View source for Biology:Composition of the human body

{{Short description|Body composition elements}}
[[File:Two pie graphs about the composition of the human body.png|thumb|300px|Pie charts of typical human body composition by percent of mass, and by percent of atomic composition (atomic percent)]]
Body composition may be analyzed in various ways. This can be done in terms of the [[Chemistry:Chemical element|chemical element]]s present, or by molecular structure e.g., [[Chemistry:Water|water]], [[Biology:Protein|protein]], [[Chemistry:Fat|fat]]s (or [[Chemistry:Lipid|lipid]]s), hydroxylapatite (in bones), carbohydrates (such as [[Biology:Glycogen|glycogen]] and [[Chemistry:Glucose|glucose]]) and [[Biology:DNA|DNA]]. In terms of tissue type, the body may be analyzed into water, fat, connective tissue, [[Biology:Muscle|muscle]], [[Biology:Bone|bone]], etc. In terms of cell type, the body contains hundreds of different types of cells, but notably, the largest ''number'' of cells contained in a human body (though not the largest mass of cells) are not human cells, but bacteria residing in the normal human gastrointestinal tract.

==Elements==
{| class="wikitable floatright" style="font-size: 86%" 
|+  align="bottom" style="text-align:left; caption-side: bottom" | The main elements that comprise the human body (including water) can be summarized as [[Astronomy:CHNOPS|CHNOPS]].
| rowspan="13"|[[File:201 Elements of the Human Body.02.svg|300px]]
! scope=col | Element
! scope=col | Symbol
! scope=col | percent<br>mass
! scope=col | percent<br>atoms
|-
| Oxygen 
| style="text-align:center;"|O
| style="text-align:right;"|65.0
| style="text-align:right;"|24.0
|-
| Carbon
| style="text-align:center;"|C
| style="text-align:right;"|18.5
| style="text-align:right;"|12.0
|-
| Hydrogen
| style="text-align:center;"|H
| style="text-align:right;"|9.5
| style="text-align:right;"|62.0
|-
| Nitrogen
| style="text-align:center;"|N
| style="text-align:right;"|3.2
| style="text-align:right;"|1.1
|-
| Calcium
| style="text-align:center;"|Ca
| style="text-align:right;"|1.5 
| style="text-align:right;"|0.22
|-
| Phosphorus
| style="text-align:center;"|P
| style="text-align:right;"|1.0
| style="text-align:right;"|0.22
|-
| Potassium
| style="text-align:center;"|K
| style="text-align:right;"|0.4
| style="text-align:right;"|0.03
|-
| Sulfur
| style="text-align:center;"|S
| style="text-align:right;"|0.3
| style="text-align:right;"|0.038
|-
| Sodium
| style="text-align:center;"|Na

| style="text-align:right;"|0.2
| style="text-align:right;"|0.037
|-
| Chlorine
| style="text-align:center;"|Cl
| style="text-align:right;"|0.2
| style="text-align:right;"|0.024
|-
| Magnesium
| style="text-align:center;"|Mg
| style="text-align:right;"|0.1
| style="text-align:right;"|0.015
|-
|  All others
| 
| style="text-align:right;"|< 0.1
| style="text-align:right;"|< 0.3
|}
[[File:element_abundance_human_body_ppm_chart.svg|thumb|300px|Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm]]
About 99% of the mass of the human body is made up of six elements: [[Chemistry:Oxygen|oxygen]], [[Chemistry:Carbon|carbon]], [[Chemistry:Hydrogen|hydrogen]], [[Chemistry:Nitrogen|nitrogen]], [[Chemistry:Calcium|calcium]], and [[Chemistry:Phosphorus|phosphorus]]. Only about 0.85% is composed of another five elements: [[Chemistry:Potassium|potassium]], [[Chemistry:Sulfur|sulfur]], [[Chemistry:Sodium|sodium]], [[Chemistry:Chlorine|chlorine]], and [[Chemistry:Magnesium|magnesium]]. All 11 are necessary for life. The remaining elements are [[Biology:Trace element|trace element]]s, of which more than a dozen are thought on the basis of good evidence to be necessary for life.<ref>{{Cite journal | doi = 10.1016/j.jinorgbio.2019.03.013 | journal = Journal of Inorganic Biochemistry | volume =195 | pages = 120–129 | date = June 2019 | title = The essential metals for humans: a brief overview |author1=M.A. Zoroddu |author2=J. Aashet |author3=G. Crisponi |author4=S. Medici |author5=M. Peana |author6=V.M. Nurchi | pmid=30939379 | s2cid = 92997696 }}</ref> All of the mass of the trace elements put together (less than 10 grams for a human body) do not add up to the body mass of magnesium, the least common of the 11 non-trace elements.

===Other elements===
Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple common contaminants without function (examples: caesium, titanium), while many others are thought to be active toxins, depending on amount (cadmium, mercury, lead, radioactives). In humans, [[Chemistry:Arsenic|arsenic]] is toxic, and its levels in foods and dietary supplements are closely monitored to reduce or eliminate its intake.<ref name="fda-arsenic">{{cite web |title=Arsenic in Food and Dietary Supplements |url=https://www.fda.gov/food/metals/arsenic-food-and-dietary-supplements |publisher=US Food and Drug Administration |access-date=20 August 2019 |date=22 May 2019}}</ref>

Some elements (silicon, boron, nickel, vanadium) are probably needed by mammals also, but in far smaller doses. Bromine is used by some (though not all) bacteria, fungi, diatoms, and seaweeds, and opportunistically in [[Biology:Eosinophil|eosinophil]]s in humans. One study has indicated bromine to be necessary to collagen IV synthesis in humans.<ref name="pmid24906154">{{Cite journal|vauthors=McCall AS, Cummings CF, Bhave G, Vanacore R, Page-McCaw A, Hudson BG |title = Bromine Is an Essential Trace Element for Assembly of Collagen IV Scaffolds in Tissue Development and Architecture|journal = Cell|volume = 157|issue = 6|pages = 1380–92|year = 2014|pmid = 24906154|doi=10.1016/j.cell.2014.05.009|pmc=4144415}}</ref> [[Chemistry:Fluorine|Fluorine]] is used by a number of plants to manufacture toxins but only functions in humans as a local topical hardening agent in tooth enamel.<ref name="Lehninger">{{cite book|first1=David L |last1=Nelson|last2= Cox |first2=Michael M|title=Lehninger Principles of Biochemistry |publisher=Macmillan |edition=8th|isbn=9781319230906|location=New York|date=2021 }}</ref>

===Elemental composition list===
{{main article|Chemistry:Mineral (nutrient)}}
The average {{convert|70|kg|abbr=on|adj=on}} [[Medicine:Human body|adult human body]] contains approximately {{val|7|e=27}} [[Physics:Atom|atom]]s and contains at least detectable traces of 60 [[Chemistry:Chemical element|chemical element]]s.<ref>{{Cite web|url=https://education.jlab.org/qa/mathatom_04.html|title=Questions and Answers - How many atoms are in the human body?|website=education.jlab.org|accessdate=4 April 2023}}</ref> About 29 of these elements are thought to play an active positive role in life and health in humans.<ref name="bare_url">"Ultratrace minerals". Authors: Nielsen, Forrest H. USDA, ARS Source: ''Modern nutrition in health and disease'' / editors, Maurice E. Shils ... et al.. Baltimore : Williams & Wilkins, c. 1999, p. 283-303. Issue Date: 1999 URI: [http://hdl.handle.net/10113/46493]</ref>

The relative amounts of each element vary by individual, mainly due to differences in the proportion of fat, muscle and bone in their body. Persons with more fat will have a higher proportion of carbon and a lower proportion of most other elements (the proportion of hydrogen will be about the same).
The numbers in the table are averages of different numbers reported by different references.

The adult human body averages ~53% water.<ref>Use WP:CALC for the mean of means for males and females, since the two groups are of about equal size</ref> This varies substantially by age, sex, and adiposity. In a large sample of adults of all ages and both sexes, the figure for water fraction by weight was found to be 48 ±6% for females and 58 ±8% water for males.<ref name="here">See table 1. [http://ajcn.nutrition.org/content/33/1/27.full.pdf here]</ref> Water is ~11% hydrogen by [[Physics:Mass|mass]] but ~67% hydrogen by atomic percent, and these numbers along with the complementary % numbers for oxygen in water, are the largest contributors to overall mass and atomic composition figures. Because of water content, the human body contains more oxygen by mass than any other element, but more hydrogen by atom-fraction than any element.

The elements listed below as "Essential in humans" are those listed by the US [[Organization:Food and Drug Administration|Food and Drug Administration]] as essential nutrients,<ref>{{cite web|url=https://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm064928.htm|archive-url=https://wayback.archive-it.org/7993/20170404170950/https://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm064928.htm|url-status=dead|archive-date=4 April 2017|title=Guidance for Industry: A Food Labeling Guide 14. Appendix F|publisher=US Food and Drug Administration|date=1 January 2013}}</ref> as well as six additional elements: oxygen, carbon, hydrogen, and nitrogen (the fundamental building blocks of life on Earth), sulfur (essential to all cells) and cobalt (a necessary component of vitamin B<sub>12</sub>). Elements listed as "Possibly" or "Probably" essential are those cited by the US National Research Council as beneficial to human health and possibly or probably essential.<ref name="Medicine2006">{{cite book|author=Institute of Medicine|title=Dietary Reference Intakes: The Essential Guide to Nutrient Requirements|url=https://books.google.com/books?id=dYZZTgjDeccC&pg=PA415|access-date=21 June 2016|date=29 September 2006|publisher=National Academies Press|isbn=978-0-309-15742-1|pages=313–19, 415–22}}</ref>

{| class="wikitable sortable" style="text-align:center;"
! Atomic number !! Element !!data-sort-type="number"| Fraction of mass<br><ref>Thomas J. Glover, comp., ''Pocket Ref'', 3rd ed. (Littleton: Sequoia, 2003), p. 324 ({{LCCN|2002091021||}}), which in</ref><ref>turn cites Geigy Scientific Tables, Ciba-Geigy Limited, Basel, Switzerland, 1984.</ref><ref>{{cite book
  | last = Chang
  | first = Raymond
  | title = Chemistry, Ninth Edition
  | publisher = McGraw-Hill
  | year = 2007
  | pages = 52
  | isbn = 978-0-07-110595-8 }}</ref><ref>[http://web2.airmail.net/uthman/elements_of_body.html "Elemental Composition of the Human Body"] {{Webarchive|url=https://web.archive.org/web/20181218074109/http://web2.airmail.net/uthman/elements_of_body.html |date=2018-12-18 }} by Ed Uthman, MD Retrieved 17 June 2016</ref><ref>{{Cite book | url = https://books.google.com/books?id=qXbKF1Pw_GsC&q=The+Chemical+Elements+of+Life+Scientific+American&pg=PA27 | title = The Biological Chemistry of the Elements: The Inorganic Chemistry of Life | isbn = 9780198508489 | last1 = Frausto Da Silva | first1 = J. J. R | last2 = Williams | first2 = R. J. P | date = 2001-08-16| publisher = OUP Oxford }}</ref><ref>{{cite book
  | last = Zumdahl
  | first = Steven S. and Susan A.
  | title = Chemistry, Fifth Edition
  | publisher = Houghton Mifflin Company
  | year = 2000
  | pages = 894
|-
| 8 || [[Chemistry:Oxygen|Oxygen]] || data-sort-value="0.65"| 0.65 || 45 || 24 || [[Chemistry:Dioxygen in biological reactions|Yes]] (e.g. [[Chemistry:Water|water]], [[Chemistry:Electrophile|electron acceptor]])<ref name="SalmAllen2015">{{cite book|last1=Salm|first1=Sarah|last2=Allen|first2=Deborah|last3=Nester|first3=Eugene|last4=Anderson|first4=Denise|title=Nester's Microbiology: A Human Perspective|url=https://books.google.com/books?id=VqhZCgAAQBAJ&pg=PA21|access-date=19 June 2016|date=9 January 2015|isbn=978-0-07-773093-2|page=21|publisher=Mcgraw-hill Us Higher Ed }}</ref> || [[Biology:Reactive oxygen species|Reactive oxygen species]] || 16
|-
| 6 || [[Chemistry:Carbon|Carbon]] || data-sort-value="0.18"| 0.18 || 13 || 12 || [[Chemistry:Organic compound|Yes]]<ref name="SalmAllen2015" /> ([[Chemistry:Organic compound|organic compound]]s) || || 14
|-
| 1 || [[Chemistry:Hydrogen|Hydrogen]] || data-sort-value="0.10"| 0.10 || 7 || 62 || [[Chemistry:Organic compound|Yes]]<ref name="SalmAllen2015" /> (e.g. [[Chemistry:Water|water]]) ||Acidosis || 1
|-
| 7 || [[Chemistry:Nitrogen|Nitrogen]] || data-sort-value="0.03"| 0.03 || 1.8 || 1.1 || [[Chemistry:Nitrogen#Biological role|Yes]]<ref name="SalmAllen2015" /> (e.g. [[Biology:DNA|DNA]] and [[Chemistry:Amino acid|amino acid]]s) || || 15
|-
| 20 || [[Chemistry:Calcium|Calcium]] || data-sort-value="0.014"| 0.014 || 1.0 || 0.22 || [[Biology:Calcium in biology|Yes]]<ref name="SalmAllen2015" /><ref name="AllowancesBoard1989">{{cite book|author1=Subcommittee on the Tenth Edition of the Recommended Dietary Allowances, Food and Nutrition Board|author2=Commission on Life Sciences, National Research Council|title=Recommended Dietary Allowances: 10th Edition|chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK234927/|access-date=18 June 2016|date=1 February 1989|publisher=National Academies Press|isbn=978-0-309-04633-6|chapter=9-10|url-access=registration|url=https://archive.org/details/recommendeddieta0000nati}}</ref><ref name="CFR FDA">{{Cite web|url=https://unblock.federalregister.gov/|title=Federal Register :: Request Access|website=unblock.federalregister.gov|accessdate=4 April 2023}}</ref> (e.g. [[Biology:Calmodulin|Calmodulin]] and Hydroxylapatite in [[Biology:Bone|bone]]s) || [[Medicine:Hypercalcaemia|Hypercalcaemia]] || 2
|-
| 15 || [[Chemistry:Phosphorus|Phosphorus]] || data-sort-value="0.011"|0.011 ||  0.78 || 0.22 || [[Chemistry:Phosphorus#Biological role|Yes]]<ref name="SalmAllen2015" /><ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. [[Biology:DNA|DNA]], [[Chemistry:Phospholipid|Phospholipid]]s and [[Biology:Phosphorylation|Phosphorylation]]) || [[Medicine:Hyperphosphatemia|Hyperphosphatemia]] || 15
|-
| 19 || [[Chemistry:Potassium|Potassium]] || data-sort-value="0.0025"| {{val|2.0|e=-3}} || 0.14 || 0.033 || [[Chemistry:Potassium#Biological role|Yes]]<ref name="SalmAllen2015" /><ref name="AllowancesBoard1989" /> (e.g. Na<sup>+</sup>/K<sup>+</sup>-ATPase) || [[Medicine:Hyperkalemia|Hyperkalemia]] || 1
|-
| 16 || [[Chemistry:Sulfur|Sulfur]] || data-sort-value="0.0025"|{{val|2.5|e=-3}} || 0.14 || 0.038 || [[Chemistry:Sulfur#Biological role|Yes]]<ref name="SalmAllen2015" /> (e.g. [[Chemistry:Cysteine|Cysteine]], [[Chemistry:Methionine|Methionine]], [[Chemistry:Biotin|Biotin]], [[Physics:Thiamine|Thiamine]]) || [[Medicine:Sulfhemoglobinemia|Sulfhemoglobinemia]] || 16
|-
| 11 || [[Chemistry:Sodium|Sodium]] || data-sort-value="0.0015"| {{val|1.5|e=-3}} || 0.10 || 0.037 || [[Chemistry:Sodium#Biological role|Yes]]<ref name="AllowancesBoard1989" /> (e.g. Na<sup>+</sup>/K<sup>+</sup>-ATPase) || [[Medicine:Hypernatremia|Hypernatremia]] || 1
|-
| 17 || [[Chemistry:Chlorine|Chlorine]] || data-sort-value="0.0015"| {{val|1.5|e=-3}} || 0.095 || 0.024 || [[Chemistry:Serum chloride|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. [[Biology:Cl-transporting ATPase|Cl-transporting ATPase]]) || [[Medicine:Hyperchloremia|Hyperchloremia]] || 17
|-
| 12 || [[Chemistry:Magnesium|Magnesium]] || data-sort-value="0.0005"| {{val|500|e=-6}} || 0.019 || 0.0070 || [[Chemistry:Magnesium#Biological roles|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. binding to [[Biology:Magnesium in biology#Essential role in the biological activity of ATP|ATP and other nucleotides]]) || [[Medicine:Hypermagnesemia|Hypermagnesemia]] || 2
|-
| 26 || [[Chemistry:Iron|Iron]]* || data-sort-value="0.00006"| {{val|60|e=-6}} || data-sort-value=".0042"| 0.0042 || 0.00067 || [[Chemistry:Iron#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. [[Biology:Hemoglobin|Hemoglobin]], [[Biology:Cytochrome|Cytochrome]]s) || Iron overload || 8
|-
| 9 || [[Chemistry:Fluorine|Fluorine]] || data-sort-value="0.000037"| {{val|37|e=-6}} || 0.0026 || 0.0012 || Yes ({{wipe|Australia}}, [[Earth:New Zealand|NZ]]),<ref>[https://www.nrv.gov.au/nutrients/fluoride Australian National Health and Medical Research Council (NHMRC) and New Zealand Ministry of Health (MoH)]</ref> No ({{wipe|United States of America}}, [[Social:European Union|EU]]),<ref>[https://www.fas.org/sgp/crs/misc/RL33280.pdf "Fluoride in Drinking Water: A Review of Fluoridation and Regulation Issues"]</ref><ref>{{cite journal|title=Scientific Opinion on Dietary Reference Values for fluoride|journal=EFSA Journal|volume=11|issue=8|year=2013|pages=3332|issn=1831-4732|doi=10.2903/j.efsa.2013.3332|url=http://orbit.dtu.dk/files/57406955/17%20dietary%20ref.pdf|doi-access=free}}</ref> Maybe ([[Organization:World Health Organization|WHO]])<ref>{{Cite web|url=https://www.who.int/water_sanitation_health/dwq/chemicals/fluoride.pdf|title=WHO/SDE/WSH/03.04/96 "Fluoride in Drinking-water"|accessdate=4 April 2023}}</ref> ||Fluorine: [[Biology:Biological aspects of fluorine#Hazards|Highly toxic]]
Fluoride: [[Medicine:Fluoride toxicity|Toxic in high amounts]]
| 17
|-
| 30 || [[Chemistry:Zinc|Zinc]] || data-sort-value="0.000032"| {{val|32|e=-6}} || 0.0023 || 0.00031 || [[Chemistry:Zinc#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. Zinc finger proteins) || Zinc toxicity || 12
|-
| 14 || [[Chemistry:Silicon|Silicon]] || data-sort-value="0.00002"| {{val|20|e=-6}} || 0.0010 || 0.0058 || [[Chemistry:Silicon#Biological role|Probably]]<ref>{{cite journal |author1=Muhammad Ansar Farooq |author2=Karl-Josef Dietz |title=Silicon as Versatile Player in Plant and Human Biology: Overlooked and Poorly Understood |journal=Front. Plant Sci. |date=2015 |volume=6 |issue=994 |page=994 |doi=10.3389/fpls.2015.00994 |pmid=26617630|pmc=4641902 |doi-access=free }}</ref> || || 14
|-
| 31 || [[Chemistry:Gallium|Gallium]] || data-sort-value="0.00002"| {{val|4.9|e=-6}} || 0.0007 || 0.00093 || No || [[Chemistry:Gallium#Precautions|Gallium halide]] poisoning<ref>{{cite journal |last1=Ivanoff |first1=C. S. |last2=Ivanoff |first2=A. E. |last3=Hottel |first3=T. L. |date=February 2012 |title=Gallium poisoning: a rare case report. |journal=Food Chem. Toxicol. |volume=50 |issue=2 |pages=212–5 |doi=10.1016/j.fct.2011.10.041 |pmid=22024274}}</ref> || 13
|-
| 37 || [[Chemistry:Rubidium|Rubidium]] || data-sort-value="0.0000046"| {{val|4.6|e=-6}} || 0.00068 || 0.000033 || No ||  [[Chemistry:Potassium|Potassium]] replacement || 1
|-
| 38 || [[Chemistry:Strontium|Strontium]] || data-sort-value="0.0000046"| {{val|4.6|e=-6}} || 0.00032 || 0.000033 || No || [[Chemistry:Calcium|Calcium]] replacement || 2
|-
| 35 || [[Chemistry:Bromine|Bromine]] || data-sort-value="0.0000029"| {{val|2.9|e=-6}} || 0.00026 || 0.000030 || Maybe<ref name=bromine>{{cite journal |vauthors=McCall AS, Cummings CF, Bhave G, Vanacore R, Page-McCaw A, Hudson BG |title=Bromine is an essential trace element for assembly of collagen IV scaffolds in tissue development and architecture |journal=Cell |volume=157 |issue=6 |pages=1380–92 |date=June 2014 |pmid=24906154 |pmc=4144415 |doi=10.1016/j.cell.2014.05.009 }}</ref> || [[Medicine:Bromism|Bromism]] || 17
|-
| 82 || [[Chemistry:Lead|Lead]] || data-sort-value="0.0000017"| {{val|1.7|e=-6}} || 0.00012 || 0.0000045 || No || [[Medicine:Lead poisoning|Lead poisoning]] || 14
|-
| 29 || [[Chemistry:Copper|Copper]] || data-sort-value="0.000001"| {{val|1|e=-6}} || 0.000072 || 0.0000104 || [[Chemistry:Copper#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. copper proteins) || Copper toxicity || 11
|-
| 13 || [[Chemistry:Aluminium|Aluminium]] || data-sort-value="0.00000087"| {{val|870|e=-9}} || 0.000060 || 0.000015 || No || Aluminium poisoning || 13
|-
| 48 || [[Chemistry:Cadmium|Cadmium]] || data-sort-value="0.00000072"| {{val|720|e=-9}} || 0.000050 || 0.0000045 || No || [[Medicine:Cadmium poisoning|Cadmium poisoning]] || 12
|-
| 58 || [[Chemistry:Cerium|Cerium]] || data-sort-value="0.00000057"| {{val|570|e=-9}} || 0.000040 || || No || || 
|-
| 56 || [[Chemistry:Barium|Barium]] || data-sort-value="0.00000031"| {{val|310|e=-9}} || 0.000022 || 0.0000012 || No || toxic in higher amounts || 2
|-
| 50 || [[Chemistry:Tin|Tin]] || data-sort-value="0.00000024"| {{val|240|e=-9}} || 0.000020 || data-sort-value="0.00000060"| {{val|6.0|e=-7}} || Maybe<ref name=essentialmetals>{{cite journal |last1=Zoroddu |first1=Maria Antonietta |last2=Aaseth |first2=Jan |first3=Guido |last3=Crisponi |first4=Serenella |last4=Medici |first5=Massimiliano |last5=Peana |first6=Valeria Marina |last6=Nurchi |date=2019 |title=The essential metals for humans: a brief overview |url= |journal=Journal of Inorganic Biochemistry |volume=195 |issue= |pages=120–129 |doi=10.1016/j.jinorgbio.2019.03.013 |access-date=}}</ref> || || 14
|-
| 53 || [[Chemistry:Iodine|Iodine]] || data-sort-value="0.00000016"| {{val|160|e=-9}} || 0.000020 || data-sort-value="0.00000075"| {{val|7.5|e=-7}} || [[Chemistry:Iodine#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. thyroxine, [[Chemistry:Triiodothyronine|triiodothyronine]]) || Iodine-induced [[Medicine:Hyperthyroidism|hyperthyroidism]] || 17
|-
| 22 || [[Chemistry:Titanium|Titanium]] || data-sort-value="0.00000013"| {{val|130|e=-9}} || 0.000020 || || No || || 4
|-
| 5 || [[Chemistry:Boron|Boron]] || data-sort-value="0.00000069"| {{val|690|e=-9}} || 0.000018 || 0.0000030 || [[Chemistry:Boron#Biological role|Probably]]<ref name="Medicine2006" /><ref name="EVM2003">[https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf Safe Upper Levels for Vitamins and Mineral (2003), boron p. 164-71, nickel p. 225-31, EVM, Food Standards Agency, UK] {{ISBN|1-904026-11-7}}</ref> || || 13
|-
| 34 || [[Chemistry:Selenium|Selenium]] || data-sort-value="0.00000019"| {{val|190|e=-9}} || 0.000015 || data-sort-value="0.000000045"| {{val|4.5|e=-8}} || [[Chemistry:Selenium#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. [[Chemistry:Selenocysteine|selenocysteine]]) || [[Chemistry:Selenium#Toxicity|Selenium toxicity]] || 16
|-
| 28 || [[Chemistry:Nickel|Nickel]] || data-sort-value="0.00000014"| {{val|140|e=-9}} || 0.000015 || 0.0000015 || [[Chemistry:Nickel#Biological role|Maybe]]<ref name=essentialmetals/> || [[Chemistry:Nickel#Toxicity|Nickel Toxicity]] || 10
|-
| 24 || [[Chemistry:Chromium|Chromium]] || data-sort-value="0.000000024"| {{val|24|e=-9}} || 0.000014 || data-sort-value="0.000000089"| {{val|8.9|e=-8}} || [[Chemistry:Chromium#Biological role|Maybe]]<ref name=essentialmetals/><ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> || || 6
|-
| 25 || [[Chemistry:Manganese|Manganese]] || data-sort-value="0.00000017"| {{val|170|e=-9}} || 0.000012 || 0.0000015 || [[Chemistry:Manganese#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. Mn-SOD) || [[Medicine:Manganism|Manganism]] || 7
|-
| 33 || [[Chemistry:Arsenic|Arsenic]] || data-sort-value="0.00000026"| {{val|260|e=-9}} || 0.000007 || data-sort-value="0.000000089"| {{val|8.9|e=-8}} || [[Chemistry:Arsenic#Biological role|Maybe]]<ref name=essentialmetals/><ref name=fda-arsenic/> || [[Medicine:Arsenic poisoning|Arsenic poisoning]] || 15
|-
| 3 || [[Chemistry:Lithium|Lithium]] || data-sort-value="0.000000031"| {{val|31|e=-9}} || 0.000007 || 0.0000015 || [[Chemistry:Lithium#Biological|Possibly]] (intercorrelated with the functions of several [[Biology:Enzymes|enzymes]], hormones and [[Chemistry:Vitamin|vitamin]]s) || [[Medicine:Lithium toxicity|Lithium toxicity]] || 1
|-
| 80 || [[Chemistry:Mercury (element)|Mercury]] || data-sort-value="0.00000019"| {{val|190|e=-9}} || 0.000006 || data-sort-value="0.000000089"| {{val|8.9|e=-8}} || No || [[Medicine:Mercury poisoning|Mercury poisoning]] || 12
|-
| 55 || [[Chemistry:Caesium|Caesium]] || data-sort-value="0.000000021"| {{val|21|e=-9}} || 0.000006 || data-sort-value="0.00000010"| {{val|1.0|e=-7}} || No || || 1
|-
| 42 || [[Chemistry:Molybdenum|Molybdenum]] || data-sort-value="0.00000013"| {{val|130|e=-9}} || 0.000005 || data-sort-value="0.000000045"| {{val|4.5|e=-8}} || [[Chemistry:Molybdenum#Biological role|Yes]]<ref name="AllowancesBoard1989" /><ref name="CFR FDA" /> (e.g. the [[Biology:Molybdenum oxotransferase|molybdenum oxotransferase]]s, [[Biology:Xanthine oxidase|Xanthine oxidase]] and [[Biology:Sulfite oxidase|Sulfite oxidase]]) || || 6
|-
| 32 || [[Chemistry:Germanium|Germanium]] || || data-sort-value="0.00000005"|{{val|5|e=-6}} || || No || || 14
|-
| 27 || [[Chemistry:Cobalt|Cobalt]] || data-sort-value="0.000000021"| {{val|21|e=-9}} || 0.000003 || data-sort-value="0.00000030"| {{val|3.0|e=-7}} || [[Chemistry:Cobalt#Biological role|Yes]] (e.g. [[Biology:Vitamin B12|Cobalamin/Vitamin B<sub>12</sub>]])<ref name="Yamada2013">{{cite book|last1=Yamada|first1=Kazuhiro|series=Metal Ions in Life Sciences |title=Interrelations between Essential Metal Ions and Human Diseases|chapter=Cobalt: Its Role in Health and Disease|volume=13|year=2013|pages=295–320|issn=1559-0836|doi=10.1007/978-94-007-7500-8_9|pmid=24470095|isbn=978-94-007-7499-5}}</ref><ref name="Banci2013">{{cite book|last=Banci|first=Lucia|title=Metallomics and the Cell|url=https://books.google.com/books?id=gVQ_AAAAQBAJ&pg=PA333|access-date=19 June 2016|date=18 April 2013|publisher=Springer Science & Business Media|isbn=978-94-007-5561-1|pages=333–368}}</ref> || || 9
|-
| 44 || [[Chemistry:Ruthenium|Ruthenium]] || data-sort-value="0.000000022"| {{val|22|e=-9}} || 0.000007 || || No <ref name="Teoniskoetter2020">{{cite book|last1=Toeniskoetter|first1=Steve|title=Biochemical Periodic Table |chapter=Ruthenium|year=2020|url=http://eawag-bbd.ethz.ch/periodic/elements/ru.html}}</ref> || || 8
|-
| 51 || [[Chemistry:Antimony|Antimony]] || data-sort-value="0.00000011"| {{val|110|e=-9}} || 0.000002 || || [[Chemistry:Antimony#Precautions|No]] || toxic || 15
|-
| 47 || [[Chemistry:Silver|Silver]] || data-sort-value="0.00000001"| {{val|10|e=-9}} || 0.000002 || || No || || 11
|-
| 41 || [[Chemistry:Niobium|Niobium]] || data-sort-value="0.0000016"| {{val|1600|e=-9}} || 0.0000015 || || No || || 5
|-
| 40 || [[Chemistry:Zirconium|Zirconium]] || data-sort-value="0.000006"| {{val|6|e=-9}} || 0.000001 || data-sort-value="0.00000030"| {{val|3.0|e=-7}} || No || || 4
|-
| 57 || [[Chemistry:Lanthanum|Lanthanum]] || data-sort-value="0.00000137"| {{val|1370|e=-9}} || data-sort-value="0.0000008"| {{val|8|e=-7}} || || No || ||
|-
| 52 || [[Chemistry:Tellurium|Tellurium]] || data-sort-value="0.00000012"| {{val|120|e=-9}} || data-sort-value="0.0000007"| {{val|7|e=-7}} || || No || || 16
|-
| 39 || [[Chemistry:Yttrium|Yttrium]] || || data-sort-value="0.0000006"| {{val|6|e=-7}} || || No || || 3
|-
| 83 || [[Chemistry:Bismuth|Bismuth]] || || data-sort-value="0.0000005"| {{val|5|e=-7}} || || No || || 15
|-
| 81 || [[Chemistry:Thallium|Thallium]] || || data-sort-value="0.0000005"| {{val|5|e=-7}} || || No || highly toxic || 13
|-
| 49 || [[Chemistry:Indium|Indium]] || || data-sort-value="0.0000004"| {{val|4|e=-7}} || || No || || 13
|-
| 79 || [[Chemistry:Gold|Gold]] || data-sort-value="0.000000003"| {{val|3|e=-9}} || data-sort-value="0.0000002"| {{val|2|e=-7}} || data-sort-value="0.00000030"| {{val|3.0|e=-7}} || No || uncoated nanoparticles possibly genotoxic<ref name="FratoddiVenditti2015">{{cite journal|last1=Fratoddi|first1=Ilaria|last2=Venditti|first2=Iole|last3=Cametti|first3=Cesare|last4=Russo|first4=Maria Vittoria|title=How toxic are gold nanoparticles? The state-of-the-art|journal=Nano Research|volume=8|issue=6|year=2015|pages=1771–1799|issn=1998-0124|doi=10.1007/s12274-014-0697-3|hdl=11573/780610|s2cid=84837060|hdl-access=free}}</ref><ref>{{cite journal|title=Scientific Opinion on the re-evaluation of gold (E 175) as a food additive|journal=EFSA Journal|volume=14|issue=1|year=2016|issn=1831-4732|doi=10.2903/j.efsa.2016.4362|page=4362|doi-access=free}}</ref><ref name="HillyerAlbrecht2001">{{cite journal|last1=Hillyer|first1=Julián F.|last2=Albrecht|first2=Ralph M.|title=Gastrointestinal persorption and tissue distribution of differently sized colloidal gold nanoparticles|journal=Journal of Pharmaceutical Sciences|volume=90|issue=12|year=2001|pages=1927–1936|issn=0022-3549|doi=10.1002/jps.1143|pmid=11745751}}</ref> || 11
|-
| 21 || [[Chemistry:Scandium|Scandium]] || || data-sort-value="0.0000002"| {{val|2|e=-7}} || || No || || 3
|-
| 73 || [[Chemistry:Tantalum|Tantalum]] || || data-sort-value="0.0000002"| {{val|2|e=-7}} || || No || || 5
|-
| 23 || [[Chemistry:Vanadium|Vanadium]] || data-sort-value="0.00000026"| {{val|260|e=-9}} || data-sort-value="0.000020"| 0.000020 || data-sort-value="0.000000012"| {{val|1.2|e=-8}} || [[Chemistry:Vanadium#Biological role|Possibly]]<ref name="Medicine2006" /> (suggested osteo-metabolism (bone) growth factor) || || 5
|-
| 90 || [[Chemistry:Thorium|Thorium]] || || data-sort-value="0.0000001"| {{val|1|e=-7}} || || No || toxic, radioactive ||
|-
| 92 || [[Chemistry:Uranium|Uranium]] || || data-sort-value="0.0000001"| {{val|1|e=-7}} || data-sort-value="0.0000000030"| {{val|3.0|e=-9}} || No || toxic, radioactive ||
|-
| 62 || [[Chemistry:Samarium|Samarium]] || || data-sort-value="0.000000050"| {{val|5.0|e=-8}} || || No || ||
|-
| 74 || [[Chemistry:Tungsten|Tungsten]] || || data-sort-value="0.000000020"| {{val|2.0|e=-8}} || || No || || 6
|-
| 4 || [[Chemistry:Beryllium|Beryllium]] || || data-sort-value="0.000000036"| {{val|3.6|e=-8}} || data-sort-value="0.000000045"| {{val|4.5|e=-8}} || No || toxic in higher amounts || 2
|-
| 88 || [[Chemistry:Radium|Radium]] || || data-sort-value="0.00000000000003"| {{val|3|e=-14}}  || data-sort-value="0.00000000000000001"| {{val|1|e=-17}}  || No || toxic, radioactive || 2
|-
| 2 || [[Chemistry:Helium|Helium]] || data-sort-value="0.00000000000000000002039"| {{val|20.39|e=-21}} || data-sort-value="0.000000000000024"| {{val|2.4|e=-14}}  || data-sort-value="0.00000000000000001"| {{val|1|e=-17}}  || No || noble gas || 18
|-
| 10 || [[Chemistry:Neon|Neon]] || data-sort-value="0.000000000000000000000085"| {{val|8.5|e=-23}} || data-sort-value="0.00000000000001"| {{val|1|e=-14}}  || data-sort-value="0.00000000000000001"| {{val|1|e=-17}}  || No || toxic, noble gas || 18
|-
| 18 || [[Chemistry:Argon|Argon]] || data-sort-value="0.0000000000000000000000425"| {{val|4.25|e=-23}} || data-sort-value="0.000000000000005"| {{val|0.5|e=-14}}  || data-sort-value="0.00000000000000001"| {{val|1|e=-17}}  || No || toxic, noble gas || 18
|-
| 36 || [[Chemistry:Krypton|Krypton]] || data-sort-value="0.00000000000000000000002125"| {{val|2.125|e=-23}} || data-sort-value="0.0000000000000025"| {{val|0.25|e=-14}}  || data-sort-value="0.00000000000000001"| {{val|1|e=-17}}  || No || toxic, noble gas || 18
|}
<nowiki>*</nowiki>Iron = ~3 [[Gram|g]] in males, ~2.3 g in females

Of the 94 naturally occurring chemical elements, 61 are listed in the table above. Of the remaining 33, it is not known how many occur in the human body.

Most of the elements needed for life are relatively [[Chemistry:Abundance of the chemical elements|common in the Earth's crust]]. [[Chemistry:Aluminium|Aluminium]], the third most common element in the [[Earth:Earth's crust|Earth's crust]] (after [[Chemistry:Oxygen|oxygen]] and [[Chemistry:Silicon|silicon]]), serves no function in living cells, but is toxic in large amounts, depending on its physical and chemical forms and magnitude, duration, frequency of exposure, and how it was absorbed by the human body.<ref name="Willhite">{{cite journal | last1=Willhite | first1=Calvin C. | last2=Karyakina | first2=Nataliya A. | last3=Yokel | first3=Robert A. | last4=Yenugadhati | first4=Nagarajkumar | last5=Wisniewski | first5=Thomas M. | last6=Arnold | first6=Ian M.F. | last7=Momoli | first7=Franco | last8=Krewski | first8=Daniel | title=Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts | journal=Critical Reviews in Toxicology | volume=44 | issue=sup4 | date=2014-09-18 | issn=1040-8444 | doi=10.3109/10408444.2014.934439 | pages=1–80|pmid=25233067|pmc=4997813}}</ref> [[Chemistry:Transferrin|Transferrin]]s can bind aluminium.<ref>{{Cite journal | last1 = Mizutani | first1 = K. | last2 = Mikami | first2 = B. | last3 = Aibara | first3 = S. | last4 = Hirose | first4 = M. | title = Structure of aluminium-bound ovotransferrin at 2.15 Å resolution | doi = 10.1107/S090744490503266X | journal = Acta Crystallographica Section D | volume = 61 | issue = 12 | pages = 1636–42 | year = 2005 | pmid = 16301797}}</ref>

===Periodic table===

==Composition==
The composition of the human body can be classified as follows:
*[[Chemistry:Water|Water]]
*[[Biology:Protein|Protein]]s
*[[Chemistry:Fat|Fat]]s (or [[Chemistry:Lipid|lipid]]s)
*[[Chemistry:Hydroxyapatite|Hydroxyapatite]] in bones
*Carbohydrates such as [[Biology:Glycogen|glycogen]] and [[Chemistry:Glucose|glucose]]
*[[Biology:DNA|DNA]] and [[Biology:RNA|RNA]]
*Inorganic [[Physics:Ion|ion]]s such as [[Chemistry:Sodium|sodium]], [[Chemistry:Potassium|potassium]], [[Chemistry:Chloride|chloride]], [[Chemistry:Bicarbonate|bicarbonate]], [[Chemistry:Phosphate|phosphate]]
*[[Physics:Gas|Gas]]es mainly being [[Chemistry:Oxygen|oxygen]], [[Chemistry:Carbon dioxide|carbon dioxide]]
*Many [[Biology:Cofactor (biochemistry)|cofactor]]s.

The estimated contents of a typical 20-micrometre human cell is as follows:<ref name="Freitas">{{cite book |first=Robert A. |last=Freitas Jr. |title=Nanomedicine |url=http://www.foresight.org/Nanomedicine/Ch03_1.html |publisher=Landes Bioscience |year=1999 |isbn=978-1-57059-680-3 |no-pp=true |pages=Tables 3–1 & 3–2 }}</ref>
{| class="wikitable sortable" style="text-align:center;"
! Compound type !! Percent of mass !! Mol. weight (daltons) !! Compound !! Percent of molecules
|-
| [[Chemistry:Water|Water]] || 65 || 18 || {{val|1.74|e=14}} || 98.73
|-
|  Other inorganics || 1.5 || N/A || {{val|1.31|e=12}} || 0.74
|-
| [[Chemistry:Lipid|Lipid]]s || 12 || N/A || {{val|8.4|e=11}} || 0.475
|-
|  Other [[Chemistry:Organic compound|organics]] || 0.4 || N/A || {{val|7.7|e=10}} || 0.044
|-
| [[Biology:Protein|Protein]] || 20 || N/A || {{val|1.9|e=10}} || 0.011
|-
| [[Biology:RNA|RNA]] || 1.0 || N/A || {{val|5|e=7}} || {{val|3|e=-5}}
|-
| [[Biology:DNA|DNA]]|| 0.1 || {{val|1|e=11}} || 46 || {{val|3|e=-11}}
|}

==Tissues==
{| class="wikitable floatright" style="border: 1px dashed black; font-size: 86%; " 
|+  align="bottom" style="text-align:left; caption-side: bottom" | The main cellular components of the human body<ref name="hatton">{{Cite journal |last=Hatton |first=Ian A. |last2=Galbraith |first2=Eric D. |last3=Merleau |first3=Nono S. C. |last4=Miettinen |first4=Teemu P. |last5=Smith |first5=Benjamin McDonald |last6=Shander |first6=Jeffery A. |date=2023-09-26 |title=The human cell count and size distribution |url=https://pnas.org/doi/10.1073/pnas.2303077120 |journal=Proceedings of the National Academy of Sciences |language=en |volume=120 |issue=39 |doi=10.1073/pnas.2303077120 |issn=0027-8424 |pmc=10523466 |pmid=37722043}}</ref><ref>{{Cite journal |last1=Sender |first1=Ron |last2=Fuchs |first2=Shai |last3=Milo |first3=Ron |year=2016 |title=Revised estimates for the number of human and bacteria cells in the body |journal=PLOS Biology |volume=14 |issue=8 |pages=e1002533 |biorxiv=10.1101/036103 |doi=10.1371/journal.pbio.1002533 |pmc=4991899 |pmid=27541692 |doi-access=free }}</ref><ref>{{Cite journal|display-authors=3 |last=Bianconi |first=Eva |last2=Piovesan |first2=Allison |last3=Facchin |first3=Federica |last4=Beraudi |first4=Alina |last5=Casadei |first5=Raffaella |last6=Frabetti |first6=Flavia |last7=Vitale |first7=Lorenza |last8=Pelleri |first8=Maria Chiara |last9=Tassani |first9=Simone |last10=Piva |first10=Francesco |last11=Perez-Amodio |first11=Soledad |last12=Strippoli |first12=Pierluigi |last13=Canaider |first13=Silvia |date=2013-11-01 |title=An estimation of the number of cells in the human body |url=http://www.tandfonline.com/doi/full/10.3109/03014460.2013.807878 |journal=Annals of Human Biology |language=en |volume=40 |issue=6 |pages=463–471 |doi=10.3109/03014460.2013.807878 |issn=0301-4460|doi-access=free }}</ref>
| rowspan="6"|[[File:Cells of the human body by mass.svg|300px]]
! scope=col | Cell type
! scope=col | % mass
! scope=col | % cell count
|-
| Erythrocytes (red blood cells)
| style="text-align:right;"|4.2
| style="text-align:right;"|85.0
|-
| Muscle cells
| style="text-align:right;"|28.6
| style="text-align:right;"|0.001
|-
| Adipocytes (fat cells)
| style="text-align:right;"|18.6
| style="text-align:right;"|0.2
|-
| Other cells
| style="text-align:right;"|14.3
| style="text-align:right;"|14.8
|-
| Extracellular components
| style="text-align:right;"|34.3
| style="text-align:center;"|-
|}

[[Biology:Body composition|Body composition]] can also be expressed in terms of various types of material, such as:
*[[Biology:Muscle|Muscle]]
*Fat
*[[Biology:Bone|Bone]] and [[Medicine:Human tooth|teeth]]
*[[Biology:Nervous tissue|Nervous tissue]] ([[Biology:Human brain|brain]] and [[Biology:Nerve|nerve]]s)
*Hormones
*Connective tissue
*[[Biology:Body fluid|Body fluid]]s ([[Biology:Blood|blood]], [[Biology:Lymph|lymph]], [[Biology:Urine|urine]])
*Contents of digestive tract, including intestinal gas
*Air in lungs
*[[Biology:Epithelium|Epithelium]]

===Composition by cell type===
There are many species of [[Biology:Bacteria|bacteria]] and other [[Biology:Microorganism|microorganism]]s that live on or inside the healthy human body. In fact, there are roughly as many microbial as human cells in the human body by number.<ref name=hatton/><ref name="AAM2014">American Academy of Microbiology [http://academy.asm.org/index.php/faq-series/5122-humanmicrobiome FAQ: Human Microbiome] {{Webarchive|url=https://web.archive.org/web/20161231092333/http://academy.asm.org/index.php/faq-series/5122-humanmicrobiome |date=31 December 2016 }} January 2014</ref><ref name="Rosner">Judah L. Rosner for Microbe Magazine, February 2014. [http://www.asmscience.org/content/journal/microbe/10.1128/microbe.9.47.2 Ten Times More Microbial Cells than Body Cells in Humans?]</ref><ref>{{Cite journal|last1=Gilbert|first1=Jack|last2=Blaser|first2=Martin J.|last3=Caporaso|first3=J. Gregory|last4=Jansson|first4=Janet|last5=Lynch|first5=Susan V.|last6=Knight|first6=Rob|date=2018-04-10|title=Current understanding of the human microbiome|journal=Nature Medicine|volume=24|issue=4|pages=392–400|doi=10.1038/nm.4517|issn=1078-8956|pmc=7043356|pmid=29634682}}</ref><ref name="Sender">{{Cite journal |vauthors=Sender R, Fuchs S, Milo R |date=January 2016 |title=Are We Really Vastly Outnumbered? Revisiting the Ratio of Bacterial to Host Cells in Humans |journal=Cell |volume=164 |issue=3 |pages=337–40 |doi=10.1016/j.cell.2016.01.013 |pmid=26824647 |doi-access=free}}</ref>
(much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal organisms.

==See also==
*[[Medicine:List of organs of the human body|List of organs of the human body]]
*[[Medicine:Hydrostatic weighing|Hydrostatic weighing]]
*Dietary element
*[[Medicine:Reference ranges for blood tests|Composition of blood]]
*[[Biology:List of human blood components|List of human blood components]]
*[[Biology:Body composition|Body composition]]
*[[Earth:Abundance of elements in Earth's crust|Abundance of elements in Earth's crust]]
*[[Chemistry:Abundance of the chemical elements|Abundance of the chemical elements]]

== References ==
{{Reflist|30em}}

{{Navbox periodic table}}

[[Category:Biochemistry]]
[[Category:Human anatomy]]

{{Sourceattribution|Composition of the human body}}