Fjordman: Did Lactose Tolerance Trigger the Indo-European Expansion?

Fjordman’s latest essay has been published at HonestThinking. Some excerpts are below:

Did Lactose Tolerance Trigger the Indo-European Expansion?

Following the rapid advances in our understanding of genetics in recent years a new branch of biological history or biohistory has emerged, where human history is seen through the prism of genetic changes and the theory of evolution. For my long essay Why Did Europeans Create the Modern World? I included biohistory as one of the aspects explaining different levels of accomplishment, informed especially by the book Understanding Human History by the American astrophysicist Michael H. Hart, which is available online as a pdf file. Another recent title is The 10,000 Year Explosion: How Civilization Accelerated Human Evolution by Gregory Cochran and Henry Harpending from the University of Utah in the United States.

Evolution proceeds by changing the frequency of genetic variants known as “alleles.” An allele is one of two or more versions of the same gene. The advent of agriculture vastly increased the total amount of food available, as humans didn’t merely have to rely on food readily available in nature but could grow their own in addition to this. The larger and more permanent settlements associated with agriculture gave birth to new infectious diseases, as a critical mass of humans lived in close contact with each other and with domesticated animals and their germs. Food production allowed for the accumulation of wealth, trade specialization and the rise of nonproductive elites, who ruled others simply because they could.

Agriculture allowed those who practiced it to greatly expand their numbers, but it is distinctly possible that the nutritional quality of the food of early farmers was initially worse than that which had traditionally been available to hunter-gatherers. Consequently, the health of each individual was not necessarily better in the Neolithic period than it had been in the Paleolithic era. The bodies of those who practiced agriculture had to adapt to a new diet consisting of foods that had either not been eaten before or had previously been of only minor importance.

According to The 10,000 Year Explosion, “For example, we see changes in genes affecting transport of vitamins into cells. Similarly, vitamin D shortages in the new diet may have driven the evolution of light skin in Europe and northern Asia. Vitamin D is produced by ultraviolet radiation from the sun acting on our skin — an odd, plantlike way of going about things. Less is therefore produced in areas far from the equator, where UV flux is low. Since there is plenty of vitamin D in fresh meat, hunter-gatherers in Europe may not have suffered from vitamin D shortages and thus may have been able to get by with fairly dark skin. In fact, this must have been the case, since several of the major mutations causing light skin color appear to have originated after the birth of agriculture. Vitamin D was not abundant in the new cereal-based diet, and any resulting shortages would have been serious, since they could lead to bone malformations (rickets), decreased resistance to infectious diseases, and even cancer. This may be why natural selection favored mutations causing light skin, which allowed for adequate vitamin D synthesis in regions with little ultraviolet radiation.”

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Alcoholic drinks, which became important with the rise of agriculture, have plenty of bad side effects, yet essentially all agricultural peoples enjoyed some form of alcoholic brew. The consumption of fermented beverages containing modest amounts of alcohol could be beneficial to your health as drinking wine or beer provided some protection against waterborne pathogens. For this reason, alleles that reduced the risk of alcoholism prevailed among agricultural populations in Eurasia. Many of those who did not have extensive food production before the modern era, such as Australian Aborigines, Eskimos or Native Americans in North America, are particularly vulnerable to alcoholism and have special health problems more frequently than others when exposed to a Western diet.

Before the rise of agriculture no one past infancy, the first years of our lives when we drink human breast milk, could digest milk sugar, or lactose. Lactase is the name of the enzyme that allows us to digest the complex milk sugar. After cattle were domesticated, cow’s milk became a nutritious addition to the diet. Several different populations, all raising cattle or camels in Europe, East Africa and the Middle East, independently evolved the ability to digest milk for life. Genetic evidence indicates that such a mutation probably first occurred in central Europe, perhaps before 5000 BC. Pioneer farmers in northern Europe used crops from the Near East that were not necessarily ideally suited for a cooler, northern environment, and cow’s milk may have become an increasingly important staple for survival in these regions.

Read the rest at HonestThinking.