Organic produce is more expensive than the conventional variety, and there are many reasons why consumers fork over that extra money. But if one of those reasons is a belief that organic fruits and veggies are healthier, Danish researchers have some bad news.
A detailed scientific assessment of carrots, potatoes and onions – some grown conventionally and some grown organically – found that all of the veggies had essentially the same levels of flavonoids and phenolic acids, two types of nutrients that are thought to be helpful in preventing ailments such as heart disease, cancer and dementia.
The scientists grew all three veggies on multiple plots for two growing seasons. They found that nutrient levels changed from year to year, but that those changes occurred no matter which type of growing system was used. The one exception was for a phenolic acid called 5-CQA in potatoes – it was “significantly higher” in spuds grown in one organic system than it was in spuds grown in another organic system or using conventional methods.
For a whole lot more detail on how the scientists washed, peeled, freeze-dried, crushed and homogenized the veggies before storing them in nitrogen and removing the flavonoids and phenolic acids using “pressurized liquid extraction” techniques, check out the full study in the Journal of Agricultural and Food Chemistry. But if you just want the bottom line, here it is:
“It cannot be concluded that organically grown onions, carrots, and potatoes generally have higher contents of health-promoting secondary metabolites in comparison with the conventionally cultivated ones,” they
A comprehensive review of research comparing the nutritional content of food that was organically raised with food produced with the use of synthetic pesticides has found no significant differences between the two.
Conducted by researchers from the London School of Hygiene and Tropical Medicine, the study is the first to bring a heated debate over the value of organic food to a rigorous conclusion. It is published today in the American Journal of Clinical Nutrition.
"Our review indicates there is currently no evidence to support the selection of organic over conventionally produced foods on the basis of nutritional superiority," said Alan Dangour of the London School's Public Health Intervention Research Unit.
Surveying 50,000 studies conducted over 50 years, the authors focused on 55 that met their standards of scientific rigor. The studies that led to the group's controversial conclusions covered a wide range of crops and livestock that are raised and marketed under organic standards.
For 10 out of 13 food crops studied, the researchers found no significant differences. Where they did find differences, those were attributed to differences in fertilizer use (say, the use of nitrogen vs. phosphorus) and the ripeness level at which the crops were harvested. The authors judged the differences observed "unlikely" to "provide any health benefit" to consumers.
The study was commissioned and funded by Britain's Food Standards Agency, the governmental office that regulates food production and sales in Britain.
Estimated to have surpassed the $23-billion mark last year, sales of organic food in the United States have grown sharply in the last 20 years, fueled by consumers' concerns about pesticide exposure, damage to the environment and the nutritional value of food raised by conventional means.
The study released today will likely do little to allay the first two fears. But for those who pay premiums for organic food in the belief it is richer in nutrients, the new analysis is likely to be a blow.
The authors did not address taste or freshness, an area unlikely to yield to science anytime soon.
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