How Does Your Garden Grow? Organic vs. Conventional Food
How Does Your Garden Grow? Organic vs. Conventional Food
Abstract & Commentary
By Russell H. Greenfield, MD, Editor
Synopsis: Authors of a recently published systematic review concluded that organic foods offer no significant nutritional benefit when compared with conventionally raised fare; however, the conclusions reached were based on extremely limited data, as stated by the authors, and focused solely on a small number of nutrients, with no attention paid to potential chemical/pesticide exposure to those ingesting the food, nor to environmental issues.
Source: Dangour AD, et al. Nutritional quality of organic foods: A systematic review. Am J Clin Nutr 2009 Jul 29; Epub ahead of print; doi:10.3945/ajcn.2009.28041.
The researchers behind this systematic review sought to quantify the differences in nutrient content between organic and conventionally raised foodstuffs. The research team performed a literature search for articles published in peer-reviewed journals with an English language abstract that directly compared the nutrient composition of foods raised organically vs. conventionally. Searching and data extraction were performed by two research assistants, with project leader oversight, and data from foreign language articles were extracted by native speakers. A total of 162 articles were finally assessed for study quality. Studies included in the analysis used one of three different study designs: field trials (comparing adjacent parcels of land), farm surveys (comparing products from organic and conventional farms), and basket studies (comparing foods available through retail outlets).
From the start, the authors state they did not attempt to address differences in potential contaminant exposure or associated environmental consequences of the two agricultural practices. Instead, the focus was solely on nutrient content. Data were found on more than 400 nutrients and nutritionally relevant substances, but there were not sufficient data to allow direct analysis by specific food, so the authors chose to make comparisons based on nutrient content across all study designs, ultimately choosing a pragmatic approach that statistically assessed only those nutrient categories reported in at least 10 studies (n = 11 nutrients) and at least four livestock trials (n = 2 nutrients).
Crop studies showed no evidence of a difference in nutrient content for eight of the 11 nutrient categories assessed (vitamin C, phenolics, magnesium, potassium, calcium, zinc, copper, and total soluble solids). Conventionally grown crops contained higher nitrogen levels, while organic produce was found to contain more phosphorous and titratable acidity. The researchers state these differences could be due to differences in ripeness at harvest, as well as differences in fertilizer use. For the two nutrient categories evaluated for livestock (ash and unspecified fats), no differences were identified.
The authors conclude that their analysis suggests no significant nutritional benefit of organic foods over conventionally raised foodstuffs with respect to nutrient composition.
Commentary
The organic food movement has gained tremendous momentum over the past few years largely because shoppers believe they may be getting healthier fare, and also perhaps in part due to a sense of environmental and social responsibility. Recall that the very term "organic" implies the use of agricultural methods that limit or eliminate use of fertilizers, pesticides, fungicides, and genetically modified seeds, and as relates to livestock, less risk of exposure to antibiotics and growth hormones. Yet there has been constant debate about whether organic foods actually provide noticeable health benefits for the usually higher store price. Such were the circumstances in which the authors of this paper began their work; however, they quickly found that even with all the research published in this arena, there were major limitations.
Some of the articles examined did not specify the organic certifying body, which is important since the associated regulations can vary, and others employed a variety of laboratory methods to gain their results. Study quality was a major issue, with the authors stating, "Our review again highlighted the heterogeneity and generally poor quality of research in this area." The researchers forthrightly acknowledge they could not find the full text of 11 articles of potential interest to the study, and that two new studies of possible impact to their findings had recently been published but not reviewed.
The authors pragmatically focused on a total of 11 nutrients in produce and two nutrients in livestock across all study designs. Their reasoning makes sense, but they extend their reach too far when making broad conclusions based upon such limited data points. Consider all the phytonutrients already identified that offer potential health benefits that were not included in the assessment, organic or not, and the limited scope of the published conclusions comes further into view. Previous studies suggest that organic fare actually contains higher levels of select nutrients compared to matched conventional food, while others refute these findings.
Perhaps most importantly, however, is the fact that the authors did not "address differences in contaminant contents ... or the possible environmental consequences of organic and conventional agricultural practices because this was beyond the scope of our review." Debate continues about the nutrient contents of organic vs. conventionally raised foods, but there is no debate about the increased potential for chemical exposure through the ingestion of conventional fare when compared to certified organic produce and livestock, an area of growing concern to scientists across the globe, especially as relates to the proper development of young children.
Regularly eating a wide variety of produce and moderate intake of animal protein can be the cornerstone for a healthy diet, but issues around organic and conventional farming methods have yet to be fully fleshed out. The present study does little to clarify matters, only pointing out the need for methodologically sound investigations to help answer persistent questions of nutrient content and chemical exposure. In general, it's fair to ask our patients to lean organic for the foods we know to be more likely tainted with chemicals associated with conventional agriculture methods (peaches, milk, and strawberries, for example) where accessible and affordable, but not to scare them away from eating a wide variety of conventional foods. We don't have to eat everything organic to be healthy, but in certain instances organic may be the prudent choice.
Authors of a recently published systematic review concluded that organic foods offer no significant nutritional benefit when compared with conventionally raised fare; however, the conclusions reached were based on extremely limited data, as stated by the authors, and focused solely on a small number of nutrients, with no attention paid to potential chemical/pesticide exposure to those ingesting the food, nor to environmental issues.Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.