Glyphosate & Arsenic Detected Inside Oat Milk — Purchasing Guide for Popular Oat Milk Brands

Is there toxic glyphosate or heavy metals inside oat milk? That’s the question we were asked inside the Mamavation community. Glyphosate is a broad-spectrum herbicide classified as a probable human carcinogen by the World Health Organization (WHO) and has been found in many popular oat-based foods according to a recent consumer study. Arsenic, cadmium, lead, & mercury are all problematic heavy metals found in popular foods. But do these contaminants reside in oat milk? To answer this question, Mamavation sent 13 of the most popular oat milk products to an EPA-certified lab and found glyphosate & heavy metals. You’ve trusted Mamavation to bring you other consumer studies like best yoga pants without PFAS “forever chemicals,” best nut butter without PFAS, and best ketchup without PFAS, now join us for our consumer study on popular oat milk.

Disclosure: This consumer study is released in partnership with Environmental Health News. Scientific reviews were performed by (1) Terrence Collins, Teresa Heinz Professor of Green Chemistry & Director of the Institute for Green Sciences at Carnegie Mellon University, (2) Linda S. Birnbaum, Scientist Emeritus and Former Director of the National Institute of Environmental Health Sciences and National Toxicology Program & Scholar at Residence at Duke University, North Carolina University, & Yale University, & (3) Pete Myers, Chief Scientist at Environmental Health Sciences, Adjunct Professor of Chemistry at Carnegie Mellon University, and Co-Author of Our Stolen Future. This post was medically reviewed by Sondra Strand, RN, BSN, PHN. Donations were provided by Environmental Health News and Mamavation community members. This post contains affiliate links. 

Mamavation Finds Glyphosate & Heavy Metals In Popular Oat Milk

First, let’s review oat milk and its use. Store-bought oat milk is a popular staple in many households that are seeking dairy-free milks. Many brands add additional ingredients to improve texture, flavor, nutrients, and consistency. While some people make homemade oat milk by straining oats in cheesecloth or a fine mesh sieve, most people (including many vegans) are still purchasing their plant-based milks from the grocery store aisle for convenience, better taste, and longer shelf life. Not all oat milk is safe for people with gluten intolerance, celiac disease, or gluten sensitivities. Certified gluten-free oats must be used in order to protect that population. It’s also important to mention that not everyone likes oat milk. Some people refer to it as slimy and need to cover up the taste with vanilla, maple syrup, or a pinch of salt. However, this plant-based milk alternative has become very popular and the Mamavation community asked us to test it for glyphosate and heavy metals.

Mamavation’s Oat Milk Consumer Study

Mamavation sent 13 oat milk products to an EPA-certified lab testing for glyphosate, its main metabolite aminomethylphosphonic acid (AMPA), and heavy metals. AMPA is a breakdown chemical that emerges when glyphosate has been in the environment and is breaking down over time. The detection level of our EPA-certified lab to determine the presence of glyphosate and AMPA was 10 parts per billion (ppb). Our lab also tested for heavy metals (arsenic, cadmium, lead & mercury) at 10 parts per billion because sometimes glyphosate can bind to metal ions during testing when complex matrices are present.

Here are the main findings of our consumer study:

• 15% of oat milk sent to the lab was reported to contain either glyphosate or some type of heavy metal (arsenic, cadmium, lead, & mercury). That’s 2 out of 13 products.
• About 8% of oat milk sent to the lab was reported to contain glyphosate above 10 ppb. That’s 1 out of 13 products.
• About 8% of oat milk sent to the lab was reported to contain a heavy metal — arsenic, above 10 ppb, the US water standard. That’s 1 out of 13 products.
• 2 popular oat milk brands with Prop. 65 warnings (Rise & Elmhurst) did not contain detectable heavy metals above 10 parts per billion (ppb). In other words, if they contain dangerous amounts of heavy metals, it wasn’t present in the batches we tested.
• No organic or “glyphosate residue-free” certified brands had any detection of glyphosate above 10 parts per billion (ppb).
• Because widespread use of glyphosate was established in prior consumer studies looking at common oat products, we believe that it’s possible glyphosate could be present in some products but just not in detectable levels based on how diluted the oats are in oak milk.
• No cadmium, lead, or mercury were found in any products (above 10 ppb).

Linda Birnbaum, Mamavation’s Scientific Advisor and Scientist Emeritus and Former Director of the National Institute of Environmental Health Sciences (NIEHS) and National Toxicology Program & Scholar at Residence at Duke University, North Carolina University, & Yale University, had a few things to say: “Oat milk is consumed by many people as a drink alternative that goes into coffee, cereals, baked goods, and other foods. This is why it’s important to select products that do not have detectable glyphosate or other heavy metals in order to protect your family (and yourself) from the complications that can arise from daily exposure to hormone-disrupting chemicals. One exposure would be fine, but daily exposure is concerning. “

Glyphosate Is Problematic to Human Health & Use Has Skyrocketed

The use of glyphosate spraying skyrocketed with the introduction of genetically engineered Roundup Ready crops, such as GMO corn, soybeans, cotton, canola, & sugar beets. It was first approved in 1996 under the Clinton administration. In contrast, in 1995 farmers were using 40 million pounds of glyphosate, but by 2014 that number has increased to 280-290 million pounds according to the Environmental Protection Agency (EPA). More recently, since 1992 Midwestern corn and soybean farmers have increased their usage of glyphosate nearly 40 times and by 2016 were using a total of 188.7 million pounds.

This is very problematic to the surrounding community because the International Agency for Research on Cancer (IARC) found glyphosate is linked to cancer in humans, thus making it a probable human carcinogen. In addition to cancer, scientists have linked glyphosate exposure to the following human health risks:

• Harms beneficial gut bacteria
• Birth defects
• Infertility 
• Reproductive issues, such as miscarriages
• Shorter pregnancies
• Increased infant mortality
• Certain cancers, like non-Hodgkin lymphoma and breast cancer
• Liver and kidney damage with exposure as low as 0.05 parts per billion (ppb) and linked to altering gene function of over 4,000 genes in the kidneys and livers of rats at 0.1 parts per billion (ppb) from glyphosate formulations.

Our Scientific Advisor Terrence Collins, Teresa Heinz Professor of Green Chemistry & Director of the Institute for Green Sciences at Carnegie Mellon University had this to say:

“To my thinking, glyphosate residues in food products are troubling at any level. Beyond the broad evidence of adverse effects of glyphosate itself, it is well-known that glyphosate can bind metal ions, including toxic ones like lead, cadmium, mercury, and arsenic. Thus, glyphosate agricultural usage can bring doubly whammy toxicants into food products. So it was excellent of Mamavation to check for these key toxic elements in the various oat milk products. And it is encouraging that most products were found to be free of such heavy metal contamination above 10 parts per billion. Similarly, Mamavation found most products to be free of glyphosate above 10 ppb and this also is an encouraging finding. Clearly, the company with glyphosate and arsenic above 10 ppb would be well advised to discover why these are there and eliminate them.”

Why is Glyphosate Found in Oat Products?

According to a study by the Detox Project, which is an organization certifying food products as “glyphosate residue-free” many types of oat products have been reported to contain glyphosate. Here are some examples from their report.

• Quaker Oats (from HyVee) — 535 parts per billion (ppb) glyphosate
• The Grainery Fresh Milled Oats (from HyVee) — 214 parts per billion (ppb) glyphosate
• General Mills CheeriOats (aka Cheerios from Target) — 118 parts per billion (ppb) glyphosate
• Natural Grocers Organic Thick Rolled Oats (from Natural Grocers) — 26 parts per billion (ppb) glyphosate
• Whole Foods Market Organic Steel Cut Oats (from Whole Foods) — 13 parts per billion (ppb) glyphosate
• 365 Barley & Lentils (from Whole Foods Market) — 134 parts per billion (ppb) glyphosate

According to the Detox Project, pre-harvest desiccation could be the reason why glyphosate is found in such high amounts in healthy foods. What is pre-harvest desiccation? This is when glyphosate is sprayed on crops in the late season just before they are due to be harvested. The extra spraying of glyphosate works to dry out the crops in the field early and thus it shortens the time they are in the field. This saves money and resources for the farmer and food companies, which is why it’s done. But at what cost do consumers pay for early crop drying? Glyphosate has staying power and persists on food and can be found at higher levels because of this practice.

Crops that are most likely to be desiccated are wheat, chickpeas, yellow peas, oats & other beans. So how is this impacting oat milk? Oats are diluted heavily with water and other additives when made into oat milk, so it makes sense that if glyphosate is present, it would be present in far lower amounts. This is exactly what our labs found — little to no glyphosate present at detectable levels.

Pete Myers, Chief Scientist at Environmental Health Sciences observes “I used to eat oat products frequently, but when I learned about pre-harvest desiccation I stopped eating any oats that weren’t grown organically. This includes oatmeal breakfasts at breakfast bars and instant oatmeal, even oatmeal cookies. I’d apply the same standard to oat milk. Over 100 ppb is not a low amount.”

Heavy Metals in Food & Beverages & California Prop. 65

Mamavation decided to also test oat milks for heavy metals because glyphosate can bind to metal ions in complex matrices. We are unsure if this is happening inside the glyphosate testing of Oatmilk, but decided that having heavy metal testing done was still valuable to our audience in general.

California’s Prop. 65 has established “safe harbor levels” for most of the heavy metals we tested: arsenic, cadmium, lead, & mercury. Prop. 65 requires businesses to provide warnings to consumers living in California about significant exposures to chemicals that cause cancer, birth defects, or other reproductive harm. These chemicals can be in the products they purchase, in their homes or workplaces, or released into the environment. By requiring this information to be provided, it enables consumers in California to make informed decisions about their exposure to these chemicals.

Here are the No Significant Risk Levels (NSRL) and the Maximum Allowable Dose Levels (MADL) established by the State of California for the heavy metals we tested:

• Arsenic: 0.06 ug/day (inhalation), 10 ug/day (except inhalation)
• Cadmium: 0.05 ug/day (inhalation), 4.1 ug/day (oral)
• Lead: 0.5 ug/day level for reproductive toxicity, 15 ug/day (oral) for carcinogens
• Mercury: no established levels

Our EPA-certified lab tested each heavy metal at 10 parts per billion (ppb), which is below each safe harbor level established by California. Therefore, we are going beyond what California would establish to be a warning level.

So how do heavy metals find their way into oat milk? Officially, we are not certain, but here are some theories based on how other food products are contaminated:

• Naturally Occurring: Heavy metals are naturally present in the soil in different concentrations based on the geology of the land. For instance, more cadmium is found in certain soils in South America and less in certain African soils.
• Legacy Pesticide Use: For many decades, heavy metals were added to pesticides as an adjunct and can still be found in soils that had a history of certain pesticide use.
• Manufacturing Contamination: Heavy metals can be found in many situations in terms of manufacturing, like with machinery, joints, storage containers, etc. and can contaminate food and personal care products that way.
• Storage: In places where heavy metals are present in the soil, storing and drying certain crops outside can present a contamination risk like with dark chocolate.
• Air Pollution: Heavy metals can start as air pollution from manufacturing byproducts from polluted industrial areas and can find their way into other parts of the world through the wind and through bodies of water. An example of this is how mercury is found in high levels in Tunafish but likely starts as air pollution from coal-burning plants.

Product Brands We Tested
To help our community make safer choices, Mamavation sent a variety of oat milk products to our EPA-certified laboratory for testing. All products were evaluated for glyphosate, AMPA, and heavy metals, including arsenic, cadmium, lead, and mercury.

Below is the complete list of oat milk products included in our investigation.

Oat Milk Brands Tested by Mamavation

• Oat Malk Original Organic

• Silk Original Oat Deliciously Creamy

• Califia Farms Oat Barista Blend Oatmilk

• Chobani Oatmilk Extra Creamy

• Elmhurst Milked Oats Sweetened

• Nut Pods Barista Oat Milk Cinnamon Dolce

• Oatly Barista Edition Oat Milk

• Planet Oat Oatmilk Unsweetened Original

• Califia Farms Organic Oatmilk Original

• Kirkland Signature Organic Oat Non-Dairy Beverage

• Oatsome Organic Oat Milk

• Rise Brewing Company Organic Oatmilk Original

• Three Trees Organic Oatmilk with Seeds

Want full access to the raw data, contaminant results, and our recommendations for the safest oat milk products? Become a Member and get Free Access to the complete buying guide with detailed lab results for every product.