There is strong evidence for health benefits from whole-grain wheat consumption and these have been linked to their higher fibre, antioxidant/(poly)phenolic and mineral contents. However, there is still scientific controversy about the relative effect of wheat species (Triticum aestivum vs T. spelta) and production methods (conventional vs organic) on the nutritional composition of wheat. The retail survey reported here showed that, the use of spelt varieties and organic production results in significantly higher (between 10 and 64%) levels of phenolics and some minerals in wheat flour. However, the relative effect of removing the outer bran and germ during milling was substantially larger; levels of antioxidant activity, and many phenolic compounds and mineral nutrients were 2-5 times higher in whole-grain than white flour. Organic flour contained higher concentrations of the undesirable metals Al and Ni (12% and 81% respectively), and spelt flour had 28% higher concentrations of the toxic metal Cd.

The environmental and biodiversity benefits of organic farming are widely recognized, but there is still controversy about the effects of organic production methods on the nutritional composition of food and human health. In the first part of this article therefore, we critically review the evidence that organic farming methods improve the nutritional quality of food crops. Moreover, we summarize our current understanding of how quality gains are linked to the implementation of the “innovations” introduced into conventional crop production during the intensification or “green revolution” of agriculture over the last 100 years. In the second part of the article, we critically review the evidence for the range of health benefits related to organic food consumption. Specifically, we describe and discuss the results from: (i) dietary intervention studies which have found that organic food consumption substantially reduces pesticide exposure in humans and affects feed intake, growth, hormone balances and immune system responsiveness in animal models; (ii) human cohort/epidemiological studies which have reported significant positive associations between organic food consumption and the lower incidence of a range of diseases including obesity, metabolic syndrome, cancer, hypospadias, pre-eclampsia, eczema and middle ear infections in infants; (iii) interactions and trade-offs between diet (e.g., whole-grain, fruit and vegetables and reduced red-meat consumption) and food types (organic versus conventional) concerning public health and future food security. The article also identifies knowledge gaps and highlights the need for (i) long-term, factorial field experiments to understand the relative effects of agronomic and pedoclimatic drivers on crop quality and safety, and (ii) clinical trials and additional human cohort studies to confirm the positive health outcomes linked to organic food consumption. The main conclusions from our review are that there is growing evidence that (i) agricultural intensification has resulted in a reduction in the nutritional quality of food and the sustainability of food production, and (ii) organic farming practices not only improve food quality and human health, but also food security. This is particularly true where current nutritional guidelines (increasing whole-grain, fruit and vegetable products, while reducing red-meat consumption) are implemented.

Observational studies have linked pesticide exposure to various diseases, whereas organic food consumption has been associated with positive health outcomes. Organic farming standards prohibit the use of most pesticides, and organic food consumption may therefore reduce pesticide exposure. To determine the effects of diet (Western compared with Mediterranean) and food type (conventional compared with organic) and sex on urinary pesticide residue excretion (UPRE), as well as associations between specific diet components and UPRE. In this 2-wk, randomized dietary intervention trial, healthy adults were randomly allocated to an intervention (n = 13) or conventional (n = 14) group. Whereas participants in the intervention group consumed a Mediterranean diet (MedDiet) made entirely from organic foods, the conventional group consumed a MedDiet made entirely from conventional foods. Both groups consumed habitual Western diets made from conventional foods before and after the 2-wk intervention period. The primary outcome was UPRE. In addition, we assessed diet composition and pesticide residue profiles in foods eaten. Participants were aware of group assignment, but the study assessors were not. During the intervention period, total UPRE was 91% lower with organic (mean 17 μg/d; 95% CI: 15, 19) than with conventional (mean 180 μg/d; 95% CI: 153, 208) food consumption (P < 0.0001). In the conventional group, switching from the habitual Western diet to the MedDiet increased insecticide excretion from 7 to 25 μg/d (P < 0.0001), organophosphate excretion from 5 to 19 μg/d (P < 0.0001), and pyrethroid residue excretion from 2.0 to 4.5 μg/d (P < 0.0001). Small but significant effects of sex were detected for chlormequat, herbicide, and total pesticide residue excretion. Changing from a habitual Western diet to a MedDiet was associated with increased insecticide, organophosphate, and pyrethroid exposure, whereas organic food consumption reduced exposure to all groups of synthetic chemical pesticides. This may explain the positive health outcomes linked to organic food consumption in observational studies. This trial was registered at www.clinicaltrials.gov as NCT03254537.

There is still considerable controversy about the relative risk of mycotoxin exposure associated with the consumption of organic and conventional cereals. Using validated protocols, we carried out a systematic literature review and meta‐analyses of data on the incidence and concentrations of mycotoxins produced by Fusarium, Claviceps, Penicillium , and Aspergillus species in organic and conventional cereal grains/products. The standard weighted meta‐analysis of concentration data detected a significant effect of production system (organic vs. conventional) only for the Fusarium mycotoxins deoxynivalenol, with concentrations ∼50% higher in conventional than organic cereal grains/products ( p  < 0.0001). Weighted meta‐analyses of incidence data and unweighted meta‐analyses of concentration data also detected small, but significant effects of production system on the incidence and/or concentrations of T‐2/HT‐2 toxins, zearalenone, enniatin, beauvericin, ochratoxin A (OTA), and aflatoxins. Multilevel meta‐analyses identified climatic conditions, cereal species, study type, and analytical methods used as important confounding factors for the effects of production system. Overall, results from this study suggest that (i) Fusarium mycotoxin contamination decreased between the 1990s and 2020, (ii) contamination levels are similar in organic and conventional cereals used for human consumption, and (iii) maintaining OTA concentrations below the maximum contamination levels (3.0 μg/kg) set by the EU remains a major challenge.