Foods Linked to ALS

Image Credit: Peter Miller / Flickr. This image has been modified.

Foods Linked to ALS

As explored in my video ALS (Lou Gehrig’s Disease): Fishing for Answers, there may be a link between the consumption of the neurotoxin BMAA, produced by algae blooms, and increased risk of ALS. It now appears that BMAA could be found in high concentrations in aquatic animals in many areas of the world.

This could explain ALS clustering around lakes in New Hampshire—up to 25 times the expected rate of ALS with some families eating fish several times a week. Or in Wisconsin, where the most significant ALS risk factor was the past consumption of fish out of Lake Michigan. Or clustering in Finland’s Lakeland district, or seafood eaters in France, or around the Baltic sea, building up particularly in fishes, mussels and oysters.

When I think of algae blooms I think of the Chesapeake bay near where I live, that gets choked off thanks in part to the poultry industry pollution. And indeed, there was a recent report linking BMAA exposure to ALS in Maryland. The ALS victims, all of whom ate Chesapeake Bay blue crabs every week, lived within a half mile of each other, which raised some eyebrows at the Johns Hopkins ALS center. And so, researchers tested a few crabs, and two out of three tested positive for BMAA, indicating that the neurotoxin is present in the aquatic food chain of the Chesapeake Bay and is a potential route for human exposure.

To bring the story full circle, things in Guam, where the link between BMAA consumption and ALS was first discovered, are looking up. The ALS epidemic there may have been triggered by their acquisition of guns. Now though, the epidemic appears to be over thanks to near-extinction due to over-hunting of the fruit bats they were eating. But while the rates decline in Guam, neurodegenerative diseases like ALS around the rest of the world are on the rise.

It’s plausible that humans have been exposed to some level of BMAA throughout their evolutionary history, but the increase in algae blooms as a result of human activities is probably increasing this exposure. There is a general consensus that harmful algal blooms are increasing worldwide thanks in part to industrialized agriculture (as shown in my video Diet & Amyotrophic Lateral Sclerosis-ALS). More people means more sewage, fertilizer, and manure, which can mean more algae, which may mean more exposure to this neurotoxin, leading to a possible increased incidence of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and ALS.

BMAA is considered a strong contender as the cause of, or at least a major contributor to, both endemic and sporadic ALS and Alzheimer’s disease, and possibly conferring risk for Parkinson’s diseases as well. The ramifications of this discovery are enormous.

As researchers from Australia stated, “With substantial and ever growing evidence that BMAA does play a role in the onset and progression of neurodegenerative diseases, the most important question is, what mode of activity does BMAA exert?” Huh? That’s not the most important question we should be asking. The most important question is “How can we reduce our risk?”

We know that the presence of BMAA in aquatic food chains could be a significant human health hazard. There may even be a synergistic toxicity between mercury and BMAA, making human consumption of certain species of fishes even riskier. Until more is known about the possible link of BMAA to Alzheimer’s and ALS, it may be prudent to limit exposure of BMAA in the human diet.

For other neurotoxins found in the food supply, see Amnesic Seafood Poisoning, Essential Tremor and Diet, Ciguatera Poisoning & Chronic Fatigue Syndrome.                           

Other toxic substances can also build up in the aquatic food chain, for example:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

70 responses to “Foods Linked to ALS

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    1. I haven’t ate any type of meat for over a year.
      (Plant based diet)
      I am sincerely thankful not to have to deal with things like this that could prove to be deadly.
      Maybe that would be a solution?

      1. Unfortunately vegetarians often eat blue green algae in form of spirulina or chlorella, etc. Make sure your powdered greens are BMAA free. Because vegans get ALS, Alzheimer’s and Parkinson’s disease.

    2. Hi, Kris. I am Christine, a NF volunteer moderator. Generally speaking, the lower animals on the food chain have less toxins concentrated in their bodies than the higher predators. This is because the higher predators eat animals that eat animals that eat animals that are contaminated, and that contamination builds up each time. That said, BMAA has been found in mollusks, which are lower on the food chain. Perhaps the safest choice is to avoid seafood altogether. I hope that helps!

    1. After being scared stiff that I had poisoned myself by taking chlorella for years, I did a little research. I found out that blue green algae are not really algae, but bacteria–cyanobacteria. Some cyanobacteria contain toxic amounts of BMAA. Others, like spirulina, are supposedly edible, but who knows, plus they may be contaminated = careful!

      Brown algae, like kelp and other seaweeds, are in a completely different biological kingdom–not bacteria, not fungi, not plants, but chromista. They are not closely related to blue green “algae,” and I see no reference to them containing BMAA.

      Green algae, like chlorella, are actually in the plant kingdom, just like oats, peas, beans and barley. They do not contain BMMA.

        1. Hi, Adrienne. Interesting question! I found nothing in the medical literature linking lichens with BMAA. It may be that this has not been studied, or it may be that there is little risk, since lichens grow on land, and are not aquatic. Land organisms would presumably not be exposed to aquatic contaminants. I hope that helps!

  1. Can BMAA be ingested from swimming in the high risk bodies of water if you accidentally swallow some water or it is on your lips and in your nose?

    1. I don’t think so. I think concentration of BMAA in the water is extremely low compared to animals higher on food chain where it gets compounded, as per Mic the Vegan’s video on ALS cause and cure.

    1. hi Kay, to answer your question, BMAA is produced by blue green algae. Last weeks article related to this topic has links and comments that might be of interest to you Also, Dr Greger has made videos on the topic too In short, Dr Greger does not recommend the blue green algae supplements and says chlorella does not present the same risks.

    2. hi Kay, I replied to your question a while ago but it seems my response was swalliwed up by the program.. Dr Greger has made videos about blue green algae, addressing spirulina and chlorella as well. Last weeks article related to this topic has links and comments you may find useful /interesting In short, BMAA is made by bluegreen algae, and Dr Greger does not recommend the supplements

  2. There is a bottle of algae based vegan DHA sitting in my fridge. I am leery of ingesting any of it as a daily supplement. Dr. Greger should appease our fears immediately as it was based on his recommendation that I take it. Is anything safe to eat anymore? I am feeling the classic ‘dammed if I do, dammed if I don’t’

    1. Not all algae are the same, and in fact despite all being called “algae”, some aren’t even from the same phylogenetic Kingdom. Algae based DHA/EPA come from golden algae, a true algae, which does not produce any BMAA. So your supplement is completely safe to take. It is blue-green algae, not a true algae at all, but a type of cyanobacteria, that produces BMAA.

      Here is a link to an “ask the doctor” post Joseph Gonzales RD (who used to work for NutritionFacts) answered back in 2015

  3. I was wondering can you be exposed through BMAA through any other means. I live on the St. Lawrence River in New York. My next door neighbor died from ALS. Can swimming cause exposure or is it mainly through eating contaminated fish or drinking contaminated water?

  4. For all worried about vegan DHA supplements: Thea pointed out in a post to the video on the subject of BMAA that the algae used for these supplements is golden algae, not blue-green algae, and doesn’t have the same risk of contamination with BMAA. The golden algae is also grown in vats on land under carefully controlled conditions, and so it isn’t exposed to whatever is slopping about in our natural waters. In short, vegan DHA supplements are safe.

    1. So I have been taking Ovega-3 for a few years now & emailed them after reading this post. Their reply is below, I hope this is constructive to the conversation.


      Thank you for taking the time to contact us. We appreciate your interest in Ovega-3. Neither the Ovega-3 softgels, nor the Algal oil that is used, are actively tested for BMAA. This has been discussed with our Algal oil provider and they had performed research regarding the potential contamination of the Schizochytrium algal oil with toxic cyanobacteria (producer of BMAA). Their findings and conclusion was that it was not practically possible, based on the processing steps and conditions of the oil.

      We hope this helps explain and appreciate you choosing Ovega-3.

    1. Interesting. (and wow!) When I was in college (late 70s) I worked at a gas station in NJ. An elderly guy used to like to hang out there with the owner’s dad. Turns out, he was close friends with Lou Gehrig growing up – (and actually went into the famed Yankees’ locker room with them in the late 20s).

      But I distinctly remember him telling me how he really loved the eel that Lou’s mom would serve!

  5. A follow-up post from someone on Dr. Greger’s staff or Dr. Greger himself to answer the several questions above regarding spirulina and other forms of algae marketed would be very appreciated.

    1. susan: re: “…I replied a couple of times to Kay…” One of the problems with our new forum system is that it is constantly catching legitimate posts in an area marked “pending”. I rescue these posts several times throughout the day, but it may be that you have to wait a bit before you see your post. Bummer!

      1. thanks Thea! I even tried different browsers thinking they might show up but to no avail.. please feel free to delete away all but one maybe. No sense in having repetition. I will keep that in mind for future postings.. thanks again.

        1. susan: :-) No worries. We now have lots of duplicate posts due to this problem. I think it’s just going to be par-for-the-course for a while. Argh. As a frequent poster, I just wanted to let you know what is going on.

      2. Thea, What has happened to many of those who have been commenting for the last few years? I miss hearing from them. I welcome the newcomers, but find it strange to be ONLY hearing from newcomers. I’ve always been pleased and impressed with the level of education, the intelligent comments and answers from the old timers who are so well versed in plant based whole food eating, especially since so many of them are doctors and scientists who have contributed relevant links and answered questions with facts, not conjecture.

        Could this be connected with the change from Discus to WordPress? I find the change a bit of a bummer, but there is often a learning curve with a big change, so I’m willing to stick it out and hope it’s an improvement in the long run.

        1. I’m back! I decided to change my user name on the new WordPress system and was locked out for about a week. With the help of the fine technical staff at NF, we got the problem solved. Regarding the new comments system, I think Disqus is more user friendly, but if they now force one to view advertisements, that would seriously detract from the website. I wonder if there’s a way to pay an extra fee to Disqus and have their service without the advertisements? WFPB-Hal

        2. Rebecca Cody: I miss hearing from them too! I don’t know what is going on. The switch to wordpress could certainly be part of the problem, but it maybe that people come and go and we are seeing a swing of things?

          1. I did hear from WFPB-Hal about his problems with being locked out. There are always glitches with a big change, so let’s hope the wandering (or locked out) sheep find their way back to their flock.

  6. Chazz Rose, as you can see from Maureen Okun’s response above, vegan DHA is safely derived from golden algae grown in tanks, not in the ocean.

  7. I’m curious to know if there are ways to reduce the effect of BMAA once ingested. Are there foods that will help the body to get rid of it or is it a case that the levels decrease over time assuming a person stops eating the source foods?

  8. I would also like to know the answers to the questions posed by others here…the safety of swimming in such waters, fish oil supplements, spirolina, etc.

  9. To Cathy, Kay, and others that have questions, last week Dr Greger did a related post on ALS and the connection to BMAA. The links and comments on that page relate to the questions you ask. Re: blue green algae , chlorella and spirulina, this video may help explain more. Blue green algae and spirulina may contain toxins, so Dr Greger does not recommend them.

    For other nutrition/diet questions not covered here, try the search bar at the top of the page.

  10. Cytotoxic Effects of Environmental Toxins on Human Glial Cells. Neurotox Res. 2017 Feb;31(2):245-258
    … This study aimed to examine the cytotoxic effects of BMAA, microcystin-LR (MC-LR), saxitoxin (STX) and ciguatoxin (CTX-1B) on primary adult human astrocytes… Herein, we are the first to show that all of these toxins are capable of causing physiological changes consistent with neurodegeneration in glial cells, via oxidative stress and excitotoxicity, leading to a reduction in cell proliferation culminating in cell death. Abstracted at: More Journal cites at

  11. I bought a bottle of Vegan Omega 3 algae supplement a few weeks ago for $29. Now, I refuse to take any of it, and now I am out $29. I wish the author of these articles would get his INFORMATION together.

  12. In the article I read about this in 3/16 -about Stephen Cox’s research on this – they mentioned that because the BMAA in susceptible individuals inserted itself in proteins instead of L-serine, they were going to start some studies to see if people with ALS did any better when given high doses of serine. Have you heard anything more about the L-serine trials? Thank-you, Kathleen Talbot

  13. I heard of the algae blooms several years ago when I was researching ALS. I like Mussels and switched to farm raised New Zealand GreenShell Mussels which are inexpensive and large. Am I correct in assuming that these should be algae free.

  14. I’d really like to know if there’s any contamination risk from eating common seaweeds such as Nori, or Kombu? What about other plants that grow in or near the sea, such as Samphire which is becoming popular in the UK.

  15. Does anyone know if BMAA builds up in fish oil? I contacted Nordic Naturals but they have not replied yet…and it’s been 3 months. Considering sardines have a high concentration of BMAA and many manufactures concentrate their fish oils from sardines then it’s possible BMAA is passing through the manufactures filtrations and concentrating into their final fish oil products.

  16. Hi Laurence,

    I could not find much data on this topic. However, given that there are well-documented other toxins in fish oil, it should be recommended to take an algae-based omega 3 supplement instead, regardless of whether fish oil contains BMAA or not. However, it does seem likely that BMAA would be present in fish oil supplements.

    I know it’s not a direct answer to your question, but I could not find any reliable data on BMAA concentrations in fish oil. I hope my response helps, nonetheless!

  17. Is there any way I can forward this article on ALS to a friend. His mother has ALS, an I think he would really benefit from this information. ThankYou. Ardith Willner

    1. Thank for you for sharing this information! To pass it on, you can either copy and paste the URL or use the red email button on the left side of this window. Hope that helps!

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