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Organic broccoli: is it really better for you?

Broccoli Marathon - more antioxidants when organically grown? Image ©Marshalls SeedsMany of us feel that organically grown food is better for us then food grown by what have become conventional methods but rarely is it actually proved that organically grown food is more nutritious. Perhaps, says he, because it isn’t more nutritious – it's just that it doesn’t have the chemicals.

But the other day I noticed a small piece in the ResearchMatters column of the British trade magazine Horticulture Week (login required) which summarizes research published in the latest issue of The Journal of Horticultural Science & Biotechnology. And this research finds that organically grown broccoli has higher levels of antioxidants than conventionally grown broccoli.

The variety ‘Marathon’ (above, click to enlarge), popular with both home gardeners and commercial growers, was grown on the same site by both conventional and organic methods. Florets were tested for a range of factors, and organically grown and conventionally grown broccoli showed no difference – except in antioxidant content.

I don’t subscribe to The Journal of Horticultural Science & Biotechnology, perhaps I should, so I’m not able to study the research paper in full but the publically available abstract looks promising. And study reported in Britain’s Guardian newspaper four years ago also shows the promise of organic culture as does a paper on blueberries in The Journal of Agricultural and Food Chemistry.

Of course, I'm not an organic chemist, So I popped downstairs and asked judy, who holds double-major B.S. degree from Rutgers University's College of Agriculture and Environmental Science. She told me: “There is a lot of controversy in the scientific world about how bad most of the studies have been. The broccoli one is not statistically significant. Also, the word “antioxidant” is not even used the same way by different studies; various compounds are given a number of different names and it's not regularized.”

Hmmm… So we have to be a little careful and not get carried away. But whatever proves to be true about the nutritional content, at least we know organically grown food has not been sprayed with chemicals.

Just one other thing… Many years ago, the British organic gardening charity Garden Organic (known back Potato 'Desiree' - more Vitamin C than other varieties. Image ©Marshalls Seedsthen as the Henry Doubleday Research Association) did some studies on the nutritional content of different varieties of potatoes, I think it was, and carrots. They found that varieties varied enormously in their vitamin content.

And I just come across a study from Slovakia which showed that the popular potato variety ‘Desiree’ (right, click to enlarge) can have more than twice the Vitamin C content of other potato varieties.

So the variety you choose to grow may well turn out to be more important, from a nutritional point of view, than anything else.

BTW British gardeners can buy both the varieties mentioned from Marshalls Seeds. In North America Broccoli 'Marathon' is available from Harris Seeds, and potato 'Desiree' is available from Seed Savers Exchange.

Comments

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Fiona Gilsenan

Thanks for this Graham (and clever judy). The 'organic is best' is an emotional topic.I heard Alan Dangour speak in 2009after his big survey paper came out.* He said he was subject to hundreds of angry emails for strictly sticking to the science, which showed no nutritional difference in organic vs non-organic produce. I look forward to more of your posts on this subject, which is an important one. Gardeners need to be evidence-based, too!

* Dangour, A. D., Lock, K., Hayter, A., Aikenhead, A., Allen, E. & Uauy, R. (2010), Nutrition-related health effects of organic foods: a systematic review. Am J Clinical Nutrition 92, 203-210, published online doi:10.3945/ajcn.2010.29269

Graham Rice

Exactly, Fiona, exactly. As in the invasives/natives debate, what we need is good science and less wild rhetoric. And as I said, I think the secret story is how much different varieties of the same fruit or vegetable vary in their nutritional content.

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