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The Dirty Dozen - The "Dirtiest" Fruits & Veggies of 2018

By Casey Thaler, B.A., NASM-CPT, FNS
June 18, 2018
The Dirty Dozen - The

If “the dirty dozen” reminds you of a classic 1967 film – you are not alone. But alas, that’s not what we are talking about today! Just a few weeks ago, the Environmental Working Group (EWG) released their annual list of the ‘dirtiest’ fruits and vegetables – meaning which foods were sprayed with the highest amounts of pesticides.[1] Every year since 2004, the EWG has compiled a consumer-friendly list to help guide towards the best fruit and vegetable choices. I personally use this list to give to clients, so they can make the most well-informed choices, for their diets.

This year, strawberries (a personal favorite) top the list of the dirtiest fruits and vegetables, followed by spinach (which is also disappointing). Now before we delve further into the list, it is important to note that the list essentially informs you which fruits and vegetables are much better to buy in organic form – and strawberries and spinach would be the most important to take note of. These foods should absolutely be purchased in organic form, whenever possible. It is absolutely not worth the risk of buying these in non-organic form – even if you save a little bit of money.

Perhaps the most important takeaway from the new publishing? That roughly 70 percent of all non-organic produce sampled was contaminated with pesticides. Now – perhaps more than ever – it definitely pays to buy organic. Without spoiling anything (and with limited data to back this up with), I would venture to guess that things are only going to get worse, in terms of pesticide use. So it makes a lot of sense to start buying organic now, so you are always in the habit of consuming the best fruits and vegetables.

Note: regular potatoes are not part of The Paleo Diet, but sweet potatoes are
Note: regular potatoes are not part of The Paleo Diet, but sweet potatoes are

Nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery, sweet potatoes and sweet bell peppers were the other foods rounding out the most contaminated produce. Since the United States Department of Agriculture and Food and Drug Administration performed these tests on 38,000 samples – there is good reason to believe the results are accurate.

For the dirtier details, strawberries were found to have 20 (!) different pesticides, while spinach had almost twice as much pesticide residue, compared with any other crop. Even more sadly, one of my absolute favorite foods, hot peppers, was the ‘bonus’ item, as the 13th most heavily contaminated crop. Since I frequently consume hot peppers, I will be sure to make sure I avoid any non-organic choices, from here on out.

As astute Paleo Diet® readers probably know, cooking will alleviate some of the residues on these foods, but it still pays dividends to always buy organic, as much as you can afford to. For those that cannot, rinsing produce under water for 30 seconds (or longer) should rinse away a substantial amount of pesticide residue. For those really concerned, you can even mix in some baking soda, which has been shown to remove even more pesticides.

Encouragingly, there is also the flip side to this list – the ‘clean 15’. This – as you would expect – lists the 15 least contaminated fruits and vegetables tested. This list is topped by avocados (the least contaminated fruit or vegetable tested), and followed by sweet corn, pineapples, cabbage, onions, frozen sweet peas, papayas, asparagus, mangoes, eggplant, honeydew melon, kiwi, cantaloupe, cauliflower and broccoli. The takeaway here is that these foods are generally pretty safe to buy, in non-organic form.

Since I am a big consumer of avocados, asparagus, cauliflower and broccoli – this was great news for me! There has also been interesting research that shows that due to decreasing mineral concentrations in the soil, foods no longer have the same nutrient levels that they once did.[2] Whether these foods are organic or not, was not relevant to the research. This is a fairly alarming reminder that we always need to be eating more vegetables, just to keep our health at a ‘good’ level – let alone to make it great!

If one digs deeper into the EWG report, there are even more disturbing facts. Spinach – one of my most frequently consumed (and recommended) foods – was reported to contain DDT in 40 percent (!) of all non-organic samples. DDT, for those who may not remember, received a huge amount of negative press in the 1970s and 1980s, for being neurotoxic.[3] The fact that it was found in this much of our non-organic spinach, was a truly disturbing find.

In fact, many of the pesticides and substances found in the ‘dirty dozen’ list are completely banned from being used in other countries. The United States has more lax rules and regulations, and thus – we are consuming more pesticides, as a result. Though somewhat unproven, there is some alarming research that suggests mothers consuming pesticides end up giving birth to children with significant problems, as a direct result.

This research suggests behavioral issues, mental development issues, and possibly even diseases – are all possible as a result of too much pesticide exposure in utero.[4] [5] [6] [7] [8] [9] [10] [11] It must again be re-stated that this research is mostly preliminary, and is far from conclusive or definitive. However, what is not debatable, is that there is definitely no upside to consuming any amount of pesticides – let alone on a regular basis. It is also hard to argue that the rate of mental issues, as well as developmental issues, has not increased alarmingly, concurrently with our increased use of pesticides.

However, remember that there is always the ‘clean 15,’ and that these foods will not put you at risk for exposure to pesticides. And you can also take the very practical step of washing your produce under water for 30 seconds, and be able to remove many pesticides – even from foods found on the ‘dirty dozen’ list. Still, if you are really looking to avoid any risk, and maximize your health, it makes the most sense to always buy organic, if you can afford to. A Paleo Diet is high in beneficial nutrients, largely due to the quantity of healthy vegetables – so make sure you pay attention to these two lists, and choose wisely!


[1] EWG. (2018). OUT NOW: EWG’s 2018 Shopper’s Guide to Pesticides in Produce™. [online] Available at: [Accessed 3 May 2018].

[2] Davis, D. (2009). Declining fruit and vegetable nutrient composition: What is the evidence?. HortScience, 44(1), pp.15–19.

[3] Franco R, Li S, Rodriguez-rocha H, Burns M, Panayiotidis MI. Molecular mechanisms of pesticide-induced neurotoxicity: Relevance to Parkinson's disease. Chem Biol Interact. 2010;188(2):289-300.

[4] Frazier LM. Reproductive disorders associated with pesticide exposure. J Agromedicine. 2007;12(1):27-37.

[5] Rappazzo KM, Warren JL, Meyer RE, et al. Maternal residential exposure to agricultural pesticides and birth defects in a 2003 to 2005 North Carolina birth cohort. Birth Defects Res Part A Clin Mol Teratol. 2016;106(4):240-9.

[6] Rocheleau CM, Bertke SJ, Lawson CC, et al. Maternal occupational pesticide exposure and risk of congenital heart defects in the National Birth Defects Prevention Study. Birth Defects Res Part A Clin Mol Teratol. 2015;103(10):823-33.

[7] Garry VF, Schreinemachers D, Harkins ME, Griffith J. Pesticide appliers, biocides, and birth defects in rural Minnesota. Environ Health Perspect. 1996;104(4):394-9.

[8] Winchester PD, Huskins J, Ying J. Agrichemicals in surface water and birth defects in the United States. Acta Paediatr. 2009;98(4):664-9.

[9] Larsen AE, Gaines SD, Deschênes O. Agricultural pesticide use and adverse birth outcomes in the San Joaquin Valley of California. Nat Commun. 2017;8(1):302.

[10] Heeren GA, Tyler J, Mandeya A. Agricultural chemical exposures and birth defects in the Eastern Cape Province, South Africa: a case-control study. Environ Health. 2003;2(1):11.

[11] Garry VF, Schreinemachers D, Harkins ME, Griffith J. Pesticide appliers, biocides, and birth defects in rural Minnesota. Environ Health Perspect. 1996;104(4):394-9.

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