Pesticides: What you need to know about what’s on your food

Functional medicine | Digestion

Pesticides are the chemicals used to kill or harm various organisms or pests – so they’re inherently toxic. But they’re part and parcel of modern food production systems as they stop organisms and bacteria from infecting, destroying or contaminating food and livestock. Every type of farming makes use of pesticides in some form. Yes, even organic farming.

The difference is the composition of the chemicals that get used. The development of pesticides has played an essential role in increasing the rate at which food can be produced at scale. But are the benefits offset by a cost to our health? Let’s look at the myths and facts:

What exactly are pesticides?

There are numerous different types of pesticides. These include herbicides (which kill unwanted weeds), insecticides (to keep crops clear of insects and their larvae), rodenticides (which target rodents), fungicides (which prevent fungal rot in seeds and harvested crops), algicides (target algae) and bactericides (which kill specific bacteria).

While ideally, pesticides should act only on the organisms they target, without any effect on humans or the environment, it’s unfortunately not that simple. When pesticides first emerged, a lack of research and knowledge of the potentially harmful ramifications meant they were largely unregulated1 and only as the health effects became apparent over time, were they scrutinized.

How are they regulated?

Now, when pesticides are approved for use, they have to be evaluated in terms of any potential risks they pose to humans and the environment. Various regulations and checks are in place to ensure that little to no residue ends up in the food we ingest.

Regulatory bodies set Maximum Residue Limits (MRLs) – that is the highest level of a pesticide residue that is allowed in food or animal feed, by law in a specific country when used correctly2. The MRL is set at a threshold significantly higher (sometimes 100 to 1000 times higher) than that which is known to cause even the slightest adverse event. Average daily intake ratios and lifetime consumption are also taken into consideration when considering whether a pesticide is safe to use.

What are the potential health effects?

According to the EPA, when regulatory limits are exceeded, health effects of pesticides can vary from impacting the nervous system, to causing skin irritation, to even being carcinogens3. Some have also been known to disrupt the endocrine system in the body.

Thankfully, it is fairly uncommon for limits to be exceeded in foods (a European study found regulatory limits to be exceeded in just 4% of 40 600 different foods4). Most cases of health events in connection with pesticides in foods are linked to isolated cases of accidental overuse or farm workers being overexposed to specific pesticide chemicals5.

But what about organic?

There is a misconception that ‘organic’ means ‘free of pesticides’. In reality, organic farming simply uses organic pesticides while standard farming methods use what are known as synthetic pesticides. What’s the difference? Organic or biopesticides are derived from natural sources. Just because of their natural origin they are often assumed to less harmful than man-made pesticides – but this is not the case.

Organic pesticides can also be harmful to humans or the environment in certain use cases and quantities6. It’s also been noted that some organic pesticides are used in higher quantities than their synthetic counterparts because they aren’t as effective in small doses. So while switching to organic produce will lower your exposure to synthetic pesticides, it increases your exposure to biopesticides.

So should we be avoiding foods produced with pesticides?

Since it is rare for produce to exceed the regulatory levels of pesticide residues, it is not necessary to avoid all store-bought produce and start your own back yard veggie garden. Due to the MRL standards and regulations, the amount of produce you would have to eat to be negatively affected by pesticide residue (synthetic or natural) is extremely high.

If you’re concerned about it, or have consulted with your doctor on potential allergies you may have, here are some tips to keep in mind to reduce your intake of pesticide residue:

1) Always thoroughly wash fresh produce. Some research has shown that rubbing produce under running water was effective in removing nine out of the 12 pesticides tested7.

2) Try to buy local. Get to know your local suppliers and seek to understand their farming practices and pest control solutions.

3) Know which foods contain more residue than others. Follow the Environmental Working Group’s Shopper’s Guide which identifies the produce with the highest concentrations of synthetic pesticide residue. This can help you make an informed choice on which produce to buy organic when possible.

4) Keep eating fruit and vegetables! The health benefits of eating fresh produce significantly outweigh the risk posed by residue from pesticides.


1, 4, 5 Thorpe, M. 2017. Are Pesticides in Foods Harming Your Health? Healthline.

2 Ortuzar, J.E. 2018. Pesticide residues in food: myths and reality Cornell Alliance for Science.

3 Food and Pesticides. United States Environmental Protection Agency

6 Magkos, F., Arvaniti, F., Zampelas, A. 2003. Putting the safety of organic food into perspective. Nutrition Research Reviews. 16, 211-221.

7 Here’s The Best Way to Wash Fruit And Vegetables To Remove Pesticides. 2018. Huffington Post.

Dr. Matt le Roux is a man of many talents: chiropractor, sports scientist and functional medicine practitioner. His science-based approach motivates him to explore the synergy between health and performance that changes the way you move, live, train, think, and eat.

Dr Matt le Roux

Chiropractor, Functional medicine practitioner

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