This is a theory that I am proposing which I have sort of reached after doing research for only less than 1 year. In this post I wanted to go deeper on the old mother’s tale of telling their children to drink their milk so that they will grow taller. The relationship between drinking milk and increasing one’s growth rate and ending up with a taller final height has been around at least as long as I have. I wrote about this connection a long time ago in the post “The Real Correlation Between Milk, Calcium, Bone Growth, And Height”

In that old post I had said that there is some evidence in showing that children who are malnourished in general will obviously lead to stunted growth. The fact is that height is correlated to how well calcium is absorbed into the body. The actual mineral that determines whether Calcium will be absorbed into the bone while the growth plates are still around and endochondral ossification is still going on is Vitamin D. Vitamin D is what will really determine whether the ossification will go faster and lead to more bones building on top of each other while the longitudinal growth was still going on.

The primary focus when mothers and nutritionists talk about is the calcium in the milk but they don’t tak much about the vitamin D. The truth is that in most diets in the developed world, Calcium deficiency is not a very big problem. The bigger issue could be Vitamin D. There is usually enough Calcium in the blood but if there is no way for the bone to absorb it, then the milk that is ingested will be wasted and will probably eventually be passed through the urinary tracts and expelled out of the body.

My theory is that drinking milk and getting calcium will only help increase the growth rate and height in pre-pubsecent girls. – due to low bone density in females and that fact that the effect of calcium is overtaken by the effect of estrogen when puberty does start.

From source #1 – “Height and Height Z-Score Are Related to Calcium Absorption in Five- to Fifteen-Year-Old Girls”

Clearly, an adaptive mechanism of increased calcium absorptive efficiency could be inadequate to meet the needs of very tall individuals or those with a severely deficient calcium intake, especially over a prolonged period of time (22). However, the results of recent controlled trials generally suggest that adequate mineralization of the skeleton does not require very high calcium intake levels during growth (11, 32). The ability to adapt calcium absorptive efficiency to biological needs for calcium is likely part of the reason that more moderate calcium intakes are adequate even during pubertal growth (9, 11, 32)

The section from this study shows that for even developing kids, they don’t need excess levels of Calcium concentration before they reach a level for optimum/highest growth rate of the bone.

From source #2 – “Calcium supplements in healthy children do not affect weight gain, height, or body composition.”

This 2nd article seems to show that if the developing kid tried to increase the calcium level in their blood from taking calcium supplements, they would see almost no increase in increased height. The value from this study was an increase of just 2 mm.

From source #3 – “Does a LOW Intake of CALCIUM Retard GROWTH or Conduce to STUNTEDNESS?”

Where calcium supplements have been fed for short periods to children and youths accustomed to intakes of calcium less than the recommended allowances, there appears to be no critical evidence that these additions have specifically produced increments in height beyond such observed in controls.

The conclusion is reached that it has not been established that calcium intake per se is of importance in regulating height. It is suggested that apart from gross undernutrition, the critical intake of calcium below which retardation of growth occurs, lies below the wide range of calcium contents of everyday diets consumed in different parts of the world.

The 3rd source shows that even when calcium supplements are given to kids who are accustomed to lower calcium rates, their growth rates and final height don’t increase much. They conclude that calcium intake is not that important in regulating height. Most diets around the world, besides malnutriton, already has enough calcium intake to not need to worry about deficiency calcium levels which would lead to stunted growth.

Source #4 – Calcium—Good for Teen Growth and Bone Building

This source was the first one that showed that adolescent males who take calcium supplements seem to show a final height on average 0.25 inches greater than a controlled group. However the researchers noted at the end stated that the 1/4 th of an inch greater height was only for the short term, and did not indicate whether the higher height was really for the boys’ ultimate final height.

As for girls, they state. “In a previous study, adolescent girls who were past puberty (ages 16 to 18) experienced an increase in bone-mineral density but did not increase in height more than girls who did not take calcium.” – The calcium supplements did help give them stronger bones by increasing the BMD but not their height.

Source #5 – “Effect of cow milk consumption on longitudinal height gain in children”

A section of the paper…

“Bonjour et al (6) found that prepubertal girls who consumed a diet including calcium-enriched foods grew in height in a randomized, double-blind, placebo-controlled study. In our longitudinal study, the mean height gain in the high-consumption group was higher than that in the low-consumption group, and the difference in height gain between the 2 groups was 2.5 cm/3 y.”

We could say that this source seems to suggest that girls who take high levels of calcium when they are still in the ages before puberty have on average 2 cm more in height for every 3 years of growth then girls who has low levels of calcium in their diet. The researchers concluded for this paper that drink large amounts of milk would be good for a person.

Source #6 – Adolescent height: relationship to exercise, milk intake and parents’ height.

The researchers here concluded that “Milk intake of female adolescents from Group I was significantly more than the other groups. It is concluded that parents’ height in both males and females and milk intake in females contribute to a greater adolescent height.”

Group 1 had the adolescents which were in the 97% percentile of height.

Conclusion:

These 6 sources which I had used before seem to point at the relationship that milk only has a reasonable effect on a child’s growth rate in kids who are in the pre puberty ages. There is evidence in the last 3 sources which seem to suggest that calcium intake from milk ingestion would help increase height, but the difference seems to be a couple of cms, not the 4-5 inches of difference those “Got Milk” commercial would make a parent believe. In most diets in the developed nations, Calcium and Vitamin D can be obtained from many other sources besides milk, cheese, or any other type of milk derivative. The calcium at moderate levels in girls seem to have the same rate of bone growth as high levels of calcium.

Source 5 and source 6 shows that girls who are still very young seem to have some benefit towards height from high milk consumption, and the result is just around 2 cms for every 3 years. Beyond the puberty stage, there is no more benefit towards height in girls. For boys, the increase is around .25 inches or a little less than 1 cm. The affect however was only for the short term, not the overall affect towards final height.