Vegan Health ArticlesTreating Springtime Allergies with Spirulina?
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From Michael Greger, M.D.

People have been harvesting pond scum for thousands of years. The Aztecs, for example, were skimming it off lakes and into their diets half a millennia ago. Were they onto something?

Spirulina is one of the most popular blue-green algae supplements on the market. In addition to being one of the most concentrated known source of nutrients (though how much of it can you really eat?), there is building evidence of its anti-inflammatory properties. To see if it might be of therapeutic value to seasonal allergy sufferers, researchers at the University of California at Davis School of Medicine enrolled 3 dozen sniffley sneezers into a randomized, double-blind, placebo-controlled crossover study (one of the most rigorous study designs to minimize various biases). Compared to placebo, participants taking 2 grams of spirulina a day were able to cut their production of inflammatory mediator Interleukin-4, a chief conductor of allergic reactions within the body, by over 30%.[1]

So should those with runny noses run out and grab some? Two months ago I would have said yes, but not now. I was actually in Hawai'i, the spirulina export capital of the world, when the bombshell hit. Published in the journal of the most prestigious scientific body in the United States, the National Academy of Sciences, researchers came to a disturbing revelation about the safety of blue-green algae in general.

We've known for years that a few rare types of blue-green algae could produce hepatotoxins (compounds toxic to the liver), but spirulina was considered generally[2] free of any such toxins.[3] But in April 2005 a coordinated effort of researchers across the world found evidence that almost all blue-green algae seem to be able to produce a neurotoxin called BMAA (beta-N-methylamino-L-alanine). BMAA is bad stuff. It's been implicated in a neurodegenerative disease as horrible as its name sounds, amyotrophic lateral sclerosis/parkinsonism-dementia complex. This disease attacked the Chamorro people of Guam who were eating flying foxes, who in turn were eating seeds of a cycad tree, whose watery roots concentrated the toxin from a certain type of algae.

Now with this new study we know that the production of this neurotoxin is not limited to some rare Guam algae, but may be produced by almost all blue-green algae under the right conditions. So it turns out the only two places you may be likely to find BMAA is in the brains of Alzheimer's patients[4] and on the store shelves of your local natural foods store in the form of blue-green algae.[5]

Until we know more, I strongly discourage people from eating blue/green algae (including the spirulina that, until April, was what made the popcorn I always smuggled into the movie theatre such a brilliant green hue). Those interested in reducing inflammation will have to choose other plant foods like--as one recent article published in the Journal of Nutrition discovered--gazpacho, a vegetable soup which "decreased biomarkers of inflammation in both women and men."[6]


[1] Mao TK, et al. "Effects of a Spirulina-Based Dietary Supplement on Cytokine Production from Allergic Rhinitis Patients." Journal of Medicinal Food 8(2005):27-30.

[2] Iwasa M, et al. "Spirulina-associated hepatotoxicity." American Journal of Gastroenterology 97(2002):3212-3.

[3] "Health Canada Announces Results of Blue-Green Algal Products Testing--Only Spirulina Found Microcystin-Free."Health Canada news release 17 Sept 1999.

[4] Murch SJ, et al. Acta Neurologica Scandinavica. 110(2004)267-269.

[5] Cox PA. "Diverse Taxa of Cyanobacteria Produce Beta-N-Methylamino-L-Alanine, a Neurotoxic Amino Acid." Proceedings of the National Academy of Sciences 102(2005):5074-5078.

[6] Sanchez-Moreno C, et al. "Consumption of High-Pressurized Vegetable Soup Increases Plasma Vitamin C and Decreases Oxidative Stress and Inflammatory Biomarkers in Healthy Humans." Journal of Nutrition 134(2004):3021-3025.

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We began this archive as a means of assisting our visitors in answering many of their health and diet questions, and in encouraging them to take a pro-active part in their own health. We believe the articles and information contained herein are true, but are not presenting them as advice. We, personally, have found that a whole food vegan diet has helped our own health, and simply wish to share with others the things we have found. Each of us must make our own decisions, for it's our own body. If you have a health problem, see your own physician.