Those who consume high levels of organic foods are 25 per cent less likely to get cancer, a large French study has concluded.
However, the study of 69,000 French adults who were tracked for an average of five years, found that the reduction in cancer risk was not solely because of their consumption of organic food.
It found people who ate the most organic foods were less likely to develop certain kinds of cancer compared to those who ate the least. Because of the way the study was conducted, it is impossible to say that the organic foods people ate were the reason why they had fewer cases of cancer. But the results are significant enough to warrant follow-up studies, the Paris-based researchers have said.
The findings point to the need to do definitive studies of diet and health impact from consuming organic foods and produce containing pesticides – particularly in the Irish context, according to the Irish Organic Association (IOA).
While the study has a large sample size, it does not demonstrate that organics reduce the risk of cancer, lead author Dr Julia Baudry acknowledged – it could be other healthy lifestyle factors that were not accounted for in the analysis, because people who make a point of eating organic food may well take steps to be more healthy.
Preventive strategy
The study published on Tuesday in the US journal JAMA Internal Medicine, says “promoting organic food consumption in the general population could be a promising preventive strategy against cancer”.
This is “speculative and not entirely justified”, however, because they have not demonstrated a causal link, an evaluation by the Science Media Centre in London pointed out.
The volunteers who participated in the study had access to the internet. They provided information via web-based questionnaires. Frequency of organic food intake was assessed consistently using a web-based questionnaire that asked them how frequently they ate 16 different types of organic food.
Despite finding an association of higher organic intake with lower risk of cancer overall, the data was only statistically significant for post-menopausal breast cancer and lymphomas.
IOA development officer Grace Maher said it was good to see such studies carried out because they used a new approach by focussing on diet; the consumption of organic food and of conventionally-grown produce. She accepted that linking consumption of pesticides to cancer was very difficult to prove and more in-depth studies were needed. "They should also look at broader environmental consequences," she added.
Less pesticides
Residue sampling conducted by the IOA had, however, shown Irish organic food had less pesticides, which was the number one reason why Irish people buy organic foods.
In 2015, the International Agency for Research on Cancer classified three pesticides frequently used in agriculture – glyphosate, malathion, and diazinon – as carcinogenic to humans based on evidence from studies of occupational exposure in humans and laboratory studies in animals.
Through occupational exposure (primarily in agricultural settings), malathion is associated with prostate cancer, diazinon is associated with lung cancer, and all 3 pesticides are individually linked to non-Hodgkin lymphoma.
In the general population, low-level pesticide exposure is widespread, and the primary route of exposure is diet, especially intake of conventionally-grown fruits and vegetables. In the US, more than 90 per cent of the population have detectable pesticides in their urine and blood.
Organic food intake is notoriously difficult to assess, and the “self-report” process deployed in the French study “is highly susceptible to confounding by positive health behaviours and socioeconomic factors”, noted a JAMA commentary published with the research.
