By Dr. Carl L. Keen, Professor Of Nutrition And Internal Medicine, University Of California, Davis
Physicians, government agencies, nutritionists and environmental groups collectively agree the health benefits of eating a diet rich in fruits and vegetables outweighs the theoretical risks from the pesticide residues that can be found on these foods — when the measured residue levels are within the acceptable limits set by the FDA. This position is supported by numerous peer-reviewed toxicology studies and decades of nutrition research. Regrettably, recent surveys show many consumers believe the opposite position is true and that residues can pose a significant health risk. Cancer is among key consumer concerns.
Recently, my colleagues and I examined the theoretical cancer risk and benefits associated with a potential increase in the consumption of conventionally grown fruits and vegetables. We began by conducting an analysis of the potential number of cancer cases that might be prevented if half of the U.S. population increased its fruit and vegetable consumption by one serving per day. This number was contrasted by an upper-bound estimate that might be theoretically attributed to the intake of pesticide residues arising from the same level of additional fruit and vegetable consumption.
Our analysis indicated approximately 20,000 cancer cases would be prevented each year by increasing fruit and vegetable consumption by a single serving, while less than 10 cases of cancer would be added as a consequence of an increased consumption of pesticide residues. (Estimated cancer cases from residues are likely an over-estimate of the risk, but we chose to take a conservative approach.) While the concept of benefit/risk calculations is often difficult to embrace, the dramatic difference between benefit and risk estimates for consuming foods with detectable, but allowable, pesticide residues should provide confidence that consumers do not have to be unduly concerned about cancer risk from consuming conventionally grown produce.
Following peer review, a paper summarizing our methodology and findings were published in the Journal of Food and Chemical Toxicology in the fall of 2012. It is our hope this information will be useful for nutritionists and other health professionals who are concerned about the potential negative effects of pesticide residues on fruits and vegetables. We suggest this approach provides a practical way to evaluate risk-benefit issues as they relate to foods, and that it provides an example as to how one might discuss this concept with patients and/or concerned consumers.
Peer-reviewed research consistently indicates a diet rich in fruits and vegetables reduces the risk of certain diseases, improves overall health and leads to a longer life. A recent study from the University College of London published in the Journal of Epidemiology and Community Health in March 2014 found people who consumed seven or more servings of fruits and vegetables daily reduced their risk of premature death by 42 percent. That study also found this level of produce consumption reduced the risk of heart disease by 31 percent and cancer by 25 percent.
Importantly, this study and our study found even slight increases in produce consumption can have a significant impact on health. Their results suggest by eating just one to three servings per day, you reduce your risk of premature death by 14 percent and by 29 percent if you eat three to five servings. Because of these results, the study’s lead author stated: “We all know that eating fruit and vegetables is healthy, but the size of the effect is staggering.”
So why are consumers’ risk/benefit perceptions about produce safety skewed in the wrong direction? One hypothesis is over the past several years consumers have been repeatedly exposed to negative messages regarding the safety of conventionally grown fruits and vegetables. These foods are often referred to as “dirty” or “toxic laden.” This messaging, often aggressively promoted, has almost become mainstream thinking. While the motivations underlying such messaging are typically well-intentioned, the result may be that food safety fears have created an inappropriate barrier to increasing the consumption of these healthy foods. This factor has an undermining effect on public health initiatives, which promote healthier eating. For individuals who work in public health, advise patients and/or consumers regarding nutrition, or are part of the scientific community, it is important we engage in issuing our messages to consumers to regain accurate risk/benefit perceptions among consumers. That message is quite simple:
• There are uniform and widespread agreement among health experts that consumption of fruits and vegetables needs to be substantially increased.
• Consumers can choose either organic or conventionally grown produce without safety concerns about pesticide residues — government sampling data repeatedly shows “residues do not pose a food safety concern.”