Eating food produced by organic farming significantly reduces the levels of agrochemicals in the human body, a study by a nonprofit group in Fukushima Prefecture showed.
Those who ate organic food produced without the use of pesticides or chemical fertilizers for five days had about half the level of pesticides in their body, compared with those in a control group that ate conventional foods.
The level fell below 10% among those who consumed organic foods for a month.
In conducting the study, the Fukushima Prefecture Organic Farming Network (FPOAN) was assisted by Yoshinori Ikenaka, an associate professor of toxicology at the Hokkaido University School of Veterinary Medicine.
The group, which is working to forge links between farmers and consumers, recruited study participants whose urine was tested for six neonicotinoid insecticides and another substance generated as a result of their decomposition in the human body.
Results from the analysis of about 330 samples showed that the total concentrations of the seven substances in the urine were on average 5,0 parts per billion (ppb) in a group of 48 individuals who consumed supermarket-bought foods.
Corresponding levels averaged 2,3 ppb, or 46%, in a group of 38 individuals who consumed only organic food provided by FPOAN, including tea, for five days.
Content levels were on average 0,3 ppb, or 6%, in four individuals in a single household who consumed only organic foods for one month.
The average among the 12 individuals from five families who are engaged in organic farming and who consume their own crops in their homes was 0,5 ppb, or 10 percent.
Neonicotinoid insecticides, which dissolve rapidly in water, began to be used in increasing volumes during the 1990 decade because of their convenience.
In recent years, about 400 tons of chemicals have been shipped annually to Japan. However, some experts question the safety of their food waste and its impact on the environment.
Ikenaka's analysis showed that neonicotinoids were found in almost all commercially available tea product samples in plastic bottles, with concentrations ranging from several ppb to several dozen ppb.
Dinotefuran, of all pesticides studied, was found in the highest concentrations. The safety standards for residual dinotefuran are set at 2.000 ppb in rice, 100 ppb in soy and 25.000 ppb in tea.
Recent research results, however, have shown that some types of neonicotinoids affect the nervous system, even at levels previously considered “non-toxic”.
Some experts have questioned Japan's safety standards, which are considered less stringent than in other countries.
"Our study allowed us to present methods for reducing the agrochemicals that enter the human organism through food, along with their effects, in terms of hard data," said Hiroshi Hasegawa, FPOAN director who worked on the study. "I hope it will promote a greater understanding of organic farming among the public and provide greater support for the farming method."
Nobuhiko Hoshi, professor of animal molecular morphology at Kobe University Graduate School, who is well-versed in the toxicity of agrochemicals and other substances, said he hopes the study will appeal to organic farmers.
“I think the research results are almost unprecedented and highly valuable because they have real measurement values, showing that you can dramatically reduce the levels of pesticides in your body by simply changing the way you select plant products,” he said.
"It is significant that the effects have been shown quantitatively, particularly as the effort-intensive organic farming has been widely appreciated only in qualitative terms, as being 'green'."