Talk:Composition of the human body

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Out of curiosity, the exact elemental composition of a male human who was perfectly healthy with a mass of 90,000 grams would be what exacty? As well, what would the mass of the chemicals, and what chemicals, be for the chemical composition? This question also is asked for the material and tissue composition. (talk) 23:10, 4 July 2008 (UTC)

You may get an answer to this question at the Reference desk. --Commander Keane (talk) 08:55, 5 July 2008 (UTC)
This article answers that exact question. I guess the only thing lacking is how to convert the percentages given into masses: If 65% of a 90,000 gram body is oxygen, then there is 0.65x90000=58500 grams of oxygen, the others are calculated the same way, just replace the 0.65 with the appropriate number. --Tango (talk) 22:36, 8 July 2008 (UTC)


It is not very sensible to deconstruct the human body into its elements. If you sold all of those at the best market prices it would still be worth less than one kidney. Deconstructing into the various proteins and other molecules would be more interesting than knowing that there is enough iron to make one nail. SpinningSpark 11:20, 18 January 2009 (UTC)

People are often curious about the quantities of various elements in the human body. It is not necessarily related to monetary value. Dratman (talk) 21:26, 22 May 2011 (UTC)

"Enough iron to make one nail." Cool! One-ply (talk) 18:06, 16 August 2012 (UTC)

Sounds like OP wants to sell body parts on the black market. How about, no?

-G — Preceding unsigned comment added by (talk) 15:45, 3 October 2012 (UTC)

Merge proposal[edit]

It has been (anonymously) proposed to merge this with Chemical makeup of the human body. If anything, that one should be merged into this one, because this one is more general, in that it discusses the composition from other points of view besides chemical. Eric Kvaalen (talk) 18:32, 10 June 2010 (UTC)

Merged. The table could be flagged somehow to indicate "elements essential to life", "elements not known to be biologically active" and "elements known to be only toxic". --Wtshymanski (talk) 16:40, 6 April 2011 (UTC)

Fuzzy bars[edit]

I don't see the point of the bar charts. Oxygen dominates and the others are invisible anyway on a bar chart basis. Wouldn't it make more sense to have a pie chart showing fractions of the total graphically, instead of hard-to-compare unscaled bars? --Wtshymanski (talk) 00:47, 3 June 2011 (UTC)

First of all, what do you mean by “unscaled”? They are clearly to scale. — Secondly, why does it matter that some of the bars are invisible, since in the textual table there are no bars at all? Besides, they would certainly be just as invisible in a pie chart. — Thirdly, oxygen clearly doesn’t dominate in the second column, which the bars make clearly apparent but bare numbers do not. — Finally, the additional space used is a mere 40 pixels, and it is only in the horizontal where there is way enough space anyway. — Timwi (talk) 23:49, 4 June 2011 (UTC)

And more importantly, it would be nice if the two tables agreed, and if the useless counts of atoms were removed. --Wtshymanski (talk) 00:47, 3 June 2011 (UTC)

This is a separate point and may warrant a separate discussion. — Timwi (talk) 23:49, 4 June 2011 (UTC)

Useful bits[edit]

Gosh that admin bit is handy. You can lock down any version you like as your preferred edition and never have to worry about anyone else changing it. --Wtshymanski (talk) 03:19, 28 June 2011 (UTC)

Gosh that revert button is handy. You can keep reinstating the version you like and never have to actually discuss the matter with any real reasons or arguments. — Timwi (talk) 12:35, 28 June 2011 (UTC)
See above under "fuzzy bars". If we must have a graphic, it should be a pie chart - those bars are visually meaningless. --Wtshymanski (talk) 13:01, 28 June 2011 (UTC)
Surely a pie chart would be less readable. The human eye is not good at judging angles; the bar chart is much clearer. Also, I thought you were worried about space? A pie chart would be a lot bigger. — Timwi (talk) 22:00, 30 June 2011 (UTC)

Is this protection really necessary? Evercat (talk) 19:15, 3 July 2011 (UTC)

Oh, absolutely. How else will we ensure only the Right Version is on display? --Wtshymanski (talk) 20:45, 3 July 2011 (UTC)
I still think the bars are useless clutter. A pie chart shows the fractions of a whole, whereas the bars are visually hard to align and sum. If we need to compare values, we have the actual numbers, the eye is just as bad at judging lengths as judging angles, but *areas* seem to be the key here. --Wtshymanski (talk) 16:06, 13 July 2011 (UTC)


The two tables don't agree. --Wtshymanski (talk) 21:46, 14 July 2011 (UTC)

That's because they don't show the same thing. One shows the fraction of atoms, the other the fraction by weight. Water is 2/3 hydrogen by atoms but 2/18 = 1/9 hydrogen by weight. These are not the same. SBHarris 01:28, 13 October 2011 (UTC)
The first table has two columns captioned "percent by mass" and "atomic percent". The second table has two columns captioned "percent of mass" and "percent of atoms". Surely these two tables should agree? They don't; first table says, for example, 64% of the mass of a human being is oxygen, and that 25.6% of the atoms in a human being are oxygen. The second table says that 65% of the mass of a human being is oxygen, and 24% of the atoms. Which of these is right? --Wtshymanski (talk) 03:09, 13 October 2011 (UTC)
Such differences are minor! They have their origin in the variance in body composition of humans, which goes from less than 50% water in an overweight woman to 70% in a thin man. Different sources use different means, and fat does not have the same amount of oxygen as water. Your complaint is rather like saying that THIS source says that the average weight of an adult person is 70 kg, and THIS OTHER source says it's 65 kg!! ZOMG, which one shall we believe? Which one is right? Call the harmonization-police. SBHarris 03:30, 13 October 2011 (UTC)
If all that could be referenced, with a brief discussion on the limits of errors and precision of these assays, it would be a worth while addition to the article. It would help move it toward encyclopedia quality instead of "Mr. Science Fun Facts" for column-filler in the paper. (Remember column-fillers? I'm older than dirt...)--Wtshymanski (talk) 13:23, 13 October 2011 (UTC)
If I'm designing elevators or life jackets or airline seating, I'd damn well better understand why one source says 65 kg and another 70 kg. --Wtshymanski (talk) 13:25, 13 October 2011 (UTC)
I agree with SBHarris, that the difference is insignificant. People are different. The numbers are not used for calculations. It's just to get a sense of the relative abundance of the elements relative to each other.Carstensen (talk) 15:52, 14 October 2011 (UTC)
Indeed, the errors in element composition are far larger than suggested in this article in populations of adults, due to variance in body composition (bone, muscle, fat ratios). Since (AGAIN) each type of tissue varies greatly in element composition. Example: obviously the hydrocarbon in fat gives it more C and H. While the water and protein in muscle more O, N, and S. Meanwhile your skeleton stays (approximately) the same weight after adulthood, no matter if you pack on extra pounds of fat or muscle, and almost all your Ca and P is there, so these go down in body %, the more time you spend at the table or gym. Etc. One practical application of the last is that the mass of cremated remains depends on your skeletal mass, not your total weight. The muscle and fat goes up in smoke, you see, but the calcium phosphate does not.

Lastly, airline seating is exactly where you see that none of this does you any good. You cannot design seats for everybody, but can only go up to 90% or something and will end up requiring a few superwides to buy two tickets. That's a real-life problem which the airlines have solved by doing exactly that. I'll leave the question of why it's not such a problem for life jackets, as exercise for the student. SBHarris 00:33, 15 October 2011 (UTC)

Again, if we could document all this, it would be a relevant qualifier. Right now, it's just factoids, worthy of bar-stool experts. --Wtshymanski (talk) 17:25, 15 October 2011 (UTC)
Strange that the overall assay can vary so much, but a barely-detectable change in the concentration of, oh, say, hydrogen ions in the blood will kill you. --Wtshymanski (talk) 17:25, 15 October 2011 (UTC)
And a barely detectable amount of Clenbuterol will get you banned from the Tour de France. What is your point? Nothing needs to be changed. The article is fine as it is. — Preceding unsigned comment added by Carstensen (talkcontribs) 17:28, 16 October 2011 (UTC)

Political Correctness: "lower organisms"? I suspect zoologists have found a more accurate term we could substitute. - One-ply (talk) 18:10, 16 August 2012 (UTC)

Filter for Ordering Number of Atoms[edit]

Because the number of atoms column uses powers of ten very heavily, the filter to order them from greatest to least fails as it only orders by the first term, and disregards the magnitude. Is there any way to fix this? (talk) 05:29, 3 October 2011 (UTC)

Why should we worry about that when we have fuzzy grey bars to give us the information we need? Sorted tables often do surprising things, rarely are the surpises useful. --Wtshymanski (talk) 13:36, 3 October 2011 (UTC)

Source of atomic % and number of atoms?[edit]

Are the values in the columns 'Atomic percent' and 'Atoms' from a source, or are they calculated based on the masses given in various sources? If we calculated the # of atoms ourselves then someone was either sloppy in their calculations, or the masses have been updated afterwards and the number of atoms not changed to match.

  • Example 1: Gold has a reported mass of 0.0002 g in our table, which should represent 1.01E-6 mol or 6.1E+17 atoms (compared to 2.0E+19 atoms in our table).
  • Example 2: Chromium has a reported mass of 0.014 g in our table, which should represent 2.69E-4 mol or 1.6E+20 atoms (compared to 6.0E+18 atoms in our table).

Would someone be willing to go through and make sure that our values for numbers of atoms match the mass values we've cited? -- (talk) 09:26, 20 January 2012 (UTC)

A source would be preferable to a hand calculation, but since the idea of counting the number of atoms in a macroscopic object is inherently foolish, I don't see much utility. It's the sort of thing you see on "Science TV" - "This spoonful of table salt contains over twenty billion trillion atoms! Wooo! Isn't that all sciencey-sounding and impressive? ". I don't think the list of numers of atoms has any educational value. If for some bizarre reason you actually need the estimated number of atoms, it's a trivial calculation if you know the atomic mass and total mass, and if you don't, you'll never remember how many "-illions" anyway. --Wtshymanski (talk) 15:10, 20 January 2012 (UTC)
Agree with comment above. Can we kill this column? The numbers of various atoms in (say) an HIV virus is kind of interesting since it comes out to be numbers that we're used to in everyday life (like billions or less). But for the whole body, it's ridiculous. SBHarris 22:36, 20 January 2012 (UTC)
I agree and I'm removing the column now. I never liked it. Carstensen (talk) 15:44, 21 January 2012 (UTC)
To get this into human scale we'd have to have some comparison, like number of atoms of (some element) vs. how much money under Bush the Republicans borrowed to pay for tax cuts for the wealthy and an unnecessary war with Iraq. 3 million cobalt atoms per dollar. Or, if you like, a mere 500,000 cobalt atoms per Yuan. ;) SBHarris 21:26, 21 January 2012 (UTC)

Some of the "atomic percents" currently shown in the table are substantially wrong. The biggest offenders are N and P. Assuming these were calculated from the Pct of Mass numbers, the most important corrections are:

  • element: currently shown as -> should be
  • H: 63 -> 62
  • N: .58 -> 1.1
  • Ca: .24 -> .22
  • P: .14 -> .22

— Preceding unsigned comment added by Neuron1 (talkcontribs) 02:06, 5 January 2014 (UTC)

I just made the above correction to the atomic # percentages. — Preceding unsigned comment added by Neuron1 (talkcontribs) 02:12, 5 January 2014 (UTC)


I see "Yes/No (topically hardens teeth; toxic in higher amounts)" in regards to fluorine. The "No" part in my opinion, is unnecessary. ALL of these elements can be harmful in higher amounts. — Preceding unsigned comment added by (talk) 20:37, 11 January 2013 (UTC)

Sure but fluorine has a lower ratio between how much is good for you (1 ppm in your water) and how much causes problems. 3 ppm turns your teeth brown and how much starts to cause bone brittleness is under debate, but worrisome levels are over 4 ppm. Only iron has anything like such narrow differences between "good" and "toxic" dietary ingestion amounts. SBHarris 01:11, 12 January 2013 (UTC)
According to this Wikipedia article "economy tea" contains about 4 mg/L of fluoride (i.e. 4 ppm of fluorine). Shouldn't that worry tea-drinkers? Especially those who drink nothing but tea. Vaughan Pratt (talk) 01:07, 21 September 2015 (UTC)

Phosphorus and Calcium[edit]

In this article Phosphorus has an atomic percentage of 0.14, calcium has 0.24. At the same time the given mass percentages are 1.1 for phosphorus and 1.4 for calcium while the molar mass of calcium is 1.3 times of that of phosphorus. Based on the given atomic percentages the difference in mass percentages should be much higher than 1.1 to 1.4, rather 1.1 to 2.44. So at least one of those values has to be wrong. — Preceding unsigned comment added by (talk) 16:52, 12 March 2013 (UTC)

You are right, and the last value for mass ratio is the best candidate for being incorrect. Ca/P ratios vary from bone to bone and species to species (they are about equal in birds for example). I can't immediately find good figures for human cremains but a value in human ribs is 2.33 [1]. Dividing by the molar mass ratio of 1.29 gives a mole or atom Ca/P ratio in the range of 1.8. The common wt/wt ratio in mammalian bone ashes is assumed to be about 2, which would lower that still further to 1.55.

If we can't get cremains data for this the bone ash data is the best we can do. They are't quite the same as 99% of your Ca is in bone but only 85 to 90% of P. Thus, cremains figures are true but bone ash Ca/P ratios must be multiplied by about 0.88 to correct for non-bone phosphorus in the body. SBHarris 19:27, 12 March 2013 (UTC)

Positive health role in mammals[edit]

I think this column needs to be fixed up. Currently, different editors are trying to use it to say things other than the answer to the question "does this element play a positive health role in mammals". e.g. "No(?)/Yes (suspected bone growth factor)" for Strontium. If you mean "possible" then say "possible", not "No/Yes". Same for fluorine: currently says "Yes/No". Fluorine should say "Yes". The fact that there could also be a negative effect in excess doesn't change the answer to the question about the positive role. Perhaps there should be two columns: one concerning the positive role, one concerning negative effects of excess.Ordinary Person (talk) 02:38, 3 October 2014 (UTC)

More elements[edit]

I'd like to add some more elements to the list. Unfortunately, I can't find any figures for amounts relative to the entire human body. For five noble gases (all but radon), numbers are available for whole blood, blood serum, and red blood cells. The numbers for whole blood (in parts per billion are) He 37, Ne 138, Ar 230000, Kr 550, and Xe 9.7. Determination of Natural In Vivo Noble-Gas Concentrations in Human Blood

Blood and urine figures are available for platinum (0.01 and 0.005 µg/L respectively) from 'Recommendation from the Scientific Committee on Occupational Exposure Limits for Platinum and Platinum compounds SCOEL/SUM/150 September 2011', Section 2.1.3. Biological Monitoring (page 11)

Of the 92 naturally occurring chemical elements we currently have 60, which leaves 32. From my reading, it looks as if many of the remaining 32 may be present. For this reason, I was thinking of adding a new section below the section 'Elemental composition list'. This new section would have information on any elements for which some data is available, e.g., occurrence in specific tissue or organs. Then we could include a mention of elements where some inconclusive data is available, Finaly, we could round out the list by indicating which of the remaining 92 elements data are still missing.

Right now I'm looking into erbium (in the bones, very strong candidate) and possibly the entire lanthanide series (15 elements, of which we already have 2). Zyxwv99 (talk) 00:13, 14 May 2016 (UTC)

Fluorine essential?[edit]

I'm pretty sure fluorine is not essential to human health. It's a prophylactic, like quinine to ward off malaria, or a vaccine. Or to put it another way, it's a drug. Zyxwv99 (talk) 00:17, 19 June 2016 (UTC) Update: I went ahead and changed it. That's because I've begun adding references to all the yes and no items. I found a reliable source that says no. If someone has a more recent reliable source that says yes, then we can always change it. Zyxwv99 (talk) 02:33, 19 June 2016 (UTC)

The reference you site says that fluorine IS essential for the human body to process calcium -- just the opposite of what you claim. — Preceding unsigned comment added by (talk) 14:56, 21 June 2016 (UTC)

Okay, I just changed it to Probably. The source cited actually says, "either essential for, or complementary to, the proper utilization of calcium." This is from Chapter 9 of the source. What I should have put in was Chapter 10 "The status of fluorine as an essential nutrient has been debated. ... These contradictory results do not justify a classification of fluorine as an essential element, according to accepted standards. Nonetheless, because of its valuable effects on dental health, fluorine is a beneficial element for humans." Recommended Dietary Allowances: 10th Edition, National Academy Press However, I've been looking at newer sources, and this might actually turn to be a Yes. If I can find one from a competent authority that says Yes I will change it. Zyxwv99 (talk) 15:27, 21 June 2016 (UTC)

Positive health role in mammals[edit]

Our element tables have a column entitled Positive health role in mammals. Two problems: 1) this article is about the human body, not mammals in general, and 2) a wide range of substances are used medicinally, even when they are non-essential and toxic. That's because medicine is about doing more good than harm. The worse the disease, the more harm the medicine can inflict and still do more good than harm.

I propose changing it to "essential to human health." That doesn't mean it needs to be an all-or-nothing proposition. For example, we currently have such items as:

Yes (not confirmed)

Yes (probable)

Yes in rats, hamsters, goats. Probably humans.

Possible (suspected bone growth factor)

No (probable)

No, probably

My proposal is just to change the heading. Zyxwv99 (talk) 18:57, 19 June 2016 (UTC)

Kill bromine, lithium, and strontium[edit]

In the US, two agencies decide which nutrients are officially designated as essential, the Food and Drug Administration and the United States Department of Agriculture. They both rely on the National Research Council (United States) and the National Academy of Medicine for their advice. The UK has something similar, as does the EU and the WHO. These people all seem to agree that arsenic, silicon, boron, nickel, and vanadium are possibly essential nutrients, in some cases even "probably." None of them are taking bromine, lithium, or strontium seriously. I'm going to change these three to a no. Zyxwv99 (talk) 03:56, 24 June 2016 (UTC)

Update: We could probably use some material above the table to explain what criteria are used to define "essential." It should probably include what I just said above, about the agencies and scientific bodies that decide these things. We could also mention that many substances have been proposed as essential, often to the detriment of public health, which is why those agencies have been given their authority.

Also, I'm wondering if we should really be using the word "No" or if we should switch to some sort of very long dash to indicate "blank." That's because elements are constantly being investigated. Unfortunately, health quacks tend to promote elements for which evidence is very weak. I don't think we should be in the business of vetting those claims. Instead, we should leave it to the scientific advisory bodies to decide which ones merit serious consideration (because of notability and undue weight). For other elements, we should just remain silent because we are not qualified to say "No." Zyxwv99 (talk) 14:17, 24 June 2016 (UTC)

Inconsistent Info[edit]

The image in the header section lists %'s that differ from the list in the elemental composition section. Why? Should the image / table be removed or adjusted? -- (talk) 18:28, 16 July 2016 (UTC)

I noticed that too. The data for the most abundant elements apparently comes from the ICRP (International Commission on Radiological Protection) which defines the Standard person of 70 kg. However, many of the numbers we have here are from John Emsley, who for several decades has been editing and updating his book The Elements, since re-titled Nature's Building Blocks. For the most abundant elements, he relies on Environmental Chemistry of the Elements (1979) which in turn relies on an older version of the ICRP's numbers. I found a 2013 source here for the 17 most abundant element in the body, referenced to a more recent version of the ICRP's list.
Meanwhile, the graphic was uploaded to Wikimedia Commons as a JPEG file, taken from an online open-source textbook on anatomy and physiology. However it's not referenced. Part of that graphic is actually good, the part with the diagram of the person. It only has four numbers (for the most abundant elements) and they coincide with the latest ICRP numbers. I could cut that graphic in two, get rid of the text on the right, and replce with whatever numbers we decide to use. I'll keep working to see what I can do. Zyxwv99 (talk) 03:55, 18 July 2016 (UTC)