The introduction of a new crop can be a hazardous business. The first grain farmers of the near east suffered malnutrition for many generations until a larger suite of crops and livestock came together, coupled by changes in human culture and genetics. More dramatic results are common when a fully domesticated crop is transferred between different regions.
As one of the most productive grain crops so far domesticated, maize stood out as a major force of disruption when it was introduced to the old world (Africa, Europe and Asia). It first arrived in Spain, replacing wheat as the foundation for the peasant diet by the 1700s. In the 1730s a disease called pellagra was first described, characterised by rough skin lesions, digestive disturbances and a range of severe psychological effects. Untreated, the condition progressed to death, with epidemics of hundreds of thousands of suffers plaguing southern Europe over the next two centuries. Pellagra sufferers were confined to mental asylums, often making up more than half of the patients.
From the very beginning maize was suspected to cause the condition, possibly due to some unidentified toxin (named pellagrozeine). Another prominent scientist debunked the maize theory and argued that pellagra was caused by a microbe, spread by insects. The true cause and cure for pellagra would not be discovered for another two hundred years, eventually tied to the lack of vitamin B3 (niacin) in the diets of poor peasants subsisting on little more than maize meal and lard. Increasing levels of alcohol consumption during the spread of industrialisation also contributed since this depletes niacin.
If some aspect of the modern diet or environment was secretly causing an epidemic of mental illness and chronic conditions would our scientists discover it? Just as was the case for maize and pellagra, researchers probably already discovered such causes, but the scientific consensus has not coalesced and any response is lacking due to institutional or economic incentives. The maize based explanation of pellagra was opposed by authorities for centuries since it was such a cheap way to feed peasants.
Tragically, the niacin that sufferers needed had always been present in their diet. Maize has a modest amount of this nutrient but it is bound up in a way that makes it impossible to absorb in polenta and the other forms consumed in Europe. In central America, where maize was first domesticated, people had long figured out that soaking the grain in alkaline solution before cooking resulted in a more nutritious product in a process called nixtamalization. This not only liberates the niacin, but helps remove mycotoxins, and adds a range of minerals depending on which form of alkali is used. Modern populations are spared from pellagra and related vitamin deficiencies by the fortification of processed food products with synthetic B vitamins. Perhaps future generations of old world subsistence farmers will once again suffer this unnecessary scourge simply for lack of an appropriate food culture to accompany the crop, since nixtamalization is still not practiced outside the new world.
Maize also spread into sub-Saharan Africa by the late 1500s and was essential in the transatlantic slave trade. Maize produced large surpluses of storable calories along the coastal areas where slaves were collected, and it was essential for keeping them (barely) alive during the crossing. Maize replaced indigenous grains from the region like sorghum and millets which gave lower yields. Introduced cassava and sweet potato have since replaced maize as the dominant calorie crop since they are not vulnerable to locusts. Interestingly the first slave populations in the region were ordered to grow cassava and were poisoned by this crop as well due to incorrect preparation. By the 1800s maize cultivation had spread everywhere in Africa, and it is still a major component of the diet in more temperate southern Africa. Minor outbreaks of pellagra still occur in this region and the habit of nixtamalization is unknown.
The introduction of maize into China triggered its own special form of chaos. The crop proved especially bountiful in the Loess plateau, a region of steep, silty soil that was unsuitable for paddy rice cultivation. The region experienced a population boom in the early 1800s due to the spread of maize and potatoes, which in turn led to a massive increase in erosion. The yellow river accumulates 90% of its sediment as it runs through the Loess plateau, and the impacts of maize amplified a worsening cycle of droughts and floods. An especially bad series of floods in the mid 1800s was a major contributor to the Taiping rebellion which led to the death of 25 million people, all tracing back to a sack of maize seeds introduced decades earlier.
All this makes me reflect on recent discoveries about the origins of maize. The crop descended from a wild ancestor called teosinte (Zea parviglumis), a lowland perennial streamside grass with tiny rock-hard seeds. The domestication of this species began around 9000 years ago, but the crop did not spread more widely until it hybridised with a separate wild highland species (Z. mexicana) around 5000 years ago. Once again, the power of hybridisation is at the foundation of civilisation, though the capacity for the abundance of a single crop to upturn cultures, peoples and economies should never be underestimated.
The abandonment of sorghum and millet, and spread of maize growing cultures into previously useless soil types, is a great example of how local agricultural systems get stuck on “good enough solutions”. Why risk domesticating a new wild grass when you already have established species which will provide a dependable crop. New domesticates take many years to make progress, and many attempts end in failure. And yet, it is very probable that crops even better than maize are waiting to emerge from wild grasses growing at the weedy margins of fields.
It is also worth questioning if maize is in fact superior to other grains. Living things operate within physical constraints, and generally crops that produce more calories have to sacrifice the production of other nutrients. Maize produced more energy (and potentially more export dollars) but it ultimately led to the misery of countless people in return.
Pellagra is rare today since we have a much better diet than peasants. Or maybe that is just what we like to tell ourselves. Our industrial food system is dependent on a narrower range of crops than ever before, with highly processed commodity crops like industrial maize making up the bulk of many products. Cheap soybean meal is added to many products to boost nominal protein levels, but this recent addition to the industrial food system is probably contributing to its own epidemic of chronic health conditions due to culturally ignorant methods of preparation.
We avoid the worst consequences of this processed food by adding synthetic vitamins and minerals, but just like those ignorant 19th century peasants we don’t really understand the foundation of our food system. When it inevitably shifts beneath our feet, will our culture be ready to reclaim the techniques necessary to sustain human health in the long centuries ahead of us?
A few things I've learned so far in this life...
1. Most legumes are at least a little toxic, especially if soaked and undercooked. Kidney beans and black beans are major offenders and both can be causes of serious food poisoning. Even thorough cooking won't completely remove toxins. Get a pressure cooker.
2. Soy is also toxic, but generally in a slower-moving way. Even pressure cooking won't get rid of the toxins. Fermented soy in the form of tamari, miso and tempeh are the best ways to make it edible.
3. The indigenous people of the Andes never cook dry quinoa like rice. They ferment it first. It contains proteins which block absorption of some nutrients, and fermentation consumes those proteins. All you need to do is combine 3 parts water with one part quinoa, but don't fill the container more than 2/3 full. Since processing may kill naturally occurring yeasts and bacteria, use a few spoons of kefir or a probiotic capsule as starter. Ferment two days in warm weather or three in cold. That empty 1/3 of your container will fill with foam, so empty that out at least daily. Rinse thoroughly after the ferment until the water is mostly clear, then cook gently. Besides being better for you, it also tastes MUCH better, sort of like sourdough.
Very interesting, as always. Thank you!