Study Links Prostate Cancer Risk in Men to Over 20 Pesticides: Key Foods at Risk
A new study has found a significant connection between prostate cancer risk and exposure to nearly two dozen common pesticides used in the United States. Conducted by researchers at Stanford University, the study examined exposure to 295 types of pesticides across the country from 1997 to 2006. Since cancer can take years to develop, researchers analyzed prostate cancer rates from 2011 to 2020, focusing on whether regions with higher pesticide use had higher prostate cancer incidences.
The findings reveal that men exposed to 22 specific pesticides are more likely to develop prostate cancer than those with lower exposure, with 19 of these chemicals being linked to cancer for the first time. Additionally, four pesticides were found to increase the risk of dying from prostate cancer, raising questions about the safety of pesticide use in agriculture and its potential impacts on human health.
Widespread Use of High-Risk Pesticides on Major Crops
These pesticides are often applied to the most common U.S. crops, including soybeans, wheat, corn, and oats. These crops are not only staples in American agriculture but also widely used in various food products like cereals, snack bars, and plant-based milks. Previous reports from environmental organizations show that approximately 90 percent of certain fruits and vegetables, such as strawberries, apples, and spinach, contain pesticide residues. While much of the corn and grain grown in the United States is used for ethanol production or livestock feed, some of it still makes its way into food products for human consumption.
The Environmental Working Group has previously highlighted the presence of pesticides in oats and other grains, finding traces of these chemicals in common food products. A 2018 study detected the pesticide glyphosate in 71 out of 73 oat-based products, including cereals and snack bars, and a 2023 follow-up study confirmed glyphosate was still found in about 30 percent of oat products tested.
The Impact on Public Health and Prostate Cancer Risk Rates
In 2023 alone, nearly 288,300 men in the United States were diagnosed with prostate cancer risk, with approximately 34,700 deaths attributed to the disease. Prostate cancer is the second most common cancer among men in the U.S., affecting the prostate gland, which is crucial for semen production. Statistics show that one in eight men will be diagnosed with this cancer during their lifetime.
For years, prostate cancer has been linked to chemical exposure, including certain pesticides. This new study, published in Cancer, the journal of the American Cancer Society, used county-level data to estimate people’s exposure to pesticides and the potential risk associated with different chemicals. The researchers analyzed pesticide exposure from two-time frames: 1997-2001 and 2002-2006, comparing each period to prostate cancer rates in subsequent years to identify patterns.
In the first period, from 1997 to 2001, there were over 953,000 prostate cancer diagnoses and around 140,000 deaths. The second period, from 2002 to 2006, saw over 1 million diagnoses and 156,000 deaths. This analysis confirmed that 22 pesticides were linked to a higher prostate cancer risk
Research Highlights Key Chemicals
The study’s lead author, Dr. Simon John Christoph Soerensen, emphasized the importance of examining environmental exposures to understand geographic variations in prostate cancer rates and mortality across the United States. Some of the pesticides, such as 2,4‐D, linuron, and carbaryl, were previously linked to cancer, while others were newly associated with prostate cancer. Chemicals like 2,4-D have been classified as possibly carcinogenic by the International Agency for Research on Prostate Cancer Risk, which cautions against inhaling or ingesting the chemical.
Newly identified chemicals in the study include cloransulam‐methyl, a herbicide used on soybeans, thiamethoxam, an insecticide applied to corn, wheat, and potatoes, and glyphosate, commonly found in the weed-killer RoundUp. Additionally, the study linked four pesticides—trifluralin, cloransulam-methyl, diflufenzopyr, and thiamethoxam—to an increased risk of prostate cancer mortality.
Pesticides and Human Consumption
While not all of these crops are directly consumed by humans, some of these pesticides may still end up in food products. According to the World Resources Institute, less than 2 percent of corn in the U.S. is grown for human consumption, with the majority used for ethanol or animal feed. Only 15 percent of soybeans are grown for direct consumption by people, with the rest going towards livestock feed and fuel.
Regulatory Oversight and Future Research
The Environmental Protection Agency (EPA) oversees pesticide regulations in the U.S., with over 350 pesticides registered for use. The agency conducts periodic reviews to ensure these chemicals do not pose unreasonable risks to human health and the environment. However, the study’s findings suggest that stricter oversight may be warranted.
Professor Oliver Jones, a chemistry expert, noted that while this study highlights statistical associations between certain pesticides and prostate cancer, it does not confirm causation. He emphasized the need for more research to confirm the link and better understand the risk factors.
As scientists continue to investigate these associations, there is potential for new preventive measures and treatments. Dr. Soerensen believes these findings could help guide future studies, ultimately reducing the number of men affected by prostate cancer.
