News Release

Cyanobacteria from Lake Chad analyzed for toxins

Dried cyanobacteria from Lake Chad in Africa supplements protein deficient diets, but toxic risks remain

Peer-Reviewed Publication

Brain Chemistry Labs

(JACKSON, Wyo. - July 14, 2020) - Indigenous people near Lake Chad in Africa have historically used dried cakes, called Dihe;, made from aquatic cyanobacteria to supplement their protein deficient diets. However, Dihe wafers have not been previously analyzed for toxins which can contaminate some samples of spirulina and other cyanobacterial-based food supplements. The Oregon Health Division has banned commercial products made from Aphanizomenon cyanobacteria which have more than 1 ug/g of the liver toxin microcystin.

Eighty years ago, French anthropologists recorded the widespread consumption of Dihe wafers made from Arthrospira cyanobacteria skimmed from the surface of Lake Chad. At the Brain Chemistry Labs in Jackson Hole, Wyoming, scientists wondered if Dihe cakes are indeed safe for human consumption. Ethnobotanist Dr. Paul Alan Cox explains, "We have studied human consumption of cyanobacteria in western China and the high mountains of Peru. In Africa, Dihe could be an important source of protein for undernourished villagers, but we wanted to know if it is toxin free."

Cyanotoxin expert Dr. James Metcalf led the toxinological analysis of Dihe wafers purchased in Chad makes at the Brain Chemistry Labs. "We were unable to detect the neurotoxin BMAA in the Chad samples, although we did find 5 out of 12 Dihe samples to have microcystin content greater than 1 ug/g, which suggests that seasonal monitoring of the toxin in Lake Chad should be implemented."

Offsetting these concerns were the scientists' finding that Dihe wafers are rich in dietary amino acids. "Amino acid analysis of the Lake Chad material indicates that this cyanobacterium is a rich source of amino acids and may help supplement the local people who are undernourished," the scientists wrote in a new paper published this week in Neurotoxicity Research.

"It appears that cyanobacteria wafers are consumed primarily by people somewhat distant from the lake, and not by those who live directly on the lake's shore," Cox said. "Further research is needed to find out why this is the case."

Dr. Metcalf agrees. "Ultimately, we have shown that people who live in Chad may be able to supplement their diet with locally-sourced cyanobacteria that could significantly add needed amino acids. However, regular monitoring of the toxin content is required to protect human health from long-term adverse effects.


The full article can be seen at Metcalf, J.S., Dunlop, R.A., Banack, S.A., Souza, N.R. and Cox, P.A., 2020. Cyanotoxin Analysis and Amino Acid Profiles of Cyanobacterial Food Items from Chad. Neurotoxicity Research, pp.1-9.

About Brain Chemistry Labs

Brain Chemistry Labs is a non-profit research institute based in Jackson Hole, Wyoming which is sponsoring advanced FDA approved clinical trials for ALS and early-stage Alzheimer's disease. With five PhDs currently on staff, the Brain Chemistry Labs anchors a consortium of 50 leading scientists from 28 institutions representing 12 different disciplines. For more information about Brain Chemistry Labs, go to


Dr. Paul Alan Cox
801 375 6214

Dr. James Metcalf
307 734 1680

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