Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses

Abstract

Demand for organic foods is partially driven by consumers' perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences. In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods. Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95 % CI 5, 33) %, 69 (95 % CI 13, 125) %, 28 (95 % CI 12, 44) %, 26 (95 % CI 3, 48) %, 50 (95 % CI 28, 72) % and 51 (95 % CI 17, 86) % higher, respectively. Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd. Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons.

The effect of compost on growth and yield of Phaseolus vulgaris plants grown under saline soil

“…compared to inorganic crops (Baranski et al 2014). This is in accordance with our results (Table 5), which showed that plants that received the full recommended NPK fertilizer dose had Cd 2?…”

“…Cd 2? was found to bind to the organic matter existing in soil, and to rule out away from the plant roots (Baranski et al 2014). …”

Are Ready for Market Genetically Modified, Conventional and Organic Soybeans Substantially Equivalent as Food and Feed?

“…Organic crops may be more variable in phenotype than industrially produced plant products, but are in general richer in some nutritionally important elements, in antioxidant phytochemicals and lower in pesticide residues (Crinnion 2010). Another recently published meta-analysis reported that organic crops, on average, have higher concentrations of antioxidants and certain other vitamins and micronutrients, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons (Baranski et al 2014). Our data support the conclusions of these two reviews.…”

Dietary intakes and diet quality according to levels of organic food consumption by French adults: cross-sectional findings from the NutriNet-Santé Cohort Study

“…Consumers are becoming more and more demanding with regard to the quality and safety of foods, which they want to have high nutritional values and be pesticide free (10) . Organic foods are perceived as healthier because of the absence of pesticide residues (11)(12)(13)(14) and more nutritious based on growing evidence for some foodstuffs (12)(13)(14)(15)(16) , while the studies on the direct health impacts of organic foods are scant and inconsistent (17)(18)(19)(20)(21)(22)(23) .…”