There are large differences in human height across the world. These differences are not just geographical: human heights have changed significantly over our history , with increases in every country over the past century. Height is determined by a combination of genetic and environmental factors. How our height might reflect our environment — today and in the past — has been a key focus area for research. Here we see that people are taller in countries with a higher standard of living.
Nutrition is the one of the strongest determinants of human height. Humans convert the chemical energy stored in the macronutrient constituents of food into energy.
Dietary energy intake from food must balance energy expenditure due to metabolic functions and physical activity, plus extra energy costs such as growth during childhood. Humans can adapt to an enduring low dietary energy intake, or undernourishment, by reducing the rate of growth, which leads to stunting , and restricts adult height.
Insufficient dietary energy intakes across a population therefore result in a low average adult height. Protein is an essential macronutrient in a healthy diet, and is necessary for a wide range of biological processes, including growth.
It is made up of basic building blocks called amino acids. Some amino acids — known as the nutritionally essential amino acids — cannot be made in the body, and so must come from the diet. Diets must provide adequate quantities of the full range of amino acids for human growth and metabolism. The table shows the protein quality of different foods. Animal source food usually contains higher quality protein than plant source food. They are also a good source of micronutrients, such as iron and zinc, which are necessary for metabolism.
A study by Headey of dietary patterns in lower-income countries suggests there is a strong association between the consumption of animal sourced foods and height. For instance, animal proteins comprise 9. But even larger height disparities begin to arise at high levels of animal protein intake. In high-income countries, where animal protein intake is high, Grasgruber found that the strongest predictor of male height is the ratio of high-quality animal proteins — from milk products, red meat, and fish — to low-quality plant proteins — from wheat, rice and other cereals.
Appropriate mixtures of plant source proteins — such as cereals plus legumes or oil seeds — are capable of providing the essential amino acids and micronutrients necessary for growth. However, diets in low-income countries are often dependent on a single staple food source.
By contrast, cereals and grains constitute less than a quarter of dietary energy in the United States. As such, low-income countries are unlikely to exhibit enough dietary diversity. Animal proteins form an increasingly large part of our diets as income increases. Since nutrition plays a key role in determining height, there is an obvious relationship between income and height. Health — particularly in childhood — also influences human height. Disease during childhood can restrict growth because it reduces the availability of nutrients and raises metabolic requirements.
Children fighting disease have higher nutritional requirements during a period when nutrients are less available. As such, high incidences of disease should lead to shorter average heights. Grasgruber found that the socioeconomic factor most strongly correlated with male height is child mortality. This relationship is illustrated in the scatter plot, with child mortality rate on the y-axis and mean male height on the x-axis.
A low child mortality rate suggests low incidences of disease, as well as sufficient nourishment, and hence predicts a taller average height. For example, 0. The relationship between health and height is reinforced by the significant impact of healthcare expenditure.
We see this reflected in Arab states where health expenditure is much lower than their income level would predict. For example, compare Oman and the Netherlands: the average male height of the Dutch is cm — 13 centimeters taller than the average in Oman. Both countries have high levels of income per capita. Both child mortality and healthcare expenditure impact life expectancy: we would therefore expect them to be strong determinants of the relationship between standard of living and average height.
Total fertility rate the number of children per woman also interacts with these determinants, making it the second strongest socioeconomic correlate of height. The role of fertility in high-income countries is marginal since fertility rates are already very low. But it gains statistical significance at lower incomes, where fertility rates are relatively high.
In families where there are a large number of children, expenditure and food availability for each child is often lower. We might therefore expect that in countries where the fertility rate is high, health expenditure and nutritional quality per child is low, while incidence of disease is high.
In a pioneering study of Japanese immigrants to Hawaii published in , Harry Shapiro found there to be a significant difference between the heights of Hawaiian-born Japanese and the Japanese immigrant population. The underlying idea here is that migration from poor countries to rich ones may lead to dramatic changes between generations. In a similar study, Marcus Goldstein found there to be differences in the heights and other characteristics of the children of Mexican immigrants and their parents, as well as with native born Mexican children.
Height is partly determined by the interaction of different genes. Recent breakthroughs in sequencing the human genome have enabled researchers to identify variants of genes that are associated with height. These variants have a large number of combinations; these can lead to a wide range of potential heights. Specific combinations of these variants are much more common to some populations than others.
This could help to explain disparities in average heights around the world. Certain haplogroups — groups of variant clusters that are inherited from one common ancestor — have observable associations with height. For example, one haplogroup J1-M is most commonly observed in populations that spread from the Zagros mountains in Iran to the Arabian peninsula, particularly Yemen. By contrast, one haplogroup I-M is most concentrated in Germanic-speaking Europe, and the Western Balkans, particularly Herzegovina.
These regions are characterised by tallness, which strongly suggests a correlation between this haplogroup and height. Is height determined by genetics or environment? The short answer is that it depends on the countries you are comparing. Differences in average heights could be due to different genes, different environments, or — more likely — some combination of both. For instance, the average male height in Bosnia and Herzegovina is cm — far higher than the global mean of cm, and even the regional mean of cm.
This height cannot be explained by high standards of living nor high animal protein consumption: its HDI is one of the lowest in Europe, and the ratio of animal protein to plant protein consumption is only 0. The cause in this case must be genetic: nature over nurture.
Differences in average heights between North and South Korea tell a very different story, as told by Pak The two halves of the Korean Peninsula share a genetic lineage, but since the partition in there has been a great divergence in average heights.
While the average height of South Korean men increased by 3. This disparity is much more likely to be due to differences in standards of living: nurture over nature.
The equation that determines human height is made up of many components. No single factor can predict height at an individual or even a national level. Included is detail on average height and the genetic factors involved. A look at when girls stop growing. Included is detail on when puberty starts and finishes, in addition to what can prevent or delay development.
Short stature can happen because of a family trait, a genetic condition, or a growth hormone deficiency. Treatment may be available. What is the average height for women? Medically reviewed by Judith Marcin, M. Evolution Decline Worldwide average What influences height? Sex Takeaway The average height for a woman varies, depending on where she was born and raised.
Evolution of height in women. Decline in rate of height in America. Share on Pinterest Many factors may determine the average height for women. Worldwide average height for women. What influences height? Share on Pinterest Height may be affected by where a person grows up. Latest news Adolescent depression: Could school screening help? Exposure to air pollutants may amplify risk for depression in healthy individuals.
Related Coverage. Shop for a tape measure. Consider purchasing an inexpensive wall-mounted meter specifically for height, or follow the steps below:.
Shop for a tape measure or a wall-mounted height meter. You may get a relatively accurate measure at home, especially if you have help and follow all of the steps. He stood at a whopping 8 feet The shortest? Chandra Bahadur Dangi of Rhimkholi, Nepal. He was just Currently, the tallest and shortest living males are 8 feet 2.
There are certainly trends with regard to height in the United States and worldwide. Countless factors affect height, including age, nutrition, and health conditions.
Many people are unhappy with their height and wonder if there's anything they can do. Read on to learn whether it is really possible to increase your….
The average American man is about 5 foot 9 inches. Curious about how long it takes him to reach that height? This makes the United States the 40th tallest nation in the world. Childhood nutrition is believed to be a large factor in adult height. Race plays a large role in average heights in populations.
White men average height of 5 feet 10 inches and black men 5 feet 9 inches tend to be taller than Asian 5 feet 7 inches and Hispanic 5 feet 7 inches men.
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