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On his first day of life, an infant is hospitalized with seizures. The researchers concluded that his mother’s daily spirulina use, starting in the fourth month of pregnancy, was likely to blame. I’ve talked previously about the liver and nerve toxins present in many spirulina supplements, but the supplement companies swear up and down that spirulina doesn’t produce these toxins—and they may be right.

But if spirulina doesn’t produce toxins, how is it that toxins have repeatedly been found found in spirulina supplements? It appears to be contamination of spirulina with toxin-producing blue-green algae.

So, for example, if you look at the new U.S. “Pharmacopeia Safety Evaluation of Spirulina,” they conclude “the available evidence does not indicate a serious risk…or other public health concern when [spirulina is] properly identified, formulated, and used.” Ah, but that’s the catch. You collect spirulina in some open lake, and you have no idea what other algae are going to crop up.

The researchers report all sorts of adverse reactions in people taking spirulina products, but they attribute these issues to non-spirulina algae toxin contaminants within spirulina supplements, known to be toxic to the liver and cancer-causing. So, unless there’s third-party testing of each batch, which no company could presumably afford to do, I continue to encourage people to avoid spirulina products.

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