Rising levels of chlormequat, an agricultural chemical linked to infertility, in grain products

Researchers in a 2024 study measured levels of chlormequat in the US population and US food supply, finding increased levels since 2017. Chlormequat has been linked to reproductive problems in animals, and it’s not clear if this applies to humans.

Chlormequat is a chemical used in agriculture to help plants from growing too tall and bending over. It’s approved for use in Canada, Europe and the UK, and in the US is only allowed to be used on ornamental plants.

However, the US Environmental Protection Agency (EPA) approved the import of crops treated with chlormequat in 2018, with acceptable food tolerance levels in imported oat, wheat, barley and some animal products. These levels were increased in 2020 for products containing oats.

There is some evidence linking chlormequat to reproductive problems in animals:

• Pig farmers noted declined fertility in pigs that ate grains treated with the chemical, which was linked to disrupted estrous cycling (Sørensen et al. 2006).
• Male mice exposed to the chemical showed decreased fertilization capacity (Torner et al. 1999).
• Various rat studies have shown delayed puberty onset, reduced sperm motility and decreased testosterone levels (Hou et al. 2020, Xiao et al. 2021, Hou et al. 2018).
• Rat embryos exposed to the chemical show disrupted embryonic growth (Xiagedeer et al. 2020).
• Not all studies have found effects on reproductive health (Sørensen et al. 2009, Liu et al. 2019).

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Temkin et al. (2024) did a study and measured chlormequat levels in the US population and US food supplies. Since the 2020 decision to allow higher levels of chlormequat in important food products, they wanted to see if this had any effect.

Between 2017 to 2023, they were able to detect chlormequat in 77 of 96 (80%) of urine samples from US individuals. From 2017 to 2023, the detection frequency increased from 69% to 90%. This means that more people had chlormequat in their urine in 2023 compared to 2017.

Concentrations of chlormequat also increased from 2017 to 2023, from about 0.9 ug/g of creatine to 5 ug/g of creatine (average). You can see the concentrations below. Note that “per g creatine” is used to normalize the urine measurements, since some urine might be more or less diluted.

They also examined common food products to see if chlormequat could be detected, with concentrations ranging from non-detectable to 291 ug/kg. Higher levels were detected in oat products and there were lower levels in wheat products. Organic oat-based products were mostly free of chlormequat.

You can check out all the products they tested below. Note that “ppb” refers to “parts per billion” and is the same as 1 ug per 1 kg, and “ND” means “not detected.”

Brand	Product	Food Type	Production Type	Collection Date	Chlormequat (ppb)
General Mills	General Mills Cheerios	oats	Conventional	June 2022	107
General Mills	General Mills Honey Nut Cheerios	oats	Conventional	June 2022	30
Kellogg’s	Kellogg’s Special K Fruit & Yogurt	oats	Conventional	June 2022	ND
Quaker	Quaker Oatmeal Squares Honey Nut	oats	Conventional	June 2022	160
Quaker	Quaker Old Fashioned Oats	oats	Conventional	June 2022	291
365 Whole Foods Market	365 Whole Foods Market Organic Raisin Granola	oats	Organic	August 2022	ND
General Mills	General Mills Cheerios Oat Crunch Oats n’ Honey	oats	Conventional	August 2022	90
General Mills	General Mills Frosted Cheerios	oats	Conventional	August 2022	40
Target	Good & Gather French Vanilla Almond Granola	oats	Conventional	August 2022	90
Quaker	Quaker Chewy Dark Chocolate Chunk	oats	Conventional	August 2022	80
Quaker	Quaker Instant Oatmeal Maple & Brown Sugar	oats	Conventional	August 2022	170
Quaker	Quaker Oatmeal Squares Brown Sugar	oats	Conventional	August 2022	90
Quaker	Quaker Simply Granola Oats Honey & Almonds	oats	Conventional	August 2022	70
Walmart	Walmart Great Value Oats & Honey Granola	oats	Conventional	August 2022	180
365 Whole Foods Market	365 Whole Foods Market Fruit & Nut Muesli	oats	Conventional	May 2023	ND
365 Whole Foods Market	365 Whole Foods Market Organic Chocolate Chip Chewy Granola	oats	Organic	May 2023	ND
365 Whole Foods Market	365 Whole Foods Market Organic French Vanilla Granola	oats	Organic	May 2023	ND
365 Whole Foods Market	365 Whole Foods Market Organic Old Fashioned Rolled Oats	oats	Organic	May 2023	ND
General Mills	General Mills Cheerios	oats	Conventional	May 2023	123
General Mills	General Mills Cheerios Oat Crunch Oats n’ Honey	oats	Conventional	May 2023	104
General Mills	General Mills Frosted Cheerios	oats	Conventional	May 2023	122
General Mills	General Mills Honey Nut Cheerios	oats	Conventional	May 2023	116
Kellogg’s	Kellogg’s Special K Fruit & Yogurt	oats	Conventional	May 2023	12
Quaker	Quaker Chewy Dark Chocolate Chunk	oats	Conventional	May 2023	60
Quaker	Quaker Instant Oatmeal Maple & Brown Sugar	oats	Conventional	May 2023	112
Quaker	Quaker Instant Oatmeal Organic Maple & Brown Sugar	oats	Organic	May 2023	ND
Quaker	Quaker Oatmeal Squares Brown Sugar	oats	Conventional	May 2023	199
Quaker	Quaker Oatmeal Squares Honey Nut	oats	Conventional	May 2023	189
Quaker	Quaker Old Fashioned Oats	oats	Conventional	May 2023	209
Quaker	Quaker Simply Granola Oats Honey & Almonds	oats	Conventional	May 2023	69
Simple Truth (Harris Teeter)	Simple Truth Organic Instant Oatmeal Maple & Brown Sugar	oats	Organic	May 2023	ND
Simple Truth (Harris Teeter)	Simple Truth Organic Oats & Honey Granola Clusters	oats	Organic	May 2023	ND
Simple Truth (Harris Teeter)	Simple Truth Organic Toasted Oats Cereal	oats	Organic	May 2023	17
Arnold	Arnold Whole Grains Healthy Multi-Grain Bread	wheat	Conventional	February 2023	12.6
Band of Bakers	Band of Bakers Harvest Loaf	wheat	Conventional	February 2023	ND
General Mills	General Mills Cinnamon Toast Crunch	wheat	Conventional	February 2023	ND
Gold Medal	Gold Medal Premium Quality All Natural Whole Wheat Flour for Baking, 5 lb.	wheat	Conventional	February 2023	ND
Great Value (Walmart)	Great Value Half-Length Spaghetti	wheat	Conventional	February 2023	ND
Kellogg’s	Kellogg’s Frosted Mini Wheats	wheat	Conventional	February 2023	ND
King Arthur	King Arthur Flour All-Purpose Unbleached Flour	wheat	Conventional	February 2023	ND
Nabisco	Nabisco Ritz Crackers	wheat	Conventional	February 2023	ND
Nature’s Own	Nature’s Own 100% Whole Grain Bread	wheat	Conventional	February 2023	3.5

So is this anything to be worried about?

The data on the negative effects of chlormequat are based on animals studies, and have mixed results. It’s hard to draw conclusions based on this, because the reproductive system of pigs and rodents are very different from humans.

This study is also simply showing higher levels of the chemical, without any association to infertility in humans. These higher levels might not have any impact at all.

There’s been biomonitoring studies done in other countries, specifically Sweden (Lindh et al. 2011, Noren et al. 2020) and the UK (Galea et al. 2015) where chlormequat is permitted to be used on crops. The UK in particular has shown high median levels of chlormequat in the urine in 2011/2012, at 15.1 ug/g of creatine. These concentrations are much higher than in the US, at 1.4 ug/g of creatine.

You can see the median (middle) levels of chlormequat from these studies below, along with the “limit of detection” (LOD) that indicates the lowest accurate measurement.

Again, it’s not clear if any of this has any impact on human fertility and more studies are needed to see the effects. For those concerned, it may be best to eat organic products as these seem to have lower levels of the chemical.

Given the toxicological concerns associated with chlormequat exposure in animal studies, and widespread exposure to the general population, in European countries, and now also likely in the U.S., monitoring of chlormequat in foods and people, in conjunction with epidemiological and animal studies, is urgently needed to understand the potential health harms of this agricultural chemical at environmentally relevant exposure levels, particularly during pregnancy.

Reference

Temkin AM, Evans S, Spyropoulos DD, Naidenko OV. A pilot study of chlormequat in food and urine from adults in the United States from 2017 to 2023. J Expo Sci Environ Epidemiol. 2024 Feb 15. doi: 10.1038/s41370-024-00643-4. Epub ahead of print. PMID: 38355783.

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About Embryoman

Embryoman (Sean Lauber) is a former embryologist and the founder of Remembryo, an IVF research and fertility education website. After working in an IVF lab in the US, he returned to Canada and now focuses on making fertility research more accessible. He holds a Master’s in Immunology and launched Remembryo in 2018 to help patients and professionals make sense of IVF research. Sean shares weekly study updates on Facebook, Instagram, and Reddit regularly. He also answers questions on Reddit or in his private Facebook group.

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