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Canadian Organic Growers on the nutritional content of organically grown foods

Aug 4, 2009

Response to:

In late July, an advance copy of an article (Nutritional quality of organic foods: a systematic review Alan Dangour, at the London School of Hygiene and Tropical Medicine, funded by the United Kingdom's Food Standards Agency) slated for publication in a September issue of The American Journal of Clinical Nutrition was released to great sound and fury in the media. The report stated that organically grown foods contain no more nutritional value than conventionally grown foods. Below is Canadian Organic Growers’ response to that study.

The Big Picture

Organic is not a health claim – it is an alternative food production system that aspires to avoid many of the problems of modern food production. At its core, organic agriculture is about the soil. Unlike modern agriculture, organic agriculture improves soil quality by nurturing unseen underground workers – the dozens of species of earthworms, bacteria and fungi that function to improve soil quality, to transform nutrients into forms that plants can use and transfer them to the root zones of plants.

By fostering this underground army, organic methods work with nature, rather than against it. By getting essential plant nutrients such as nitrogen from nature, rather than from a bag, and enhancing plant immune systems to enable plants to fight their own battles against disease and insects, organic production avoids much of the environmental tragedy that modern agriculture begets, including contamination of surface and subsurface water sources, inefficient energy use related to the production and distribution of fossil-fuel based chemicals, reduced soil quality and impoverished and toxic habitat for the species that live above and below the soil.

Organic farming also offers a ray of hope for Canadian farmers embattled by years of negative net farm incomes and it is one of the few options for ending the farm exodus that has continued unabated for generations. In 1926, Canada boasted over 800,000 farmers. Today, there are fewer than 300,000. Those that remain are on average 52 years old according to Statistics Canada. By appealing to a new younger generation of farmers and by offering a living wage, organic farming may be our only future.

Is organic food better for you?

Absolutely! You can rest assured that organic farmers and processors do not add any substances that have been linked to negative health outcomes to food. That doesn’t mean that organically grown food is 100% free of genetically modified organisms, pesticide residues or synthetic fertilizers. It just means that organic farmers don’t put them there since these substances are banned in organic production. Unfortunately, however, on our polluted planet these substances are ubiquitous and often find their way into the food system through air and water currents despite the best intentions and actions of organic farmers.

Does organically grown food contain higher nutritional levels?

The Science:

Two scientific teams – the Food Standards Association (FSA) in Europe and the Organic Agriculture Center (TOC) in the US have conducted literature reviews of studies comparing the nutritional benefits of organic grown vs. conventionally grown food and interestingly, both groups have arrived at different conclusions. Both the TOC and FSA scientists agree that the quality of science on this topic has been abysmally poor. Both groups set up criteria to evaluate existing science and exclude studies not up to scientific standards. The TOC group eliminated more studies, partly because they set the bar higher by developing stricter criteria, but also because they eliminated studies done prior to  the 1980’s, unlike FSA which included English-language studies dating back to the 1950’s. The TOC argued that because nutritional science was nascent in the 1950’s and because nutritionists had never heard of phytochemicals, let alone had the capacity to measure them, that they should be excluded.

From COG’s perspective, since plants take in nutrients from the soil and because soils vary widely in nutrient content, it is extremely important to conduct these studies in exactly the same soils. While the FSA did include scientific studies using this “paired” methodology, they also included other types of data, including “food basket” studies where researchers picked “organically” and “conventionally” grown foods from grocery stores. TOC excluded any studies that did not control for soil nutrient variability which would have left out the food basket data used by FSA since this food was of unknown provenance.

The FSA found no difference between organically and conventionally grown crops on eleven measured nutrients with the exception of nitrogen, which was higher in conventional crops, and phosphorus and tritratable acids, which were higher in the organic crops. The TOC study replicated the findings with respect to nitrogen and phosphorous. According to TOC, elevated levels of nitrogen in food are regarded by some scientists as a public health risk because of the potential for cancer-causing nitrosamine compounds to form in the human GI tract, a strike against the conventionally grown food.

Overall, the TOC findings were similar for some of the nutrients analyzed by the FSA team, but differ significantly for a class of nutrients which plays a role in promoting human health – phytochemicals. TOC examined two of these: total polyphenols and total antioxidant content. While the FSA team did not look at total antioxidant capacity, they did look at phenolic compounds but observed no differences between conventional and organic.

So why the differences? FSA did not examine total antioxidant content. For the phenolic compounds, TOC argues that the differences they observed for specific phenolic compounds were washed out by the FSA statistical analysis that lumped different phenolic compounds into a single analysis.

So is organic food more nutritious?

Probably, but we need to wait for more and better science before we can unequivocally say that. This science is coming so we won’t have long to wait.

Recently, a pan European study involving some 31 universities completed a five-year study investigating questions related to the quality and safety of organically grown food. These studies, which have not been included in the FSA or TOC reviews, are the organic sector’s best hope for getting these questions answered. To date, over 100 studies have been published in scientific journals. These studies stand apart because they have been designed using a factorial model that allows investigators to gauge the impact of multiple factors while controlling for variables that can impact nutrition such as soil and climate etc. The final report is not out yet, but researchers are confident in saying that “organic food production methods resulted in higher levels of nutritionally desirable compounds (e.g. vitamins, antioxidants and polyunsaturated fatty acids such as CLA and omega-3) and lower levels of nutritionally undesirable compounds such as heavy metals, mycotoxins, pesticide residues, and glycol-alkaloids in a range of crops and/or milk.”