Why do people have different heights?

When it comes to height, it can be said that it is a topic that everyone is concerned about. The heights of different people vary greatly, which has also aroused the curiosity of many people about height. Is heredity important? Or is acquired factors important?

Today let’s talk about the impact of genetics and acquired factors on height.

01. Height is determined by fate

"Like father, like father" can be said to be people's simple understanding of heredity. As a physical trait affected by genes, height is undoubtedly also affected by innate genetic factors. Of course, this is not innate determinism. In fact, as innate factors, there are still different influence ratios. So, what proportion does innate genetic factors occupy? This has to be studied using the most classic twin experiment in biology. Identical twins have basically the same genome, so they can avoid the influence of genetic factors to the greatest extent, which can reveal the role of non-genetic factors such as nutrition and exercise.

Studies on twins have shown that the overall influence of genetic factors on height is approximately 60-70%[1].

02. Height, 4 points depends on hard work

This means that acquired factors may account for 30-40%, and these four points have a huge impact.

The authoritative medical journal The Lancet published a study on the height of adolescents around the world[2], covering 65 million adolescents and children in 193 countries around the world. One point in the study results is particularly noteworthy, that is, the change in average height.

For example, from 1985 to 2019, the average height of 19-year-old boys in China increased by 8 cm, ranking among the largest in the world.

(Chart of changes in average height of 19-year-old Chinese youth)

Over the past few years, for a certain ethnic group, the genetic factors have basically not changed much. This means that the changes in height in our country over the past few decades are mainly due to acquired factors, especially nutrition and other factors.

03. Nutritional effects vary at different ages

Since your height is determined by nature, and your height is determined by what percentage you can achieve it, does nutrition have the same impact on every age group?

The answer is no. A simple logic is that a person's height does not increase at a uniform rate, but there is a period of rapid height growth.

As shown in the figure above, this is the height and weight percentile curve of boys aged 2-18 in my country. The upper curve in the figure is the height change trend chart. We can see obvious changes in the height growth curve.

This is also reflected in nutrition, that is, for height, the contribution of nutrition is not the same for different age groups.

For example, the following figure shows a study on the contribution of genes to height at different ages [3]

We can see that for East Asians, the highest contribution of genes occurs after the age of 6. For children aged 1-5, genes only contribute 20%-40% to height, which means that acquired factors such as nutrition account for 60%-80%.

Because of this, the most critical acquired influence on height is achieved at this stage.

Therefore, nutritional supplementation should be started as early as possible, and the younger the child is, the more important it is.

04. Which nutrients may affect your height?

1. Mineral elements

I believe this is the most familiar to many parents. The typical one is calcium. As an important component of bones, calcium supplementation is crucial for height. Especially for younger babies, their diet is relatively simple, so they need to pay attention to calcium supplementation in their daily diet. Of course, it is not just calcium, other mineral elements such as iron and zinc are also important.

2. Vitamins

When talking about mineral elements, we naturally have to mention vitamins. Vitamins also play an important role in height. A typical example is vitamin D. Vitamin D plays a vital role in the absorption of calcium. Sunbathing can effectively promote the synthesis of vitamin D, which further helps the absorption of calcium. Therefore, parents should pay attention to letting their children engage in appropriate outdoor activities.

Of course, in addition to vitamin D, other vitamins also play a role, such as vitamin K2. Normal calcium supplementation is systemic calcium supplementation, which will lead to a large amount of calcium not only in the bones, but also in other parts of the body. The initial osteocalcin secreted by normal osteoblasts lacks biological activity and must rely on an additional substance to be activated. This substance is vitamin K2.

3. Protein

Protein is an ingredient that is easily overlooked, but it plays a key role in height. As a component of enzymes, it is an indispensable nutrient. In addition, some amino acids have special functions. For example, arginine is a typical example. For height, there is a very important protein component that plays a role, that is, growth hormone. There are even people who inject growth hormone to promote the height development of patients with dwarfism. One of the main significances of arginine is that it promotes the release of growth hormone from the pituitary gland [4].

In general, when it comes to height, 60% is determined by fate and 40% depends on hard work, and these 40% are the important factors that determine whether you can reach your ideal height.

05. How do babies supplement nutrition during their growing period?

For babies who are in the growing period, nutritional supplements are very important. If you find that the baby's height is lower than expected, then you need to supplement the baby with nutrition. When choosing nutrition, you need to do more homework.

First of all, we need to pay attention to whether it is related to development, such as whether there is vitamin D and mineral element calcium, which are recognized to be related to bone development. Of course, it is better to have ingredients like vitamin K that can make calcium more effectively supplemented into bones and promote calcium absorption.

We also need to pay attention to protein, whether the protein ratio is balanced and whether a continuous protein supply can be guaranteed;

Some products also add arginine, an amino acid that can stimulate the secretion of growth hormone, to help balance nutrition from an all-round nutritional perspective, helping children grow taller and successfully reach or even exceed their genetic height.

If you are often overwhelmed when choosing nutritional powder for your child, my advice is to try to choose well-known and trustworthy international brands.

In fact, a child's height growth is related to many factors. From a nutritional point of view, a normal and scientific diet can supplement sufficient nutrition. In addition, other factors such as exercise are also helpful to children's growth.

1.Li, Miao-Xin, et al. "A major gene model of adult height is suggested in Chinese." Journal of human genetics 49.3 (2004): 148-153.

2. Rodriguez-Martinez, Andrea, et al. "Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants." The Lancet 396.10261 (2020): 1511-1524.

3 Jelenkovic, Aline, et al. "Genetic and environmental influences on height from infancy to early adulthood: An individual-based pooled analysis of 45 twin cohorts." Scientific reports 6.1 (2016): 1-13.

4 Jiang Mingyu. Study on the effect and mechanism of oral arginine on promoting linear growth of long bones. MS thesis. Fudan University, 2011.