Why 12 genetic markers for ADHD are exciting news for New Brain Nutrition

We are finally here: for the first time, genome-wide significant markers are identified that increase the risk for Attention Deficit / Hyperactivity Disorder (ADHD). This research was conducted by an international consortium of more than 200 experts on genetics and ADHD, and includes several researchers that are also involved in our Eat2beNICE project (the scientific basis of this New Brain Nutrition website). The findings were recently published in the prestigious journal “Nature Genetics” and will greatly advance the field of ADHD genetics research.

Why is this finding so important?

The genetics of ADHD are very complex. While ADHD is highly heritable, there are likely to be thousands of genes that contribute to the disorder. Each variant individually increases the risk by only a tiny fraction. To discover these variants, you therefore need incredibly large samples. Only then can you determine which variants are linked to ADHD. The now published study by Ditte Demontis and her team combined data from many different databases and studies, together including more than 55,000 individuals of whom over 22,000 had an ADHD diagnosis.

We can now be certain that the twelve genetic markers contribute to the risk of developing ADHD. Their influence is however very small, so these markers by themselves can’t tell if someone will have ADHD. What’s interesting for the researchers is that none of these markers were identified before in much smaller genetic studies of ADHD. So this provides many new research questions to further investigate the biological mechanisms of ADHD. For instance, several of the markers point to genes that are involved in brain development and neuronal communication.

Why are our researchers excited about this?

A second important finding from the study is that the genetic variants were not specific to ADHD, but overlapped with risk of lower education, higher risk of obesity, increased BMI, and type-2 diabetes. If genetic variants increase both your risk for mental health problems such as ADHD, and for nutrition-related problems such as obesity and type-2 diabetes, then there could be a shared biological mechanism that ties this all together.

We think that this mechanism is located in the communication between the gut and the brain. A complex combination of genetic and environmental factors influence this brain-gut communication, which leads to differences in behaviour, metabolism and (mental) health.genetic markers for adhd

The microorganisms in your gut play an important role in the interaction between your genes and outside environmental influences (such as stress, illness or your diet). Now that we know which genes are important in ADHD, we can investigate how their functioning is influenced by environmental factors. For instance, gut microorganisms can produce certain metabolites that interact with these genes.

The publication by Ditte Demontis and her co-workers is therefore not only relevant for the field of ADHD genetics, but brings us one step closer to understanding the biological factors that influence our mental health and wellbeing.

Further Reading

Demontis et al. (2018) Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder. Nature Genetics. https://www.nature.com/articles/s41588-018-0269-7

The first author of the paper, Ditte Demontis, also wrote a blog about the publication. You can read it here: https://mind-the-gap.live/2018/12/10/the-first-risk-genes-for-adhd-has-been-identified/

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Mediterranean diet could prevent depression, new study finds” [CNN]; “Mediterranean diet ‘may help prevent depression‘” [BBC]. The publication of Lassale and her colleagues in the prestigious scientific journal Molecular Psychiatry on the association between Mediterranean Diet and depression, received a lot of attention in the media last week.

So, can diet really influence your mental health? The publication of Lassale shows that there are indications that what you eat is related to how you feel. But because this study is an observational study, we can’t conclude anything yet about causation. In other words, we don’t know yet whether eating healthy causes you to feel less depressed, or whether feeling depressed causes you to eat unhealthy.

Causal links between diet and mental health

Diet and mental healthThe researchers of the European consortium Eat2beNICE are investigating exactly this causal link. The way we do this is through clinical trials. In this way, we first let chance decide whether a person receives a particular diet or is part of the control group. Through this randomization we can be sure that the differences that we find between the two groups are really due to the dietary intervention that people received, because all other factors are the same between the two groups.

Specifically for the effects of the Mediterranean diet on behaviour, in the Eat2beNICE project we are using the information and measurements available from the PREDIMED-PLUS trial. In this study, we are looking specifically for the effect of a calorie-restricted Mediterranean diet, combined with physical activity, on several behavioral outcomes related with several psychiatric diseases of adults at high cardiovascular risk.

At the same time, we are conducting three other clinical trials:

  1. In Nijmegen (The Netherlands), we investigate the effects of a very strict, hypo-allergenic diet on behavioural problems in children with ADHD.
  2. We are investigating the effects of vitamin supplements in a clinical trial that will be conducted in Mannheim(Germany) and Groningen(The Netherlands).
  3. Researchers in Barcelona (Spain) and Frankfurt (Germany) are investigating the effects of probiotics (i.e. bacteria that are good for you) on mental health in adults that are highly impulsive and/or aggressive.

Through these studies we hope to be able to identify if these types of food improve mental health and in which circumstances. This can have big implications for psychiatry, where putting someone on a specific, personalised diet may be a way to improve treatment. Also, people who are at a risk for developing mental health problems may benefit from specific diets to reduce this risk. But before this can be put into action, we first need good scientific data on what really works.

How can food drive human behaviour?

A second aim of our large research consortium is to identify the mechanisms between nutrition and the way the brain works. We think that the bacteria that live in your gut play a large role in this, as they interact with other systems in your body, including your brain. So we are collecting poop samples of the people that are participating in our clinical trials to identify which bacteria are more or less common in our participants compared to the control population. We are also measuring our participants’ behaviour and we will scan their brains. We hope that this will help us understanding better why certain types of food can be beneficial for mental health, and why some others increase the risk for mental health problems. This too will help to elucidate, and understand, the causal links between food and behaviour.

In short, we are very thankful for the study of Lassale and her colleagues, for backing up the evidence that what you eat is related to how you feel and behave. Now there’s work for us to do to prove the causal and mechanistic links. We’ll keep you posted here!

 

Authors Jeanette Mostert and Alejandro Arias-Vasquez work at the department of Genetics at the Radboud University Medical Center in Nijmegen, The Netherlands. Alejandro Arias-Vasquez is the project coordinator of the Eat2beNICE project. Jeanette Mostert is the dissemination manager.

 

Further reading

Lassale C, Batty GD, Baghdadli A, Jacka F, Sánchez-Villegas A, Kivimäki M, Akbaraly T. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Mol Psychiatry. 2018 Sep 26. doi: 10.1038/s41380-018-0237-8.

 

Blog by Jordi Salas explaining the Lassale paper and the PREDIMED trial:
http://newbrainnutrition.com/category/nutrition/mediterranean-diet/

Blog by Jolanda van der Meer on hypo-allergenic diet (TRACE study): http://newbrainnutrition.com/adhd-and-food-elimination-diet/

Blog by Julia Rucklidge on trials with vitamin supplements: http://newbrainnutrition.com/micronutrients-and-mental-health/

Blog by Judit Cabana on the Gut-Brain axis: http://newbrainnutrition.com/the-gut-brain-axis-how-the-gut-relates-to-psychiatric-disorders/

 

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This month, August 2018, I started as dissemination manager at New Brain Nutrition. This means that I will make sure that the information generated in this research project is spread out to society. Together with the dissemination and communication team of New Brain Nutrition, I strive to inform and educate as many people as possible about how nutrition influences our gut, our brain and our mental health.

Now I didn’t study communication or marketing. Rather, I studied Cognitive Neuroscience and did a PhD on brain connectivity in adults with ADHD. But while doing this PhD research, I became very interested in science communication. I organised an open day, started a blog with fellow PhD students, and participated in science battles. And through these experiences I learned that for science communication the most important ingredient is a willingness to convey your story to someone else.

The art of storytelling is thought to be as old as humanity itself. People are better at remembering and comprehending stories [1] and stories attract more attention than what’s called ‘logical-scientific communication’ [2]. However, storytelling is often viewed as unfit for sharing scientific results, because a story provides a subjective interpretation of data [3]. In a good story, only the elements that contribute to the story are told, while the ones that do not match the narrative are left out. That surely is not what we want to do in science communication!

New Brain Nutrition Research through StorytellingHowever, I do think that scientists should use the art of storytelling in their science communication to non-expert audiences. There is just too much and too complex data and information out there. If we want people to hear about our findings, and understand what they mean, we need to help them to read, comprehend and remember this information. Narratives are often the best way to do this. When telling these stories, we need to make careful decisions about the goal of our story (do you want to persuade your audience of something, or is the goal comprehension?), the level of accuracy (can you use a metaphor that is not entirely accurate, in order to accurately describe a certain process in an understandable way?) and whether or not to leave out certain facts of the story [2]. These decisions can be difficult, and we might sometimes make the wrong decisions, but overall I believe that we can all learn the art of telling good, honest stories.

At the same time, science can be much more open and transparent about the data and the findings themselves. I therefore think that open science, including open access publications and data sharing, should go hand-in-hand with storytelling in science communication. Share your story, your interpretation of the data, with the public. Take them along in your reasoning, which you have developed over the years as an expert in your field. And at the same time, share your data and your findings so that those who want to can come up with their own interpretations and conclusions.

So that’s my goal: telling you the stories of our research. As accurately as possible, without hiding information or twisting plots, but in an interesting, engaging and comprehensible way. And I hope that this will be a dialogue rather than a monologue. Tell us what you think, what your questions are, what you find difficult to believe, what you want to know more about. Then together we can build the story of New Brain Nutrition.

This blogpost was inspired by a recent article in The Guardian: https://www.theguardian.com/commentisfree/2018/jul/20/our-job-as-scientists-is-to-find-the-truth-but-we-must-also-be-storytellers

 

References:

[1] Schank, Roger C. & Abelson, Robert P. (1995) Knowledge and Memory:  The Real Story.  In: Robert S. Wyer, Jr (ed) Knowledge and Memory: The Real Story. Hillsdale, NJ. Lawrence Erlbaum Associates.  1-85. http://cogprints.org/636/1/KnowledgeMemory_SchankAbelson_d.html

[2] Dahlstrom, Michael F. (2014) Using narratives and storytelling to communicate science with nonexpert audiences. PNAS, 201320645. https://doi.org/10.1073/pnas.1320645111

[3] Katz, Yarden (2013) Against storytelling of scientific results. Nature methods, 10 (11). https://doi.org/10.1038/nmeth.2699

 

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