Maize flour, like cassava, is not usually made into raised bread, but the Amerindians did bake flat tortillas. Tamales, filled dumplings steamed in a covering of maize or other leaves, are another staple dish made from maize. The use of maize alone as a staple food can result in a disease called pellagra. Native American peoples avoided pellagra by using various techniques of agriculture, plant husbandry and diet:
- Ashes, lime or mollusc shells were added to process the grain by boiling, then washing, drying and grinding the kernels.
- Others buried the maize grains, still on the corn cobs, in mud to rot for two or three months.
- Maize was usually eaten in combination with beans; this dietary mix helped to ameliorate the deficiency of vitamin B4 in maize, which is what causes pellagra. Beans were also usually interplanted with maize, which helped the maize to grow by fixing nitrogen, in the same way as clover does when interplanted with grass, thus strengthening the maize crop. The agricultural system involved the two most important food stuffs. . Although there was no scientific knowledge of the fixing of nitrogen until the 19th century, or about vitamin B4 (niacin) until 1934, these beneficial husbandry and dietary practices were pursued by Amerindians many centuries before.
The first two methods broke down the cell walls in the maize grain, making the main protein, zein, less available. This prevented zein making the other proteins unavailable, as well as inhibiting the absorption of vitamin B4. No one knew it at the time, but these methods increased the availability of the essential amino acid lycine almost three-fold. Europeans took maize all over the world before they were aware of its tendency to cause pellagra when used as the sole staple and even in the Great Depression of 1929-35 more than 5 million people in the USA alone suffered from pellagra. A similar number suffered in Italy, Greece, Spain and Romania; millions in Africa still do.
In pre-Colombian times, the Aztecs of central Mexico had an 18-month agricultural cycle, around which they planned their maize growing cycle and fertility dances. It is said that in Peru some Amerindian tribes used guano as a fertiliser to increase yields. In North America, the absence of cultivating implements did not inhibit the cultivation of maize, as it only requires a stick for planting.