Analyzing the Spanish microbiome “map” for the first time


In collaboration with CAPSA Food, a leading group of companies in the dairy sector, and the Complutense University of Madrid, DARWIN has carried out the “Spanish Microbiome Project“, the first systematic effort to characterize the gut microbiome of healthy Spaniards. In addition to finding connections between key microbes and the Mediterranean diet, a reference dataset for future health and nutrition studies in the Spanish population is generated.


The ‘Spanish Microbiome Project’ was designed in 2018 and a year later, in 2019, it was approved by the Clinical Research Ethics Committee (CEIC) of the Hospital Universitario Clínico San Carlos de Madrid. Since then, and for two years, the process of recruiting volunteers and analyzing samples has been carried out, overcoming the obstacles of the pandemic. The study worked with samples contributing around 70 million data points.


Project’s trial included fecal samples from healthy citizens aged 18 to 70: 533 voluntary participants selected based on official demographic data from the National Statistics Institute (INE) to represent the Spanish population in terms of age, sex, and geography. The anonymous samples were processed at the facilities of Darwin Bioprospecting Excellence (Valencia), following the International Human Microbiome Standards (IHMS).


DARWIN was responsible for conducting all the analyses, from DNA extraction from the samples to bioinformatic and statistical analysis of the data, including the study design.




The term gut microbiome refers to the microorganisms living in the intestines. People can have more than 1,000 different species of bacteria, viruses, and fungi in their digestive tract. Some microorganisms are harmful to our health, but many are incredibly beneficial and even necessary for a healthy body.


Having greater knowledge about the composition of the gut microbial community is essential to understanding and acting on people’s nutrition and its impact on their health. However, to date, there have only been four gut microbiome studies in Europe involving healthy people: from the United Kingdom, Germany, the Netherlands, and Belgium, none of which are traditionally associated with the Mediterranean diet.




From the fecal samples, total metagenomic DNA was extracted, and microbial profiles were determined by metataxonomic sequencing of 16S rRNA. The results confirm the variability of the gut microbiome based on variables such as sex, age, or body mass index (BMI), in addition to providing new insights into the relationship between the microbiome and diet in the Spanish population. It is noted that a loss of bifidobacteria (beneficial bacteria) is related to age, which favors an increase in the total diversity of bacteria.


This study, conducted in Spain, is the first to be carried out in a Mediterranean country and yields significant conclusions about the Mediterranean diet. Additionally, the research confirms that changes in eating habits have an effect on the gut microbiome. The implications of the research will allow, in the future, the determination of whether a pathology has an effect on the gut microbiome (or vice versa) and the comparison of the microbial composition of those affected by such pathology.


Completion Year: 2021




The results of this study represent a significant step in understanding the role of each individual’s microbiota in aspects such as nutrient processing, vitamin production, or the presence of antibiotic resistance genes. The project will pave the way for the development of Precision Medicine and Nutrition, to individualize medical and nutritional interventions.


Among the main conclusions, it has been observed that a higher consumption of dairy products is associated with a greater presence of beneficial bacteria, such as Streptococcus or Bifidobacterium genera. The study also detects the connection between the consumption of fruits, vegetables, and nuts and the decrease in the abundance of genera associated with health problems, such as Flavonifractor, which in turn increase with the consumption of sugary drinks.


After analyzing eating habits, it is also discovered that men consume more foods that could be considered less healthy (beer, distilled alcohol, or sugar-sweetened drinks). A similar pattern is observed when comparing ages: young people tend to have eating habits that could be considered less healthy, such as lower consumption of citrus fruits or salads and higher consumption of soft drinks or chips.




  • Latorre-Pérez, A., Hernández, M., Iglesias, J.R. et al. The Spanish gut microbiome reveals links between microorganisms and Mediterranean dietSci Rep 11, 21602 (2021).