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Clinical Research

Presence and significance of intestinal unicellular parasites in a morbidly obese population

International Journal of Obesity volume 46, pages 220–227 (2022)Cite this article

Subjects

Abstract

Background

Obesity is a chronic disease whose pathogenesis has been related to changes in the intestinal microbiota. Yet, the role of protozoa and other unicellular eukaryotic parasites in this microenvironment is still largely unknown. Their presence within the gut ecosystem in obese subjects warrants further study, as well as their influence on the host metabolism and comorbidities.

Methods

Herein, a single center, cross-sectional study of 104 obese individuals was performed to assess the presence of six intestinal unicellular parasites in stool using a commercially available kit, and to evaluate its relationship with the presence of abdominal symptoms, metabolic comorbidities, variations in body composition and nutritional deficiencies.

Results

The overall parasitic colonization rate was 51%, with Blastocystis sp., identified as the most frequent (44.2%), followed by Dientamoeba fragilis (11.5%) and Giardia intestinalis (8.7%), and significantly related to the consumption of ecological fruits and vegetables. Contrary to what previous studies pointed out, colonization with parasites species was significantly associated with fewer abdominal symptoms and depositions per day. The presence of parasites did not correlate with any nutritional deficiencies nor differences in body composition, while it did with significant lower HOMA-IR levels and a lower trend towards metabolic syndrome.

Conclusion

Obese subjects frequently harbor unicellular enteric parasites, apparently without clinical nor nutritional harm. This evidence suggests that carrying these microorganisms, from an endocrinological perspective, has a beneficial effect, especially on insulin resistance and possibly on the development of related comorbidities.

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Fig. 1: Comorbidities clustered by colonization status and parasitic species.
Fig. 2: Hepatic ultrasonography results clustered by colonization status and parasitic species.

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Acknowledgements

This work was partially supported by a grant from Menarini Spain, SA. The funding enabled the study design, data collection, analysis and interpretation.

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Authors and Affiliations

  1. Department of Endocrinology and Nutrition, University and Polytechnic Hospital La Fe, Valencia, Spain

    J. Caudet & J. F. Merino-Torres

  2. Joint Research Unit on Endocrinology, Nutrition and Clinical Dietetics, University of Valencia-Health Research Institute La Fe, Valencia, Spain

    J. Caudet, M. Trelis, S. Cifre, J. M. Soriano & J. F. Merino-Torres

  3. Parasite & Health Research Group, Department of Pharmacy, Pharmaceutical Technology and Parasitology, University of Valencia, Valencia, Spain

    M. Trelis

  4. Food & Health Lab, Institute of Materials Science, University of Valencia, Valencia, Spain

    J. M. Soriano

  5. Department of Medicine, Faculty of Medicine, University of Valencia, Valencia, Spain

    J. F. Merino-Torres

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  1. J. Caudet
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Contributions

Conceptualization: JFM-T and MT; Methodology: JFM-T, JMS and MT; Formal analysis: JC and MT; Investigation: JC, SC and MT; data curation: JC and SC.; Writing-original draft preparation: JC and MT; Writing-review and editing: JC, JFM-T, JMS and MT; Project administration, JFM-T and MT.

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Correspondence to M. Trelis.

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Caudet, J., Trelis, M., Cifre, S. et al. Presence and significance of intestinal unicellular parasites in a morbidly obese population. Int J Obes 46, 220–227 (2022). https://doi.org/10.1038/s41366-021-00980-6

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