Glyphosate in Monsanto’s ‘Roundup’ and Alzheimer’s Disease

by Amylee Amos PhD, RDN, IFMCPNutrition
Worker tending crops

Glyphosate has been discussed in the news fairly often recently. As with any controversy deeply entrenched in big industry, the opinions on both sides of the argument are heated. Here we break down some of the facts and the potential impact on brain health.

What is Glyphosate?

Glyphosate is the active ingredient in Monsanto’s weed killer, Roundup. It is used as an herbicide for commodity foods such as oats, wheat, corn, and many other foods, and also as a drying agent on wheat pre-harvest. Glyphosate is a patented antibiotic.

Antibiotics function by killing off bacteria. If you’re suffering from a bacterial infection, the right antibiotic can be lifesaving. But we are now exposed to antibiotics far too often. In addition to potentially leading to antibiotic resistance (1), antibiotic exposure such as that from glyphosate in our food supply can kill off the healthy bacteria that live in our gut. This microbiome in our gut plays a key role in our health, especially our brain health.

The Gut Brain Connection

In order to understand how glyphosate may impact our brain health, it’s necessary to discuss the gut brain connection. The gut and the brain have a bidirectional communication pathway. They send messages back and forth to each other all day long via the vagus nerve. This nerve extends from the brain stem to the gut and connects our central nervous system with our enteric nervous system, the nervous system of the gastrointestinal tract. The gut has the responsibility of producing about 75% of the brain’s neurotransmitters. These neurotransmitters are responsible for cellular communication. The gut also houses about 70% of the body’s immune system. The immune system, specifically the innate immune system, plays a critical role in Alzheimer’s disease. In Type 3 “Toxic” Alzheimer’s disease, particularly in individuals with chronic inflammatory response syndrome, the innate immune system is chronically activated (2).

It’s for all of these reasons that compounds that harm our gut, often in turn harm our brain. Antibiotics, which wreak havoc on our gut, inadvertently hinder our brain health because of this strong connection.

Glyphosate in the Food Supply

We know that antibiotics, such as glyphosate in Monsanto’s Roundup, can disrupt the microbiome and in turn the brain. But the issue is that this damaging herbicide is ubiquitous in our food supply. In October 2018, the Environmental Working Group (EWG) conducted their second set of tests on popular oat based cereals to determine their glyphosate content. In all 28 samples from various oat based products such as those from General Mills’ and Quaker, glyphosate was detected. 26 of the 28 samples had glyphosate concentrations above the EWG’s upper limit for safety, 160 parts per billion (3). These results came just two months after the EWG tested 45 products with conventionally grown oats and found that 43 of them contained glyphosate (4). It should be noted that glyphosate was also detected in some of the organic oat products tested; however, none of the organic oats tested detected glyphosate in the range deemed unsafe by the EWG (4).

Glyphosate and Chronic Disease

Without question, the basic science indicates that glyphosate can harm our health. But in fact, the government is even now acknowledging that glyphosate contributes to chronic disease. In July of 2017, the Office of Environmental Health Hazard Assessment (OEHHA) added glyphosate to the list of chemicals known to the state of California to cause cancer for purposes of Proposition 65, despite an unsuccessful appeal by Monsanto (5). Additionally, a recent population based cohort study found that higher frequency of organic food consumption resulted in a reduced risk of cancer (6).

Just knowing that glyphosate is known to cause cancer should be reason enough to make you want to avoid it at all costs. But also, if glyphosate is known to cause cancer, what other correlations with chronic diseases have we not yet established? Only time will tell.

Glyphosate and Alzheimer’s Disease

To reiterate, the brain and the gut have an incredibly strong connection. Changes and disruptions in the gut can have catastrophic consequences in the brain. We are still far away from a causal relationship between glyphosate in Monsanto’s Roundup and Alzheimer’s disease, but given what we know about the destructive impact on glyphosate on the gut, as well as the connection between the gut and the brain, could glyphosate be a contributing factor? Quite possibly, but more research is needed to definitively say that, even though a variety of mechanisms of action have been proposed (7). What we know is that glyphosate is harmful, and if you have or are at risk for Alzheimer’s disease (or any other chronic disease), you should try to avoid glyphosate at all costs.

How to Avoid Glyphosate

As mentioned, glyphosate was found in both conventionally produced foods and organic foods; however, the organic samples that contained glyphosate had far less of the herbicide than did the conventional foods. So the best way to avoid glyphosate, even though it doesn’t mean you’ll have no exposure, is to buy organic (or, even better, grow some of your own foods). Whenever I talk with clients about the need to purchase organic foods, or when I lecture on the subject, I stress the fact that it shouldn’t have to be this way. Our food supply should be safe. We shouldn’t have to spend more money to buy produce and grains that won’t act as a slow poison in our body. But we do. Our food isn’t safe. This is what industry has done to our food supply. If you have Alzheimer's disease or cancer or any other chronic disease or are at risk for one, consuming only organic foods is extremely important.

Healthy food should be affordable and available to all. We need to keep working to find solutions to this problem. Whenever possible, choose organic foods. Encourage your local grocery store to stock more organic produce, grains, and products at a variety of price points. These companies only listen to one thing, so please, vote with your wallet.


1.) Kurenbach B, Hill AM, Godsoe W, van Hamelsveld S, Heinemann JA. 2018. Agrichemicals and antibiotics in combination increase antibiotic resistance evolution. PeerJ 6:e5801

2.) Bredesen D. E. (2015). Metabolic profiling distinguishes three subtypes of Alzheimer's disease. Aging, 7(8), 595-600.




6.) Baudry J, Assmann KE, Touvier M, et al. (2018). Association of Frequency of Organic Food Consumption With Cancer RiskFindings From the NutriNet-Santé Prospective Cohort Study. _JAMA Intern Med,_178(12):1597–1606.

7.) Samsel, Anthony & Seneff, Stephanie. (2016). Glyphosate pathways to modern diseases V: Amino acid analogue of glycine in diverse proteins. _Journal of Biological Physics and Chemistry,_16: 9-46.