The Blue-Green Algae Debate

I’ve been taking algae supplements for years, but I heard recently that they might be toxic. Are they? For many years, I too have heard concerns about the potential toxicity of blue-green algae, but I suspect the research you mention stems from a recent scientific study of the indigenous Chamorro people from the Pacific island of Guam. An unusually high percentage of that population has long been afflicted with a devastating progressive neurodegenerative illness that has features similar to ALS (Lou Gehrig’s disease), Parkinson’s and Alzheimer’s.

Scientists thought the culprit might be some kind of slow-acting poison from the seeds of the cycad plant, which is an ingredient in the tortillas that are a dietary staple in that region. The new study found that a blue-green algae that lives symbiotically in the roots of the cycad plant produces a neurotoxic amino acid called BMAA, which was highly concentrated in the brain tissues of people who had succumbed to the disease.

At first, researchers thought the problem was confined to Guam, but this same toxin was then identified in the brains of people with Alzheimer’s disease who lived in Canada and did not eat cycads. This led the researchers to speculate that BMAA and other neurotoxins from blue-green algae commonly found in drinking water could play a role in the current worldwide epidemic of Alzheimer’s and other neurodegenerative diseases. Not surprisingly, the media immediately picked up this hypothesis and warned the public of the potential dangers of taking algae supplements.

But before you get all worked up and start tossing your spirulina powder, consider these basic facts of biology. First of all, there are many different types of algae, including blue-green, green, brown, and red varieties. They can range in size from microscopic single-celled organisms to bull kelp, which is hundreds of feet in length. The biological properties of all these different algae vary as much as their size and color. Consequently, just because one strain can produce a toxin does not mean this is true of all algae. This should be reassuring to the millions of people who regularly enjoy eating kelp, wakame, hijiki, nori, and other seaweed, since these foods have never been found to contain toxins.

The biggest source of concern is wild strains of blue-green algae that thrive in the nutrient-rich–and often polluted–waters of lakes, ponds, and streams. It is well known that these types of algae have a tendency to produce liver toxins called microcystins. The only type of blue-green algae that does not have this tendency is spirulina, which is cultivated under highly controlled conditions that guarantee the absence of toxins. Similarly, chlorella, a cultivated microscopic green algae, is also known to be free of toxins so, like spirulina, it is quite safe to take as a dietary supplement.

Just make sure you investigate your supplement. Any company that sells wild blue-green algae as a dietary supplement should be able to prove that they have employed the strictest level of quality control to ensure that their product is BMAA or microcystins-free.

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By Robert Rountree, M.D., Natural Solutions magazine


Cheng Mike
Past Member 9 months ago

symptoms started out with a "foot drop" on my left foot. From there my left leg lost all muscle tone and the entire left leg muscles are gone. Also my fingers and thumbs "contract" at times. Left arm loses muscle tone too. My family doctor said there is no cure for ALS, I was just living unhappy life till I saw a blog talking about Best Health Herbal Centre. So many people said positive things about their herbal product which I don’t believe at first. I showed my daughter what I saw online about their product and my daughter decided we shall give it a try. Few days later she purchased two bottle of ALS herbal remedy which they said I will use for only six weeks. My life changed automatically after six weeks of applying the herbal remedy as instructed. All my symptoms was terminated completely and am now living ALS FREE ..
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Jeramie D.
Jeramie D2 years ago


Jim B.
Jim B.6 years ago

Just some quick facts: do you know how many different types of algae there are little alone blue-green algaes?, so when you talk blue-green algae, you're talking through the hole in your head, because you don't have a clue of what you're talking about. it's like somebody does a crime, and you blame everybody. the crime here isn't the algae's, it's the people who dump their chemical crap all over the farming fields and it washes into the streams and rivers. the algae is just doing its damn job of consuming this garbage and of coarse it gets a bad rap. it's just pathetic how humans like to pass the buck, and point the blame elsewhere. the Klamath Lake blue-green algae is awesome stuff, if you were to actually get the correct facts on it, and not listen to blow hearts who think they know everything. I'm sorry, I don't mean to go off on a rant like this, but, every time I see people shooting their mouths off about something they don't have a clue about just pisses me off, is like somebody going to jail for a crime they did not commit,next time get the facts straight. algae was the very first thing on this planet, look at Mount St. Helen's, the very first thing to come back, you guessed it, blue-green algae, just doing his job and getting another bad rap.

K s Goh
KS Goh8 years ago

Thanks for the article.

Robert O.
Robert O8 years ago


Gordana Roljic
Gordana Roljic8 years ago


Gillian M.
Gillian M10 years ago

The problem with supplements is that we all think that they are harmless because they are natural. Many supplements can cause harm eg St Johns Wort so before you take anything you need to see if anything has been written about it and contact the manufacturers for information. Bear in mind that if you are taking regular medication then the supplements can interfere. But, some supplements are known to be helpful eg peppermint oil for IBS or Efalex for dyslexia. Just be careful.

The one thing that has recently come to the forefront of science is that algae is being investigated for biofuel.

Pame Roscoe
Past Member 10 years ago

any substance in large enough quantities especially in an out of balance diet can overlong term use be potentialy toxic....

Joe F.
Rev. Joe F10 years ago

The only Absolutely Pure lake with blue green algae is Klamath Lake in Oregon. Simplexity Health who harvests, processes and sell the blue green algae has constant testing available to make sure it is clean.
You can check them out at Simplexity Health dot com/tao and there is a tab that has Science which addresses the Quality, testing and research etc. I have been taking/eating algae from them for maybe 15 years.... I like the Omega version for the mind. Wonderful and healthy food.

Ronald Johnson
Ronald Johnson10 years ago

Just a quick fact: Blue-green algae are actually a bacteria classsified as cyano-bacteria, and cause concern to water quality experts. Some watertreatment plants around the world need to close during peak water consumption periods (i.e. summer) due to algae blooms.