Nearly two-dozen of the most common pesticides used in America are linked to prostate cancer, a study warns.
Stanford University researchers looked at exposure to 295 different kinds of the chemicals across the whole country between 1997 and 2006.
Since cancer takes time to develop, the team then looked at cancer rates from 2011-2020 to see if the areas with high pesticide use also had high rates of the cancer.
They found men exposed to 22 different pesticides were more likely to be diagnosed with the disease than those less exposed to the chemicals, including 19 that had never been linked to cancer before.
Four of those pesticides were also linked to an increased risk of dying from cancer. The study authors wrote that: ‘these findings suggest that pesticide exposure may contribute to variations in prostate cancer incidence and mortality.’
These are commonly used on some of the country’s most widespread crops – including soybeans, wheat, corn and oats. These crops are found in everything from cereal to snack bars to plant based milks.
More than 95 percent of samples of strawberries, apples, cherries, spinach, nectarines and grapes had at least two pesticides on them, the EWG found
This adds to previous studies by the Environmental Working Group (EWG) which show that roughly 90 percent of strawberries, apples, cherries, spinach, nectarines and grapes tested positive for two pesticides.
However, much of the corn and grain grown in the US isn’t made directly for human consumption, but is instead processed into ethanol or used as feed for livestock.
The same EWG analysis actually found that sweet corn grown for human consumption is low in pesticides.
In 2023, 288,300 Americans were diagnosed with prostate cancer and 34,700 people died of the disease.
It’s the second most common cancer in the men in the US.
It affects the walnut-sized gland that sits at the base of the male bladder that’s important in generating semen. About one in eight men will be diagnosed with it at some point in their lives.
For years, prostate cancer has been linked to exposure to a number of different chemicals, including pesticides, according to Johns Hopkins.
Brain, kidney, lymph and blood cancers have also been linked to pesticides.
The Stanford study, published in the American Cancer Society’s journal, Cancer, looked at county-level data about pesticide use estimate the main kinds of chemicals people across the country were exposed to and at what levels.
They analyzed 295 of some of the most common pesticides over two different time periods, to check that any patterns they might find weren’t just a one time occurrence.
First, they compared pesticide exposure from 1997 to 2001 to prostate cancer rates from 2011 to 2015.
In this period, there were 953,204 prostate cancer diagnoses and 140,086 deaths over this time period.
Second, they compared pesticide exposure from 2002 to 2006 with prostate cancer rates from 2016 to 2020.
In this period, there were 1,063,671 diagnoses and 156,687 deaths.
They found that 22 of the pesticides they investigated were associated with a higher incidence of prostate cancer.
Lead author, urologist Dr Simon John Christoph Soerensen, said: ‘This research demonstrates the importance of studying environmental exposures, such as pesticide use, to potentially explain some of the geographic variation we observe in prostate cancer incidence and deaths across the United States.’
Studies performed by the EWG found the pesticide glyphosate in cereals in both 2018 and 2023. They note that the
Some of these pesticides, including 2,4‐D, linuron, and carbaryl, had already been linked to cancer by older studies.
The International Agency for Research classifies 2,4-D as ‘possibly carcinogenic to humans’ and cautions against breathing in or ingesting the chemical.
However, 19 other chemicals, used in controlling weeds, insects, fungus and other pests, had never before been linked to prostate cancer, the authors report.
Some of these include cloransulam‐methyl, a herbicide used on soybeans and Thiamethoxam, an insect killer sprayed on the seeds of corn, cotton, soybean, wheat and potatoes and glyphosate, a weed-killer found in RoundUp.
Four pesticides were also linked to an increased risk of dying from prostate cancer- including rifluralin, cloransulam-methyl, diflufenzopyr and thiamethoxam.
A DailyMail.com analysis found 14 of the 22 chemicals identified by the Stanford research are used on soybeans, 13 are used on corn, 10 are used on wheat, 10 are used on oat and 8 are used on almonds.
However, this doesn’t mean that all these products are always consumed by humans.
In 2020, less than 2 percent of the corn grown in the US was for human consumption, according to the World Resources Institute– with the majority going towards making ethanol and animal feed.
Only about 15 percent of US soybeans are grown for human consumption – the rest feeds poultry or is made into fuel, according to the USDA.
Still, some older research has found that sometimes, these pesticides end up in finished food products.
DM.com analysis found that 10 of the pesticides identified by the Stanford researchers appear to be used on wheat products
A 2018 study from the Environmental Working group found glyphosate in 71 out of 73 oat-based products- including cereal, snack bars and instant oats.
A follow up study in 2023 found that it was still present in about 30 percent of oat products tested.
The Environmental Protection Agency previously told DM.com that the over 350 pesticides registered for use in the US are strictly regulated.
A representative said: ‘EPA periodically reviews existing registered pesticides to ensure they can be used without unreasonable risks to human health and the environment.
‘The registration review program is intended to make sure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard of no unreasonable adverse effect.’
In addition, the research published here doesn’t show that pesticides cause cancer, it merely establishes a link, Professor Oliver Jones, professor of chemistry at RMIT University in Melbourne, told Cosmos.
Professor Jones said: ‘The authors don’t actually say that pesticides cause prostate cancer, just that they found 22 pesticides that were statistically associated with prostate cancer and that more research is needed.’
As research continues and scientists figure out what is and is not contributing to the cancer risk in the US, doctors can be better prepared to prevent and treat the disease.
Dr Soerensen said: ‘By building on these findings, we can advance our efforts to pinpoint risk factors for prostate cancer and work towards reducing the number of men affected by this disease.’
