Cyanotoxin Contamination in Spirulina and Chlorella Supplements: A Roundup of Liver and Nerve Toxicity Mechanisms

A review paper that synthesizes the health risks of cyanotoxins that can get into dietary supplements derived from cyanobacteria and microalgae, such as spirulina (Arthrospira), Aphanizomenon flos-aquae and chlorella (Chlorella), has been published in Food and Chemical Toxicology. Researchers in biochemistry at Dr. Harisingh Gour Vishwavidyalaya, a central university in India, compiled cases of detection in commercial products and the molecular-level toxicity mechanisms of the main toxins.

The toxins covered are microcystin, nodularin, cylindrospermopsin, anatoxin, saxitoxin and the neurotoxic amino acid BMAA (β-N-methylamino-L-alanine). For the liver, the review presented pathways in which disrupted protein phosphatase signaling, impaired mitochondrial function and oxidative stress lead to inflammation, cell death and cancer. For the nervous system, excitotoxicity, impaired neurotransmission, calcium dysregulation and neuroinflammation were named as the key mechanisms, and toxicity to the kidney, digestive, cardiovascular and reproductive systems also shares oxidative damage and inflammatory signaling as a common axis.

Remaining challenges

The review points out that data are lacking on the effects of chronic low-dose exposure, bioavailability in the supplement matrix and long-term effects in people, and it proposes that research combining toxicokinetics, multi-omics and validated biomarkers is needed to strengthen risk assessment and regulatory oversight.

This paper is a narrative review that synthesizes existing literature and did not produce new data from analyzing commercial products. Many of the mechanisms presented are based on cell and animal experiments, and actual contamination levels in products vary greatly with the origin of the raw material and the culture method, so caution is needed in generalizing.