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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Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopment disorder characterized by inattention or hyperactivity–impulsivity, or both. It might seem paradoxical, but many studies indicate that individuals with a diagnosis of ADHD suffer from overweight and obesity. Therefore, it is important to understand the underlying mechanism that put individuals with ADHD at risk for obesity.

 Evidence from within-individual study
A systematic review and meta-analysis (1) based on 728,136 individuals from 42 studies, suggested a significant association between ADHD and obesity both in children/adolescents and adults. The pooled prevalence of obesity was increased by about 70% in adults with ADHD and 40% in children with ADHD compared with individuals without ADHD. However, due to the lack of longitudinal and genetically-informative studies, the meta-analysis was unable to explain the exact direction of association and the underlying etiologic mechanisms. There are several potential explanations:

  • ADHD causing obesity: The impulsivity and inattention components of ADHD might lead to disordered eating patterns and poor planning lifestyles, and further caused weight gain.
  • Obesity causing ADHD: Factors associated with obesity, for example dietary intake, might lead to ADHD-like symptoms through the microbiota-gut-brain axis.
  • ADHD and obesity may share etiological factors: ADHD and obesity may share dopaminergic dysfunctions underpinning reward deficiency processing. So the same biological mechanism may lead to both ADHD and obesity. This is difficult to investigate within individuals, but family studies can help to test this hypothesis.

We will further investigate these possibilities in the Eat2beNICE research project by using both perspective cohort study and twin studies.

Evidence from a recent within-family study
Recently, a population-based familial co-aggregation study in Sweden (2) was conducted to explore the role of shared familial risk factors (e.g. genetic variants, family disease history) in the association between ADHD and obesity. They identified 523,237 full siblings born during 1973–2002 for the 472,735 index males in Sweden, and followed them until December 3, 2009. The results suggest that having a sibling with overweight/obesity is a risk factor for ADHD. This makes it likely that biological factors (that are shared between family members) increase the risk for both ADHD and obesity.

Evidence from across-generation study
Given that both ADHD and obesity are highly heritable complex conditions, across-generation studies may also advance the understanding of the link between ADHD and obesity.

A population-based cohort study (3) based on a Swedish nationwide sample of 673,632individuals born during 1992-2004, was performed to explore the association between maternal pre-pregnancy obesity and risk of ADHD in offspring. The sibling-comparison study design was used to test the role of shared familial factors for the potential association. The results suggest that the association between maternal pre-pregnancy obesity and risk of ADHD in offspring might be largely explained by shared familial factors, for example, genetic factors transmitted from mother to child that contribute to both maternal pre-pregnancy obesity and ADHD.

Together, based on previous evidence from various study designs, there is evidence to suggest that the association between ADHD and obesity mainly is caused by shared etiological factors. However, future studies on different population are still needed to further test these findings.

REFERENCES:
1. Cortese S, Moreira-Maia CR, St Fleur D, Morcillo-Penalver C, Rohde LA, Faraone SV. Association Between ADHD and Obesity: A Systematic Review and Meta-Analysis. The American journal of psychiatry. 2016;173(1):34-43.

2. Chen Q, Kuja-Halkola R, Sjolander A, Serlachius E, Cortese S, Faraone SV, et al. Shared familial risk factors between attention-deficit/hyperactivity disorder and overweight/obesity – a population-based familial coaggregation study in Sweden. J Child Psychol Psychiatry. 2017;58(6):711-8.

3. Chen Q, Sjolander A, Langstrom N, Rodriguez A, Serlachius E, D’Onofrio BM, et al. Maternal pre-pregnancy body mass index and offspring attention deficit hyperactivity disorder: a population-based cohort study using a sibling-comparison design. Int J Epidemiol. 2014;43(1):83-90.

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ADHD and Exercise

ADHD is among the most common psychiatric disorders, with ~3% prevalence in adulthood and ~5% in childhood. ADHD has a high risk for comorbid conditions. Comorbid means that one psychiatric disorder often comes together with another psychiatric disorder. For instance mood, anxiety and substance use disorders have high comorbid rates in adults with ADHD.

Adults with ADHD are also at risk for obesity and major depressive disorders and adolescent ADHD predicts adult obesity: 40% of adults with ADHD are also obese. These are worrying numbers. Many adults who have ADHD suffer from these negative consequences that come with their mental illness.

There is a growing body of scientific evidence of the powerful effects of nutrition and lifestyle on mental health. Exercise is one of them.It helps prevent or manage a wide range of health problems and concerns, including stroke, obesity, metabolic syndrome, type 2 diabetes, depression, a number of types of cancer and arthritis. Besides that, regular exercise can help you sleep better, reduce stress, sharpen your mental functioning, and improve your sex life. Nearly all studies revolve around aerobic exercise which includes walking, jogging, swimming, and cycling.

Recent research shows that exercise might also have a positive effect on ADHD symptoms such as improving attention and cognition1,2 Additional research is needed to explore this effect further, but we can take a look at the mechanisms underlying this effect.

One of the parts in our brain that is affected by exercise is the prefrontal cortex. The prefrontal cortex plays an important role in controlling impulsive behavior and attention, and is positively influenced by exercise. Furthermore, dopamine and norepinephrine play an important role in attention regulation. Ritalin, among one of the most well-known medication for ADHD, also increases levels of dopamine.

When you exercise regularly, the basis levels of dopamine and norepinephrine rise, and even new dopamine receptors are created. These dopamine levels are also the reason why exercise therapy can be effective for people suffering from depression: low levels of dopamine are a predictor of depressive symptoms.

Taken together: people with ADHD are at risk for obesity and depression. Exercise has a positive influence on obesity, depression and ADHD. Wouldn’t it be great if we could treat people with ADHD with an exercise therapy?

The PROUD-study is currently studying the prevention of depressive symptoms, obesity and the improvement of general health in adolescents and young-adults with ADHD. PROUD establishes feasibility and effect sizes of two kinds of interventions: an aerobic exercise therapy and the effects of a bright light therapy.

Exercise and ADHDParticipants follow a 10 week exercise intervention in which they train three days a week: one day of only aerobic activities (20-40 min) and in two of these days, muscle-strengthening and aerobic activities (35 – 60 min). An app guides them through the exercises, and the intensity and duration of these exercises increase gradually. During a 24 week course changes in mood, condition, ADHD symptoms and body composition are measured.

I am really looking forward to the results of the effectiveness of this intervention in adolescents and adults with ADHD. It is great that this study tries to alter a lifestyle instead of temporarily symptom-reducing options. A healthy life is a happy life!

For more information about the PROUD-study see www.adhd-beweging-lichttherapie.nl (only in Dutch) or contact the researchers via proud@karakter.com. For more information about a healthy lifestyle and the positive effects on mental health, see our other blogs at https://newbrainnutrition.com/

 

References

  1. Kamp CF, Sperlich B, Holmberg HC (2014). Exercise reduces the symptoms of attention-deficit/hyperactivity disorder and improves social behaviour, motor skills, strength and neuropsychological parameters. Acta Paediatrica, 103, 709-714.

 

  1. Choi JW, Han DH, Kang KD, Jung HY, Renshaw, PF (2015). Aerobic exercise and attention deficit hyperactivity disorder: brain research. Med Sci Sports Exerc, 47, 33-39.
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What is inflammation?

Inflammation is the response of the body’s immune system against external factors that can put your health in danger. When this system feels it is attacked by something that may harm your health, it activates some molecules that are called cytokines in order to neutralize or avoid any damage so you can be safe.

Why is inflammation bad? What does it do?

Inflammation isn’t bad by itself, since its purpose is to protect our body. In some cases however, when the duration of this response is extended for too long- I’m talking about years- it can cause harmful effects to your health. Especially, it can affect the brain by active transport of cytokines throughout this organ.

Neuro-inflammation may occur if this process continues past early stages. Neuro-inflammation plays an important role in the development of mental diseases such as attention-deficit/hyperactivity disorder (ADHD), autism, schizophrenia, depression, anxiety, bipolar disorder (BD), and obsessive-compulsive disorder (OCD), where elevated levels of inflammation have been found(1).

What causes inflammation? 

Inflammation can occur by different factors. Some of them could be: pathogens, injuries, chronic stress, and diseases like dermatitis, cystitis or bronchitis to mention a few.

Nutritional factors like overweight and poor diet quality can also trigger this process by increasing fat accumulation in our cells and damaging them (2). The exact mechanisms that are involved in these processes are still in research.

What decreases inflammation?

Research has found that adhering to a healthy diet, like the Mediterranean diet, characterized by high intake of fruit, vegetables, whole grains, fish, lean meats and nuts, can decrease inflammation and protect you against depressive symptoms and anxiety (3,4).

There is evidence that prebiotics, probiotics and synbiotics (a combination of prebiotics and probiotics) can also help lowering inflammation. In addition, you should avoid eating pro-inflammatory foods that have been found to increase the risk of inflammation, and with it mental disorders. Some of these are refined carbohydrates, beverages with a lot of sugar added like soda, juice and sports drinks, processed meat and foods high in saturated fats (5).

What are anti-inflammatory foods

Anti-inflammatory foods are the contrast of pro-inflammatory foods. These are foods that have been found to promote or induce low levels of inflammation in our body, which may protect us against neurological disorders. Briefly, these foods include fruits, vegetables, olive oil, fish and spices like curcuma (turmeric).

Here’s what YOU can do to minimize inflammation and improve your mental health.

Inflammation and Foods

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.

Sources

  1. Mitchell RHB, Goldstein BI. Inflammation in children and adolescents with neuropsychiatric disorders: A systematic review. J Am Acad Child Adolesc Psychiatry [Internet]. Elsevier Inc; 2014;53(3):274–96. Available from: http://dx.doi.org/10.1016/j.jaac.2013.11.013
  2. Ogłodek EA, Just MJ. The Association between Inflammatory Markers (iNOS, HO-1, IL-33, MIP-1β) and Depression with and without Posttraumatic Stress Disorder. Pharmacol Reports [Internet]. 2018;70:1065–72. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1734114017305923
  3. Lassale C, Batty GD, Baghdadli A, Jacka F, Sánchez-Villegas A, Kivimäki M, et al. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Mol Psychiatry [Internet]. Springer US; 2018;1. Available from: http://www.nature.com/articles/s41380-018-0237-8
  4. Phillips CM, Shivappa N, Hébert JR, Perry IJ. Dietary inflammatory index and mental health: A cross-sectional analysis of the relationship with depressive symptoms, anxiety and well-being in adults. Clin Nutr. 2017;37.
  5. Shivappa N, Bonaccio M, Hebert JR, Di Castelnuovo A, Costanzo S, Ruggiero E, et al. Association of proinflammatory diet with low-grade inflammation: results from the Moli-sani study. Nutrition. 2018;54:182–8.

 

 

 

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How many total food-and beverage-related decisions do you make in one day? Have a guess!

You reckon more than 15 decisions per day?! Congratulations! You are closer than the average (14.4) of 139 participants who were asked exactly the same question in a study by Wansink and Sobal (2007). However, you might still be far off. Let’s have a closer look at the study.

Being aware of the impact nutrition has on our physical and mental health as well as brain functioning, you might expect people to make well-considered food decisions. Wansink and Sobal (2007) aimed to answer the two following questions:

Are we aware of how many food-related decisions we make?

The results are clear, indicating a large degree of unawareness regarding the number of daily food decisions. The participants underestimated the number of food-and beverage-related decisions in a day by more than 200 decisions. We make an estimated 226.7 food decisions each day. Were you close? The authors conclude that we often engage in mindless eating which results in a lack of control of our food intake. There is a need to increase the awareness of the decisions we make regarding what, when and how much we eat to promote a healthy lifestyle.

These findings raise the question which factors determine our food decisions if we don’t. One potential factor that should be considered is our environment which was addressed in the second question of the study.

Food Choices cartoonAre we aware of the environmental cues that lead us to overeat?

To shed light on the second question the authors analysed data from four studies in which participants were either assigned to the control condition or a so-called exaggerated treatment condition. Environmental factors such as package size, serving bowl and plate size differed for the two conditions. In each study participants in the treatment condition served/prepared/consumed more food than the control group (between 29 and 53 % more). Afterwards the 192 participants of the treatment group were asked “How much did you eat compared to what is typical for you?” Across all four studies 19 % said “less” and 73 % “about the same” as normally. Just 8 % were aware that they consumed more. Afterwards they were informed about the environmental cues and asked a second question: “In this study, you were in a group that was given [a larger bowl]. Those people in your group ate an average of 20%-50% more than those who were instead given [a smaller bowl]. Why do you think you might have eaten more?” Interestingly, 21 % still claimed they did not eat more. 69 % justified the greater food intake with being hungry and 6 % with other reasons. Just 4 % admitted that the environmental cues influenced them.

These findings highlight the unawareness or denial of the influence our environment has on us and our food intake. However, they can be used as a starting point to improve our nutrition. Changing your immediate environment to make it less conducive to overeating can help you improve your health. Start with putting the sweets just a bit further away from you.

Further information on how to make your environment less conducive to overeating you can find in the book “Slim by Design: Mindless Eating Solutions for Everyday Life” by Brian Wansink (https://www.slimbydesign.com/book)

You can also visit Brian Wansink’s website where you find more cartoons – like the one above -amongst other things: http://mindlesseating.org/index.php

Wansink, B., & Sobal, J. (2007). Mindless eating: The 200 daily food decisions we overlook.

Environment and Behavior, 39(1), 106-123.

http://journals.sagepub.com/doi/abs/10.1177/0013916506295573

 

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Food is addictive. It has been an addiction that has kept mankind alive for thousands of years. Today, hunger is no longer a problem in the developed world; it is quite the opposite. According to the World Health Organization, worldwide obesity has nearly tripled since 1975. Obesity has reached epidemic proportions globally, with at least 2.8 million people dying each year as a result of being overweight or obese.

In order to maximize the nutritional value, humans are hard-wired to prefer foods that have either a high sugar or fat content. The amount of energy obtained from food is measured in kilocalories (kcal) per gram. Fats have the most energy (9 kcal) and carbohydrates (sugars and starches) have the same amount of energy as proteins (4 kcal). However, these nutrients differ in how quickly they supply energy. Sugars and starches have the advantage of being converted into energy faster than fats and protein. Protein is preferentially used for building and repairing different tissues, not as an energy source.

Once a beneficial adaptation of preferring fast digesting or the most energy-rich nutrients, has now become a risk factor for both physical and also mental health (1), making it an inevitable research focus.

In a recent study at the Yale University School of Medicine (2) it was determined that people not only favour fatty or sugary foods, but place the highest value on those that combine both. Participants (tasked to make monetary bids on different food items) were ready to pay the most for cookies, chocolate, cake and other treats that had both high sugar and also fat content. Equally familiar, liked and caloric fatty (e.g., cheese, salami) or sugary foods (e.g., lollipops) were assigned lower values.

Based on surges of activity, brain scans revealed that foods high in both fat and sugar were more rewarding than foods rich in only one category of nutrient.

Unexpectedly, it was also observed that participants were very accurate at estimating the energy density (kcal) of fatty foods, but poor at estimating the energy density of sugar-containing foods.

Once rare, but nowadays common and abundant treats high in both fat and sugar are most rewarding and therefore can very likely contribute to overeating. In addition, it has turned out to be difficult for people to assess the amount of calories in foods with a high sugar content. These findings taken together can help to understand and also hopefully find new treatment options for people struggling with obesity.

  • Hoare E et al (2015) Systematic review of mental health and well-being outcomes following community-based obesity prevention interventions among adolescents. BMJ Open 2015;5:e006586. doi:10.1136/bmjopen-2014-006586
  • DiFeliceantonio et al (2018) Supra-additive effects of combining fat and carbohydrate on food reward. Cell Metabolism 28, 1–12. doi:10.1016/j.cmet.2018.05.018
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