Stick out your tongue

‘Stick Out Your Tongue’ (‘Saca la Lengua’) is a citizen’s science project that aims to study the mouth’s microbiome and its possible relationship with our environmental characteristics and lifestyle.

Recent scientific studies have highlighted the importance of the set of micro-organisms that live in our bodies, our “human microbiome”, in determining both health and illnesses. In reality, we have more bacteria cells in our bodies than human cells. It is logical that these microorganisms have an enormous influence on us, ranging from protecting us from certain illnesses, helping our digestion, causing diseases (either directly or indirectly), and determining our preferences, such as taste. Scientists are now beginning to look into this and in fact have already developed therapies involving transplanting a “healthy” faecal microbiome into patients to treat intestinal infections.

Stick Out Your Tongue runned two different editions.

During the first running (2015-2016) we contacted 41 schools, familiarizing the educational community with the world of research and the microbiome. We traveled more than 7,000 km through different urban and rural areas and took over 1,500 samples from the mouths of 14-15 year-old students in good health. At the tird phase of the Project we organize with schools, universities and the general public a contest to analyse the data. We proposed different challenges at different levels, in statistics, data visualization and bioinformatics.

In the second running (2017-2019), we start with a clear picture of the oral microbiome’s diversity in healthy teens. Now the goal is to compare it with the microbiome of the same teens 2 years later, that of their family, other adults and vulnerable population groups such as individuals with Down syndrome, cystic fibrosis, anorexia, and celiac disease.

Citizen science projects are participatory project that allows scientists to work side-by-side with members of society. This project has involved the public at all three of its levels:

  1. During the first phase, we collected through this website suggestions from citizens on new variables to incorporate into the initial hypothesis of the scientific project. They came up with new ideas that the scientists had not thought of.
  2. In the second phase, researchers met with citizens to introduce them to the world of microbiome research and collect saliva samples. Citizens also filled in a questionnaire about their lifestyle habits.
  3. In the third phase, citizens were able to give their opinion on which samples should be analysed first, by voting.

Between 2018 and 2019, a card game has been developed, based on the results obtained in the research and with the aim of sharing some of the conclusions of the study.
The result is a cooperative, inclusive and educational game, for players over 10 years old, that can be played with family, friends or at school. The game is free and you can download the English version here:

PDF -> Playing DYS Guidelines
PDF -> Playing Cards FRONT
PDF -> Playing Cards BACK
PDF -> Rules of the game

Print the cards, buy some game dice and chips and play !

The project resulted in several research papers, some of them currently under review. All participants received a snapshot of their microbiome composition and a brief outline of the project’s general results.

– Citizen science charts two major “stomatotypes” in the oral microbiome of adolescents and reveals links with habits and drinking water composition. Microbiome (2018) 6:218

– Oral microbiome in down syndrome and its implications on oral health. Journal of Oral Microbiology, Volume 13, 2021

– Citizen-science based study of the oral microbiome in Cystic fibrosis and matched controls reveals major differences in diversity and abundance of bacterial and fungal species. Journal of Oral Microbiology Volume 13, 2021

– Citizen-science reveals changes in the oral microbiome in Spain through age and lifestyle factors. npj biofilms and microbiomes May 2022


More details of the project (results included) in the spanish version.

The ‘Saca la Lengua’ project is an initiative of the Centre for Genomic Regulation and the “la Caixa” Foundation, with the participation of the Centre for Research into Environmental Epidemiology (CREAL), the support of the ‘Centre d’Excel•lència Severo Ochoa 2013-2017′ programme (SEV-2012-02-08) of the Ministry of Economy and Competitiveness, and contributions by the companies Illumina and Eppendorf.