The debate surrounding the nutritional and health merits of organic food versus conventionally produced food has been ongoing for years. While there’s abundant data on the nutritional composition of organic food, less is known about its direct impact on human health. A recent systematic review has aimed to bridge this knowledge gap by examining the association between organic food intake and health effects. The findings were published in the journal Nutrition Reviews.
The systematic review delved into various databases, including PubMed, EMBASE, Web of Science, the Cochrane Library, and ClinicalTrials.gov, scrutinising both observational and interventional studies conducted in human populations from inception through 13 November 2022. The analysis categorised the association between the level of organic food intake and each outcome as “no association”, “inconsistent”, “beneficial correlation/harmful correlation”, or “insufficient”. Where ample data was available, meta-analyses were conducted to deduce standardised mean differences. The findings were published in the journal Nutrition Reviews.
Ai Zhao, PhD, one of the co-authors of the study, explained: “Our findings indicate a beneficial association between an organic diet and in vivo pesticide exposure. Nevertheless, the lack of evidence for quantitative and dose-response relationships stems from the diverse range of pesticide varieties and the limited number of studies. Future trials should encompass a broader spectrum of pesticide types.”
“Presently, the majority of intervention trials concentrate on single organic foods, predominantly fruit, which may not adequately represent a diverse diet. Future studies should prioritize varied organic dietary interventions across populations with varying health statuses, yielding more practical and generalizable findings. Additionally, we advocate for increased observational studies considering reverse causation and confounding factors, as well as rational trials in the future to explore the association between organic diets and specific diseases,” Zhao noted.
A significant finding of the review was the “beneficial correlation” between organic food intake and reduced pesticide exposure. This is noteworthy given the controversy surrounding pesticide residues in food and the drive among consumers to choose organic food to avoid them. The review also explored the impact of organic food intake on physiological parameters, including immune and endocrine biomarkers, although the findings here were less clear-cut, with variations observed depending on food type, population health status, and intervention duration.
Although the evidence for an effect on each individual disease may be insufficient, the findings suggest a beneficial association between organic foods and overall disease and functional changes. The studies covered a broad spectrum of populations, from infants to the elderly, hinting at the potential benefits of an organic food diet across all ages. However, the review noted a need for further research to establish a definitive link with individual diseases beyond obesity.
“Beyond pesticide exposure, organic food intake affects in vivo biomarkers, including plasma nutrients, antioxidant status, fatty acids in human milk, and serum proteins. Despite our attempts at qualitative categorization and evaluation, the impact of organic food on plasma phenolics appears positive, while the influence on other biomarkers remains inconclusive, with no significant results in approximately half of the studies. Notably, all existing studies with significant associations consistently support the beneficial effects of organic food,” added Zhao.
The review, while comprehensive, acknowledged several limitations, including language bias and the limited number of studies available for certain outcomes. The conclusions regarding the association between organic food and disease were primarily based on observational studies, necessitating more interventional trials for a more conclusive understanding.
The review underscores the beneficial relationship between organic food intake and reduced pesticide exposure, hinting at potential positive associations with improved health outcomes and physiological changes. As awareness about the environmental impacts of food production grows among consumers, this review adds a significant layer to the discourse on organic food’s health merits, suggesting more nuanced, long-term studies are needed to elucidate the full spectrum of benefits, especially in relation to individual diseases.