The debate over whether organic food is more “nutritious” than conventional food rages on. Some of you may have seen some media reports on a recent study out of the UK that appears in the September 2009 issue of the American Journal of Clinical Nutrition. This report is a review of 55 studies published between January 1958 and February 2008. These studies looked at levels of 13 nutrients such as vitamin C, phenolic compounds, magnesium, potassium, calcium, zinc, copper, and total soluble solids. These nutrients are vitamins, minerals, and some antioxidants (for example, vitamin C and phenolic compounds are antioxidants).
Why is it important to look at the content of these nutrients in our foods? Because vitamins and minerals support our health in a variety of ways; they are needed for healthy eyes and skin, strong bones, muscle and nerve function, etc. Some vitamins and other substances also act as antioxidants. Antioxidants can prevent or slow down oxidative damage that occurs to our bodies, hence lowering our risk for developing many health problems such as cancer, heart disease, diabetes, etc.
The researchers conducting this review did not find significant differences between conventional produce and organic produce regarding most of these nutrients. They did find that conventional produce had higher levels of nitrogen (likely due to the use of synthetic fertilizers), and organic produce had higher levels of phosphorus and acidity. This in itself is significant because foods high in nitrogen have the potential to turn into cancer causing nitrosamines in the digestive tract, which indicates organic foods are safer in this regard. Higher levels of phosphorus and acidity are protective (phosphorus being a key mineral in bone health, metabolism, as well as nerve and muscle function; acidity aiding in the absorption of various nutrients), also indicating organic foods are a better choice. However, you will notice that you will not see that conclusion reported.
Another thing they fail to emphasize is that this report admits that they did not analyze chemical residue or contaminants. These researchers actually state that herbicides, pesticides, and chemical fertilizers may also affect the chemical content of foods and that in this regard, organic foods likely have an advantage over conventional foods because they do not use these synthetic substances. In addition, because this study looks at conventional farming from over 50 years ago, the results are likely skewed as well because conventional farms in the 1950s were a lot closer to organic farms than they are in this day and age.
This particular review also failed to look at total antioxidant capacity among the nutrients studied. The Organic Center (TOC) conducted a review of these same studies. They found similar results as the UK review for most of those particular nutrients, but they did had very different results regarding phenolic compounds. In addition, the TOC also looked at antioxidant capacity.
In looking at phenolic compounds, the TOC used more rigorous selection criteria and focused on studies that had scientifically valid “matched pairs,” meaning organic and conventional farms that were grown in the same regions, on the same types of soil, using the same types of irrigation systems, harvested at the same time, and grown from the same plant variety were compared (which is why they had different results). Using these criteria, they were able to find 25 matched pairs for comparing phenolic compounds. Of these 25, 18 of the organic crops had higher phenolic compounds while only 6 of the conventional crops had higher phenolic compounds.
Regarding antioxidant capacity, there were 8 matched pairs; seven of the organic crops were higher than the conventional crops. There were also 15 matched pairs for specific antioxidants such as quercetin and kaempferol. Once again a majority the organic crops were higher than the conventional crops.
On average, across all the valid matched pairs, the nutrient levels in organic foods were 25% higher than conventional foods. In addition, the most significant differences were for key antioxidants that average Americans do not consume enough of. This is like saying by eating these organic foods, you are getting the benefit of eating an additional serving of fruits and vegetables daily.
Based on the UK report’s overall conclusion, most of the media outlets are inaccurately reporting that organic food is not any more nutritious than conventional food. This is a clear example of how often media reports will take parts of research and sensationalize it, giving consumers faulty information.
Even if organic foods were not higher in many nutrients than conventional foods, they are definitely lower in pesticide reside, which in itself is a health benefit. Organic farming methods are also more sustainable and therefore better for the environment. Having said that, there are a number of other studies that have come out in the past year (post February 2008, which was the end of the studies reviewed in the UK report) that do show organic foods are higher in many nutrients than conventional foods.
So if you are trying to decide if organic foods are really worth it, I say yes! They are “safer” when it comes to chemical contaminants, better for the environment, and higher in some key nutrients that are extremely beneficial for your health.