Swedish cave men: lactose intolerant Neolithics.
Research at Uppsala University and Stockholm University reveals that the earliest Neolithic Scandinavians could not tolerate milk products in their diets. The capacity to consume unprocessed milk into adulthood is regarded as having been of great significance for human prehistory. "This capacity is closely associated with the transition from hunter-gatherer to agricultural societies," explains Anders Götherström at Uppsala University's Department of Evolutionary Biology. This lactose intolerance factor in the Stone Age peoples on the southern coast of Scandinavia back some 4,000 years ago supports this contention by evolutionary biologists that modern Swedes, Danes and Norwegians are not the descendants of these earliest hunter-gatherers, but rather, of more recently immigrated tribes. According to the researchers, explanations for the DNA differences include the possibility that - through a powerful selection process - Stone Age Scandinavians' genes evolved to permit them to digest milk. Another possibility, which the scientists tend to favor, is that Swedish people of today are not related to the Neolithic Scandinavian population.

By 2,000 years ago, they were milk drinkers
With either scenario, it is ascertained that by 2,000 years ago, Scandinavians dwelling in what is today Sweden were farmers, milk drinkers and also fermented milk into alcoholic beverages. A related speculation about failed contact of Viking Age seafarers with Native Americans in the years of 800-900 AD could have gone awry because they brought along mead, and other, milk based beverages. If Vikings offered the natives milk, it would have reacted much like poison to the lactose intolerant natives, and may have resulted in hostile relationships that, in fact, are somewhat similarly recorded elsewhere. The researchers are continuing work that involves investigating the genetic makeup of the earliest agriculturalists in Scandinavia and seeking answers about their original ancestors.