Organic food is popular despite the price. It is often more expensive than conventional food. Consumers may purchase organic foods for several reasons, including perceived benefits to the environment, animal welfare, and worker safety, and the perception that organic foods
are safer and more nutritious. Proponents of organic food may be as passionate and as emotional in their defense of organic food as those defending their religion or political beliefs, so discussions on organic food can be volatile. I have experienced these emotionally charged discussions in seminars I have conducted. I tell organic food advocates to follow the evidence. Let science guide the way.
Organic food is defined in a variety of ways, but a key defining characteristic that most agree upon is organic is more natural than conventional food; natural substances or production methods are used in producing organic food. Synthetic pesticides, synthetic fertilizers, and gene engineering products are generally prohibited with the production of organic food. This more natural approach has led many to assume it must be safer if it is more natural. However, natural doesn’t always indicate safer. Some of the world’s most dangerous toxins are natural, including ricin, abrin, botulinum, and strychnine—highly evolved chemical weapons used by organisms for territorial expansion and self-defense (Silver 2006).
A popular assumption about organic food is that is produced without the use of pesticides; this is false. Organic food production sometimes involves the use of pesticides; the pesticides are natural (non-synthetic), and pesticide use is not as prevalent in organic food production as it is with the production of conventional food.
Organic Food and Conventional Food
A range of studies have examined organic foods in different contexts. In this article, I will provide a brief overview of some of the major findings. The primary concerns regarding organic food are whether organic food is more nutritious and safer than conventional food.
A review was conducted by Crystal Smith-Spangler and colleagues comparing the health effects of organic and conventional foods. Seventeen studies in humans and 223 studies of nutrient and contaminant levels in foods were included in the review. Only three of the human studies examined clinical outcomes; these studies found no differences by food type for allergic reactions. Two studies reported significantly lower urinary pesticide levels among children consuming organic versus conventional diets, but studies of biomarker and nutrient levels in serum, urine, breast milk, and semen in adults did not show significant differences. Phosphorus levels (higher phosphorous levels generally associated with healthy outcomes) were significantly higher in organic produce than in conventional produce, although this difference was not enough to be clinically significant. In organic produce, the risk for contamination with detectable pesticide residues was lower than in conventional produce, but differences in the risk for exceeding maximum allowed limits were small (insignificant). There was no difference in the Escherichia coli (E. coli) contamination risk between organic and conventional produce. It was common to find bacterial contamination of chicken and pork, but it was unrelated to the farming method used. The researchers concluded that the scientific evidence does not strongly support that organic foods are significantly more nutritious than conventional foods. In addition, it was found that consumption of organic foods may reduce exposure to antibiotic-resistant bacteria (bacteria that can’t be fought with antibiotics) and pesticide residues.
A review was conducted by Vanessa Vigar and colleagues to systematically analyze the evidence related to human health outcomes when an organic diet is consumed and compared to a conventional diet. Thirty-five papers were included in the review. There were few clinical trials assessing direct improvements in health outcomes associated with the consumption of organic food. “Significant positive outcomes were seen in longitudinal studies [long term studies] where increased organic intake was associated with reduced incidence of infertility, birth defects, allergic sensitization … high BMI” and a few other health related issues. The researchers concluded that current evidence does not decisively support the health benefits of consuming organic food. However, there is a growing number of findings from observational research correlating health benefits with organic food consumption. The researchers are clear in pointing out that although positive outcomes have been associated with organic food consumption in some studies, this association does not mean eating organic food causes these outcomes. Lifestyle factors must be considered as an influence on the outcomes. Organic consumers tend to be more physically active, more health conscious, and more likely to be vegetarian; all these factors can influence the outcome. Other researchers have pointed out that much of the research supporting the health benefits of organic food is correlational (association between variables), so making casual claims is incorrect.
In 2006, the Institute of Food Technologists issued a scientific status summary on organic foods. Many of the claims made in the summary of have been supported by further research since its publication. Below are some key points from the paper:
Organic fruits and vegetables contain fewer pesticide residues than conventional fruits and vegetables. In some cases, organic foods might have higher levels of plant secondary metabolites (end product of metabolism), and this may be beneficial with respect to antioxidants, but also may be harmful to health when considering naturally occurring toxins. Some studies have found potential increased microbiological hazards from organic produce or animal products due to the prohibition of antimicrobial use, but other studies have not reached the same conclusion.
Many studies show there are qualitative differences between organic and conventional foods; however, it isn’t clear that either food system is superior to the other with respect to safety or nutritional qualities. Some studies indicate organic food is higher in some nutrients while other studies report no differences. Pesticide residues and naturally occurring toxins make use of their health risks or benefits according to a dose-related basis. The differences in the levels of these chemicals between organic foods and conventional foods are often not biologically significant.
The researchers concluded that there may be tradeoffs that exist between organic and conventional food production. It is hard to make a decisive statement suggesting that one system (organic or conventional) is always superior to the other.
The reviews discussed up until this point have not shown strong support for the claim that organic foods are more nutritious and better for health than conventional food. However, some researchers have found organic food to offer health benefits superior to conventional foods. As an example, to study the benefits of organic food Yu Xiaofan and colleagues conducted an extensive literature search and combined those findings with their own research data. They found that most organic crops were more nutritious than conventional crops and that organic animal products had higher levels of polyunsaturated fats when compared to animals produced using conventional systems. In conclusion, the researchers stated, “Our investigation showed that there were obvious differences in quality and safety between the products that originated from organic agriculture systems and conventional alternatives.”
To determine health outcomes, more long-term studies using various research methods and statistics need to be conducted. In many of the studies conducted, factors other than the type of food consumed may contribute to the outcome. To control (keep constant) for other factors, single-blind, randomized controlled experiments need to be conducted. In a single blind study, the participants are not aware of which group they are in, which helps to control expectancy effects (expectations influence the outcome). With randomization, participants are randomly assigned (no pre-requisites or requirements) to either the organic food group or the conventional food group. A double-blind study could also be conducted, where neither the participants nor the researchers know which group participants are assigned to.
Reference
Silver, L.M. 2006. Challenging Nature: The clash of science and spirituality at the new frontiers of life. New York, NY: HarperCollins.
This content was originally published here.
