Organic foods have more antioxidant compounds linked to better health than regular foods and lower levels of toxic metals and pesticides, according to the most comprehensive scientific analysis to date.
The international team behind the work suggests that switching to organic fruits and vegetables could provide the same benefits as adding one or two servings of the recommended “five a day.”
The team, led by Professor Carlo Leifert from Newcastle University, concludes that there are “significant and statistically significant” differences, with a “substantially higher” range of antioxidants, between 19% and 69%, in organic foods. . It is the first study to demonstrate clear and wide-ranging differences between organic and conventional fruits, vegetables, and grains.
The researchers say that the increase in antioxidant levels is equivalent to “one or two of the five servings of fruits and vegetables that are recommended to consume daily and, therefore, would be significant and significant in terms of human nutrition, if the information that links them [compounds] to the health benefits associated with increased consumption of fruits, vegetables, and whole grains. “
The findings will bring to the boil a long-running dispute over whether those differences mean organic foods are better for people, with one expert calling the work sexed.
Tom Sanders, professor of nutrition at King’s College London, said the research showed some differences. “But the question is, are they within natural variation? And are they nutritionally relevant? I’m not convinced.”
He said Leifert’s work had caused controversy in the past. “Leifert has had a lot of aggro with a lot of people. [this report] a little. “Sanders added that the research showed that organic cereals have less protein than conventional crops.
The research was peer-reviewed and is published in a respected scientific journal, the British Journal of Nutrition. It was scheduled to be published next week, but has been featured on several academic websites.
The results are based on an analysis of 343 peer-reviewed studies from around the world, more than ever, examining the differences between organic and conventional fruits, vegetables and cereals.
“The most important thing about this research is that it breaks the myth that the way we grow does not affect the quality of the food we eat,” said Helen Browning, executive director of the Soil Association, which campaigns for organic farming.
Organic food sales in the UK, which are often considerably more expensive than non-organic ones, are rebounding after a slump during the economic crisis.
Plants produce many of their antioxidant compounds to fight pest attacks, so the higher levels in organic crops may be due to their lack of protection from chemical sprays. But scientists say other reasons may be important, such as organic varieties being grown for their toughness and not overcharging with artificial fertilizers.
Leifert and his colleagues conclude that many antioxidants “have previously been linked to a reduced risk of chronic diseases, including cardiovascular disease, neurodegenerative diseases, and certain cancers.” But they also point out that long-term studies showing the health benefits of a comprehensive organic diet have yet to be done.
The researchers found much higher levels of cadmium, a toxic metal, in conventional crops. Pesticide residues were found in conventional crops four times more often than in organic foods. The research was funded by the EU and an organic agriculture charity.
The research is sure to be criticized: including so many studies in the analysis could mean that poor quality work skews the results, although the team did ‘sensitivity analysis’ and found that excluding the weaker work did not significantly change the result.
Additionally, the highest levels of cadmium and pesticides in conventional products were still well below regulatory limits. But the researchers say that cadmium builds up in the body over time and that some people may want to avoid it, and that pesticide limits are set individually, not for the cocktail of chemicals used in crops.
An additional criticism is that the observed differences may result from different climates, soil types and crop varieties, and not from organic farming, although the researchers argue that the combination of many studies should average these other differences.
The biggest criticism, however, will be about the suggestions for possible health benefits. The most recent major analysis, which included 223 studies in 2012, found little evidence. “The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods,” he found.
This was also the conclusion of earlier smaller studies published in 2009 in a scientific journal and by the UK Food Standards Agency (pdf), although the latter considered only 11 studies. The 2012 study noted that eating organic food could help people avoid pesticide residues.
Sanders said the new job didn’t convince him. “You will not be better nourished if you eat organic food,” he said. “The most important thing is what you eat, not if it is organic or conventional. It is if you eat fruits and vegetables. People are buying a lifestyle system. They get the assurance that it is not grown with chemicals and it is not grown by big companies “.
He added that organic farming helped tackle the UK’s major problem of soil degradation and excess fertilizers polluting rivers.
A Soil Association survey (pdf) shows that healthy eating (55%) and avoiding chemical waste (53%) are key reasons shoppers cited for buying organic.
But many also say that caring for the environment (44%) and animal welfare (31%) are important, as is taste (35%).
Browning said: “This research supports what people think about organic food. In other countries, for a long time there have been much higher levels of support and acceptance of the benefits of organic food and farming. We hope these findings will put to the UK in line with the rest of Europe. “
The ecological store
Consumers spend an extra 25p on 2 pints of organic semi-skimmed milk (£ 1.14) at most large supermarkets
45p more on 800g organic whole wheat bread (£ 1.20) at Sainsbury’s
£ 1 more per kg of organic white grapes (£ 5 per kg) at both Sainsbury’s and Tesco
£ 3.23 more in organic pork chops (£ 5.50) at Tesco than standard
£ 1.03 more on a six-pack organic mixed weight eggs (£ 2) at Asda
40p more in a 340g pot of organic crunchy peanut butter (£ 1.70) at Sainsbury’s
Source: MySupermarket. Non-discounted standard prices correct on Friday, July 11