Photo/IllutrationOrganic vegetables (Provided by the Fukushima Prefecture Organic Agriculture Network)

Eating food produced by organic farming significantly reduces agrochemical levels in the human body, a study by a nonprofit group in Fukushima Prefecture has shown.

Those who ate organic food, produced without the use of pesticides or chemical fertilizers, for five days were found to have about half the level of agrochemicals in their organism compared with those in a control group who consumed conventional food.

The level dropped to less than 10 percent among those who took in organic food for a month.

In conducting the study, the Fukushima Prefecture Organic Agriculture Network (FPOAN) enlisted the help of Yoshinori Ikenaka, an associate professor of toxicology with Hokkaido University’s School of Veterinary Medicine.

The group, which is working to forge ties between farm producers 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.

Analysis results for about 330 samples showed the total concentrations of the seven substances in urine averaged 5.0 parts per billion (ppb) in a group of 48 individuals who ate food purchased at supermarkets.

The corresponding levels averaged 2.3 ppb, or 46 percent as high, in a group of 38 individuals who took in only organic food materials provided by FPOAN, including tea, for five days.

The content levels averaged 0.3 ppb, or 6 percent, in four individuals from a single household who consumed only organic food for a month.

The average among 12 individuals from five households who engage in organic farming and consume their own farm crops at their homes was 0.5 ppb, or 10 percent.

Neonicotinoid insecticides, which dissolve readily in water, started being used in growing volumes during the 1990s owing to their convenience.

In recent years, about 400 tons of the chemicals have been shipped annually in Japan. However, some experts have questioned the safety of their residue in food products and their impact on the environment.

Ikenaka’s analysis showed that neonicotinoids were found in almost all samples of commercially available tea products in plastic bottles, with concentrations ranging between several ppb and several tens of ppb.

Dinotefuran, of all the pesticides studied, was found in the largest concentrations. The safety standards for residual dinotefuran are set at 2,000 ppb in unpolished rice, 100 ppb in soybeans and 25,000 ppb in tea.

Recent research results have shown, however, that some types of neonicotinoids affect the nervous system even at levels previously deemed “nontoxic.”

Some experts have questioned Japan’s safety standards, which are said to be less stringent than in other countries.

“Our study has allowed us to present methods for reducing agrochemicals that enter the human organism through food, along with their effects, in terms of concrete data,” said Hiroshi Hasegawa, an FPOAN director who worked on the study. “I hope it will promote greater understanding of organic farming among the public and provide increased support for the agricultural method.”

Nobuhiko Hoshi, a professor of animal molecular morphology with the Kobe University graduate school, who is well-versed in the toxicity of agrochemicals and other substances, said he expects the study will hearten organic farmers.

“I think the research results are almost without precedent and are highly valuable in that they present actual measurement values showing that you can dramatically reduce the content levels of agrochemicals in your body simply by changing the way you select vegetable products,” he said.

“It is significant that the effects were shown quantitatively, particularly because organic farming, which requires a lot of effort, has largely only been appreciated qualitatively, such as for being ‘eco-friendly.’”