What Are The Dangers Of Spirulina?

Spirulina, a type of blue-green algae, contains a rich store of nutrients and was consumed as a food as early as Aztec times. In current times, these particular algae -- along with other forms -- have been touted to address every ailment under the sun. Scientific evidence confirming any benefit is lacking, however. Some concerns exist over the safety of spirulina supplements, though the most serious side effects appear rare, according to the Memorial Sloan Kettering Cancer Center. Combined with a lack of proof regarding efficacy for any purpose, you might consider using another nutritional supplement.

Toxins and Bacteria

An article discussing spirulina and other forms of algae that appeared the June 2008 issue of "Experimental and Medical Biology" reports tests of supplements found they contained neurotoxins, which can negatively brain health and various aspects of normal functioning, particularly when taken in large amounts for extended periods of time. Spirulina also naturally contains microcystins, toxins that can alter your DNA. Oregon, where many brands of spirulina get produced, has set limits on how much microcystins a product can contain, though what level constitutes a safe one remains unknown. All manufacturers might not follow a similar safeguard.

Spirulina can easily absorb toxic metals like lead and mercury, though the Beth Israel Deaconess Medical Center reports you would have to ingest more than 77 g daily of a supplement with the highest levels of contaminants detected to reach dangerous levels of ingestion. If grown with fertilizer from animal waste, spirulina supplements could contain dangerous forms of bacteria. The BIDMC reports researchers suggest limiting intake to 50 g or less daily to minimize consumption of these potentially harmful agents.Typical doses usually call for much less than this.

Side Effects

Spirulina infrequently might cause nausea, vomiting, anxiety and insomnia. Rare though serious side effects include renal failure, kidney failure, respiratory arrest, seizures, acute pancreatitis and damage to the heart muscle.

Reported Case of Rhabdomyolysis

Rhabdomyolysis is a condition where rapid breakdown of muscle tissue leads to a release of muscle fibers into the bloodstream, potentially leading to kidney damage or in some cases, complete failure. An article in a 2008 issue of "Phytomedicine" reported the first case of this condition after the consumption of a blue-green algae supplement.

Use in Specific Populations

Because of potential contamination with toxins, definitely avoid use if you suffer from liver or kidney disease. Whether or not you can safely use this supplement while pregnant or lactating has not been established, but the health concerns associated with spirulina make it prudent to forego use.

Medication Interactions

No documented medication interactions exist as of 2011.The University of Maryland Medical Center, however, notes spirulina could theoretically interfere with medications used to suppress an overactive immune system. Examples include adalimumab, azathioprine, cyclosporine, ethanercept, infliximab, leflunomide, methotrexate, mycophenolate and prednisone.