Thursday, July 1, 2010
Organic Food versus Conventional Food
After people have low-carbed for a while, they start to look better and feel better. As their health improves, one of the natural questions to ask is, "If I feel this good by dropping the carbs, wouldn't I feel even better if I ate organic food?" When this question is asked in the form of scientific studies, the short answer is, "Probably not."
To be sure, the alternative medicine community makes many claims for organic food. In Alternative Medicine Review, Walter J. Crinnion, a Nutritional Doctor, states that organic foods contain higher levels of certain nutrients, lower levels of pesticides, and may provide health benefits for the consumer. Please click the link for an extensive list of references.
On the other hand, in 2010 in the American Journal of Clinical Nutrition, Dangour et al. interviewed experts, searched bibliographies, and checked peer-reviewed articles with English abstracts. They found a total of 12 studies that evaluated health effects following the use of organic compared with conventionally produced foods. The authors reported that the largest study showed a 36% reduction in risk for allergic eczema when children under two consumed organic dairy products. Other than that, the majority of the studies showed no differences resulting from organic foods versus conventionally produced foods in nutrition-related health outcomes.
In one sense, this is not surprising. A 2009 literature review by the same group showed that there were very few differences in nutrients between organic and conventionally produced foods. In crops, eleven nutrient categories were analyzed. Conventionally produced crops had a significantly higher content of nitrogen, while organically produced crops had a significantly higher phosphorus and more acidity. The other eight categories were not different between the two groups. An analysis of the database on livestock products found no differences in nutrients between organic and conventionally produced products.
This finding is supported by the UK Food Standards Agency which found that nutrient levels vary as a result of freshness, storage conditions, crop variety, soil conditions, weather conditions and how animals are fed, rather than as a function of whether the food is produced in an organic or a conventional manner. They caution that while single papers may show differences in the nutritional content of a particular food, it is important to evaluate the weight of evidence across a range of published papers.
An important consideration favoring organic food is that organically grown foods have about one third the pesticide residues as do conventionally grown foods. A study in elementary age children found that their urinary organophosphorus pesticide metabolites were significantly lower when a conventional diet was replaced by one with organic food items. However, chemical pesticides are not the only ones available. It is important to note that while organic farming does not allow the use of synthetic pesticides, it does permit the use of plant-derived pesticides including Bt, pyrethrins and rotenone, and all of these exhibit varying degrees of toxicity in humans.
Another concern is ecological rather than health-related. Organic farming requires more land per unit of food produced. Repeated use of soil for growing crops makes it necessary to use fertilizer. In place of chemical nitrates and ammonia, organic farmers must obtain and apply manure and use crop rotation with leguminous plants to return nitrogen to the soil. When soils are phosphate-depleted, conventional farmers can use highly soluble chemically-made superphosphate while organic farmers must use poorly soluble rock phosphate. These practices, along with the poorer efficiency of organic pesticides and the need to till the land frequently to prevent weeds, means that the production of food is up to 50% less efficient when it is done organically. (See Reference 15 here.)
Even if a country has plenty of land to devote to food production, there are a couple of other items that should be considered. The use of manure rather than chemicals as fertilizer introduces the presence of bacteria, especially in fruits and vegetables that are eaten fresh. Because organic food production does not use antibacterial techniques such as food irradiation or chemical washes, it is very important to wash organic foods before they are consumed. Finally, organic foods tend to spoil more quickly than their conventionally produced counterparts, which makes it necessary to buy them when they are fresh and to use them up quickly. This is especially important with grains, seeds and nuts which are liable to produce mold and its associated toxins.
As is frequently the case, I can't come down on one side or the other in the case of organic versus conventional food. Sometimes people have worries about the possible effects of agricultural chemicals. Sometimes they prefer the taste and smell of organically produced food. Sometimes they simply want to get back to a more natural way of living. If that's the case, and if they are aware that eating natural foods is not completely risk-free, then they should go ahead and buy organic food. But speaking from a scientific perspective, and looking at groups of people rather than at individuals, it's probably fine to buy and eat food that is produced in conventional ways.