The authors tested 13 pairs of strawberries and the soil they were grown in from neighboring farms over a two year period and found that the organic strawberries had higher levels of vitamin C and antioxidants and did not rot as quickly as the conventionally grown ones.
The findings are likely to add fuel to the ongoing debate about the relative nutritional quality of organic and conventional foods in general.
“While there is strong evidence that organic foods have significantly less pesticide residues, this is not the case for organic foods being more nutritious,” the authors wrote.
“Although there is no universally accepted definition of what constitutes a nutritious food, recent scientific opinion has stressed that more nutritious foods are those that are more nutrient dense relative to their energy contents.”
The researchers note that over the past ten years there have been ten reviews of the scientific literature comparing the nutritional value of organic or non-organic foods. Eight of the ten have found some evidence that organic foods are more nutritious, while the other two have found no evidence of nutritional difference.
However, the researchers behind this latest study examined both fruit quality and soil quality and found that organic strawberries had 8.5 percent more total antioxidant activity, 9.7 percent more ascorbic acid, and 10.5 percent more total phenolics than conventional berries. Nevertheless, they had 13.6 percent less phosphorus and 9.1 percent less potassium. In terms of the soil quality, the organic soil was found to be superior in terms of total carbon and nitrogen, as well as overall enzymatic activity.
The authors concluded: “Our findings show that the organic strawberry farms produced higher quality fruit and that their higher quality soils may have greater microbial functional capability and resilience to stress.”
However they cautioned that there need to be further investigations to detect and quantify these effects and their interactions.
The full study is available online here.