Huige
20 18
July 27(th), 2008
In the last article, I said that since the late Paleolithic, population growth, technological progress and mobility decline, these three mutually promoting factors pushed human recipes off the mass spectrum. This process suddenly accelerated when the temperature warmed up after the ice age, and it advanced at an unprecedented speed throughout the agricultural era. Moreover, with the land reclamation and the simplification of crops, the ingredients of fishing, hunting and animal husbandry have shrunk, and the recipes have narrowed after moving down, and the dependence on grains has been strengthened day by day.
Only in the recovery period after some great plagues did the quality of recipes rebound, and then in the New World after Columbus Exchange (accompanied by the biggest plague on record) there was a sharp rebound. Finally, it was not until the industrial revolution and demographic transition that the middle-income areas rebounded comprehensively.
The downward movement and shrinking of recipes have caused many negative effects on human health and quality of life, so many people regard the Neolithic revolution that led to settled agriculture as a curse to human beings. From the point of view of diet and health, it is true, especially those pure grain planting groups that lack animal husbandry and fishing and hunting ingredients.
From the evolutionary point of view, grain is a particularly suspicious food, because our paleolithic ancestors never regarded it as an important food source, which means that if they are harmful, our physiological system has very limited opportunities to make adaptive changes, because the time left for evolutionary adaptation is only a few thousand years at most, and in fact, the harm of grain as a staple food to health has been clearly proved in archaeological records.
decayed tooth
Dental caries is a typical agricultural disease, which is rare among hunters and gatherers. A high-carbon water diet creates a good oral environment for bacteria. In a typical hunter's diet, carbohydrates contribute only 65,438+0/3 of energy, which is lower in high latitudes, but as high as 2/3 to 4/5 in intensive farmers. Moreover, farmers have more fully processed and cooked starch foods, and even refined them into maltose (a disaccharide), which is more easily absorbed by oral bacteria.
Here, I would like to emphasize by the way that most of my readers come from Mongolian or Caucasian people like me. Both of them lived in the cold zone near the glacier line or tundra for a long time at the end of the Pleistocene, so out of a self-centered habit, when I used the phrase "our ancestors" in the time situation of "the last 30 thousand to 40 thousand years", I thought more about them. For them, the fat content in their diet would be much higher than that of typical modern hunters.
Therefore, the transfer of food in archaeological records is always associated with the high incidence of dental caries, the only exception may be rice, and the emergence of rice cultivation in Southeast Asia seems to have no exact relationship with dental caries, and the reasons are unknown.
anaemia
Anemia is common among farmers. Some are due to insufficient intake of protein, and some are due to iron deficiency. Grain is not only low in iron, but also rich in phytic acid. Phytic acid will hinder the absorption of minerals in the intestine, thus increasing the risk of iron, calcium and zinc deficiency. Therefore, phytic acid is classified as an anti-nutrient by nutritionists, and its content is particularly high in grain bran (interestingly, whole grain food is being widely praised at present).
Anemia will force the body to increase the number of hematopoietic bone marrow, so a large number of extra honeycomb cavities are formed in some bones (especially in the dome of skull) to accommodate red bone marrow, thus leaving fossil evidence.
At present, there are still1500 million people in the world who are in iron deficiency anemia, and most of them are caused by malnutrition.
deformity
Compared with hunters, farmers have lower bone density, so their bone strength is weak, probably because of calcium deficiency; The index that can better reflect the nutritional health status is height, because height is related to many nutritional health status in the whole development period. Only when all the conditions are good can the height potential endowed by the genetic basis be realized.
The height of modern hunter-gatherers is generally not high, comparable to that of traditional farmers, but it should be remembered that since the origin of agriculture, most of the niches have been occupied by farmers and herdsmen, and hunters have no resistance to the expansion and exclusion of farmers and herdsmen (because their groups are too small and unorganized), so the existing hunter-gatherers occupy marginal niches and are in a tight situation. As I introduced in the fifth chapter, the nutritional status of the Kalahari Sankun people is extremely poor.
However, this was not the case for Paleolithic hunters, especially in high latitudes. The average height of farmers in Kroma who lived in Europe in the last ice age was 1.79m, and that in Gravit in the peak of the last ice age was above1.80m. However, after the spectral revolution, the average height of Europeans dropped to 1.66m, and then to 1.65m in the agricultural age. Of course, there may be the influence of temperature change (animals in cold regions tend to be larger in size) and changes in genetic composition caused by immigrants in the early stage after the Neolithic Revolution, but mainly not. There are two evidences: First, after the rebound of modern nutritional status, the height of most European countries rebounded to more than 1.80 meters, with the Netherlands being the most prominent. From 1.65m in the middle of the 9th century to 1.84m in the 1990s. Secondly, the downward trend of height in the agricultural era is relatively mild in Eastern Europe, and the average height remains above 1.70. As we know, the agricultural intensity in Eastern Europe has lagged behind that in Western Europe for a long time, and the climate and soil conditions have kept them so.
Archaeological records in other areas also show the same trend. In the first few thousand years of the Neolithic Age, the average height of rice growers in China and Japan decreased by 8 cm, while that of corn growers in Central America decreased by 5.5 cm for men and 8 cm for women. Two facts clearly reveal that the height of traditional farmers is suppressed by nutritional conditions: the average height of any poor agricultural country has greatly improved after its income reaches the middle level, and the height of anyone who immigrates from a poor agricultural country to a rich country has greatly improved since the second generation.
injury of joint
Another health problem revealed by fossil evidence is that the joint injury rate of farmers is generally higher than that of hunter-gatherers, including osteoarthritis, which is not only due to malnutrition, but also because farmers have heavier labor burden and longer working hours. In my last article, I said that the downward movement of recipes is the result of Malthus' innovation, which enables human beings to extract more nutrition from given resources with increased labor input.
Moreover, the body posture, body movements and load distribution involved in agricultural labor (including those housework peculiar to agricultural life) are very different from hunting and gathering activities, and our bodies are shaped for the latter. Therefore, even if the labor intensity is equal, agricultural work is even more unhealthy. We can hardly find any sports or fitness programs similar to farm work (I can only think of weightlifting and tug-of-war), but we can find the shadow of hunting and fishing in many projects.
cerebrum
The volume of human brain has shrunk 10% in the past 20000 years. There are many speculations about this, but there is no conclusion. Some people think that DHA (a polyunsaturated fatty acid that plays an important role in nerve development) deficiency plays a role in it. Fat once accounted for 1/3 of human food, but intensive agriculture has reduced it to 10% or even lower. Although DHA can be synthesized in vivo, EPA is also a fatty acid, and the efficiency of synthesis in vivo may not keep up with the demand of brain development peak.
This is a supply-side explanation, which may need to be matched with a demand-side explanation. Because brain volume generally does not rebound after modern nutrition improvement like height, it seems that it is not simply inhibited by nutritional status. Perhaps, for some reasons (such as reducing body size, reducing muscle mass, meekness, refining division of labor, increasing neuron density or rationalizing wiring ...), we no longer need such a large brain, and we also lack nutrition (especially DHA).
Gluten allergy
Gluten is unique to wheat grains (wheat, barley, oats, rye, etc.). ) has caused many health problems (at least among people who are sensitive to it), including celiac disease, non-diarrheal gluten allergy, imbalance and allergic skin rash or ulcer. Although there is no fossil evidence, the relationship between these symptoms and food and agriculture is so direct that it can be determined without archaeological evidence.
Although the problems caused by gluten have various manifestations, there is a common mechanism behind it: the immune system overreacts to this strange protein, which is not difficult to understand. Judging from the scale of evolutionary history, wheat grains are really strange to human beings.
It is not clear how widespread gluten problems are. Although in the current epidemiological statistics, the proportion of people diagnosed as gluten allergy is less than 10%, it needs to be considered that, firstly, the diagnosis of gluten allergy is not easy because of its various symptoms; Secondly, the problem of gluten has only recently begun to be concerned by the medical community, so patients and doctors rarely consider the problem in this direction; Third, politically, you can hardly count on a big agricultural country.
infectious disease
Settlements have deteriorated sanitary conditions. Garbage and food piled up in settlements feed a large number of human companion animals, such as rats, cockroaches and flies, and also provide a hotbed for many germs, which will also pollute the nearby water sources. Settlers can't get rid of them by constantly moving their camps like mobile hunters. At the same time, the living environment of human beings and animals has greatly increased the types of harmful microorganisms, such as those that cause tuberculosis, influenza, smallpox and measles.
More importantly, settled agriculture has increased the population density by several orders of magnitude, and through businessmen, mobile craftsmen, vagrants and beggars, military and administrative officials, a regular population flow has been formed among a large number of people. Markets and towns provide a central distribution node for this mobile network, which creates excellent conditions for the large-scale epidemic of infectious diseases, especially those fierce infectious diseases with high mortality, which cannot exist in sparse small groups, because pathogens will accidentally put the host group.
It is true that large settlements are more likely to survive in various plagues because of their long-term exposure to various pathogens, but this is not without cost. The long-term struggle between the immune system and pathogens not only consumes energy, but also inhibits the work of other physiological functions, leaving the body in a sub-health state. When the nutritional status deteriorates due to famine, this system with continuous high workload may collapse across the board, so plague often follows famine.
Protein's deficiency
The downward shrinking of recipes and the increasing dependence on staple foods have also brought about serious nutritional balance problems, especially in rice and corn planting areas in the middle and low latitudes. Because of the short growth period of rice, it can be planted in multiple seasons a year, so the population density is high. After paddy fields, irrigation and terraces were used, almost all other food crops were squeezed out. There is abundant rainfall in the monsoon belt of middle and low latitudes, leaving little land for livestock, and corn not only has high yield, but also has low requirements for soil.
The content of vitamin B 1 in polished rice is extremely low, which leads to beriberi widespread in rice areas in Southeast Asia. The content of vitamin B3 and tryptophan in corn is too low, so Americans who live on corn will suffer from pellagra. But the more common and serious nutritional imbalance is the lack of protein, and the protein content of cereals is generally low. Although beans can make up for it, compared with the high proportion of meat, fish and milk in the diets of hunters and herders, the content of protein is still very poor.
Moreover, plant proteins also have many problems, such as incomplete amino acids, poor amino acid composition ratio, poor absorption effect, or other incidental defects (such as allergies). Nutritionists use protein quality (PDCAAS or DIAAS) and biological value (BV) to measure the nutritional value of various protein sources. The former measures the completeness and collocation ratio of amino acids from protein. The latter measures the proportion of absorption and utilization in the body structure (rather than the source of energy). In the two measurements, the highest score is poultry eggs, followed by dairy products, and then meat. The protein score of plant origin is generally low, especially for cereals and beans.
Generally speaking, the mass fraction of plant protein is only about half that of animal protein. The only plant with the same mass fraction as animal protein is soybean (DIAAS=0.9, close to beef, and the perfect score of eggs is 1.0), but the BV score of soybean is only 74, which is still the highest among plant proteins, while the BV of eggs, milk and beef are 100 and 965438+ respectively.
Soybean, the best plant protein source, was only distributed in East Asia in ancient times, and it didn't spread to other continents until modern times. Like other seed foods, it is rich in phytic acid, and like other beans, its high purine is easy to cause gout, and its protein will make many people allergic.
The lack of protein caused by intensive cultivation forces people to find and develop all protein sources, such as fish, shrimp, frog, loach, snail, vole, weasel, sparrow, cicada, grasshopper, caterpillar and moth. When farmers have exhausted the land and completely transformed the ecology, they can only find these small animals and painstakingly collect the number of protein obtained in one year.
The most extreme manifestation of these efforts is cannibalism. The geographical distribution of cannibalism is obviously related to the lack of protein. It is Americans who push cannibalism to the extreme. In the high corn producing areas of Central America, human flesh has become a systematic and regular source of meat. Maya and Aztec city-states often killed thousands of prisoners as human sacrifices at memorial ceremonies, and then distributed the bodies to nobles and warriors to take home for food. Before prisoners are pushed to the altar, they will get enough food to fatten themselves up.
In Aztec, prisoners even became the main purpose of waging war, so tactics and strategies tended to capture as many prisoners as possible, and the number of prisoners (rather than the number of enemies killed) became the main index to assess the meritorious military service. This tendency is most obvious in the so-called xochiyaoyotl in the late Aztec period, which is a ceremonial war, and has nothing to do with the common war reasons such as expanding territory, competing for hegemony and conquering opponents. Both sides agreed.
The shortage of protein is so serious in the United States because they lack meat animals and soybeans. The only big animal domesticated by Americans is alpaca, which is very small and mainly used for wool collection and pack transportation. The only animals domesticated by Central American farmers to eat meat are guinea pigs. Each guinea pig can only provide a few hundred grams of meat, but it is also very precious.
The dark side of civilization
Many readers may ask after reading this: Since settlement, agriculture and food have brought so many problems and worsened human nutrition and health, why are you so happy in Chapter 5? Don't you think it is contradictory to regard the storage of grain, the promotion of recipes, settlement, agriculture, especially the development of grain as a key turning point towards civilization, and even call grain the touchstone of civilization?
In my opinion, there is no contradiction here. Agriculture has indeed worsened human nutrition and health, but I won't claim, like jared diamond, that "engaging in agriculture is the worst mistake in human history". I believe this is just a rhetorical device he used to emphasize the above facts, and he didn't take it literally. Otherwise, he is all wet.
The transformation to agriculture is the result of a series of scattered personal choices accumulated for a long time. Looking from a distant lens afterwards, this is a revolutionary change, but no one foresaw, planned and implemented this revolution, so it is impossible to talk about who made what mistakes (such a judgment only makes sense when you imagine that you are a great helmsman leading the course of all mankind), and every individual choice in this process may be rational and bring tangible benefits to the relevant individuals.
For example, the development of grain may initially be used as a seasonal supplement to help people survive the low yield of prey. Of course, people who did this benefited, but when this practice became popular, its long-term effect was to broaden the population bottleneck imposed by ecological conditions, so the population increased, the initial benefits were dispersed, and the recipes moved down, but this was after many generations and had nothing to do with the earliest people who developed grain. Or it's important: they left more offspring than those who didn't. Is this a mistake? )
Someone will then ask: even if no one makes mistakes, is this result good or bad? Let's state the problem more clearly: at this moment, should I turn to settled agriculture? My answer is of course no. I don't need to hesitate for a second, because without a fixed civilization, everything I cherish and indulge in, such as art, literature, movies, history, philosophy, bridges, libraries, microscopes, cars, airplanes, computers, MP3 players, the Internet, Wikipedia, science and law, would not exist, or even have a shadow.
Only a frivolous fool like the author of A Brief History of Mankind can claim that hunter-gatherers can have the same rich spiritual world and cultural life, and "may have experienced wars and revolutions, fascinating religious movements, profound philosophical theories, unparalleled artistic masterpieces ... their own invincible Napoleon, and half an empire the size of Luxembourg under his rule; Beethoven has his own genius, but there is no symphony orchestra, only the sound of bamboo flute makes people cry ... "
Wake up, most hunters only have three numbers: one, two and many. Surprisingly, they can count to more than five. Their language lacks the most basic abstract concepts, and their historical memory is only two or three generations. What is above their great-grandparents has been merged into a myth without depth and details, as if the world was created only a hundred or two years ago, and it is only an unknown one or two hundred kilometers away. The moral system is also extremely simple, lacking all the moral feelings that have appeared since the Axis era.
Do you really want to live in such a spiritual world? There are no moving plots in novels and dramas, no vicissitudes in history, no strategic planning in war, no intrigue by Lian Heng in politics, no cheers in the arena, no twists and turns of humor, no meditation when facing difficulties, no deep comfort brought by tacit understanding of values, no glory of victory and achievement, and religious piety, professional persistence, chivalrous spirit and free spirit ... all things that make you feel that life is more meaningful than survival and reproduction.
This article obviously has its dark side, but this can't hide its brilliance.