Summary

This is a well-written, well-formatted article that includes several scientific references. However, the references are not cited in-text and do not seem to cover all the salient points in the article. Furthermore, some of the information on calcium/sodium absorption contradicts prevalent scientific literature.

Positive Aspects

1. Reference List: Sources are a must-have for any article purporting to be a reliable source of information.

2. Scientific Sources: This article's sources are peer-reviewed scientific articles, which are more credible than blog posts or content aggregators.

3. Well-Formatted: The headings, sub-headings, bullet points, and image make the article seem well-structured and ease the reading process.

4. Brevity: The length of the article makes it easy to read and to fact-check the information contained therein.

Negative Aspects

1. References Not Cited In-Text: Although it's nice that this article listed several references, they do not directly refer to the information presented in the article and thus require more work on the part of the reader. For example, I was surprised to read that caffeine "allows the absorption of calcium and sodium to be more effective and lasting", but I could not find this fact described in any of the six references listed. Including an in-text citation (Example, 2018) makes it easier for readers to fact-check.

2. Questionable Information: When I couldn't locate a source for the aforementioned calcium/sodium factoid, I took a few minutes to look it up. I haven't done exhaustive research on it, but after an hour or so on Google Scholar I was unable to locate any supporting studies.

I did, however, come across a few that call this fact into question:

Massey and Whiting (1993) state: "Oral doses of caffeine increase the urinary excretion of calcium, magnesium, sodium and chloride for at least 3 h after consumption." They note that these losses may be compensated for with increased intestinal calcium absorption, but that the risk may be greater for vulnerable populations such as elderly women.

Altschwager and Sonneville (2018) state in reference to adolescent bone-health: "Other nutritional factors that can negatively impact bone health include binge drinking, caffeinated beverages, carbonated beverages, sodium, and, due to the interference of mineral absorption, dietary fiber."

Heaney and Recker (1982) state in reference to women: "Caffeine intake was associated with higher levels of both urinary calcium and intestinal calcium secretion. None of the three intake variables was associated with differences in calcium absorption efficiency." Increased calcium secretion with no change to calcium absorption suggests that caffeine results in a net loss of calcium: "For caffeine, the corresponding calcium balance shift would be predicted to be -0.006 gm/day". (Note that though this article was published 36 years ago, it has recently been cited numerous times)

Finally, the U.S. National Library of Medicine webpage on caffeine(2018) states that caffeine "May interfere with the absorption of calcium in the body".

Suffice it to say that that these sources seem to contradict the claim in this article that caffeine "allows the absorption of calcium and sodium to be more effective and lasting." This objection is particularly acute given that I was unable to locate this claim in the article's six references--a difficulty that would be solved with an in-text citation.

I could (but won't) do similar research on all the other claims. The point, however, is that this sort of factual inaccuracy and/or weak referencing calls the validity of the entire article into question.

Works Cited:

Altschwager, Deena and Kendrin R. Sonneville, 2018. "Optimizing Nutrition to Promote Adolescent Bone Health". A Practical Approach to Adolescent Bone Health by Pitts and Gordon (eds.); pp. 27-51. Springer. https://link.springer.com/chapter/10.1007/978-3-319-72880-3_3

Heaney, RP and RR Recker, 1982. "Effects of nitrogen, phosphorus, and caffeine on calcium balance in women". J Lab Clin Med Jan 1982 99(1): pp. 46-55. https://www.ncbi.nlm.nih.gov/pubmed/7054349?dopt=Abstract

Massey, LK and SJ Whiting, 1993. "Caffeine, urinary calcium, calcium metabolism and bone". J Nutr., Sep 1993 123(9): pp. 1611-1614. https://www.ncbi.nlm.nih.gov/pubmed/8360789

U.S. National Library of Medicine, 2018. "Caffeine." Medline Plus, page last updated March 2018, topic last reviewed April 2015. https://medlineplus.gov/caffeine.html