4 cm increase

At 4 cm and beyond, we leave the realm of normal height increase and must start trying a new approach to height increase.

I personally am a very scientifically mind person but to believe that height increase beyond say 1 inch is possible, we must consider beyond the normal approaches of just good nutrition , exercise, and rest.

We move into the areas of eastern mysticism and non-scientifically validated theories and try our luck at those. As of right now, there is only two approaches which I have found which does have some hope that it could work, but the amount of personal dedication to the project is enormous.

They are …

1. Grow Taller Using Qigong Part I, Part II

[Update: Recent findings suggest this person might be a fraud. I will need to do more research to check to see if this technique was a scam or not. You can still try it out though.]

The method involves the use of deep breathing, affirmations, and strong vizualizations.

2. Grow Taller Using Lateral Synovial Joint Loading Part I, Part II

This method involves putting a certain amount of load upon  certain areas on one’s leg to force distraction of the long bones. Scientifically valid.

At this point, there is no other reasonable way to increase one’s height significantly without medical procedures to be done.

Note: These methods and techniques should be added along with the program that we stated is need for the height increase of 3 cm.

3 cm increase

3 cm should be the total maximum of extra height most people can ever get from just exercising and lifestyle change. I personally woudld guess that only 5% of all people who decide to do the program will be able to increase their total height by 3 cm.

Remember that 3 cm is about 1.25 inches.

The program to get 3 cm more in height increase is mostly the same as the program for 2 cm increase. Of course the focus is always on expanding the torso and back to allow for the vertebrate to decompress. Most people won’t get 3 cm in height increase because their body has a limit to the natural ability to stretch. I personally can deviate in height by up to 2 cm in height from my morning height to my evening height.

I am not sure at this point but taking a vitamins like Calcium with Vitamin D and Glocusamine with Chodroitin may help slightly to make one’s bones stronger. And that is a big maybe. For a far more advanced and better list of supplements that can help with your height increase exercise routine, click HERE

Most orthopedics say that one can achieve an extra 1 inch and slightly more through a good program in stretching and yoga. I agree with them

An option for some people is to go to a chiropractor and get them to help you straighten out your back.

2 cm increase

An increase of 2 cm in height will of course will be more difficult than just gaining 1 cm but it should be only slightly harder. Depending on a person’s lifestyle and how active they are, the program towards gaining 2 cm in extra height can be very difficult or very easy.

The main theory is the same. For most people who live sedentary lives, a lot of extra height is hidden which proper exercise and stretching will bring out.

2 cm is only slightly longer then 3/4 th of an inch. That is perfectly reasonable for I would say 50 % of all the people who really stick to the program below for 4-5 months.

1. The main thing is again stretching only this time one should be focusing on prolonged stretching with a routine of deep breathing involved. Again it is the torso one must focus on first, and then the hamstrings and ankles.

2. Swimming should definitely be incorporated into the weekly exercise with a focus on the butterfly stroke and a trial to stretch and widen the torso.

3. One should now focus a lot of energy on certain yoga positions like the cobra, and the downward dog. Refer to past articles written about Yogic positions.

4. The type of food one intakes should be decreased. Carobohydrates (whites) should be avoided while greens and lean meat should be eaten. This is to drop excess weight and slim the torso and body to give it a leaner thinner look. That would help give the impression of height.

5. Now would be a good time to learn the fundamentals of the Alexander method. It would teach you how to walk with the correct posture.

6. Sleep should be be focused on to allow for deep rest and the entire body to relax and decompress. This means the body will be expanded more afte waking.

7. Some hanging on a bar could help a little, at least to build upper body muscle and tone one’s arms. The hanging will take more weight off of the back.

Note: A lot of the height increase from this point on and anything more will be only temporary. The body has a slight bit of elasticity and if you stop doing the exercises, the body will go back to the original condition. However, if you manage to change your lifestyle, some of the extra height, usually about 50% of the total maximum height change you can do is permanent. 

1-4 cm Increase

To get 1-4 cm in extra height is relatively easy. For most people, their own lifestyle puts their body in positions and postures which can hide certain height. Prolonged time spent in front of a computer or lying on a couch watching tv has shown that the vertebrate and spine are bent. The spine stays compressed and the person can lose up to even 2 inches of height.


For 1 cm of height increase…

Here is a quick program to add the 1 cm height increase. To gain the height you desire, work on it for 1 -1.5 months.

1. Stretch your back and torso 15 minutes everyday, once after you get out of bed, the other right before you go to bed. Focus on the body torso bending first.

2. Focus on only a few main types of yogic stances, or asanas. I wrote two older articles about increasing one’s height through yoga and stretching.

3. Mentally do visualization imagine that you body is expanding and your vertebrate is becoming decompressed and elongating. Learn to breathe properly from a few books or lessons on yoga.

Note: Please remember that gaining 1 cm of extra height is completely possible for say 85% of all people. Most people these days live a very sedentary life which means that their lifestyle can actually hide extra height from them. Learn to get that back by being healthy and staying active. The main reason you can get any height at all is from decompressing your vertebrate and elongating the spine. If you however already practice yoga, or do stretch a lot, natural height increase may not be completely possible, unless you look at other areas of your life that you can improve upon.


For 2 cm of height increase…
An increase of 2 cm in height will of course will be more difficult than just gaining 1 cm but it should be only slightly harder. Depending on a person’s lifestyle and how active they are, the program towards gaining 2 cm in extra height can be very difficult or very easy.

The main theory is the same. For most people who live sedentary lives, a lot of extra height is hidden which proper exercise and stretching will bring out.

2 cm is only slightly longer then 3/4 th of an inch. That is perfectly reasonable for I would say 50 % of all the people who really stick to the program below for 4-5 months.

1. The main thing is again stretching only this time one should be focusing on prolonged stretching with a routine of deep breathing involved. Again it is the torso one must focus on first, and then the hamstrings and ankles.

2. Swimming should definitely be incorporated into the weekly exercise with a focus on the butterfly stroke and a trial to stretch and widen the torso.

3. One should now focus a lot of energy on certain yoga positions like the cobra, and the downward dog. Refer to past articles written about Yogic positions.

4. The type of food one intakes should be decreased. Carobohydrates (whites) should be avoided while greens and lean meat should be eaten. This is to drop excess weight and slim the torso and body to give it a leaner thinner look. That would help give the impression of height.

5. Now would be a good time to learn the fundamentals of the Alexander method. It would teach you how to walk with the correct posture.

6. Sleep should be be focused on to allow for deep rest and the entire body to relax and decompress. This means the body will be expanded more afte waking.

7. Some hanging on a bar could help a little, at least to build upper body muscle and tone one’s arms. The hanging will take more weight off of the back.

Note: A lot of the height increase from this point on and anything more will be only temporary. The body has a slight bit of elasticity and if you stop doing the exercises, the body will go back to the original condition. However, if you manage to change your lifestyle, some of the extra height, usually about 50% of the total maximum height change you can do is permanent. 


For 3 cm of height increase…

3 cm should be the total maximum of extra height most people can ever get from just exercising and lifestyle change. I personally woudld guess that only 5% of all people who decide to do the program will be able to increase their total height by 3 cm.

Remember that 3 cm is about 1.25 inches.

The program to get 3 cm more in height increase is mostly the same as the program for 2 cm increase. Of course the focus is always on expanding the torso and back to allow for the vertebrate to decompress. Most people won’t get 3 cm in height increase because their body has a limit to the natural ability to stretch. I personally can deviate in height by up to 2 cm in height from my morning height to my evening height.

I am not sure at this point but taking a vitamins like Calcium with Vitamin D and Glocusamine with Chodroitin may help slightly to make one’s bones stronger. And that is a big maybe. For a far more advanced and better list of supplements that can help with your height increase exercise routine, click HERE

Most orthopedics say that one can achieve an extra 1 inch and slightly more through a good program in stretching and yoga. I agree with them

An option for some people is to go to a chiropractor and get them to help you straighten out your back.


For 4 cm of height increase…

At 4 cm and beyond, we leave the realm of normal height increase and must start trying a new approach to height increase.

I personally am a very scientifically mind person but to believe that height increase beyond say 1 inch is possible, we must consider beyond the normal approaches of just good nutrition , exercise, and rest.

We move into the areas of eastern mysticism and non-scientifically validated theories and try our luck at those. As of right now, there is only two approaches which I have found which does have some hope that it could work, but the amount of personal dedication to the project is enormous.

They are …

1. Grow Taller Using Qigong Part IPart II

[Update: Recent findings suggest this person might be a fraud. I will need to do more research to check to see if this technique was a scam or not. You can still try it out though.]

The method involves the use of deep breathing, affirmations, and strong vizualizations.

2. Grow Taller Using Lateral Synovial Joint Loading Part IPart II

This method involves putting a certain amount of load upon  certain areas on one’s leg to force distraction of the long bones. Scientifically valid.

At this point, there is no other reasonable way to increase one’s height significantly without medical procedures to be done.

Note: These methods and techniques should be added along with the program that we stated is need for the height increase of 3 cm.

Exercise Program Guide

[Update: This post has recently been changed and updated dramatically from a change in name and a integration of many old posts. It is still being edited and added upon so there is still a lot of work needed to be done for this section. Be patient with me.]

[Note: The links below will be linked to the Amazon Associates Program which makes the website act as an affiliate link to the Amazon store. If you choose to click on them and buy through the link, the website will be getting a commission from your purchase. The purchase price of the Amazon product will not be  increased. Thank you.]

1-4 cm Height Increase Program Guide

To get 1-4 cm in extra height is relatively easy. For most people, their own lifestyle puts their body in positions and postures which can hide certain height. Prolonged time spent in front of a computer or lying on a couch watching tv has shown that the vertebrate and spine are bent. The spine stays compressed and the person can lose up to even 2 inches of height. For most people who live sedentary lives, a lot of extra height is hidden which proper exercise and stretching will bring out.


For 1-4 cm of height increase…

Needed Equipment:

  1. Yoga MatCost: $22
  2. Swimming GogglesCost: $22
  3. Swimming SpeedoCost: $30 – $42
  4. Inversion TableCost: $100 w/ Free Shipping
  5. C-Clamps (6 “)Cost: $12
  6. Ankle Weights (20 lbs) – Cost: $32 w/ Free Shipping

Here is a quick program to add the 1-4 cm of height increase. To gain the height you desire, work on it for 4 – 12 months. (That’s right, something like this will really do take that long!) Results will vary from individual to individual depending on many factors including age, level of fitness, chronic illness, etc.

70% of people should be able to increase their height by at 1 cm, 10% of the people will be able to increase their height by 2 cm, 1-2% of people will be able to increase their height by up to 3 cm, and a very small percentage of people will be able to increase their height to what I believe is the theoretical limit of natural height increase through normal exercise, proper nutrition, and lifestyle habits.

  • Torso Stretching – Stretch your back and torso 40-60 minutes everyday, once after you get out of bed, the other right before you go to bed. Focus on the body torso bending first. The main thing is again stretching only this time one should be focusing on prolonged stretching with a routine of deep breathing involved. Again it is the torso one must focus on first, and then the hamstrings and ankles.
  • Yoga – Focus on only a few main types of yogic stances, or asanas. I wrote two older articles about increasing one’s height through yoga and stretching posting pictures of specific types of asanas (yogic postures) which might have the greatest impact in stretching the torso longitudinally.One should now focus a lot of energy on certain yoga positions like the cobra, and the downward dog. Refer to past articles written about Yogic positions.
  • Visualization – Mentally do visualization imagine that you body is expanding and your vertebrate is becoming decompressed and elongating. Learn to breathe properly from a few books or lessons on yoga.
  • Swimming – Swimming should definitely be incorporated into the weekly exercise with a focus on the butterfly stroke and backstroke to stretch and widen the torso.
  • Food & Diet – The type of food one intakes should be decreased. Carobohydrates (whites) should be avoided while greens and lean meat should be eaten. This is to drop excess weight and slim the torso and body to give it a leaner thinner look. That would help give the impression of height.
  • Alexander Technique – Now would be a good time to learn the fundamentals of the Alexander method. It would teach you how to walk with the correct posture.
  • Sleep & Rest – Sleep should be be focused on to allow for deep rest and the entire body to relax and decompress. This means the body will be expanded more afte waking.
  • Inversion – Some hanging on an inversion table could help a little, at least to build upper body muscle and tone one’s arms. The hanging will take more weight off of the back. Over time the effects of the spinal decompression will take effect. If that is combined with better posture and movements, that can be a more permanent path towards a little bit of height increase
  • Ankle Weights – The ankle weights can be added to the exercise time with lunges and kicks. Do them at the same time one is working on core strengthening.
  • Supplement Guide – Go to the “Supplements Guide “section to see what types of supplements you can take to assist in the height increase procross. Some will help increase cartilage thickness while others show in medical studies that they cause molecular protein pathways which cause cell proliferation. For a far more advanced and better list of supplements that can help with your height increase exercise routine, click HERE.
  • LSJL Method – Follow this method below. You will need to get a C-clamp to perform the exercise. It is possible to use the barbells and dumbbells at the local fitness, gym but one probably will get better resulting using the right type of C-Clamp. This method involves putting a certain amount of load upon  certain areas on one’s leg to force distraction of the long bones. Scientifically valid. Grow Taller Using Lateral Synovial Joint Loading Part IPart II

Most people won’t get 3 cm in height increase because their body has a limit to the natural ability to stretch. I personally can deviate in height by up to 2 cm in height from my morning height to my evening height. Most orthopedics say that one can achieve an extra 1 inch and slightly more through a good program in stretching and yoga. I agree with them

At this point, there is no other reasonable way to increase one’s height significantly without medical procedures to be done.

Note: These methods and techniques should be added along with the program that we stated is need for the height increase of up to a possible 4 cm of extra height.

Note 2: Please remember that gaining 1 cm of extra height is completely possible for say 70% of all people and 2 cm is possible with about 10% of the population through this rather general program of conditioning, stretching, and swimming. Most people these days live a very sedentary life which means that their lifestyle can actually hide extra height from them. Learn to get that back by being healthy and staying active. The main reason you can get any height at all is from decompressing your vertebrate and elongating the spine. If you however already practice yoga, or do stretch a lot, natural height increase may not be completely possible, unless you look at other areas of your life that you can improve upon.

Note 3: A lot of the height increase from this point on and anything more will be only temporary. The body has a slight bit of elasticity and if you stop doing the exercises, the body will go back to the original condition. However, if you manage to change your lifestyle, some of the extra height, usually about 50% of the total maximum height change you can do is permanent. An option for some people is to go to a chiropractor and get them to help you straighten out your back.


For 5-10 cm Height Increase Program

For 5-10 cm of height increase…

The height increase to 5-10 cm is clearly beyond anything most people is capable of. 5 cm is around 2 inches and that is a lot of height to consider. Making this type of body modificatin will be a significant and difficult process.

My personal suggestion is to follow the program  outlined in the section for height increase of 1-4 cm. Thank you.


If you have come to this webpage by clicking on the link on the main page, you probably are interested in finding out how you can increase your height by 5 cm (3.5 inches) to 10 cm (4 inches). In my personal opinion, 4 cm (or 1.25 inches) is the maximum theoretical limit that is possible for natural ways to grow taller.

The reason why there is no method, strategy, or technique on this page section is because I have not found anything that can even had the remote possibility to help on increase their height by that large of a difference. I promise you that if I ever did find some method, technique, or way to increase one’s height by 3.5 or 4 inches naturally I will be quick to edit this page.

I personally am a very scientifically mind person but to believe that height increase beyond say 1 inch is possible, we must consider beyond the normal approaches of just good nutrition , exercise, and rest.

We move into the areas of eastern mysticism and non-scientifically validated theories and try our luck at those. As of right now, there is only one approach which I have found which does have some hope that it could work.

It is …

1. Grow Taller Using Lateral Synovial Joint Loading Part IPart II

This method involves putting a certain amount of load upon  certain areas on one’s leg to force distraction of the long bones. Scientifically valid.

At this point, there is no other reasonable way to increase one’s height significantly without medical procedures to be done.

Note: These methods and techniques should be added along with the program that we stated is need for the height increase of 3 cm.

If I do not find a way to do it within 4 years of the beginning of the start of the website, (August 2016) I will instead decide to place the only other option that really works and suggest limb/leg lengthening surgery.

If you however would be content in having up wards of maybe 3, even 4 cms of height increase, that might be possible. Refer to the other sections under the height increase guide tab for height increase of 1 cm, 2 cm, 3 cm, and 4 cm.

Thank you.


The Psychology Of Success In Any Venture

This will be the first edition and first post of a special section of the website entitled “Real Height Increase Guide”. I am going to break it down by sections, specifically by 1 cm each. So for each subsection and subpage underneath the upper label, you can find a guide which can (note that I said can, and not will since there are not gaurantees to HI) give you the amount of height increase indicated.

Again, any advice or technique that I post on this site you have to use your own judgement to see if they are worthy of doing, or whether the exercises or lifestyle choices are even safe. You are an adult and you are responsible for whatever happens to you. I am not held legally responsible if you hurt your yourself in any way from trying something which possibly can be very dangerous.

Note: Remember that the goal of height increase is a very long, and possibly excruciating difficult path. Do not assume that you will get results quickly or within even the first 3 months. Most people these days do not have the discipline to actually stay on such a program which can last up to 2 years even.

READ THE NEXT PART: IT IS VERY IMPORTANT


I define discipline as commitment times focus times consistency times persistence. So before you even begin to try this program, really ask yourself whether you have the desire, drive, and personality to have the discipline to stay on this program. For most people (around 85%) who do not succeed in some project or program they start the real reason why they failed our gave up was because of the lack of discipline.

Remember: #1 reason why people don’t succeed – Lack of discipline.

Discipline = (Commitment) x (Focus) x (Consistency) x (Persistence)       (the reason why the elements are multiplied and not added is because if you are even lacking in one of the 4 main elements, you lack discipline in general. Discipline is a cumulative, compounding phenomenon)

Commitment: (These are all my own personal definition of the terms) An internal promise made to once self to accept and never let down (or let go) what is expected of ourselves.

Focus: The ability to make the mind clear and singular in its attention.

Consistency: The ability to stay on the course and do the same action or behavior at the regular scheduled time intervals.

Persistence: Not giving up even when challenges and difficulties appear during the process or path.


However you must also add the element of Action into your program. Taking action requires oneself to get through 4 main things

Remember: #2 reason why people don’t succeed – They don’t take the needed action immediately 

1. Overcoming Fear – (Anthony Robbins has famously stated that the only reason why we don’t do what we know we are supposed to do is because of fear).

Fear = Anxiety + Insecurity + Uncertainty

2. Getting Past Internal Inertia and Resistance – (We are inherently lazy and don’t like to make big changes. We prefer to coast in life and not force ourselves to do anything. That has to change)

3. Removing External Resistance – (Our other obligations and responsiblities in life will take up our time. Are you willing to put some of that aside and decide that this part of your life, this project is important enough of value that you are willing to allocate a large significant percentage of your waking hours (and your life) to pursue this one goal? Really be honest with yourself about this thing. The only person you are going to have to answer to is yourself, no one else.)

4. Do It Right NOW!! – ( We are masters are procrastination. We will keep on putting off what we need to do today for tomorrow. Make a real decision right now that you will take action. And Start!!)    

Action = (Overcoming Fear) x (Do It Right NOW!) x (Getting Past Internal Inertia and Resistance + Removing External Resistance) 

Note: Action can not occur if we do not overcome  fear or decide to procrastinate the action for a time in the future. That is why those two factors are multiplied. The effect of either not getting past our internal resistance or not being able to remove external resistance is not as important in influence as the first two because if we can override the first two factors, the last two factors will crumble.


The last element you must add into your program is Learning. Learning is just Adapting Your Strategy and Being Flexible. Your strategy is your thinking patterns, your behavior, your rituals, and your plan. Being flexible meanings being okay and willing to deal with situations that can can change quickly and easily. So…

Learning = (2 x Adapting strategy) + (1 x Being Flexible) – In this model or program I created, I personally believe that being able to adapt (a better word to use is “correct”) one’s strategy is worth more weight in importance than being flexible. When one can correct one’s strategy, one will reach one’s goal  far faster than only being flexible. When one used the factor of adapting strategy, there is an arrow of direction in progress. When one is only being flexible, there is no direction in progress.

Strategy = (Thinking Patterns + Behavior + Rituals) x Plan – (Point #1: if you don’t have a plan, you don’t have a strategy, Point #2: it is okay to be lacking in one of the other 3 elments, as long as the other 2 parts are developed to a high enough level)

so the entire program requires you to follow 3 main parts.

1. Action

2. Discipline

3. Learning

So PROGRAM = (ACTION) x (DISCIPLINE) x (LEARNING) 

Note: Again notice the formula has its factors multiplied together. That means if either 1 one of the 3 factos is not there, you will not succeed. You NEED ALL 3 parts to be at the highest level. 

The path to success in any large project or endeavor we decide to take up is filled with challenges and trials that will appear before use. Remember Murphy’s Law, “Everything that could possibly go wrong will go wrong”.

When you just look at how many elements are required, all of them needed to work in perfect sync and harmony for you to succeed, you can now understand why most of us, like 97% of us will fail. At least 12 element all must not be lacking for the entire program to work. Remember the quote that in the US, only 3 percent of people who reach retirement age will ever retire. That 3% has learned and figured out  how to control their own minds, behavior, and strategies so that they can win in life and achieve all the goals they have set out for themselves.

Good luck to all who do decide to take up the program to increase their height!

How much of human height is genetic and how much is due to nutrition?

I wanted to repost an article I just read from the magazine the Scientific American – December 2006 edition. Author is Dr. Chao-Qiang Lai. I felt that the question that was posed and answer was extremely relevant to this website. If you wanted to get to the original site where this article is found, click HERE.

What is very surprising and disheartening to hear is that apparently our height is mainly determined by our genetics by up to 80% for certain groups of people. Of course the article does end on a positive note to remind the reader that a healthy lifestyle of proper nutrition, rest, and exercise will help maximize one’s full height potential.


How much of human height is genetic and how much is due to nutrition?

December 11, 2006

Molecular biologist Chao-Qiang Lai of the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University answers.

This question can be rephrased as: “How much variation (difference between individuals) in height is attributable to genetic effects and how much to nutritional effects?” The short answer to this question is that about 60 to 80 percent of the difference in height between individuals is determined by genetic factors, whereas 20 to 40 percent can be attributed to environmental effects, mainly nutrition. This answer is based on estimates of the “heritability” of human height: the proportion of the total variation in height due to genetic factors.

Human height is a quantitative, or metric, trait, i.e., a characteristic that is measured in quantity, and is controlled by multiple genes and environmental factors. Many studies have estimated the heritability of human height. Often, these studies determine heritability by estimating the degree of resemblance between relatives. One can separate genetic effect from environmental effects by correlating genetic similarity between relatives (twin, siblings, parents and offspring) with their similarity in height. To accurately measure how genetically similar relatives are, one can measure the number of genetic markers they share. For example, Peter M. Visscher of the Queensland Institute of Medical Research in Australia recently reported that the heritability of height is 80 percent, based on 3,375 pairs of Australian twins and siblings. This estimate is considered to be unbiased, as it was based on a large population of twins and siblings and a broad survey of genetic markers. In the U.S., the heritability of height was estimated as 80 percent for white men. These estimates are well supported by another study of 8,798 pairs of Finnish twins, in which the heritability was 78 percent for men and 75 percent for women. Other studies have shown height heritability among whites to be even higher than 80 percent.

Because different ethnic populations have different genetic backgrounds and live in different environments, however, height heritability can vary from one population to another, and even from men to women. In Asian populations, the heritability of height is much lower than 80 percent. For example, in 2004 Miao-Xin Li of Hunan Normal University in China and his colleagues estimated a height heritability of 65 percent, based on a Chinese population of 385 families. In African populations, height heritability is also lower: 65 percent for the population of western Africa, according to a 1978 study by D. F. Roberts, then at Newcastle University in England, and colleagues. Such diversities in heritability are mainly due to the different genetic background of ethnic groups and the distinct environments (climates, dietary habits and lifestyle) they experience.

Heritability allows us to examine how genetics directly impact an individual’s height. For example, a population of white men has a heritability of 80 percent and an average height of 178 centimeters (roughly five feet, 10 inches). If we meet a white man in the street who is 183 cm (six feet) tall, the heritability tells us what fraction of his extra height is caused by genetic variants and what fraction is due to his environment (dietary habit and lifestyle). The man is five centimeters taller than the average. Thus, 80 percent of the extra five centimeters, or four centimeters, is due to genetic variants, whereas one centimeter is due to environmental effects, such as nutrition.

Heritability can also be used to predict an individual’s height if the parents’ heights are known. For example, say a man 175 cm tall marries a woman 165 cm tall, and both are from a Chinese population with a population mean of 170 cm for men and 160 cm for women. We can predict the height of their children, assuming the heritability is 65 percent for men and 60 percent for women in this population. For a son, the expected height difference from the population mean is: 0.65 x [(175 – 170) + (165 – 160)] / 2, which equals 3.25 cm; for a daughter, the difference is 0.6 x [(175 – 170) + (165 – 160)] / 2, which equals 3 cm. Thus, the expected height of a son is 170 + 3.2, or 173.2 cm, and of a daughter 160 + 3, or 163 cm. On the other hand, environmental effects can add 1.75 cm to a son’s height: 0.35 x [(175 – 170) + (165 – 160)] / 2, and 2 cm to a daughter’s: 0.4 x [(175 – 170) + (165 – 160)] / 2. Of course, these predictions only reflect the mean expected height for each of the two siblings (brothers and sisters); the actual observed height may be different.

From these calculations, we realize the environment (mainly nutrients) can only change about 2 centimeters for a given offspring’s height in this Chinese population. Does that mean that no matter what happens in the child’s environment, the height can never change more than this? Can special treatment and nutrient supplements increase the height further? The answer is yes. The most important nutrient for final height is protein in childhood. Minerals, in particular calcium, and vitamins A and D also influence height. Because of this, malnutrition in childhood is detrimental to height. In general, boys will reach maximum height in their late teens, whereas girls reach their maximum heights around their mid-teens. Thus, adequate nutrition before puberty is crucial for height.

In addition, although diseases of childhood can inhibit ultimate stature, human growth hormone treatments can remedy such growth defects. Height accelerated by such treatment or special supplements, however, cannot be predicted based on heritability. There are two reasons: first, heritability has not been estimated in a growth hormone-treated population. Second, genes and growth hormones can interact synergistically to affect height, i.e., their effects may not be simply adding to each other but could be multiplying the ultimate effect.

The question remains, however, why different populations of a similar genetic background might have a differing heritability. The answer is, of course, environmental effects. When a given environment maximizes the genetic potential of a population for a given trait, this population tends to have a higher heritability for that trait, and vice versa. In developed countries, nutrition for childhood development is strong, which maximizes the genetic potential for height assuming no selection or new mutations. Thus, the overall heritability estimates tend to be higher, i.e., 80 percent. In contrast, in developing countries, nutrition deficits lead to a lower heritability. The fact that the mean height of the U.S. population has almost plateaued in the past decade suggests that the nutrient environment has almost maximized the genetic potential of height, at least in this country. Improved nutrition elsewhere may have similar benefits in terms of stature.

Dr. Chao-Qiang Lai has written this article in his personal capacity and the views expressed do not necessarily represent the views of the U.S. Department of Agriculture, Agricultural Research Service.