Pesticides and Human Health

Pesticides include over 600 unique chemicals that are designed to kill living organisms. Measurable levels of many of them are found in the bodies of nearly all Americans. Eating pesticide-treated fruits and vegetables is the main source of exposure for most of us. There has been concern for years that these pesticide levels might cause some health problems, but there’s been no proof of this. Chemical companies have repeatedly assured us that any pesticide levels found are too low to cause any trouble, and our government agencies have allowed their continued use.

Pesticides and Human Reproduction

Now, for the first time, science has shown that pesticide levels can damage human reproductive capability. A research article published in JAMA Internal Medicine this month (January 2018) found a strong association between pesticide intake and lower female fertility in humans. The authors conclude that “intake of high-pesticide residue [from fruits and vegetables] was associated with lower probabilities of clinical pregnancy and live birth among women undergoing infertility treatment”1

The authors of this well-designed research article are on the faculty of Harvard Medical School and Harvard’s School of Public Health. It is a high-quality study that is likely to become known as a landmark study because it’s the first to report a relationship between pesticide intake and human health.

A commentary by Dr. Philip Landrigan from the Mount Sinai School of Medicine calls this an elegant study that uses “sophisticated biological markers to identify a sub-clinical effect of pesticide exposure on human health.” The study found that regular consumption of pesticide-treated fruits and vegetables was associated with increased risk of pregnancy loss, while consumption of organic fruits and vegetables significantly reduced that risk.

Dr. Landrigan points out that multiple lines of evidence suggest that human fertility is on the decline, and not only in females. “Sperm counts in Western countries have fallen by 54 percent  since 1973… Incidence of testicular cancer has increased by 55 percent in the United States since 1970.” He says these changes have occurred too rapidly to be of genetic origin. Environmental exposures are far more likely to be involved.

Dr. Landrigan makes three basic recommendations to physicians:

  1. Educate patients about the hidden dangers of pesticides in our environment;
  2. Encourage them to eat organic fruits and vegetables;
  3. Educate elected officials and policy makers about the hazards of pesticides, namely that “these potent chemicals can have powerful effects on human health that need to be intelligently confronted.”2

My Comments

This excellent research study connects eating pesticide-treated fruits and vegetables with the development of impaired human fertility. The fact that it was designed as a prospective study makes this connection especially strong. Dr. Landrigan’s commentary is on target. I totally agree with his recommendations.

The practical concern for many people centers around eating organic fruits and vegetables. A group called the Environmental Working Group (EWG) has studied this subject extensively and provides much helpful information for anyone interested. Organic produce is definitely worth buying. It may cost a bit more than regular produce, but the difference is now small in most cases.

applesEWG has a list of the most contaminated fruits and vegetables it calls the “Dirty Dozen.” For this list, EWG singled out produce with the highest loads of pesticide residues. This year’s list includes strawberries, spinach, nectarines, apples, peaches, celery, grapes, pears, cherries, tomatoes, sweet bell peppers and potatoes. These are heavily laced with multiple pesticides. I get them organically as much as possible.

EWG also has a list that it calls the “Clean Fifteen” because they have little or no pesticide contamination. EWG’s Clean Fifteen list includes sweet corn, avocados, pineapples, cabbage, onions, frozen sweet peas, papayas, asparagus, mangoes, eggplant, honeydew melon, kiwis, cantaloupe, cauliflower and grapefruit. Since these are “clean,” I often get them from the regular produce areas. I hope this information is helpful for you.

Concluding Thoughts

The matter of educating our elected officials and policy-makers about the pesticide issue is a serious one. Rachel Carson first alerted us about this danger over 55 years ago with her book Silent Spring, published in 1962. Some progress has been made through the years, but we remain under threat. Dr. Landrigan said this new study provides a warning “that our current laissez-faire attitude toward the regulation of pesticides is failing us.”

I’ll put it more bluntly. This study tells us that our children’s lives are under attack from the time of conception. This should get the attention that a 4-Alarm blaze does in any city. When you get down to basics, this danger to our future is greater than any 4-Alarm fire could be.

The critic might jeer: “That’s no 4-alarm blaze. It’s not even a blaze.”

The critic is right. It’s more like a smoldering fire than a 4-Alarm blaze, but smoldering fires can cause extensive damage. This one’s been smoldering for over half a century. It’s past time to call on fire-fighters to put this fire out!

Please send this article to anyone you think might benefit from it.

Be Well!

Ed Dodge, MD, MPH


  1. JAMA Intern Med.2018;178(1):17-26
  2. JAMA Intern Med.2018;178(1):26,27

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This post was published first in Dr. Ed Dodge’s Wellness Newsletter, Volume X, No. 1 • January 6, 2018.