When it comes to something as life and death important as to what to feed ourselves and our families,

we should rely not on anecdotes, but on facts.

Welcome to the Nutrition Facts podcast.

I'm your host, Dr. Michael Greger.

Today we look at new research that reveals what we should steer clear of consuming

Chlorella and spirulina.

Here's our first story.

Schizochitrium, the type of algae used to make algae-based DHA

supplements, has grown under controlled conditions, and has been found to be free of

marine biotoxins.

The same can't be said for blue-green algae products like AFA,

alpha-nizamin-floss-Aquay, a blue-green algae harvested from Klamath Lake in Oregon,

and marketed as a dietary supplement.

Studies have shown this blue-green algae can produce significant levels of

cylindrospermopsin and saxotoxin.

Cylendrospermopsin is a liver toxin and saxotoxin is a neurotoxin, listed as a Schedule

1 substance in the Chemical Weapons Convention.

The first big expose of AFA was published in 2000, with microsycinous liver toxins found in 85 of 87 samples,

72% exceeding Oregon State's safety limits of one part per million, which is based on an average

adult weighing 60 kilograms, about 132 pounds, and consuming about 2 grams a day.

AFA has the toxicogenic genes that produce these macrosystems directly, but when you're harvesting it outdoors, it's almost impossible to avoid the presence of other algae species that can produce toxins too.

Since they're released on the market and after some public inquiries

...