||Last Updated: Jul 24, 2013 - 8:42:56 AM
The logic is compelling. Food grown without the use of pesticides and insecticides should be healthier, and more nutritious. And it makes sense that we pay a little more for them. But the question remains: are organic foods safer than conventional foods? And if so, how significant is the difference?
In a report published last fall in the Annals of Internal Medicine, a team led by Dr. Crystal Smith-Spangler analyzed 240 studies that compared organic and conventional foods (17 studies dealt with human subjects, 223 measured nutrient and contaminant levels). Their conclusion: “Despite the widespread perception that organically produced foods are more nutritious than conventional alternatives, we did not find robust evidence to support this perception. Of the nutrients evaluated, only one comparison, the phosphorus* content in produce, demonstrated the superiority of organic foods.”
The report added: “The evidence does not suggest marked health benefits from consuming organic versus conventional foods, although organic produce may reduce exposure to pesticide residues and organic chicken and pork may reduce exposure to antibiotic-resistant bacteria.”
The analysis was prompted by the explosive growth in the sale of organic foods. Said the report: “Between 1997 and 2010, U.S. sales of organic** foods increased from $3.6 billion to $26.7 billion.” They added: “Although prices vary, consumers can pay up to twice as much for organic than conventional foods.” (Author’s note: this weekend, on a morning shop at Publix, I took note that a 9 oz. bag of conventional baby spinach cost $2.49 (26.7 cents per ounce) while a 5 oz. bag of organic baby spinach cost $3.69 (73.8 cents per ounce).
Before we turn to the report’s specifics – on allergies, nutrients, contamination and bacteria-resistance – it’s worth reflecting on two points made by Edward, a cashier at the Daniel Island Publix. This past Saturday, while checking out, I shared the findings of this report, after which Edward quickly posed these two pointed questions: 1. “Who funded the study?” (I explained that it wasn’t a singular study but instead was an analysis of relevant studies to date – with no outside funding); and 2. “What are the long-term effects?” The short answer is that we simply don’t know. Acknowledged the authors: “There have been no long-term studies of health outcomes of populations consuming predominantly organic versus conventionally produced food, controlling for socioeconomic factors.”
That said, here are the report’s chief findings:
1. Vitamin content. “We did not find significant differences in the vitamin content of organic and conventional plant or animal products.”
2. Allergies, food-poisoning: The authors noted that only three of the 17 human studies examined clinical outcomes, but of those three they found “no significant differences between populations by food type for allergic outcomes (eczema, wheeze, atopic sensitization) or symptomatic Campylobacter infection” (known more commonly as food poisoning).
3. Pesticide levels: “Conventional produce has a 30% higher risk for pesticide contamination than organic produce,” said the report. “However, the clinical significance of this finding is unclear because the difference in risk for contamination with pesticide residue exceeding maximum allowed limits may be small.”
4. Pathogenic bacteria. “We found no difference in the risk for contamination of produce or animal products with pathogenic bacteria. Both organic and conventional animal products were commonly contaminated with Salmonella and Campylobacter species . . ..”
5. Bacteria-resistance. “We found that conventional chicken and pork have a higher risk for contamination with bacteria resistant to three or more antibiotics than were organic alternatives. This increased prevalence of antibiotic resistance may be related to the routine use of antibiotics in conventional animal husbandry. However, the extent to which antibiotic use of livestock contributes to antibiotic-resistance pathogens in humans continues to be debated because inappropriate use of antibiotics in humans is the major cause of antibiotic-resistant infections in humans.”
*The authors added: “Higher levels of phosphorus in organic produce than in conventional produce is consistent with previous reviews . . . although it is unlikely to be clinically significant because near-total starvation is needed to produce dietary phosphorus deficiency.”
**USDA’s definition of organic agriculture: “Organic agriculture is an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony.”