Museum exhibits of historic clothing or medieval armor show just how small people were a hundred or more years ago. It wasn’t just women’s tiny waists, pinched in by industrial strength corsets; both men and women were shorter and narrower. Only in the past 150 years did humans begin reaching their true height – the result of improved health and nutrition.
“People have been getting taller and bigger,” confirms William Leonard, Ph.D., a biological anthropologist and co-director of Global Health Studies at Northwestern University. “It’s been happening particularly in the industrialized world for more than a century,” he says, “and we can certainly document it very clearly over the last 100 years because of medical and military records.”
Better food, sanitation, and disease control helped people become healthier so they could grow taller, explains Dr. Leonard. Eating well (especially during several key childhood growth spurts) and with fewer diseases to fight, humans could finally start realizing their “genetic potential” for height. In short, humans could have been taller all along, held back only by illness and poor diet. As living conditions improved in developed countries like the United States, populations were able to use their biological energy for growth.
Taller, but not the tallest
Over the past century, black and white Americans have enjoyed height increases of about one inch for women, who now average 5 feet 4 inches tall, and two to three inches for men, who stand between 5 feet 9 inches and 5 feet 10 inches. Compare that to the Netherlands, whose men grew from 5 feet 4 inches in the mid-1800s to the current average of 6 feet, and whose women stand over 5 feet 6 inches tall, on average.
The Dutch are the world’s tallest, with white American males measuring the ninth tallest and African American males the 13th tallest, according to a 2007 paper published in the Annals of Human Biology, “The Mysterious Relative Decline of American Heights in the Second half of the 20th century” by John Komlos, Ph.D. and Benjamin E. Lauderdale, Ph.D. White and black American women stand at 14th and 18th tallest, respectively, behind the Dutch.
Historical ups and downs
Scientists see evidence that human growth has fluctuated for thousands of years. For example, nomadic hunter-gatherers had very thick, long bones, Dr. Leonard says, and in many cases were about as tall as the average American is now. But human height regressed after the development of farming more than 10,000 years ago; those early farmers were shorter and had lower bone mass than hunter-gatherers, the result of significant changes in diet and lifestyle.
“From their skeletons we’ve seen paradoxically higher rates of malnutrition,” says Dr. Leonard, “because for the first time people were being drawn together in larger groups, so infectious disease became a bigger issue.” Eventually the trend rebounded and people grew taller. “Over the arc of time,” Dr. Leonard continues, “with improvements in sanitation and nutrition, you see better growth rates.”
The politics of growth setbacks
But just as things can improve, says Dr. Leonard, they can also slide backwards again. In countries where there is increased social inequality and impoverishment, he says, you can also see growth waning – a reflection of political and economic turbulence that often affects access to food and healthcare.
“Stature declined among black South Africans during apartheid,” explains Dr. Leonard, whose research found similar declines among indigenous Siberians during the depression that followed the Soviet Union’s collapse. A period of famine in the 1990s stunted growth in North Koreans so dramatically that males average four to five inches shorter than South Korean men of the same age.
Reaching a plateau
Although Americans are taller than in the past, our height has leveled off since the late 1960s, says Dr. Leonard, thanks to consistently favorable living conditions. “Our nutrition and health is now sufficiently good,” he explains, “so the average child is reaching or closely approximating their genetic potential.”
Recent immigrant populations, such as Latinos, still show some increases in height. Such groups often come to the U.S. from conditions of poverty and marginal nutrition, Dr. Leonard explains. With improved circumstances here, they are starting to realize their own genetic potential and are becoming taller.
Getting taller through socialized medicine
One theory for height differences between the United States and the Netherlands might nettle Americans who are uncomfortable with socialized medicine, a sensitive topic in today’s political climate.
“The Western and Northern European welfare states, with cradle-to-grave health and unemployment insurance, currently provide a more favorable environment for the biological standard of living than its U.S. counterpart,” conclude University of Munich economists Dr. John Komlos (professor emeritus) and Marieluise Baur, Ph.D. Countries with universal health care can provide better medical care for their children, who then grow up healthier and taller, say Drs. Komlos and Baur. The United States, which struggles with the health insurance issue, spends more per person on health care and yet has poorer health outcomes and higher infant mortality rates than many other countries. And we’re shorter.
“It’s an intriguing and controversial argument,” observes Dr. Leonard, “and I think more research needs to be done before we can nail that down.”