Aarhus, Denmark
January 7, 2011
In a series of studies carried out at the Faculty of Agricultural Sciences it was shown that there are more factors than just the production method affecting health biomarkers as measured in rats.
It is not organic farming per se that has the greatest effect on how healthy vegetables are. More important factors are which year the vegetables are harvested in and where they were grown, according to studies carried out at the Faculty of Agricultural Sciences, Aarhus University.
The results are based on a series of studies with rats that were fed organically or conventionally grown plant products. The studies were carried out by senior scientist Charlotte Lauridsen from the Department of Animal Health and Bioscience in collaboration with her colleagues from the faculty. The scientists investigated various biomarkers for health measured in a rat model.
- The studies indicate that it is possible to affect the immune status via how the plants are grown but our overall conclusion is that harvest year and growing location play more important roles than the growing system with regard to the biomarkers for health that we looked at in the rat model, says Charlotte Lauridsen about the provisional results.
Rats fed veggies
The aim of the studies was to investigate the effect of organically grown plant products on bioavailabililty, growth and health using rats as a research model. The studies were carried out over a period of several years in a series of projects financed by funds from the International Centre for Research in Organic Farming Systems (ICROFS).
Common to all the studies in the three projects was that three different treatments were used – two organic and one conventional system.
In one of the projects the rats were fed potatoes, carrots, apples, green kale, peas and rapeseed oil from one location.
The diet in the second project comprised spring barley, winter wheat, potatoes, rapeseed and fava beans. They were grown on three different locations that reflected typical Danish soil types.
In the third project the rats were fed carrots grown in the same crop rotation as in the first project and at one location, which was specialised in growing vegetables.
Several factors play a role
In the first project there were no differences between diets with regard to most of the parameters measured. There were, though, differences in the rat tissue fatty acid composition, which reflected the composition of the rapeseed oil, and there was a difference between the organic and the conventional growing system with regard to the concentration of plasma vitamin E and immunoglobulins as well as rat activity levels. Since there was only one repetition of the growing system and only one growing season it was not possible to conclude anything about the effect of growing systems.
The other study showed that growing year and location had a marked influence on the health biomarkers that the scientists measured, while there was no effect of growing system. An exception was the level of plasma immunoglobulins where the preliminary results indicate that there is a difference between organic and conventional growing systems.
In the third study the scientists found a higher level of nitrogen and nitrate in the carrot dry matter from the conventional growing system while the health biomarkers were affected by the growing season more than the diet.
- Many consumers believe that organic food products have a better quality and that they are healthier and more nutritious than food products produced non-organically. There are, however, no research results that can confirm or disprove this perception, says Charlotte Lauridsen.
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