Article suitable for older students

Aztec advances (3): diet: blue-green algae

19th May 2018

Blue-green algae (Spirulina) gathering by the Aztecs, Florentine Codex

This is the third in a series of entries based on information in the Encyclopedia of American Indian Contributions to the World by Emory Dean Keoke and Kay Marie Porterfield (Facts on File, 2002). The main image from the Florentine Codex (Book 11) shows (top) the gathering of izcauitl (tiny worms cooked and made into a paste) and (bottom) tecuitlatl (blue-green algae) from Lake Texcoco (Compiled by Ian Mursell/Mexicolore.)

‘Blue-green algae, Spirulina geitleri, is a primitive aquatic plant that has no leaves, stems, or roots but contains chlorophyll. A popular item in health food stores today, blue-green algae was a staple in the diet of the Aztec, who skimmed it from lakes in the Valley of Mexico, including Lake Texcoco, with nets or shovels (main pic)... Once it was harvested, the Aztec sun-dried the algae and cut it into bricks. When preserved this way, it would remain edible for a year. The Aztec, who called the algae tecuitlatl, ate it with tortillas or toasted corn. Sometimes it was combined with chiles and tomatoes to make a sauce...
’Some of the Spanish conquistadores referred to the blue-green algae as slime; most refused to eat it. After the Spanish conquest of the Aztec Empire, the lakes in the Valley of Mexico were drained [the canals of Xochimilco are all that remain of the lake today - pic 1]. Indigenous people stopped eating the algae that had once been a major part of their diet.

‘Rediscovered in the 1970s, spirulina is sold as a health food today (pic 2). Blue-green algae has been found to contain 70 percent protein and an essential amino acid, linolenic acid. Combined with corn/maize, another Aztec dietary staple, it makes a complete protein that the body can easily absorb. Blue-green algae (pic 3) is also high in vitamin B12 and beta carotene and has a high vitamin content, including phosphorus, thiamin, riboflavin, and niacin. A fast-growing crop, the algae from the surface of Lake Texcoco alone has been estimated to have been enough to meet the protein needs of the 1.5 million people who lived in Tenochtitlan and the surrounding before Spanish conquest.
’Drought-proof and independent of rainfall, spirulina has been investigated as a solution for famine in various parts of the world. The World Health Organisation found that eating one gram of blue-green algae a day would decrease the incidence of blindness caused by vitamin A deficiency in malnourished children. As a result, the organisation is encouraging its cultivation throughout the world.’

Picture sources:-
• Main pic: images from the Florentine Codex (original in the Biblioteca Medicea Laurenziana, Florence) scanned from our own copy of the Club Internacional del Libro 3-volume facsimile edition, Madrid, 1994
• Pic 1: photo by Ian Mursell/Mexicolore
• Pic 2: photo from Wikipedia [Spirulina (dietary supplement)]
• Pic 3: photo from HealthBenefitsTimes.com (link below).