Hva er helseeffektene av økologisk mat?

Foto: Økologisk kasse. Aktiv I Oslo.no.
Flickr. CC-BY-NC-ND-2.0

To forskere har nå gjort en systematisk oversikt over studier på økologisk mat. Studiene de har inkludert har blant annet sett på helseeffekter som astma og atopisk eksem samt bakterielle infeksjoner (inkludert campylobacter). I tillegg har de sett på forekomst av bakterier som er resistente mot tre eller flere antibiotika og utskilling av sprøytemidler i urin.

Konklusjonen er at det er usikkert hvilke helseeffekter økologisk mat har på campylobakter infeksjoner, atopisk eksem og astma, men at de som spiser mye økologisk mat får i seg mindre sprøytemidler (skiller ut mindre sprøytemidler i urinen) og har lavere forekomst av bakterier resistente mot antibiotika. Det er hittil ikke gjort studier som gir mulighet til å studere helseeffekten over lengre sikt. Det er derfor mulig at lengre oppfølging eller andre utfallsmål ville vist forskjeller. Det ble funnet rester av sprøytemidler i 38% av ikke-økologisk mat mens dette ble funnet i kun 7% av økologiske produkter. Ut fra studiene så det ikke ut til å være større forskjeller i innholdet av næringsstoffer med unntak av noe høyere/gunstigere nivå av fosfor i økologisk mat. Økologisk mat inneholdt mindre av tungmetallet kadmium og mycotoxinet deoxynivalenol. Disse faktorene kan ha gunstig effekt på andre helseforhold, men det har ennå ikke blitt godt nok studert.

Les mer på http://www.ncbi.nlm.nih.gov/pubmed/22944875

Are organic foods safer or healthier than conventional alternatives?: a systematic review.
Smith-Spangler C, Brandeau ML, Hunter GE, Bavinger JC, Pearson M, Eschbach PJ, Sundaram V, Liu H, Schirmer P, Stave C, Olkin I, Bravata DM.  Stanford Center for Health Policy and Center for Primary Care and Outcomes Research, 117 Encina Commons, Stanford University, Stanford, CA 94305-6019, USA.
Ann Intern Med. 2012 Sep 4;157(5):348-66. doi: 10.7326/0003-4819-157-5-201209040-00007.

Background: The health benefits of organic foods are unclear.

Purpose: To review evidence comparing the health effects of organic and conventional foods.

Data Sources: MEDLINE (January 1966 to May 2011), EMBASE, CAB Direct, Agricola, TOXNET, Cochrane Library (January 1966 to May 2009), and bibliographies of retrieved articles.

Study Selection: English-language reports of comparisons of organically and conventionally grown food or of populations consuming these foods.

Data Extraction: 2 independent investigators extracted data on methods, health outcomes, and nutrient and contaminant levels.

Data Synthesis: 17 studies in humans and 223 studies of nutrient and contaminant levels in foods met inclusion criteria. Only 3 of the human studies examined clinical outcomes, finding no significant differences between populations by food type for allergic outcomes (eczema, wheeze, atopic sensitization) or symptomatic Campylobacter infection. Two studies reported significantly lower urinary pesticide levels among children consuming organic versus conventional diets, but studies of biomarker and nutrient levels in serum, urine, breast milk, and semen in adults did not identify clinically meaningful differences. All estimates of differences in nutrient and contaminant levels in foods were highly heterogeneous except for the estimate for phosphorus; phosphorus levels were significantly higher than in conventional produce, although this difference is not clinically significant. The risk for contamination with detectable pesticide residues was lower among organic than conventional produce (risk difference, 30% [CI,
37% to
23%]), but differences in risk for exceeding maximum allowed limits were small. Escherichia coli contamination risk did not differ between organic and conventional produce. Bacterial contamination of retail chicken and pork was common but unrelated to farming method. However, the risk for isolating bacteria resistant to 3 or more antibiotics was higher in conventional than in organic chicken and pork (risk difference, 33% [CI, 21% to 45%]).

Limitation: Studies were heterogeneous and limited in number, and publication bias may be present.

Conclusion: The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.

Primary Funding Source: None.