The Dutch are the tallest people in the world. Dutch women average 1.71 meters tall, men 1.84 meters
That the Dutch are so tall was usually attributed to nutrition.. a diet rich in dairy and meat. But new research attributes the height of the Dutch primarily to natural selection.
The Dutch have grown twenty centimeters taller on average over the past hundred and fifty years. In the eighteenth century, with an average height of 1.68 meters, the Dutch were still among the smallest. That growth spurt has long remained a mystery.
A diet rich in dairy and meat cannot be the complete explanation. Other European countries also enjoyed ever-improving living conditions in past centuries but did not grow proportionately. Over 150 years, the average height of the American increased only 6 centimeters.
Researcher Gert Stulp of London School of Hygiene and Tropical Medicine collected data from 94,500 Dutch people who lived in the North of the country between 1935 and 1967.
From this it became clear that tall men on average had more children than men of average height. Women of average height had more children than tall women. The most fertile men were found to be 7 inches taller than the average. Statistically, they had an average of 0.24 more children than the least fertile men, who were about 14 centimeters shorter than the average height.
Because tall men have more children on average and the survival rate for children of tall parents is slightly higher, tall people's genes are better passed on.
Researchers have determined that at least one hundred and eighty genes determine how tall you become. Each gene has a small effect, but together they ensure that 80 percent of height is genetically fixed.
The study does say that better distribution of wealth and access to health care have also helped the Dutch growth spurt.
Natural selection, combined with good environmental conditions, explains why the Dutch are so tall, the researchers conclude in the journal Royal Society Journal.
"Height is highly heritable. Larger parents tend to have larger children than smaller parents," said Stulp. "Because taller individuals have more children who are also taller, the average height increases in the next generation."
There are also cultural preferences that come into play. Stulp points out that in the U.S., smaller women and men of average height have the most children. "There is a lot of variation in what men and women want," he says. "When choosing a partner, height appears to play only a small role."