Demand for organic milk is partially driven by consumer perceptions that it is more
nutritious. However, there is still considerable uncertainty over whether the use of
organic production standards affects milk quality. Here we report results of meta-analyses
based on 170 published studies comparing the nutrient content of organic and conventional
bovine milk. There were no significant differences in total SFA and MUFA concentrations
between organic and conventional milk. However, concentrations of total PUFA and
n-3 PUFA were significantly higher in organic milk, by an estimated 7 (95
% CI −1, 15) % and 56 (95 % CI 38, 74) %, respectively. Concentrations of
α-linolenic acid (ALA), very long-chain n-3 fatty acids
(EPA+DPA+DHA) and conjugated linoleic acid were also significantly higher in organic milk,
by an 69 (95 % CI 53, 84) %, 57 (95 % CI 27, 87) % and 41 (95 % CI 14, 68) %,
respectively. As there were no significant differences in total n-6 PUFA
and linoleic acid (LA) concentrations, the n-6:n-3 and
LA:ALA ratios were lower in organic milk, by an estimated 71 (95 % CI −122, −20) % and 93
(95 % CI −116, −70) %. It is concluded that organic bovine milk has a more desirable fatty
acid composition than conventional milk. Meta-analyses also showed that organic milk has
significantly higher α-tocopherol and Fe, but lower I and Se
concentrations. Redundancy analysis of data from a large cross-European milk quality
survey indicates that the higher grazing/conserved forage intakes in organic systems were
the main reason for milk composition differences.
Demand for organic meat is partially driven by consumer perceptions that organic foods
are more nutritious than non-organic foods. However, there have been no systematic reviews
comparing specifically the nutrient content of organic and conventionally produced meat.
In this study, we report results of a meta-analysis based on sixty-seven published studies
comparing the composition of organic and non-organic meat products. For many nutritionally
relevant compounds (e.g. minerals, antioxidants and most individual fatty acids (FA)), the
evidence base was too weak for meaningful meta-analyses. However, significant differences
in FA profiles were detected when data from all livestock species were pooled.
Concentrations of SFA and MUFA were similar or slightly lower, respectively, in organic
compared with conventional meat. Larger differences were detected for total PUFA and
n-3 PUFA, which were an estimated 23 (95 % CI 11, 35) % and 47 (95 % CI
10, 84) % higher in organic meat, respectively. However, for these and many other
composition parameters, for which meta-analyses found significant differences,
heterogeneity was high, and this could be explained by differences between animal
species/meat types. Evidence from controlled experimental studies indicates that the high
grazing/forage-based diets prescribed under organic farming standards may be the main
reason for differences in FA profiles. Further studies are required to enable
meta-analyses for a wider range of parameters (e.g. antioxidant, vitamin and mineral
concentrations) and to improve both precision and consistency of results for FA profiles
for all species. Potential impacts of composition differences on human health are
discussed.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.