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Biodiversiteit goed voor de gezondheid*
Volgens een kleine Finse studie is de afnemende biodiversiteit in de wereld nadelig voor de menselijke gezondheid. In de studie werd van 118 tieners uit verschillende regio’s in Finland hun omgeving, de diversiteit en aantal bacteriën op hun huid en hun gevoeligheid voor allergieën vastgesteld. Bekend is dat een diverse bacterieflora goed is voor het immuunsysteem tegen bijvoorbeeld allergieën. Uit de studie bleek dat zij die in een erg biodiverse gebied wonen, meer verschillende bacteriën op hun huid hadden en ook een lagere gevoeligheid voor allergenen lieten zien dan de tieners wonend in een minder biodivers gebied, bijvoorbeeld de stad.
Environmental biodiversity, human microbiota, and allergy are interrelated
1. Ilkka Hanskia,1, 2. Leena von Hertzenb, 3. Nanna Fyhrquistc, 4. Kaisa Koskinend, 5. Kaisa Torppaa, 6. Tiina Laatikainene, 7. Piia Karisolac, 8. Petri Auvinend, 9. Lars Paulind, 10. Mika J. Mäkeläb, 11. Erkki Vartiainene, 12. Timo U. Kosunenf, 13. Harri Aleniusc, and 
14. Tari Haahtelab,1
+ Author Affiliations
1. aDepartment of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland; 
2. bSkin and Allergy Hospital, Helsinki University Central Hospital, FI-00029 Helsinki, Finland; 
3. cFinnish Institute of Occupational Health, FI-00250 Helsinki, Finland; 
4. dInstitute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland; 
5. eNational Institute for Health and Welfare, FI-00271 Helsinki, Finland; and 
6. fDepartment of Bacteriology and Immunology, Haartman Institute, University of Helsinki, FI-00014 Helsinki, Finland 
Abstract
Rapidly declining biodiversity may be a contributing factor to another global megatrend—the rapidly increasing prevalence of allergies and other chronic inflammatory diseases among urban populations worldwide. According to the “biodiversity hypothesis,” reduced contact of people with natural environmental features and biodiversity may adversely affect the human commensal microbiota and its immunomodulatory capacity. Analyzing atopic sensitization (i.e., allergic disposition) in a random sample of adolescents living in a heterogeneous region of 100 × 150 km, we show that environmental biodiversity in the surroundings of the study subjects’ homes influenced the composition of the bacterial classes on their skin. Compared with healthy individuals, atopic individuals had lower environmental biodiversity in the surroundings of their homes and significantly lower generic diversity of gammaproteobacteria on their skin. The functional role of the Gram-negative gammaproteobacteria is supported by in vitro measurements of expression of IL-10, a key anti-inflammatory cytokine in immunologic tolerance, in peripheral blood mononuclear cells. In healthy, but not in atopic, individuals, IL-10 expression was positively correlated with the abundance of the gammaproteobacterial genus Acinetobacter on the skin. These results raise fundamental questions about the consequences of biodiversity loss for both allergic conditions and public health in general. 
Footnotes
· ↵1To whom correspondence may be addressed. E-mail: ilkka.hanski@helsinki.fi or tari.haahtela@hus.fi. 
· Author contributions: I.H., L.v.H., M.J.M., E.V., T.U.K., and T.H. designed research; N.F., K.K., K.T., P.A., and L.P. performed research; N.F., K.K., and H.A. contributed new reagents/analytic tools; T.L. contributed data on allergies; I.H., K.K., T.L., P.K., P.A., and L.P. analyzed data; and I.H., L.v.H., and T.H. wrote the paper. 
· The authors declare no conflict of interest.
· Data deposition: The sequences reported in this paper have been deposited in the Sequence Read Archive at the European Bioinformatics Institute (accession no. ERP001059). 
De volledige studie. (Mei 2012)