Let's discuss. While we each may have our own (possibly strong) opinion on this topic, my goal is to present what we know from the scientific literature. And I'll be honest, we need more research. That said, independent studies have reported that various pesticides are linked with a host of health problems, including brain and nervous system toxicity, cancer, and hormone disruption.
One study that always comes to mind when discussing organic versus conventional foods is this one. The study enrolled 40 Mexican-American children, 3-6 years old: 20 from an urban neighborhood in Oakland and 20 from the nearby agricultural Salinas Valley. The scientists swapped out non-organic food for organic in the kids’ diets and measured the concentrations of pesticides in urine. Urine samples were collected over 16 days – 4 days of the conventional diet, then 7 days of the organic diet, and then 5 days of the conventional diet.
The amount of pesticides in the children in both communities, as measured by urine metabolites, plummeted after they switched to organic food. Metabolites of two neurotoxic organophosphate pesticides dropped by an average of 40% and 49%. Levels of the weedkiller 2,4-D, a possible carcinogen, dropped by 25%. While this study does not prove that organic foods are better or more nutritious per se, it illustrates how quickly diet can positively and negatively affect our pesticide concentrations, suggesting that our health could indeed be impacted by what we choose to eat.
Organic Labels
Organic labels can be used only when foods have been produced in accordance with standards set by the USDA. USDA standards outline production methods that foster “cycling of natural resources, promote ecological balance, and conserve biodiversity”. If a food is labeled as organic, the following are NOT allowed: synthetic fertilizers, sewage sludge, irradiation, &/or genetic engineering. Organically raised animals cannot be given growth hormones or antibiotics.
Pasture-Raised Meat & Dairy
Dioxins and polychlorinated biphenyls (PCBs) are persistent, bio-accumulative and toxic environmental contaminants. Over 95% of human exposure to these concerning chemicals occurs with the consumption of fatty meat and dairy products. Be aware that most toxins are lipophilic, meaning they 'love fat' and will reside in fatty foods. Hence, if including meat in your diet, the thought is that choosing organically-raised meat would result in a lower intake of these toxins. Additionally, pasture-raised meat has been shown to have a higher concentration of the healthful omega-3 fatty acids compared with grain-fed or feedlot raised meat.
Some researchers have indicated that pasture feeding conventional cows will remove differences previously reported for organic and conventionally produced milk. The demand for dairy products from grass-fed cows is likely due to the more desirable fatty acid profile, containing higher beneficial omega-3 fatty acids and conjugated linoleic acid.
Organic Produce
Several studies (*, **) have concluded that organic foods have been convincingly demonstrated to expose consumers to fewer and lower levels of pesticide residues.
The Environmental Working Group (EWG) found that conventionally grown strawberries contained an average of 7.8 different pesticides per sample, almost four times the average of all other produce. A different study reported that organic strawberry farms produced higher quality fruit and their higher quality soils may lead to greater microbial functional capacity and resilience to stress.
Beyond pesticide residues, some research suggests that organic produce yields higher concentrations of protective phytochemicals. Organic plums had significantly greater overall antioxidant capacity and specifically higher polyphenol and anthocyanin concentrations. Additionally, this study reported that organic tomatoes contained a 20% higher concentration of lycopene, a 30% greater amount of vitamin C, a 24% increase in total phenolics and 21% more flavonoids compared with conventional tomatoes. Furthermore, in this study, organic oranges had statistically significantly higher phytochemical content than conventional oranges.
EWG annually publishes the 'Dirty 12' - the 12 produce items that contain the highest level of pesticide toxicity and the 'Clean 15' - the 15 produce items with the least amount of pesticides and pesticide toxicty. For 2020, the ‘Dirty 12’ include: strawberries, spinach, kale, nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery, and potatoes. The ‘Clean 15’ include: avocados, sweet corn*, pineapple, onions, papayas*, frozen sweet peas, eggplant, asparagus, cauliflower, cantaloupe, broccoli, mushrooms, cabbage, honeydew melon, and kiwi.
Summary
Consuming organic foods can reduce organochlorine pesticide exposure and the amount of pesticides in our bodies. Some research indicates a greater phytochemical profile with the consumption of organic foods. Opting for organic foods is an environmentally friendly decision working to improve the biodiversity of soils. There may be potential health benefits in regards to different chronic diseases. Additional data on food composition of organic food and dietary intervention studies are needed before health claims about organic food can be confidently made.
Bottom line - if you choose to include meat and dairy in your diet, given that those foods are higher on the food chain, it is most important to consider purchasing organic meat and dairy. Regarding produce, consider opting for organic, particularly for the 'Dirty 12' or instead, substitute a produce item from the 'Clean 15' list. And, if you find that organic foods taste superior, which is certainly possible, even better.