- Williams, C.M. Nutritional quality of organic food: shades of grey or shades
of green? Proc Nutr Soc. 2002 Feb;61(1):19-24. Review.
Abstract: Consumer concern regarding possible adverse health effects of foods
produced using intensive farming methods has led to considerable interest in
the health benefits of organically-produced crops and animal products. There
appears to be widespread perception amongst consumers that such methods result
in foods of higher nutritional quality. The present review concludes that evidence
that can support or refute such perception is not available in the scientific
literature. A limited number of studies have compared the nutrient compositions
of organically- and conventionally-produced crops, with a very small number
of studies that have compared animal products (meat, milk and dairy products)
produced under the two agricultural systems. Very few compositional differences
have been reported, although there are reasonably consistent findings for higher
nitrate and lower vitamin C contents of conventionally-produced vegetables,
particularly leafy vegetables. Data concerning possible impacts on animal and
human health of diets comprising organic or conventional produce are extremely
sparse. Data from controlled studies in animal models, particularly within single
species, are limited or poorly designed, and findings from these studies provide
conflicting conclusions. There are no reports in the literature of controlled
intervention studies in human subjects. Comparison of health outcomes in populations
that habitually consume organically- or conventionally-produced foods are flawed
by the large number of confounding factors that might contribute to any differences
reported. If consumer perceptions regarding potential health benefits of organic
foods are to be supported, more research of better quality is needed than that
which is currently available.
