Height has historically been regarded as a marker of health and robustness. We seem to implicitly accept that bigger is indeed better, even if we don’t want to admit it. On average, tall people attain more professional success and make more money, the taller presidential candidate almost always wins, and women are more attracted to tall men. On a very visceral level, the taller person is more physically imposing. After all, who would you rather fight – the dude with a long reach raining punches from up high or the shorter guy with stubby arms who has to work his way inside your guard (although Mike Tyson did pretty well for himself with such “limitations”)? And on that note, who would you prefer as a mate – the physically imposing specimen or the shorter, presumably weaker male?
Your height in adult life significantly affects your quality of life, with short people reporting worse physical and mental health than people of normal height. A large, peer reviewed study, which appears in Clinical Endocrinology, showed that adult height is linked to how good a person thinks their health is. Short people judge their state of health to be significantly lower than their normal height peers do.
We in the Primal health community are quick to point out that agriculture reduced physical stature. Generally speaking, bone records indicate that Paleolithic (and, to a lesser extent, Mesolithic) humans were taller than humans living immediately after the advent of agriculture. Multiple sources exist, so let’s take a look at a couple of them before moving on:
According to one study on remains of early Europeans, prior to 16,000 BC, European males stood 179 cm tall, or 5’10.5″, and females stood 158 cm, or 5’2″. Between 8,000 to 6,600 BC, average heights had dropped to 166 cm for males. Heights fell even further in Neolithic populations, dropping down to 164 cm for males and 150 cm for females, only reaching and surpassing 170 cm at the end of the 19th century.
Another source found that Paleolithic humans living between 30,000 and 9,000 BC ran almost 5’10″, which is close to the average modern American male’s height. After agriculture was fully adopted, male height dropped to 161 cm, or 5’5.4″. Females went from 166.5 cm to 154.3 cm under the same parameters.
We know these changes to height also reflected worsened health, because with shortness came dental pathologies like caries, plaque, and decay, signs of arrested growth indicating instances of severe malnutrition, and skull abnormalities that stem from iron deficiency. People got shorter, sicker, and less healthy. Height wasn’t a cause of poor health, of course, but it was an indicator.
And that’s where the statistic of height shines – as an indicator. On a large scale, height increases indicate improved nutritional or socioeconomic status, while decreases indicate poor nutrition, famine, war, or economic hardship. Thus, as a population increases in height, it’s safe to assume that its people are either eating better, making more money, or both. If a population shows decreasing height (or stagnation, which the US is showing), we surmise that something is amiss. There exists no better modern day example of height following health than with North and South Korea. Several studies show that South Koreans are taller than their counterparts to the north. Since the two populations are so closely related, genetic differences can’t explain the discrepancy; it’s got to be environment, especially childhood nutrition. North Koreans are famously malnourished, and the height discrepancy between North and South – about three or four inches on average – is similar to the height discrepancy observed between Paleolithic and Neolithic populations.
There are numerous other examples. Up until the late 1800s, Northern Plains Indian tribes were the tallest people in the world, standing over 172 cm (or about 5’8″) and subsisting on a nourishing diet of wild game, fish, berries, and native plants. That height advantage disappeared with reservation life, of course. Fry bread, vegetable oil, sugar, and white flour mixed with extreme stress and economic hardship are poor substitutes for fresh buffalo and open plains. What about Americans, the ones who supplanted the Plains tribes? For most of the past two hundred years, Americans have been the tallest people in the world, until about fifty years ago when height began to stagnate. Today, American males stand around 5’10.5″, but we haven’t grown in decades and other countries have long since passed us. Meanwhile, European and Asian countries have steadily gained on us. The Dutch, whose men stand over 6′ and whose women stand over 5’7″, are now the tallest in the world. American males are ninth tallest and American females are fifteenth, and any regular reader of mine knows that the nutritional situation in America needs a lot of work. It’s no surprise that we’re stagnating while other countries with better nutrition are growing.
And yet for all the concrete links between a population’s height, health, and nutrition (especially childhood nutrition), some researchers have linked “excessive” height to poor health and longevity. Barring the obvious examples of short-lived people with gigantism and other endocrine disorders, there is some evidence that the shorter among us live the longest. Thomas Samaras, a height/health researcher, has authored several papers arguing that bigger is not necessarily better. In one, he reviews human and animal evidence and seems to present a strong argument, but others have argued that Samaras overlooks evidence to the contrary. While Samaras chooses to focus on increased mortality from non smoking-related cancers in the tall, he ignores the bevy of evidence showing that in industrialized nations, taller people enjoy more protection from all-cause mortality, including heart disease, stroke, and respiratory disease.
But what about those centenarians? As Samaras notes, they, along with nonagenarians (between 90 and 99 years old), are on average shorter than the rest of the population. The long-lived Okinawans are famously dimunitive, and it seems like every other Mediterranean centenarian in the news is a spry old lady.
I like one possible explanation for centenarians being shorter and slighter while enjoying better health and longevity: insulin-like growth factor, or IGF-1, a protein produced in the liver and stimulated by growth hormone that induces systemic growth in almost every cell of the body, including muscle, bone, various organs, cartilage, skin, nerves, and lungs. It even affects DNA synthesis and individual cell growth. IGF-1 is perhaps the biggest determinant of height in humans: in infants, IGF-1 correlates strongly with growth, IGF-1 is highest during growth spurts in pre-teens and teens, and higher levels of IGF-1 usually correlate with adult height. Clearly, enough IGF-1 is required for proper musculoskeletal development, but what about too much? Can you have too much IGF-1?
Staffan Lindeberg thinks that excessive serum levels of IGF-1 from diet-induced hyperinsulinemia are causing unhealthy amounts of growth, which manifest as higher rates of cancer and, yes, height, in Western populations. Simply put, Lindeberg agrees that a population’s height is an indicator of health, but only to a point, after which it indicates excessive and potentially problematic levels of IGF-1. There’s probably something to this; female centenarians are more likely to have an IGF-1 receptor mutation that results in elevated serum levels of IGF-1 while reducing IGF-1 receptor activity. In other words, the body was producing more IGF-1 to make up for the lack of receptor activity. This same receptor mutation has been linked to longevity in multiple animal models resulting in higher serum IGF-1 and lower IGF-1 receptor activity – just like in the human centenarians. In male and female offspring of the centenarians, however, only females showed elevated serum levels. Male offspring had similar IGF-1 levels to control males (those with no familial history of longevity). Female offspring were also 2.5 cm shorter than control females; male offspring were of similar height to control males. Perhaps short stature is more beneficial to women?
Maybe so. Gavrilova looked at draft cards filled out by 30 year-old Americans who would eventually grow up to become centenarians and analyzed the differences between the physical stats of those who would eventually grow up to become centenarians and those who didn’t. While obesity (or “stoutness,” as it was called back then) had strong negative links to longevity, height did not. The group of future centenarians was mostly people of medium height. Being soldiers, however, these were exclusively males. According to the IGF-1 receptor mutation study, only in females is the mutation linked to lower heights and greater longevity.
Overall, though? Height is linked to a population’s health and good childhood nutrition. In certain individuals, given certain genetic differences, short stature may indicate the potential for greater longevity, but not on a population-wide scale. Besides – barring pharmaceutical (or cybernetic) interventions, there’s not a whole lot we full-grown adults can do to alter our heights.