The Netherlands is officially the tallest country on planet Earth. For the most part, scientists believed this was due to wealth, a rich diet and quality health care. But a new study suggests that the overall height of Dutch people may actually be human evolution in action.
Scientists have identified 180 genes that influence your height. Individually, all account for a very small effect, but combined, may explain up to 80% of the variation in height of a population.
Environmental factors may also play a role. For example, children of Japanese immigrants to Hawaii are much taller than their parents. Scientists attribute this to a diet that is rich in milk and meat.
The Dutch have grown so quickly in a short period of time that most of the growth is attributed to their changing environment. They are one of the world’s largest producers and consumers of cheese and milk. Scientists also wonder if natural selection may have played a role: height is associated with better health, attractiveness, better education and higher income – potentially leading to more reproductive success.
Gert Stulp, behavioral biologist at the London School of Hygiene & Tropical Medicine led the study. Including people over the age of 45 born in the Netherlands to Dutch-born parents, the sampling of 42,616 people showed that taller men, on average, had more children. Since tall men are more likely to pass on genes that made them tall, the study suggests that the Dutch population is evolving to become taller.
Similar studies in the U.S. do not show a similar pattern. Stulp’s research of people born in Wisconsin in the late 1930’s show average height men had more children and that shorter women had children of average height. These factors suggest that natural selection in the U.S. is opposite of environmental factors like diet, although this likely explains why the average height of American’s have leveled off.
The surge in height of the Dutch population is likely only temporary, similar to Americans growth in height during the 18th century. Natural selection tends to favor one trend for a few generations, and then stabilize or decrease in subsequent generations.
• How can a diet rich in milk and meat affect a country’s overall height and health?
• Are there other factors that may affect a populations overall change in height? How would they affect the changes?
• Natural selection
• Environmental Factors
By Celeste Beley