Organic: worth the hype? Part I. Plants.
Over the past few years, there has been an explosion in the organic food market. National chains and small independent grocers alike are offering organic versions of their foods to meet consumer demand. Is there really a difference? Is organic food really worth the price tag?
This is a huge topic, so today, we will focus on produce.
The Environmental Protection Agency (EPA) regulates the types of pesticides used in farming in the United States, and in produce farmed internationally and imported to the US. Pesticides have to be registered by the EPA and most (but not all) are required to remain under a safe ”tolerance limit” when the produce hits the shelves. The EPA reports that they ensure that the tolerances are within a safe level for consumption. According to the EPA, their recommendations are based on scientific studies to ensure a “reasonable certainty of no harm.”
However, pesticides are not benign. They are chemicals intended to disrupt the cellular functioning of animals. Pesticides are very toxic when humans are exposed in high concentrations. Agriculture workers are commonly at risk of these acute toxicities.
1. Organochlorines. These compounds (which include DEET) are stimulants to the central nervous system. Acute toxicity can include symptoms such as tremors, hyperexcitability and seizures. These chemical and their breakdown products have been found in human breast milk and In plants, animals and soil from around the world. They persist in tissues and build up in animals at the top of the food chain. Many of the organochlorine pesticides have been banned, however, in California, it is still allowed to use the organochlorines lindane and parathione.
2. Organophosphates and Carbamates. These compounds interfere with neural signaling and acute toxicity can cause symptoms of headache, dizziness, confusion, nausea, vomiting, diarrhea, chest pain and muscle pain. In higher doses, they can cause seizures, coma and even death. Hundreds of thousands of people around the world develop acute poisoning from organophosphates and carbamates each year.
3. Fumigants. (Methyl bromide, metate sodium) These pesticides are typically sprayed onto the plants. dangerous when them come in contact with any body tissue. They can cause irritation, itching or burning of the skin and eyes, and if inhaled, can cause severe cough, nose bleeds and damage to lung tissue.
4. Pyrethroids. These are synthetic versions of a toxin made by the chrysanthemum flower. Unlike the natural variety, these synthetic versions last for weeks in the environment and are a potent neurotoxin and carcinogen.
Consumers eating pesticide residue are not at risk for these acute toxicities, however, a growing body of research is showing that chronic small exposures have effects too. Children are particularly susceptible: Proportionally greater intake of food and water, rapidly growing and dividing cells, active brain growth and development, and immature excretory systems all contribute to the buildup of pesticide residues in children. A pesticide residue level that might have little toxicity to adults might be more harmful to children.
Pesticides have been shown to have effects on the developing brains and bodies of our children. Studies have linked pesticide exposure to damage to the respiratory system, immune system, endocrine system, reproductive system and neurological system. Studies have identified adverse effects from exposure to pesticides in children during infancy, toddler age, school-age and adolescents. Children can suffer from developmental delay, ADHD and possibly autism related to chronic pesticide exposure. There are effects to the immune, respiratory, endocrine, reproductive and neurologic systems.
There are concerns for adult exposure too! There is a large body of evidence showing the link between pesticide exposure and several chronic diseases including various cancers, diabetes, neurodegenerative diseases (Parkinson’s disease, Amyotrophic Lateral Sclerosis, Alzheimer’s disease), birth defects, and reproductive disorders. There is also some evidence associating pesticide exposure to other diseases include chronic obstructive pulmonary disease (COPD), autoimmune diseases, cardiovascular disease.
Pesticides are used on fruits and vegetables, and also on nuts. Nuts have a high fat content, so they absorb pesticides very easily. Studies of nuts grown in China and Iran show high levels of pesticide residues on nuts grown with pesticides.
Can we wash the pesticides off?
Partially. But not completely.
Fruits and vegetables have porous skin, so they absorb some of the pesticide residue into the flesh. No washing method is able to remove these absorbed chemicals. In fact, washing with dish soap or bleach is discouraged because these chemicals can also be absorbed under the skin, which effectively adds more residues!
A study published in 2000 by the Journal of Agriculture found that rinsing produce for 60 seconds under running water was effective at removing 9 of the 12 pesticides studied. Other studies report more pesticide removal with baking soda solution, but in these studies, researchers submersed the produce in the solution for 12–15 minutes; which is not feasible for busy families.
Commercial fruit and vegetable washes can also remove dirt and residues, but it is debatable if they are any more effective than running water. None of these methods can remove 100% of pesticide residues from the surface and they cannot touch any pesticides that were absorbed through the skin. Washing the produce with ozonated water or in an ultrasonic cleaner is more effective than using commercial produce wash or tap water, but still can't remove all the pesticides.
What other steps can we take to limit our risk?
The best way to avoid pesticide residues is to avoid them all together by eating organic produce when you can. A few different studies have shown that consumption of an organic diet reduced the amount of pesticide residues in the urine by up to 90%.
Different fruits and vegetable have different levels of pesticide residues. The Environmental Working Group releases yearly lists of the most and least contaminated produce.
The “Dirty Dozen”, 2019
The “Clean Fifteen”, 2019
Sweet peas (frozen)
Stay healthy, friends.
Want to learn more? See these resources below.
Aydin S, M Ulvi. Residue levels of pesticides in nuts and risk assessment for consumers. Quality Assurance and Safety of Crops & Foods: 11 (6). Pages: 539 - 548.
Bilek, Seda Ersus and Fulya Turantaş. Review: Decontamination efficiency of high power ultrasound in the fruit and vegetable industry, a review. International Journal of Food Microbiology. Volume 166, Issue 1, 16 August 2013, Pages 155-162
Volume 307, 10 May 2013, Pages 123-135
Liu, Jianghong, and Erin Schelar. “Pesticide exposure and child neurodevelopment: summary and implications.” Workplace health & safety vol. 60,5 (2012): 235-42
Lozowicka, Bozen et al. Removal of 16 pesticide residues from strawberries by washing with tap and ozone water, ultrasonic cleaning and boiling. Environmental monitoring and assessment vol. 188,1 (2016): 51.
Volume 268, Issue 2, 15 April 2013, Pages 157-177. Department of Toxicology and Pharmacology, Tehran University of Medical Sciences, Tehran, Iran
Oates, Liza, Marc Cohen, Lesley Braun. Reduction in urinary organophosphate pesticide metabolites in adults after a week-long organic diet. Environmental Research. Volume 132, July 2014, Pages 105-111
Taghizadeh SF, Goumenou M, Rezaee R, Alegakis T, Kokaraki V, Anesti O, Sarigiannis DA, Tsatsakis A, Karimi G. Cumulative risk assessment of pesticide residues in different Iranian pistachio cultivars: Applying the source specific HQS and adversity specific HIA approaches in Real Life Risk Simulations (RLRS). Toxicol Lett. 2019 Oct 1;313:91-100.
Wu, Yangliu et al. Comparison of Different Home/Commercial Washing Strategies for Ten Typical Pesticide Residue Removal Effects in Kumquat, Spinach and Cucumber. International journal of environmental research and public health vol. 16,3 472. 6 Feb. 2019.
Yang T, Doherty J, Zhao B, Kinchla AJ, Clark JM, He L.J Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples. Agric Food Chem. 2017 Nov 8;65(44):9744-9752.