State of Science :: Food Safety
Italian Scientists Develop Novel Approach to Compare the Safety of Organic and Conventional Foods
According to a team of Italian scientists, the pesticides applied to conventional foods "can be seriously dangerous for human health and the environment" whereas some studies suggest organic food is more frequently contaminated with natural toxins. The team developed a new method to rigorously test which set of potential hazards - the chemical toxins in conventional foods or the natural ones in organic food - pose the greater risk.
The method works by comparing the impact of conventional and organic diets fed to rats on highly sensitive markers of cell responses to toxins consumed through food, in this case a diet composed of eight varieties of conventional and organic wheat. Two markers were studied. One involves the degree of proliferation in lymphocytes found in the intestine and in the spleen. The second is based on the short-term response of the liver to the presence of toxins ingested via food.
Stress, disease, and hunger are among many factors that can impair an animal' s ability to detoxify or otherwise overcome exposure to toxins. The team decided to study how protein energy malnutrition (PEM) impacted the animals' response to toxins in the diet, so the rats were divided into a well-nourished group (WN) and a PEM group and fed the conventional or organic wheat for 30 days. The eight varieties of conventional and organic wheat were grown under carefully controlled conditions and were mixed in equal parts in preparing the rations fed to the experimental animals.
The scientists then analyzed lymphocyte proliferation in the two groups of rats. They did this through the use of a cell culture medium composed of either fetal calf serum (FCS) or the rat' s own serum (RS). They stimulated rat lymphocyte cells in each culture medium with a chemical known to trigger cell division in order to mimic the proliferative response.
They found no differences in the proliferative response of lymphocytes cultured with FCS in rats fed organic versus conventional wheat, under either well-fed or PEM conditions. The proliferative response of lymphocytes cultured with the rat' s own serum, however, was depressed in PEM rats on conventional feed compared with the animals fed organic wheat. This effect was thought to be due to contaminants other than mycotoxins in the conventionally grown wheat.
The results showed that under the conditions of this study, conventionally grown wheat poses a higher risk for impaired lymphocyte function than wheat that is organically grown, at least, in animals under stress because of inadequate food intake. The authors highlight the fact that the organic wheat did have about 3-X higher levels of mycotoxins, suggesting that the toxic impacts of synthetic chemicals and/or other toxins in the conventional wheat elicited a greater biological response than the mycotoxins in the organic wheat.
The development of this novel method to compare the impacts of different mixes and levels of toxins in food on an animal' s immune system promises to accelerate progress in rigorously measuring and comparing risk levels following exposures to different combinations of toxins in food.
Source: "Novel Approach for Food Safety Evaluation. Results of a Pilot Experiment To Evaluate Organic and Conventional Foods."
Authors: Alberto Finamore, Maria Serena Britti, Marianna Roselli, Diana Bellovino, Sancia Gaetani, and Elena Mengheri.
Journal of Agricultural and Food Chemistry, Volume 52, No. 24, December 1, 2004.