3 July 2019

‘Pest MD:’ Medical Doctor Finds Cures in Agriculture

S. Eliza Halcomb, MD, FACMT

Medical Sciences and Outreach Lead
Bayer U.S. Crop Science

Three years ago, I left emergency medicine for a career in agriculture. The surprise amongst my colleagues was palpable. Questions swirled: “What is an ER doc doing in ‘Big Ag?’ Don’t you miss medicine? Don’t you want to help people?”

The answer is simple. I became a physician after meeting a starving child in Haiti in 1989. Twenty-one years later, I returned to Haiti for a relief mission after the 2010 earthquake; sadly, nothing much had changed since my first trip. Again, I saw the impact of grinding poverty, food insecurity and insect-borne illnesses. It then dawned on me that addressing those issues would have a much more lasting and meaningful effect on people in developing countries than any brief relief mission I would make as a doctor.

Two Tiers of Health

About 10,000 years ago, an innovative farmer decided to give up the hunter/gatherer lifestyle and stay put on a plot of land. This was the dawn of agriculture, which led to the birth of civilization and remains at its roots. Food security is the first tier of health. Once it is met, people can pursue education, which leads to knowledge and innovations that benefit individuals, their families and society.

The second tier of health comes from avoiding preventable diseases. Over the millennia, plants, animals and humans have evolved to produce their own protective mechanisms in order to survive and reproduce. Since plants cannot run away from predators, they make their own pesticides to defend themselves. It turns out that pesticides are critical for plant, animal and human health. The word “pesticide” is an umbrella term that refers to any chemical, natural or human-made, that is designed to kill another organism. Regarding human health, this term covers the following classes of chemicals: insecticides kill bugs like ticks, fleas, lice and mosquitoes; fungicides control the growth of naturally occurring toxins in crops; and antibiotics like penicillin are chemicals secreted by molds that kill bacteria. In agriculture, insecticides target crop-eating insects, herbicides control weeds that compete with crops for resources, fungicides prevent fungal diseases and rodenticides ward off rodents in crop storage bins. We use such products regularly to protect crops and keep our families and pets healthy. Many of them are analogues of natural pesticides that organisms make to protect themselves. For example, permethrin is a synthetic insecticide that is derived from pyrethrum, a natural chemical made by certain species of the flowering plant chrysanthemum.

No Blues Over Residues

Some people worry about ingesting trace amounts of pesticides on food crops. The fact is that when we eat a plant-based diet, we are eating many of the natural chemicals that plants produce to protect themselves. According to research,[1] 99.99 percent of pesticides consumed fall into this category and are commonly found in concentrations thousands of times higher than most synthetic pesticides used in agriculture. Since we know that fruits and vegetables are essential to a healthy diet, we don’t worry about eating these natural pesticides. Nor should we worry about consuming synthetic pesticide residues because if they are present at all, they are in very trace amounts (parts per billion). Plus washing produce in clean, running water significantly reduces any residues.

Moreover, pesticide residues are heavily regulated by government authorities such as the U.S. Department of Agriculture and Environmental Protection Agency. These agencies set maximum exposure limits for each pesticide, which is about 100 to 1,000 times lower than the allowable daily intake calculated from animal studies. Therefore, we can say with certainty that any low level of pesticide exposure that comes through the diet poses no risk of adverse health effects assuming pesticides are used as labeled. Yet the benefits of consuming healthy, whole foods are numerous.

Synthetic pesticides that protect our crops are highly tested for human and environmental safety before being approved by regulatory authorities. Additionally, many organic farmers use approved pesticides – mostly from natural sources but a few synthetic – which when applied properly, will not cause adverse health effects either.

Sustainable Agriculture, Sustainable People

In summary: 1) a secure food supply is the foundation of civilization; 2) pesticides are critical for human health because they augment food security and protect people from insect-borne illnesses; 3) plants have evolved to make their own pesticides to protect themselves; 4) residues left by plant-made pesticides are much higher than synthetic pesticides; 5) residues of any type do not have adverse health effects on humans and 6) the nutritional value of eating healthy crops like fruits, vegetables and nuts far outweighs any hypothetical risk of pesticide residues.

So why did I leave medicine? The answer is simple: Innovations in agriculture are fundamental to human health. They protect the food supply and lift people out of poverty to help them lead healthy and productive lives. How much better can I do than that?

S. Eliza Halcomb, M.D., F.A.C.M.T., is medical sciences and outreach lead at Bayer U.S. Crop Science in Chesterfield, Missouri.

[1] Ames, B et al. Dietary pesticides (99.99% all natural). 1990. PNAS; 87:7777-81.


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    One response to “‘Pest MD:’ Medical Doctor Finds Cures in Agriculture”

    1. An interesting article, Dr Halcomb see a more productive future in Agriculture and keeping populations fed, and consequently healthy, so they shouldn’t need as much medical intervention. She explained the interwoven topics well in non-technical terms so a non-scientific person can easily understand it. The statements are scientifically sound. Also Bayer Crop Science obviously sees the value of having a “medical sciences and outreach” group in their organisation, which she leads.

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