We live in a day and age where everything is go go go and people hardly get any sleep anymore. So, instead people live off coffee and the caffeine within it to keep them awake and able to function. I know if you are anything like me you may need a cup or two before you can even fully wake up, and then another to keep you awake. We know caffeine can be bad for you especially when consumed in mass amounts or if it is too string hence the ban on certain energy drinks. This is also why it was, for so long, considered an adult drink. However, that has drastically changed and kids of all ages are getting either straight coffee or coffee related drinks. I mean even my high school had a full Starbucks style cafe for students. This becomes an issue when we look at the question of whether or not coffee can stunt your growth.

An article on ProQuest.com states that Coffee is not, in fact, the reason for the stunting of growth among people. Instead it explains how people are really seeing the effects of osteoporosis. Coffee has been linked to cause osteoporosis due to two reasons according to this source. The first is that “Caffeine can increase the body’s elimination of calcium”, and the second being that this “Lack of calcium can contribute to osteoporosis” (View the article here). This is a prime example of the issue that correlation does not necessarily mean causation. It is most likely true that when the statistics are viewed that it shows a relationship between caffeine intake and the lack or growth. However, there is a lurking third variable and that is osteoporosis, which is truly what causes the stunted growth. Now, the question becomes does coffee truly cause osteoporosis?

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Many of the studies on this issue focus solely on women who are about to go through or have been through menopause already. One of the studies can be found on The Journal of the American Medical Association’s webpage. The overall goal of this study was to find an association between caffeine intake and and bone mineral density (BMD), which can be a way to measure lack of growth from osteoporosis, from analyzing a population of older women. This cannot be an experiment because those administering it had no control over one of the factors, so it was an observational study that measured a women’s BMD and then had them fill out a brief background on caffeine consumption. Now, the results of this study, of course a correlation between those with a higher intake of caffeine and those with a low BMD count. However, this too had a third variable that could affect it, and that would be the amount of milk that these women drank. The study claimed that it wanted “to determine the effect of regular milk intake on this association” between caffeine and BMD. The results found that caffeine intake did not have as much of an effect on BMD if a glass of milk was drank each day. So, this concludes that there is actually more specifically a correlation between milk intake and osteoporosis, and that coffee, if milk is not drank, speeds up this effect the one has on the other. (Note, the above is a combination of summarization and paraphrasing from the study, fine the full study details here).

Another study summary can be found on LexisNexis Academic’s webpage. This study was carried out by Dr. Elizabeth Barrett-Connor at the University of California, San Diego. The goal was to show that in women who do not drink milk at all, the bone marrow density decreases more rapidly when caffeine intake is present. Their conclusion was ” calcium supplements in middle age or beyond can not offset the bone loss induced by a lifetime of coffee drinking” (quote located here). The solution then would be to worry about it at a young age as well as throughout the course of your life by drinking milk and cutting back on the caffeine.

The main point here is that third variable are everywhere. The only way to try to eliminate them would be through experimentation. With this there would need to be multiple groups. One where they didn’t drink coffee or milk, one with just coffee, one with just milk, and another with an equal balance of both. Then after the course of years the BMD’s of each groups would need to be recorded over time and analyzed and compared. But, an experiment like this cannot necessarily be done, one because it is lengthy, and two because it could cause long term negative effects on relatively healthy and normal people. A way around it would be to find people who already fit each of the groups and place them into their respective groups, but this however can be extremely hard, and also takes away the idea of randomization.

The takeaway from this would be that no one can outright state that coffee does indeed stunt people’s growth. These effects occur later in life over the course of time after many have already reached their maximum height. Genetics and family history also need to be taken into account for a person’s short nature. Also, the issue lies between calcium, caffeine and bone density. So, this is not just limited to coffee and milk, but anything from which one could receive caffeine or calcium adding a whole other component of third variables. The studies on this topic need to be more specified, and more need to be done, however it can only stick to observational studies, so third variables will always be present.