McGill Alert / Alerte de McGill

Updated: Thu, 07/18/2024 - 18:12

Gradual reopening continues on downtown campus. See Campus Public Safety website for details.

La réouverture graduelle du campus du centre-ville se poursuit. Complément d'information : Direction de la protection et de la prévention.

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Organic Food and Nutrition

Is organic produce safer and more nutritious than the conventional variety? Curiously, organic really used to be conventional. That was the only kind of farming that was practiced.

The battle has been raging back and forth ever since pesticides and synthetic fertilizers were introduced into agriculture. Is organic produce safer and more nutritious than the conventional variety? Curiously, organic really used to be conventional. That was the only kind of farming that was practiced. If you wanted to fertilize your fields, you used sewage or decomposing plant material. If you wanted to control insects, you used toxic, but of course “natural,” compounds of arsenic, mercury or lead. Nicotine sulfate extracted from tobacco leafs was a possibility, and by the 19th century pyrethrum extracted from chrysanthemums was also available. Dusting crops with elemental sulfur was an aage-old practice of controlling insects and fungi. This was what “conventional” farming was all about until the twentieth century when synthetic pesticides and fertilizers were developed. And why were these developed? Well, necessity is the mother of invention. Crop losses were too great to feed the growing population and the toxic effects of arsenic, mercury and lead based insecticides had become apparent.

Chemists went to work and developed an array of pesticides that effectively protected crops and fertilizers that delivered nutrients in an effective fashion. Yields increased and the hungry were fed. And the full tummies and abundant produce allowed people to concentrate on other issues than hunger and limited food choices. Like the risks of the new-fangled agrochemicals. There were reports of insecticides interfering with the egg- laying abilities of birds and concerns were raised about their effect on human health. After all, insecticides were meant to kill insects so they obviously had toxic potential. So people harkened back to the good old days when produce was chemical-free, or so they thought. They wanted uncontaminated, pesticide free food grown without synthetic fertilizers. They wanted to go “organic.”

Some farmers complied. If that is what people wanted, they would go back to growing food the old-fashioned way. No pesticides, no synthetic fertilizers and none of those novel boogeymen, genetically modified crops. Sure, yields would be reduced, and the produce would look less perfect, but as long as consumers were willing to pay a premium, farmers would fulfil their needs. Indeed consumers fearful of pesticide exposure were willing to pay more for organic produce which they surmised would also be more nutritious. After all, they thought, food grown the “natural” way must contain more nutrients. Well, does it?

A number of field trials have explored this issue with varying results. Focus usually has been on measuring the antioxidant content of the food, which has generally been assumed to responsible for health benefits. This measure is itself controversial. While there is overwhelming evidence that a diet high in fruits and vegetables is healthy, there is no hard evidence that this is due specifically to antioxidant content. In theory, this is a reasonable assumption because antioxidants, at least in the laboratory, can neutralize free radicals which have been linked with a variety of health problems. But no study has shown that antioxidant content in foods is linked to health.

And now the pot has really been stirred by a four year long study from the University of Newcastle which supposedly has shown, although the data has not been published, that organic food and produce are some 40% richer in antioxidants. The researchers even suggest this means we can eat fewer fruits and vegetables as long as they are organic to satisfy our antioxidant needs. This is not totally compelling. Foods are extremely complex chemically and measuring the amounts of a few antioxidants may not be a proper reflection of nutritional value. For that we need feeding studies. Do rodents thrive on organic diets? Nobody knows. And are humans who eat organically healthier? It would be great to know. We can’t just assume that this is the case.

What about disease causing organisms that may be present in sewage used as organic fertilizer? Or fungal metabolites which are more likely to be found in organic foods because they are not protected by insecticides? Fumonisins produced by Fusarium moulds are carcinogenic and have been linked with birth defects in humans. Such moulds take root where insects have damaged the crop. This of course is not the case for crops protected through genetic modification. Insertion of a gene that codes for the production of the Bt toxin which has no effect on humans protects these crops from insects, but of course genetic modification is not allowed in organic agriculture. Too bad, because if we look to increase nutrient content, this is the way to go. A line of genetically modified tomatoes with almost eighty times more antioxidants has already been developed at the University of Exeter. Now that is a far greater difference than between organic and conventional produce.

If cost is of no concern, organic may indeed be an appropriate choice. There is no doubt that it is environmentally a more sound practice. But for most people, cost is an issue and if they buy organic they often end up consuming fewer nutrients because they can only afford limited amounts. There is one more point to be made. Pretty soon, there will be 10 billion people coming to dinner. And they are not going to be fed organically.

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