively the present article suggests that production of bacterial SCFA’s play a pivotal role in the regulation of metabolic traits such as blood insulin levels and are associated with the onset of T2D.

Since the study was observational and did not include any T2D patients, confirmation of the results is essential. Follow up studies including T2D patients would be highly informative. With the rising prevalence of obesity in adults, which is reaching epidemic levels, the prevalence of T2D will also continue to rise. In the past years, scientists have mainly focused on the role of human gene data, but this has not led to major breakthroughs. Perhaps knowledge of the microbiome will elucidate molecular mechanisms which can be translated to novel effective treatments for metabolic disorders such as T2D.

REFERENCES
Sanna, S., van Zuydam, N. R., Mahajan, A., Kurilshikov, A., Vila, A. V., Võsa, U., . . . Oosting, M. (2019). Causal relationships among the gut microbiome, short-chain fatty acids and metabolic diseases. Nature genetics, 1.

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We, human beings in Western society, make over 200 food choices each day (1). That’s a lot! Fortunately (or, according to others, unfortunately), we don’t actually have to think about each and every one of them, or at least not consciously. If our food choices are not so much a conscious decision, then how do we make them? A lot has been written about external factors influencing our food choices, for instance, alluring displays in supermarkets or the availability of unhealthy foods in our day-by-day environment. In this blog, I will address the potential role of genetics on food choices: to what extent do our genes determine what we eat?

Eating behaviours are complex, i.e. they are very diverse and influenced by many different factors. When we investigate complex behaviours, we are unlikely to find simple explanations. In other words: we do not expect to find one gene that makes me prefer pizza margarita over pizza fungi, nor will we find a single gene responsible for my triple-chocolate ice cream consumption. There are, however, some instances in which specific genes have relatively simple and straightforward effects on our food choices. This is the case when genetic variants code for food sensitivities.

A famous example is the LCT gene (or, more precisely, the C>T change at 13910 bases upstream of the LCT gene in the 13th intron of the MCM6 gene). The LCT gene codes for lactase persistence, or lactose tolerance after childhood. Worldwide, the majority of people (and most other mammals, for that matter) no longer tolerate dairy products after childhood. For them, consuming milk products causes nausea, bloating and cramping within 2-3 hours. As a result, they will soon learn not to consume dairy products. Those who have the lactase persistence gene, however, don’t have any problems digesting dairy products and, thus, are more likely to consume them (2). Geographical region is important here: while in Northern European countries such as the UK and Finland, 90-100% of people tolerate dairy products, in South-East Asia and Australia this number is close to 0% (3).

A similar situation seems to occur for genes coding for certain taste receptors on the tongue. The TAS2R38 gene, for instance, makes some people extremely sensitive to bitter taste. This, of course, will cause them to avoid bitter foods such as cruciferous vegetables (4). A recent study has even identified a small number of genes that together cause people to either love or hate marmite (5)! Another gene variant (CYP1A1), coding for caffeine clearance from the body, causes carriers to drink less or more coffee and tea (6).

Thus, when food sensitivities are involved, food choices can be driven by specific genes. Most food choices, however, have very little to do with food sensitivities and are much more complex. Pizza Margarita or Pizza Funghi? Triple-chocolate ice cream today or maybe tomorrow? While for such complex food choices there is no single gene responsible, our genetic make-up still does have influence. Typically, for complex behaviours, many different genes can be identified. While each gene individually contributes only a little bit, together they can actually have quite an effect on your food choices. For instance, a recent study identified seven genetic variants each having a small effect on carbohydrate intake. Taken together, genes explained 8% of the variation in carbohydrate intake between individuals (7).

In conclusion: while some genetic variants have rather drastic effects on our food choices, by giving us a physical adverse reaction to certain foods, there are only few of them. Most of our food choices are much more complex. These are influenced by multiple genes at the same time, and even together these genes have only limited influence.

REFERENCES
1. Wansink, B., & Sobal, J. (2007). Mindless eating: The 200 daily food decisions we overlook. Environment and Behavior, 39(1), 106-123. doi: 10.1177/0013916506295573

2. Szilagyi, A. (2015). Adaptation to Lactose in Lactase Non Persistent People: Effects on Intolerance and the Relationship between Dairy Food Consumption and Evolution of Diseases. Nutrients, 7(8):6751-79. doi: 10.3390/nu7085309

3. Itan, Y., Jones, B.L., Ingram, C.J.E., Swallow, D.M. & Thomas, M.G. (2010). A worldwide correlation of lactase persistence phenotype and genotypes. BMC Evol Biol, 10:36. doi: 10.1186/1471-2148-10-36

4. Feeney, E., O’Brien, S., Scannell, A., Markey, A. & Gibney, E.R. (2011). Genetic variation in taste perception: does it have a role in healthy eating? Proc Nutr Soc, 70(1):135-43. doi: 10.1017/S0029665110003976.

5. Roos, T.R., Kulemin, N.A., Ahmetov, I.I., Lasarow, A. & Grimaldi, K. (2017). Genome-Wide Association Studies Identify 15 Genetic Markers Associated with Marmite Taste Preference. BioRxiv (preprint). doi: 10.1101/185629

6. Josse, A.R., Da Costa, L.A., Campos, H. & El-Sohemy, A. (2012). Associations between polymorphisms in the AHR and CYP1A1-CYP1A2 gene regions and habitual caffeine consumption. Am J Clin Nutr, 96(3):665-71. doi: 10.3945/ajcn.112.038794.

7. Meddens, S.F.W., de Vlaming, R., Bowers, P., Burik, C.A.P., Karlsson Linnér, R., Lee, C., et al. (2018). Genomic analysis of diet composition finds novel loci and associations with health and lifestyle. BioRxiv (preprint). doi: 10.1101/383406

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Recently, I participated in the Radboud Talks 2019, a scientific pitch competition, where I was lucky to be one of the eight finalists.

Why Radboud Talks? It is a perfect opportunity to share my work/ideas with the world and to gain more experience regarding presentation skills. They organized two workshops beforehand, where I had the opportunity to learn presentation techniques from professionals (actors and science communication advisors). We also received a lot of feedback, so I really learned a lot about how to present my scientific work to a general audience.

Below you can find the video from the preliminaries based on which I was chosen as a finalist. There you can hear about my research project which is about gut bacteria and their potential role in ADHD (Attention Deficit Hyperactivity Disorder). ADHD is a common worldwide neurodevelopmental disorder. Every person with ADHD has a unique combination of symptoms and challenges. Importantly, it has a significant social impact on patients’ lives, causing disruption at school, work and relationships. Despite its societal importance, progress in understanding disease biology has been slow.

 

The study of the human microbiome has become a very popular topic, because of their revealed importance in human physiology and health maintenance. Numerous studies have reported that gut bacteria may have an effect on our mental health. Some studies showed a potential role of gut bacteria in a psychiatric disorder like depression, autism or Parkinson (1). Above all, diet showed to have a profound effect of ADHD symptoms. This was earlier described in this blog: https://newbrainnutrition.com/investigating-the-effects-of-a-dietary-intervention-in-adhd-on-the-brain/ and we know that diet is one of the main factors influencing gut bacteria. Taking all together, I am curious (and investigating) if gut bacteria play a role in ADHD and if yes what kind of effect do they have on ADHD symptoms.

REFERENCES:
Bastiaanssen, T., Cowan, C., Claesson, M. J., Dinan, T. G., & Cryan, J. F. (2018). Making Sense of … the Microbiome in Psychiatry. The international journal of neuropsychopharmacology22(1), 37–52. doi:10.1093/ijnp/pyy067

 

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Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with an estimated prevalence rate of 5.3% among children and of about 2.5% among adults. It is characterized by a persistent pattern of inattention and/or hyperactivity-impulsivity, being associated with significant impairment of social, academic, and occupational functioning across the lifespan.

However, despite many efforts, the exact etiology of ADHD still remains unknown and data about modificable risk and protective factors are largely lacking. Recent evidence has suggested an association between inflammation, immunological disturbances and ADHD. Supporting this idea, an increased incidence of immune-mediated disorders (e.g. asthma, allergic rhinitis, atopic dermatitis, allergic conjunctivitis, psoriasis, thyrotoxicosis or type 1 diabetes) accompanied by elevated serum/plasma and cerebrospinal levels of inflammatory markers (especially interleukin (IL)-6) or auto-antibody levels (e.g. antibasal ganglia antibodies, antibodies against the dopamine transporter) have been found in these patients.

Importantly, recent studies have shown the gut flora as an important immunoregulator (1-3) and it is hypothesized that an imbalance in the gut microbiota (dysbiosis) may have a negative effect on cerebral development and behavior (4). About 95% of all circulating serotonin, dopamine or noradrenaline precursors are produced by our gut microbiota, being this ‘enteric nervous system’ bidirectional connected to the central nervous system through hormonal or immune/inflammatory pathways.

In line with this, recent findings suggest that some aliments as probiotics can not only revert dysbiosis, but also modulate brain neurodevelopment, activity and improve cognition, mood and behavior due to their immunoregulatory and anti-inflammatory properties (5-7).

Therefore, understanding the microbiota and how the gut connects to the brain would be important both for the better comprehension of the biological bases that underlie some psychiatric disorders such as ADHD, as for the future development of new evidenced-based drugs for these conditions.

This was co-authored by Josep Antoni Ramos-Quiroga, MD PhD psychiatrist and Head of Department of Psychiatry at Hospital Universitari Vall d’Hebron in Barcelona, Spain. He is also professor at Universitat Autònoma de Barcelona.

REFERENCES:

1. Felix KM, Tahsin S, Wu HJ. Host-microbiota interplay in mediating immune disorders. Ann N Y Acad Sci. 2018; 1417(1):57-70.

2. Yadav SK, Boppana S, Ito N, Mindur JE, Mathay MT, Patel A, et al. Gut dysbiosis breaks immunological tolerance toward the central nervous system during young adulthood. Proc Natl Acad Sci U S A.2017; 114(44): E9318-27.

3. Mandl T, Marsal J, Olsson P, Ohlsson B, Andreasson K. Severe intestinal dysbiosis is prevalent in primary Sjögren’s syndrome and is associated with systemic disease activity. Arthritis Res Ther.2017;19(1):237.

4. Rogers GB, Keating DJ, Young RL, Wong ML, Licinio J, Wesselingh S. From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Mol Psychiatry. 2016; 21(6):738-48.

5. Slykerman RF, Kang J, Van Zyl N, Barthow C, Wickens K, Stanley T, et al. Effect of early probiotic supplementation on childhood cognition, behavior and mood. A randomized, placebo-controlled trial. Acta Paediatr.2018; 107(12):2172-78.

6. Kane L, Kinzel J. The effects of probiotics on mood and emotion. JAAPA. 2018; 31(5):1-3.

7. Mayer EA. Gut feelings: the emerging biology of gut-brain communication. Nat Rev Neurosci.2011;12(8):453-66

 

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Our body is colonized by trillions of microorganisms that are important for vital processes. Gut microbiota are the microorganisms living in the intestinal gut and play an essential role in digestion, vitamin synthesis and metabolism, among others. The mouth and the large intestine contain the vast majority of gut microbiota whether the stomach only contains few thousands of microorganisms, especially due to the acidity of its fluids. Microbiota composition is constantly changing, affecting the well-being and health of the individual.

Each individual has a unique microbiota composition, and it depends on several factors including diet, diseases, medication and also the genetics of the individual (host) (Figure). Some medicines, especially antibiotics, reduce bacterial diversity. Strong and broad spectrum antibiotics can have longer effects on gut microbiota, some of them up to several years. Genetic variation of an individual also affects the microbiota composition, and the abundance of certain microorganisms is partly genetically determined by the host.

The main contributor to gut microbiota diversity is diet, accounting for 57% of variation. Several studies have demonstrated that diet’s composition has a direct impact on gut microbiota. For example, an study performed on mice showed that “Western diet” (high-fat and sugar diet), alters the composition of microbiota in just one day! On the other hand, vegetarian and calorie restricted diet can also have an effect on gut microbiota composition.

Prebiotics and probiotics are diet strategies more used to control and reestablish the gut microbiota and improve the individual’s health. Probiotics are non-pathogenic microorganisms used as food ingredients (e.g. lactobacillus present in yoghurt) and prebiotics are indigestible food material (e.g. fibers in raw garlic, asparagus and onions), which are nutrients to increase the growth of beneficial microorganisms.

In the last years the new term psychobiotics has been introduced to define live bacteria with beneficial effects on mental health. Psychobiotics are of particular interest for improving the symptomatology of psychiatric disorders and recent preclinical trials have show promising results, particularly in stress, anxiety and depression.

Overall, these approaches are appealing because they can be introduced in food and drink and therefore provide a relatively non-invasive method of manipulating the microbiota.

AUTHORS:
Judit Cabana-Domínguez and Noèlia Fernàndez-Castillo

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Download your FREE REPORT

How do you eat in a healthy fashion?  Anne Siegl, PhD writes that a big part about eating healthy is nutritional diversity.  Not eating the same thing every day, but providing your body with a rich variety of all kinds of foods and nutrients.  Part of our objective is to keep our gut happy, because our gut drives so much of our health.  And we are discovering that the gut is in continual high-speed two-way communication with the brain.  If the bacteria (microbiota) in your gut are happy, you will lead a more healthy physical life, and we are learning, a more healthy mental life as well.  We are one organism, and it’s all connected.  Keep your gut microbiota healthy with a varied diet.

Download this important report today.

 

 

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The more diverse we eat, the more diverse our gut microbiome (i.e., the composition of trillions of microbes in our intestine) will become. Sounds reasonable, right? But – why is that a good thing?

Well, research has shown that a diverse gut microbiome is less susceptible to diseases, such as the well-known western lifestyle associated diseases like diabetes or Crohn’s disease (1). This might be because one’s microbiome and one’s immune system are closely linked. A healthy and diverse microbiome thus might support proper functioning of our immune system and help keeping us healthy.

Eating a variety of different food items also enhances the odds that your body gets all the nutrients like vitamins or minerals it needs for proper functioning. This can have an effect on our well-being as well as on our physical appearance, like shiny hair, strong fingernails and healthy-looking skin.

Besides, research suggests that the more diverse we eat, the better our cognitive abilities might be at older age (see my blog on this topic here:
http://newbrainnutrition.com/four-easy-rules-for-healthy-eating-and-lifestyle/)! Well, how about that!? Research supports the notion that our gut and our brain are more closely linked than we would have assumed. This would mean that our food choices can actually have an effect on our mental health. Great, right?

So let’s have a look at a few simple tips with which you can easily enhance your dietary diversity, and can have fun along the way, too!

1. Add seeds and nuts to your meals
2. Eat a set menu
3. Grow your own fresh herbs
4. Enlarge the variety of what you drink
5. Try alternatives to your staple foods
6. Try new dishes, restaurants and cuisines
7. Join a food cooperative
8. Distribute your homemade meals across different days
9. Experiment with seasonings
10. Try smoothies and soups
11. Share your meals
And the golden rule you should keep in mind:
12. Avoid antibiotics

Add seeds and nuts to your meals
By keeping a variety of seeds and nuts at home, you can easily add them to your meals. If you tend to overeat on nuts (and believe me, many people do), make sure to buy unsalted ones, and simply sprinkle them on top of your muesli, salad or sandwich. Nuts (like peanuts, walnuts, hazelnuts) and seeds (like sesame or flaxseed) are a great source of very healthy fats, important vitamins like B-vitamins and vitamin E, and they contain fibres, which our gut simply loves!

Eat a set menu
Yes, you heard me. This is my advice to select a sequence of dishes, instead of only one.
This will definitely result in a larger variety of what you eat. Of course, you should be aware of the overall amount of food – listen to your gut feeling! And I’m serious, this also includes dessert! If you have a little soup, a colorful salad, a light main course and a small treat, you’ve supplied your body with a variety of different nutrients it needs to stay healthy. My extra tip: Keep in mind to include your ‘five a day’ to make sure you eat enough fruit and especially enough vegetables.

Grow your own fresh herbs
Do you notice that food pictures look more appealing when the food is sprinkled with fresh herbs? It will also appeal to your gut! Adding one or two fresh herbs to a dish will give it that little extra twist that it deserves. All it takes is a plant pot on your window sill. Some herbs can be harvested throughout the whole year, and for even more diversity, you can experiment with different plants as you go.

Enlarge the variety of what you drink
Tea or coffee? Both, please! When we think of nutritional diversity, let’s not only consider solid food. Imagine having your coffee and a glass of orange juice (or even a multivitamin drink) with your breakfast. How about some green or black tea as the day goes by? Or an apple spritzer? Herbal teas also offer a great range of different ingredients, and can be soothing in the evening. Just keep in mind that if you taste a few different lemonades, you well might enhance your variety of drinks, but you will consume a lot of sugar, too. The world health organization recommends that maximally 10% of your energy should come from sugar (2), which should be considered when ordering a drink.

Try alternatives to your staple foods
Are you a muesli guy? Or more of a bread person? Do you prefer pasta as your everyday dish or is your menu dominated by rice? Most of us tend to eat the same basic food items every day. But even here is the chance to enhance diversity: Instead of rice, try couscous, amaranth or millet. Buy a different type of bread every time you go to the bakery. Muesli offers a great chance of variety, you can add honey, yoghurt, marmalade, berries, spices… Talk to your friends to get more ideas.

Try new dishes, restaurants and cuisines
Every cuisine has its own flavours, specific components, and style. So why not raiding cook books and food blogs for inspiration? If you go out to eat, just be curious and pick the restaurant you always wanted to try, yet ending up at the same place you always went. This doesn’t only increase your daily diversity, but also the one across days, which is especially important: Imagine you create a super diverse menu and then eat it day after day after day… Sounds boring, right? Your gut will share this opinion! My extra tip: Choose restaurants that offer a buffet every now and then. This is specifically handy around lunchtime because you don’t have to wait for your food. Again, take a bit of everything, but be careful not to overload your plate. This gives you the chance to try out what you like when you taste a novel cuisine. And imagine the looks you get when you say “Hey, I’m doing this for my microbiome!”

Join a food cooperative
You know that homemade cooking is great. You are in charge of what goes into the pan, you control the ingredients’ quality. But, of course, it requires planning, shopping, cooking – not to forget cleaning the kitchen. An easy step towards a diverse, regular cooking habit is joining a cooperative or booking home delivery from organic farms nearby. You get a box full of seasonal, fresh, local fruit and veg delivered to your door weekly. If you know where it comes from, you might be more reluctant to throw it out, hence you might actually cook it and eat it! The surprising variety of what a season has to offer will boost your cooking creativity and enhance your nutritional diversity even further.

Some might object now and remark that when they look at the back of their ready-to-eat supermarket meals, is states that there are so many ingredients in one package, that there is no need to enhance nutritional diversity even more. Sure, there is a point there! But keep in mind that these foods are massively processed, thus having lost many of the original ingredients’ benefits like vitamins, etc. Also, if you look closely, you might detect declarations you don’t even know what they mean! Those different additives, like E-numbers, are mostly artificially produced, and there is long-term research missing what they actually do to our bodies – especially in interaction with all the other additives found in processed food. Don’t get me wrong – every now and then I also grab a bag of ready-to-eat food from the counter.
But what I personally do is to subtract the artificial ingredients from my daily diversity calculation (and now you also know that I like math).

Distribute your homemade meals across different days
This is the same approach as eating a set menu. Imagine you make yourself a nice pasta dish for the evening, and prepare a mixed salad for lunch the next day. How about splitting both in half? That way you expand your food across days, yet adding more daily eatables at the same time. Your microbiome will like the variety that goes along with this. Plus, you don’t have to buy canteen food the next day and might save some money – money that could be spent at the fancy restaurant we talked about earlier on!

And yes, distributing food across days also applies to cake and desserts. If you baked a cake (consider adding lots of fruit), have one piece now and one tomorrow! And remember to send your mum a picture of your delicious achievements, she will love it!

Experiment with seasonings
If you go through the seasonings in your kitchen cupboard, you will notice that some seasonings provide a literal boost for your nutritional diversity. I just found a curry powder with 13 ingredients! Of course, if you start and mix different seasonings, a few compounds will be redundant. But when you cook – or simply heat up a bought dish – add that little extra. That way, you can even reduce the amount of salt without giving up on flavour. The world health organization recommends 5 grams of salt per day (2). Simply use high-quality seasoning and herb mixtures instead, maybe add a drop of fine oil for flavour, and let it surprise you!

Try smoothies and soups
For a quick energy boost in the morning, I recommend a smoothie. What I love about smoothies? You can virtually throw everything in there, and by adding just a few ingredients for flavour (like oranges) and texture (like bananas) you can create a tasty and always different vitamin shot. Again, remember seasoning like curcuma or cinnamon to increase variety and diversity. For later meals, there are great recipes for soups – even some that don’t require cooking! If you blend your soup, you can easily ‘hide’ some leftovers in there, or some bits of a vegetable you don’t really like.

Share your meals
This is my favourite tip. Have you noticed that also during lunch with colleagues, the grass is always greener on the other side? In our lab, we have switched to a food sharing concept where everybody can take a bit of everyone’s meal. In some cultures, like Corea, it is common to place all the food one orders in the middle of the table. They know that sharing is caring – especially caring about one’s microbiome diversity!

And last, not least: Avoid antibiotics!
Of course, there are some illnesses where antibiotics are essential. But did you know that animals are fed large amounts of antibiotics, and that we consume them, too, when we indulge into our chicken breast or piece of veal? These antibiotics not only kill unwanted microbes, they also heavily disrupt the ecology of our microbiome (3). So in order to keep your gut happy and to get the most out of your nutritional diversity experiment, think twice before you buy or order conventionally produced meat. Consider organic meat or vegetarian alternatives – hence adding even more possibilities for a diverse menu.

(1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3577372/
(2) http://www.who.int/news-room/fact-sheets/detail/healthy-diet
(3) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4831151/

Want to learn more? Visit http://www.bbc.co.uk/guides/zpf27hv#z8qrg82 for a little quiz and some more information and https://experiencelife.com/article/your-microbiome-the-ecosystem-inside/ to find out more about your microbiome.

 

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Increasing evidence is showing that the gut microbiota can alter the brain and behavior, and thus may play a role in the development of psychiatric and neurodevelopmental disorders, such as autism and schizophrenia.

Animal models are a useful tool to study this mechanism. For example, germ-free (GF) mice, which have never been exposed to microorganisms, are compared with mice exposed to microorganisms, known as conventional colonized mice (CC). Recent studies have schizophrenia and autismreported that GF animals show increased response to stress, as well as reduced anxiety and memory. In most cases, these alterations are restricted to males, in which there are higher incidence rates of neurodevelopmental disorders compared with females.

Mice, like humans, are a social species and are used to study social behavior. A recent study compared GF and CC mice using different sociability tests. GF mice showed impairments in social behavior compared with CC mice, particularly in males. Interestingly, they demonstrate that social deficits can be reversed by bacterial colonization of  the GF gut (GFC), achieving normal social behavior.

Microbiota seem to be crucial for social behaviors, including social motivation and preference for social novelty. Microbiota also regulate repetitive behaviors, characteristic of several disorders such as autism and schizophrenia.

Bacterial colonization can change brain function and behavior, suggesting that microbial-based interventions in later life could improve social impairments and be a useful tool to effect the symptoms of these disorders.

This blog was co-authored by Noèlia Fernàndez and Judit Cabana

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‘If two people eat the same, do they also have the same poop?’

Our microbiologist, dr. Clara Belzer answered this question from Noa (age 12) on Dutch national radio and explained her research on gut-microbes and health.

“Well the answer is yes and no”, starts Clara Belzer. So it’s a great question!

Yes: feces gets to be more similar (both in looks and in smell) if you eat similar things. For instance, eating corn or red beets gives a distinct colour to poop, and eating eggs a distinct smell. So what you eat directly influences your feces.

At the same time, everyone’s excrements are unique. This is due to the unique assembly of bacteria that live in your gut. When you’re born, the first bacteria colonize your gut. During the rest of your life, this colony of bacteria and other microbes keeps developing; growing and changing in response to your diet, illnesses, stress, antibiotic treatments and other influences. The bacteria in your gut help with the digestion of the food you eat. By breaking down the food molecules they can convert these to vital substances such as vitamins and energy. The substances that are not digested, or are left over, leave the body as poop. So because every individual has a unique composition of gut-bacteria, everyone’s poop is unique.

Interestingly, genetics also influence the composition of gut-bacteria. Therefore, the feces of family members is more similar than that of non-family members, and even twins have more similar poop compared to other siblings.

But diet has the biggest influence on your gut-bacteria. If you eat healthy, your bacteria can function well and produce essential substances and energy. If you eat unhealthily, this can disturb the functioning of your gut-bacteria, and this may even contribute to developing for instance diabetes or obesity. Clara Belzer tells that we can even see from someone’s feces if this person has diabetes, or an infection in the intestines.

So studying someone’s poop can tell if the person is healthy or unhealthy. In Clara Belzer’s research she analyzes the gut-bacteria of an individual, to explore if in the future we can give advice to this person on how to adapt his or her diet to improve the assembly and functioning of the gut-bacteria. “For instance, if we can’t find certain important bacteria in someone’s feces, we want to be able to advise this person to eat whole-wheat bread. Then hopefully this stimulates the growth of this specific bacteria and makes the person feel healthier and have a better stool”, she explains.

Clara Belzer is also using mouse models to study a special bacteria, called Akkermansia muciniphila, that in the future may help in treating diabetes and losing weight. She hopes that within the next ten years this will appear as a substance that you can buy in supermarkets in order to improve your health.

You can listen to the interview (in Dutch) here: https://www.nporadio1.nl/wetenschap-techniek/13810-hebben-mensen-die-hetzelfde-eten-ook-dezelfde-poep?fbclid=IwAR1Ihrnmqcq-APOqWGIyvnBTC0ST-KGnhVeRFF2zO0epT0eGuLvbzykc1Eo

Article written by By Clara Belzer, PhD, and Jeanette Mostert, PhD.

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Real time measurements of intestinal
gases: a novel method to study how food is being digested

Researchers in Wageningen (The
Netherlands), have been able to identify for the first time, how gut microorganisms
process different types of carbohydrates by measuring in real time the intestinal
gases of mice. This is not only a novel method to understand how food is
digested but could also tell us more about the role of gut microorganisms in
gut health.

Intestinal gases

The intestinal microbiota is a diverse and
dynamic community of microorganisms which regulate our health status. The
advancement of biomolecular techniques and bioinformatics nowadays allows
researchers to explore the residents of our intestines, revealing what type of microorganisms
are there. However, studying only the microbial composition of an individual
provides limited insights on the mechanisms by which microorganisms can
interact with the rest of our body. For example, far less is understood about
the contribution of the gut microorganisms in the production of intestinal
gases such as hydrogen, methane and carbon dioxide through the breakdown of
food and how these gases affect the biochemical pathways of our bodies.

Intestinal gases consist mostly of
nitrogen, and carbon dioxide, which originate primarily from inhaled air. Hydrogen
and methane though, are produced as by-products of carbohydrate fermentation
(break down), by intestinal microorganisms. However, not all carbohydrates are
digested in the same way. For instance, food with simple sugars can be rapidly absorbed
in the small intestine unlike complex carbohydrates such as fibers, which reach
the colon where they are digested by the colonic microbiota.

Lower_digestive_system

Measuring hydrogen in mouse intestines

To study these interactions and gain
knowledge on how microorganisms process carbohydrates, the research team led by Evert van
Schothorst from the Human and Animal Physiology Group of Wageningen University
(WU) in collaboration with the WU-Laboratory of Microbiology fed mice two
different diets with the same nutritional values but with different types of carbohydrates
(1). The first diet contained amylopectin,
a carbohydrate which can be digested readily in the small intestine while the
second diet contained amylose, a slowly digestible carbohydrate that is
digested by intestinal microorganisms in the colon.

Animals fed the easily digestible carbohydrates
showed minimal production of hydrogen whereas the group fed with the complex
carbohydrates presented high levels of hydrogen. Moreover, the two groups were
characterized not only by distinct microbial composition (different types of
bacteria present) but also distinct metabolic profiles (short chain fatty acids),
suggesting that the type of carbohydrate strongly affects microbial composition
and function.

The importance of
hydrogen

Hydrogen consumption is essential in any anoxic
(without oxygen) microbial environment to maintain fermentative processes. In
the intestine it can be utilised through three major pathways for the
production of acetate, methane and hydrogen sulphide. These molecules are
critical mediators of gut homeostasis, as acetate is the most predominant short
chain fatty acid produced in mammals with evidence suggesting a role in inflammation and obesity (2). Methane, which is produced by a specific type of microorganisms,
called archaea, has been associated with constipation related diseases, such as
irritable bowel syndrome(3) and also recently with athletes’ performance (4)! Finally hydrogen sulphide
is considered to be a toxic gas, although recent findings support the notion
that it also has neuroprotective effects in neurodegenerative disorders such as
Parkinson and Alzheimer diseases (5).

To the best of our knowledge, this is the first time that food-microbiota interactions have been studied continuously, non-invasively and in real time in a mouse model. Hydrogen is a critical molecule for intestinal health and understanding its dynamics can provide valuable information about intestinal function, and deviations in conditions such as Crohn’s disease or irritable bowel syndrome (IBS).

Further reading

1. Fernández-Calleja, J.M., et al., Non-invasive continuous real-time in vivo analysis of microbial
hydrogen production shows adaptation to fermentable carbohydrates in mice.

Scientific reports, 2018. 8(1): p.
15351.

https://www.nature.com/articles/s41598-018-33619-0

2.
Perry, R.J., et al., Acetate mediates a
microbiome–brain–β-cell axis to promote metabolic syndrome.
Nature, 2016. 534(7606): p. 213

3. Triantafyllou, K., C. Chang, and M. Pimentel,
Methanogens, methane and gastrointestinal
motility.
Journal of neurogastroenterology and motility, 2014. 20(1): p. 31.

4. Petersen, L.M., et al., Community characteristics of the gut microbiomes of competitive
cyclists.
Microbiome, 2017. 5(1):
p. 98.

5. Cakmak,
Y.O., Provotella‐derived hydrogen sulfide, constipation,
and neuroprotection in Parkinson’s disease. Movement Disorders, 2015. 30(8): p.
1151-1151.

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