A new study from Great Britain has revived the old controversy about whether organic food is better for you.
The study by a team from the London School for Hygiene and Tropical Health found no major difference in the nutrient content of organically-grown food compared to conventionally-grown food.
Any differences that do exist are not significant, it says.
The study, done for the Food Standards Agency of the UK, reviewed the scientific literature on nutrient content in organic foods published over the last 50 years. Researchers found 52,471 studies and identified 162 on crop and livestock products. The team then analyzed the 55 articles they considered scientifically reputable.
“On the basis of a systematic review of studies of satisfactory quality, there is no evidence of a difference in nutrient quality between organically and conventionally-produced foodstuffs,” says the paper published in a recent edition of the American Journal of Clinical Nutrition.
“The small differences in nutrient content detected are biologically plausible and mostly relate to differences in production methods.”
The study did not look at pesticide residues on organic versus conventional food. Nor did it examine the environmental footprint of organic agriculture.
It follows recent research at the University of Guelph, which also found no significant difference between the nutritional content of organic food and conventional food.
But that doesn’t settle the debate among researchers and farmers about the benefits (or not) of organic food.
Rick Holley, a University of Manitoba food scientist, said plants grow in a fashion dictated by their genetics and using (or not using) pesticides is unlikely to affect their nutritional content.
“It’s unlikely that the chemical basis of two differently grown food products is going to be more significant than the genetics of the plant,” he said.
Holley said consumers should feel free to buy organic foods, but they shouldn’t automatically assume such foods are more wholesome.
“Go ahead. But don’t think for a moment that the premiums you pay will mean that the product is going to deliver on your desire to have a higher level of nutrition,” he said. “Be fully aware when you make that choice that you’re not necessarily buying a healthier product.”
However, Martin Entz, a University of Manitoba plant scientist, said the study looked only at nutrients and not secondary benefits such as antioxidants.
Entz said organic crops are known to contain higher levels of antioxidants – substances believed to protect cells from damage caused by unstable molecules known as free radicals.
“I don’t think they’ve measured every aspect of organic food. If they’ve just measured the minerals, they’re only telling us part of the story,” he said.
Entz and his colleagues will publish a research paper later this year in the Canadian Journal of Plant Science which finds that cereal crops grown organically contain higher levels of zinc, a micronutrient.
Brian Hunt, a vegetable and greenhouse specialist with Manitoba Agriculture, Food and Rural Initiatives, said the study also failed to look at whether nutrients in organic food might be more bioavailable (meaning the human body may be more readily able to absorb them). [email protected]