Talk:Calcium/Archive 1

This is an archive of past discussions about Calcium. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

Archive 2

Article changed over to Wikipedia:WikiProject Elements format by User:maveric149. Elementbox converted 12:11, 1 July 2005 by Femto (previous revision was that of 22:31, 25 June 2005).

Tensile strength

I know it's not commonly used structurally in its pure form but some kind of strength would be nice to have. a cast strength and a forged one. because of its superior weight specific electrical conductivity it might be interesting for motors if it has strength similar to aluminium or even close. 85.83.19.103 (talk) 19:54, 7 November 2009 (UTC)Dan Frederiksen

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory. Additional text was taken directly from USGS Periodic Table. Other information was obtained from the sources listed on the main page but was reformatted and converted into SI units.

Talk

Does anyone know if calcium could be a possible alternative fuel source? I understand that in water, calcium produces hydrogen??. If anyone cares to respond feel free to leave a message on my talk page if the topic isn't appropriate for here. Wjbentley 10:17, 8 November 2005 (UTC)

Not really. Calcium isn't found in a native state and the energy needed to extract calcium from a calcium compound is much more than the energy available in the hydrogen released when calcium reacts with water. The only reason coal and petroleum are practical fuel sources is that plants can efficiently produce their precursors using photosynthesis. --PeterJeremy 22:57, 23 April 2006 (UTC) "Good idea though"--122.104.167.28 (talk) 10:48, 21 February 2009 (UTC)

maybe but i would like to know how it is used in the cell

this article should be expanded with the physiological and biological roles of calcium.

Precautions

I think someone ought to do a bit oln avoiding touching it with damp hands, not nice!

The history of calcium should be added. I am not familiar enough with the Wikipedia to do it myself without possibly screwing something up :(.

Be BOLD man! Feel free to add it here if you're still too scared to add it yourself, someone will transfer it to the main article. Don't worry about screwing it up though, someone can always revert your edit if you make a mess of it! -81.99.181.231 18:54, 8 October 2005 (UTC)

Silvery White

I'm no chemist, but if I was, would those brown pellets appear to be "silvery white"? Why does this page describe brown pellets as silvery white? Is this a mistake? -asx- 01:34, 21 July 2005 (UTC)

It refers to a clean, freshly cut surface of the pure metal, which quickly tarnishes and is hard to keep like that, however. http://www.theodoregray.com/PeriodicTable/Elements/020/index.s7.html shows a picture from the Everest sample set which is very similar to that in the article. Femto 18:01, 6 August 2005 (UTC)

calcium

who ever said 11 year olds couldn't do 9th grade research!?. the symbol is CA. the atomic number is 20 the atomic mass is 40.08 the melting point is 1112c the boiling point is 1757c the cost is $11 per 100g it is a metal in the alkali family it was discovered in 1808 by Humphry Davy it is a solid when it is burned it flames in brihgt colours but i dont know the origin of the name or the # of protons nuetrons and electrons or the normal phase . where can i find them????

This sounds more like your homework! Here's a couple of hints:

'Normal phase' means state at room temperature, as in 'solid', 'liquid' or 'gas'.
Number of protons = the number of electrons = the atomic number.
The number of neutrons = atomic mass - atomic number.

Feel free to post back if you want me to check your answers for the above! -81.99.181.231 18:53, 8 October 2005 (UTC)

You have all the wrong answers! I have a project i am doing for school and i need 2 know alot of things... i havn't finished searching for everything i need but soo far i have found all my answers. I was just wondering if you could relate calciums properties of other elements in its group/family and what are some of the similarities and differences? thanks!

Hey! I'm looking for the cost of calcium, and I can't find it anywhere. I'm doing a project for school, and I need this info!!! Please tell me if you find anything! Thanks so much! signed, desperate 7th grader —Preceding unsigned comment added by 75.111.230.86 (talk) 03:08, 27 October 2008 (UTC)

upcoming edit

Just to tell everyone here, this edit IS going to be a stab at the milk industry and the United States Department of Agriculture, who designed the food pyramid.

I'm not going to mention these two things, but I am going to emphasize the large number of alternative calcium sources, as a passive agressive attack on our acceptance of thinking what the dairy industry and the government tells us.

The edit is not going to be biased, but my intent is.

ok. ^_^ Blueaster 03:50, 5 December 2005 (UTC)

hi i just wanted to thank u guys here for adding my stuff to the calcium article...still think u should add chemical properties, though. but! u guys rock!

The question is do they rock the rock? —Preceding unsigned comment added by 121.220.116.116 (talk) 09:38, 17 April 2008 (UTC)

eLiZaH WuS ErE 17/04/2008 7:40pm!!!!!!!!!! LMFAO —Preceding unsigned comment added by 121.220.116.116 (talk) 09:41, 17 April 2008 (UTC)

After being interrogated about my source of Calicium after giving up dairy, I found this useful site about the nutritional value of sardines in particular: http://www.nutritiondata.com/facts/finfish-and-shellfish-products/4114/2 —Preceding unsigned comment added by Marghanita da Cruz (talk • contribs) 03:59, 22 February 2010 (UTC)

DYING!!!

Ok, well, I've been dying to pelt my own two-cents at this website. It doesn't have enough info!!! (But it's still the best) Anyway, below the "MAN" person says if I find, it will be added (maybe)... so... it better be!!!!

1)Place discovered: This element was discovered in England, or first seperated anyway. The Romans apparently prepared it as lime. (which they called calyx) lime => calyx (whatevr language the romans spoke. was it latin?) => calx (latin => calcium.. tada!!!

2)Location of most abundance: I don't know. I'm hoping someone will find out. Intrestingly, it's the 5th most abundant sunstance in the Earth's Crust, and 4th most abundant in the lunar whatevr. I think outerspace.

3)CHEMICAL PROPERTIES: I don't feel like listing them, so go to <http://environmentalchemistry.com/yogi/periodic/Ca.html#Chemical> and that site will have all the gory details like what it's ionization potential and electromagnetic equivalent is. fascinating stuff. PLEASE ADD THESE. i'm trying to help ur site and users, so ADD THEM!!!

4) COST PER GRAMS: it's around $ .10 according to some bodybuilding site. i'm hoping you'll find a more reliable source. and wondering who really takes pure calcium for their body... ew...

Well, I'm sure had more to add, but I can't think of it. In the meantime, put this in the article!!! —The preceding unsigned comment was added by 68.101.39.118 (talk • contribs) .

i think that this needs to have more info on the ELEMENT itself! thanxs!

signed the frustrated freshmn

Calcium absorption

I think this article needs a section on absorption of calcium supplements. For example: that sodium intake decreases calcium absorption. I get some sources and hopefully add my edits but if anyone else wants to step in please do.

I agree this artlicle does not do as good as a job as I would like about supplemental calcium facts. I also have seen numbers such as men between the ages of 13-24 should take between 1200-1500mg a day of calcium. I would also like to know the difference between calcium citrate and calcium citrate malate. Also, how does vitamin D, magnesium, zinc, copper, and boron help absorption? I also want to state that people buying supplements should check to see if they conform to USP<2091> for weight and USP<2040> for disintegration. Independent potency verification is always a good thing as well. Killer Swath 07:30, 22 December 2006 (UTC)

Fat reduced dairy a bad idea

Please. Butter fat is essential for optimal mineral absorption from milk, because of it's vitamin A and D content. Don't forget the fact, that rickets is prevented not primarily by calcium supplementation, but by supplementation with cod liver oil or plain butter, which are both abundant sources of A and D.

There are tons of books documenting various people living on traditional diets high in saturated fats (like butter fat) and displaying extraordinarily robust health, with perfect teeth and bone structure. Do some research, for God's sake.

If saturated fats, cholesterol and such (contrary to popular(ized) belief) vital substances, do somehow clog arteries, then a high percentage of mammals are at serious health risk when growing up exclusively on their mother's milk, that's obviously not fat reduced. We have some conflicting ideas here, because milk is considered, on the other hand, as the perfect food for babies, without which normal physical development and health of the baby is at risk.

Correlation of increased cholesterol (mainly found in saturated fat, such as butter) with increased incidence of vascular diseases can not possibly be interpreted as a cause-consequence relationship. There are numerous other nutritional, life-style and environmental factors, beside saturated fat intake, that influence cholesterol levels. And there are numerous studies that fail to show a clear connection between dietary cholesterol and blood cholesterol. And there are studies, connecting higher cholesterol to prolonged life span, and low cholesterol to shortened life span. And there is the pharmaceutical industry making billions, because they have studies showing how the pills they're selling lower cholesterol. Unfortunately, there are also studies showing that those medications indeed lower cholesterol, but also increase the risk of dying. And ... there are studies, showing that saturated fats have the most pronounced triglyceride lowering effect among all the fats. What I personally care about are documented traditional diets, that were able to keep the people perfectly disease free - and almost without exception, all such diets were based on foods high in saturated fats (milk, butter, cheese, lard, eggs, meat with fat, ... coconuts).

And. Lastly, saturated fat intake in USA was nearly constant in the last 100 years, while the intake of vegetable oils and margarine, together with refined sugars and grains, has exploded. Correlating along that line, the country suffered obesity epidemic, with cancer and heart disease being number one killers. Talking about countries, England eradicated rickets by essentially ordering its people to eat high staurated-fat foods like eggs and butter and I personally know about some old lady (that lived in times where rickets was common) still putting lard in a stew "for strong bones". Lard is abundant with vitamin D, so she's basically right.

Vitamin D is not naturally present in butter and lard (or milk) in large enough quantities to prevent rickets. It is added to these products, or formed in them as a result of intentional UV irradiation. Rickets was cured in the US by adding ergocaciferol to milk and then irradiating it to produce D2. Now D2 is produced by irradiating yeast cultures, and D2 produced in this way simply is added to milk. In Europe margarine and butter are fortified in the same way. Over the years other things, from peanut butter to beer, have been similarly fortified (interestingly, some beers naturally contain vitamin D concentrations similar to that of fortified milk). Egg yolks have some vitamin D, but not much (about 20-30 IU/yolk).Struvite (talk) 20:32, 9 March 2010 (UTC)

Speaking about vitamin D, it just came to my mind, that vitamin D deficient people are more likely to be affected by cardio-vascular diseases and cancer than people whose diets or sun exposure provides ample amounts.

Bottom line is, if we are talking about milk as a calcium source, you definitely need all the butter fat there is in milk for your body to actually be able to utilize the calcium.

But if you're consuming lots of dairy products, you will probably get an adequate amount of dairy fat from low-fat choices. If you're consuming lots of dairy products and they are high-fat choices, you will probably acquire a fat arse.

Thanks for not paying attention to anything the other person said about there being no link between fat intake and bad health. Anyway, if you consume low-fat dairy, that means you get more lactose. Lactose is sugar, and too much sugar is not good for you. I think I'll take my chances with the dairyfat.

Is it necessary to consume any dairy products at all? Many Asians traditionally do not, and yet they are fine. My boyfriend has recently got the results back from a comprehensive blood test. He is a vegetarian, and has an allergy to dairy products. He takes no supplements and yet he was normal for all nutrients. For example, he had 2.36 mmol/l of calcium, with the reference range for healthy people given as 2.15–2.65. Silversmith Hewwo 05:59, 21 July 2006 (UTC)

Calcium deficiency rarely will show up in blood work, because Ca in blood is tightly regulated. If your serum Ca falls too far outside of the normal range you simply die, immediately. In the absence of sufficient dietary Ca your body will absorb bone to get the necessary Ca. so the real question is not how much Ca is in your blood, but where it's coming from. There is no simple test for that. Struvite (talk) 20:31, 9 March 2010 (UTC)

There *are* plant sources of calcium. I can only surmise your boyfriend cooks them properly so as to take maximum advantage of the calcium they contain. That said, try to wrap your brain around the fact that much of the world is not Asian, that some Asians (Indian subcontinent) consume dairy regularly, and that ALL of us have to have consumed dairy during at least one time in our lives, being that we're mammals and all.

Something should be included on the ice cream diet. --70.111.218.254 23:45, 13 December 2006 (UTC)

Sources?

I think it might be helpful to list sources for claims about dietary sources of calcium because the two sections about it seem to claim two different things with regard to dairy products. Outside of this page, I haven't ever heard anyone claim that dairy isn't a good source of calcium, I don't think, but it's a long time since I took either a biology class or a health class. On a more general note, the section "dietary sources of calcium" could probably be combined with "nutrition".AwesomeTruffle 20:33, 25 September 2006 (UTC)

If you read a few comments above, there is a user that seemed to have added some NPOV information into that area. However, I cannot verify that as of this point. 154.20.61.157 07:21, 2 December 2006 (UTC)

A) Nobody ever said that one has to drink milk or consume dairy products to get sufficient dietary calcium - they are merely a GOOD SOURCE of calcium.

B) I deleted the parts that said the milk reduces calcium because you need it to digest the protein in milk (casein). There was no citation for this. And I don't know in detail how your body goes about digesting casein and if it indeed does require the use of calcium, but I do know that MILK AND DAIRY PRODUCTS DO NOT REMOVE CALCIUM FROM THE BODY. If this were true a lot of soceties that we know today never would have existed - a lot of societies have and some still do LIVE ON DAIRY PRODUCTS. The Masai and other East African cultures wouldn't exist, modern English and other Northern European cultures wouldn't exist, a lot of the Indian cultures wouldn't exist because they all WOULD HAVE DIED FROM CALCIUM LOSS. So can we please stop claiming that dairy products REMOVE calcium from the body? -EDWIN—Preceding unsigned comment added by 67.83.21.28 (talk)

OK, somebody reversed the changes that I had made that I discuss in B) above and put in the part that makes it sound like dairy products REMOVE calcium from your body. I said it before and I'll say it again, DAIRY PRODUCTS DO NOT REMOVE CALCIUM FROM THE BODY. That's impossible, read my comments above to see why. If you think I am wrong please post why here in the discussion board, instead of just passive-aggressively changing the article back with absolutely no explanation. -EDWIN—Preceding unsigned comment added by 67.83.21.28 (talk)

   The masai... bad example ?

Well interestingly only the Masai seem to suffer from osteoporosis while their neighbours across tanzania and other african countries and who do not consume large qties of milk usually have healthy bones. Also the Masai life expectancy is only around 46 or so.... not enough to show cardiovascular disease. It would really be interesting to have post-mortem data from these populations.-- Deavman 14:57, 12 February 2007 (UTC)

I call bullshit. Have you had a look at any traditional Maasai people lately, even in photographs? I don't mean the ones who have taken up farming. I mean the ones practicing their old way of life. How many hunchbacks do you see? How many rotten teeth? How many lame people? Good luck finding any. Heh. They say the Inuit have lots of osteoporosis too... but that's only true of the ones eating industrial foods. The traditional ones are fine. —Preceding unsigned comment added by 65.60.143.194 (talk) 09:38, 19 February 2010 (UTC)

COMMENT Nonsense. That baloney comes from Cohen's rabid www.notmilk.com site, and is supported by NO evidence. Nor is it true. Also, heart disease is studied in an age adjusted way, so Cohen's other idea that Maasai (also spelled Masai) don't live long enough to get it, is really dumb. Life expectancy of 46 merely means a lot of infants die. It's an average. It doesn't mean no old people. Sheesh! S B H arris 21:56, 25 November 2007 (UTC)

By the way the link between protein intake and calcium loss is ass-backwards and you need to find some more recent sources if you're going to make medical claims. One of your links is to a HYPOTHESIS, not a theory, and the early studies they did that showed calcium excretion in the urine didn't follow the test subjects for long enough. Turns out the calcium excretion was temporary as a means of achieving homeostasis with the increased protein intake--those guys stopped pissing calcium after a week or two. Bones are organs last I checked, and organs require protein for their structure--even bones do, and especially as they are constantly tearing down and rebuilding themselves. Vegans need to quit giving other people medical advice until they've started eating animals again and gotten back to their right minds. You're going to kill people giving them stupid advice like this. —Preceding unsigned comment added by 65.60.143.194 (talk) 09:42, 19 February 2010 (UTC)

Stellar absorption lines

It would be helpful if this article discussed the topic of Calcium absorption lines from a stellar astronomy perspective. In particular, with regard to the H and K lines that are commonly used to measure chromospheric activity.[1] Thank you! — RJH (talk) 17:16, 15 November 2006 (UTC)

Done. — RJH (talk) 15:49, 18 May 2007 (UTC)

Maximum allowances for calcium supplements: mg of what?

From the first paragraph about calcium supplements:

Calcium supplements are used... ...most experts agree that no more than 500 mg should be taken at a time... Recommended daily calcium intake varies from 1000 to 1500 mg...

Because the subject of the paragraph is supplements, it's not very clear what that quote means: experts recommend mgs of what substance? Is it elemental calcium, or a supplemental form? That is, Calcium carbonate (40% elemental calcium), Calcium citrate (21% elemental calcium), Calcium phosphate (??% elemental calcium), etc.

If the writer meant to say that 1000-1500mg of elemental calcium is recommended, it can be written like so:

"Calcium supplements are used... ...most experts agree that no more than 500 mg of elemental calcium should be taken at a time... Recommended daily elemental calcium intake varies from 1000 to 1500 mg..."

--AC 05:34, 13 July 2007 (UTC)

Melting point

Calcium's melting point is 1112 K not 1115 K —Preceding unsigned comment added by 68.238.90.56 (talk) 21:48, 23 October 2007 (UTC)

I already have one source that agrees. If I can find several others, I will change it later this evening. Karl Hahn (T) (C) 21:51, 23 October 2007 (UTC)

Merck, 9th ed. gives mp as 850°C (1123K), CRC 44th ed. gives mp as 842°C (1115K). A software package I have on my computer gives it as 1112K. So there is enough diversity among authoritative sources to leave the mp in the article as it is. Apparently measuring this mp to 4 digit accuracy is not a trivial exercise. Karl Hahn (T) (C) 01:53, 24 October 2007 (UTC)

See Melting points of the elements (data page) for a table with three references for each element. In this case, all three sources agreed on the value currently used: CRC, Lange, and Webelements (although the latter might be taken from one of the other two...). --Itub 11:33, 25 October 2007 (UTC)

Electronic structure notable?

We have a lot more interesting notable facts about calcium than a whole paragraph giving its electronic structure in lengthy English description. How about we put it in as [Ar]4s² (see the table) or even with the [Ar] completely written out in compact notation, and put some interesting stuff in this space. S B H arris 21:06, 25 November 2007 (UTC)

Sure, be bold and add more interesting information! --Itub (talk) 12:00, 26 November 2007 (UTC)

Coral Calcium Merge

Resolved

It is my opinion that coral calcium is too closely related to calcium, and should be merged into this article. Coral Calcium has become a POV Fork that needs to be monitored to avoid contradictions between articles. Magnonimous (talk) 01:37, 18 December 2007 (UTC)

Oppose: Coral Calcium is notable for the marketing that was used to promote it, and the dubious claims made about it. While, of course, it should have some overlap with Calcium, what's notable about Coral Calcium is independent and unrelated to anything else in Calcium. --Ronz (talk) 02:52, 18 December 2007 (UTC)

Counter: Coral Calcium has become a POV Fork that does not belong in encyclopedic media. Given the fact that there is not enough reliable information about coral calcium to create a neutral article, it should be merged back into the calcium supplement section, and radical views removed. If you feel so strongly about the marketing of coral calcium, we should merge this back into calcium, and then make a new article called "coral calcium claims" which contain specific points of view about coral calcium, with supporting reasons for each side's opinion. Magnonimous (talk) 18:01, 18 December 2007 (UTC)

Oppose. Although Wikipedia officially discourages POV forks for the sake of isolating a POV completely, they are permitted so long as a summary of the other POV is left in the original article. In many places they are unavoidable to separate the believers from the unbelievers in whatever. Thus, trinitarian vs. nontrinitarian. There's a longish article in Wikipedia on Apollo Moon Landing hoax accusations. And another on Flat Earth Society, and yet another on Young Earth creationism. Another on Free energy suppression. One on homeopathy. These are minority opinions important enough to have articles devoted mainly to them as major topics (though most of the contra evidence actually exists in other articles). For eample, the article on the Apollo program has a mention of the hoax wiki, and that's enough.
As for the present subject, I'm not sure that coral calcium is important enough to even be worth a mention as a summary. Perhaps it could go in a dietary calcium section, in an embedded list with calcium citrate, TUMS, caltrate, and all the other supplements out there. But even those products are probably inappropriately commercial and minor for a mention in the element article, and should (at most) be an embedded list in the calcium in biology sub-article. S B H arris 03:47, 27 January 2008 (UTC

Magnesium/Manganese?

I was reading a nutrition guide that stated that one should find a high quality calcium supplement "consisting of calcium citrate (since it is better absorbed) and containing vitamin D, manganese, and boron so your body can best utilize the calcium ingested." I assumed this was a typo and it meant magnesium, as this is a common additive to calcium supplements. However, this article states that magnesium primarily had the function of reducing resultant constipation particularly from calcium carbonate. Any thoughts? Livingston 14:04, 6 September 2008 (UTC)

Indeed the magnesium salt are often added to try to make up for the constipative effect of the calcium. Indeed, calcium citrate is better absorbed than carbonates, hydroxides, etc. But the other stuff seems to be typical semi-quack nutritinal advice where somebody finds some common pathway where X works along with Y to do something, and sits down and writes a book in which they therefore suggest your supplements of X contain Y with them, to help them "work better." In general, nonsense. The body stores all vitamins and minerals quite well. Certainly over days and weeks, and generally over time-scales of even months. It's not like you have to eat ANY two given nutrients of ANY kind in the same supplement or the same sitting. All that is anxiety producing bollocks. S B H arris 01:49, 21 January 2009 (UTC)

In the human body

In the third episode of the third series of QI, it is stated that calcium is the most abundant metal in the human body. It that correct, and should that be listed here? --BiT (talk) 15:14, 14 December 2008 (UTC)

It's true, but since the stuff never has the chance to act like a "metal" (calcium in metal form is very reactive) I don't see the point of it. Your body is constructve of various elements in various amounts, and yes, this is the first one that (if it was separated out and isolated) would be metalic, but (shrug). S B H arris 01:42, 21 January 2009 (UTC)

The metallic nature of Ca (its ability to act as an electron receptor) is central to its biological role and distinguishes it from biologically important non-metals like sulfur and phosphorus. No metal at all is present in any organism in its elemental form. That does not mean that no metals are present or that they don't act like metals. Struvite (talk) 01:11, 10 March 2010 (UTC)

There is nothing in the article that I could find, about the importance of extra calcium in the diet during pregnancy. V (talk) 18:15, 28 June 2010 (UTC)

editsemiprotected

{{editsemiprotected}} I would like to add something about applications of calcium isotopes, but do not have sufficient privileges. Here is the text I'd like to add:

"As with the isotopes of other elements, a variety of processes fractionate, or alter the relative abundance of, calcium isotopes (1). The best studied of these processes is the mass dependent fractionation of calcium isotopes that accompanies the precipitation of calcium minerals, such as calcite, aragonite and apatite, from solution. Isotopically light calcium is preferentially incorporated into minerals, leaving the solution from which the mineral precipitated enriched in isotopically heavy calcium. At room temperature the magnitude of this fractionation is roughly 0.25‰ (0.025%) per atomic mass unit (AMU). Mass-dependant differences in calcium isotope composition conventionally are expressed the ratio of two isotopes (usually 44Ca/40Ca) in a sample compared to the same ratio in a standard reference material. 44Ca/40Ca varies by about 1% among common earth materials (2).

"Calcium isotope fractionation during mineral formation is the basis of several applications of calcium isotopes. Changes over time in the calcium isotope composition of marine sediments reflect changes in the flux of Ca++ into the ocean, which in turn is related to the rate of removal and long-term storage of atmospheric CO2 (3). In animals with skeletons mineralized with calcium the calcium isotopic composition of soft tissues reflects the relative rate of formation and dissolution of skeletal mineral. In humans changes in the calcium isotopic composition of urine have been shown to be related to changes in bone mineral balance. Because of this, calcium isotopes may be useful in the early detection of metabolic bone diseases like osteoporosis (4)."

Refs: 1. Russell WA, Papanastassiou DA, Tombrello TA. Ca isotope fractionation on the earth and other solar system materials. Geochim Cosmochim Acta 1978;42:1075–90.

2. Skulan J, DePaolo DJ. Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates. Proc Natl Acad Sci U S A 1999;96:13709–13.

3. Fantle M, DePaolo D. Ca isotopes in carbonate sediment and pore fluid from ODP Site 807A: The Ca2+(aq)–calcite equilibrium fractionation factor and calcite recrystallization rates in Pleistocene sediments. Geochim Cosmochim Acta 2007;71:2524–2546.

4. Sklan J, et. al. Natural calcium isotopic composition of urine as a marker of bone mineral balance. Clinical Chemistry 2007;653:1155-1158.

[Note: mass numbers of isotopes (as in 44Ca) should be superscripts.]

I like to make some other changes here and there, but will wait until I have more privileges. Struvite (talk) 03:03, 8 March 2010 (UTC)

Done Please verify that the citations I added are correct. On Wikipedia we typically don't write out the citation in the format you specified, but rather segregate it into sections, like the following:

{{cite journal|last1=Russell|first1=WA|last2=Papanastassiou|first2=DA|last3=Tombrello|first3=TA|title=Ca isotope fractionation on the earth and other solar system materials|journal=Geochim Cosmochim Acta|year=1978|volume=42|pages=1075–90}}

This is automatically converted into an appropriate citation style. The reason this is done is so that any change to the formatting can be done automatically across all pages. Please double check that I pulled it apart correctly. Thanks for your contribution, and welcome! --Shirik (Questions or Comments?) 06:40, 8 March 2010 (UTC)

The citations are correct, except that "Skulan" in citation 8 is misspelled.

Thanks, and thanks for your patience. I will try to improve my formatting in the future. Struvite (talk) 18:30, 8 March 2010 (UTC)

The name is correct in the article. The reference formatting mentioned above might seem complicated, but it can be automatically generated from a doi or pmid number of an article. Thus, as a minimum, you can merely provide such a number only as a reference. Materialscientist (talk) 23:17, 8 March 2010 (UTC)

Also, it was a mistake since there is an article on calcium isotopes. Isotopes_of_calcium should have been linked instead of the main Isotope article. — Preceding unsigned comment added by 71.196.246.113 (talk) 08:01, 26 September 2011 (UTC)

Addition alert

I'm planning to add a new section on the geochemical cycling of Ca and how it connects tectonic activity to climate.Struvite (talk) 21:22, 9 March 2010 (UTC)

Thanks! I will try to have a look.--Stone (talk) 06:29, 10 March 2010 (UTC)

Toxicity vs overdose

The section titled "overdose" should be changed to "toxicity." This is more appropriate to the discussion of an element. It should include information on acute and chronic toxicity of elemental (metallic) Ca, the Ca²⁺ ion, and common Ca compounds. The information that currently is there refers to the effect of chronic over-consumption of CaCO₃, and should link to the page on milk-alkali syndrome. Struvite (talk) 20:34, 14 March 2010 (UTC)

Edit request from Nihods, 20 May 2010

{{editsemiprotected}} I would like to add an external link to this fact sheet - an evidence-based fact sheet on calcium from the National Institutes of Health, Office of Dietary Supplements: http://ods.od.nih.gov/factsheets/calcium.asp I think this link would be very valuable to readers. The inserted text would be as follows:

Calcium Fact Sheet from the U.S. National Institutes of Health

Thank you! Nihods (talk) 18:25, 20 May 2010 (UTC)

Nihods (talk) 18:25, 20 May 2010 (UTC)

Done Thanks for providing the link. - EdoDodo ^talk 18:36, 20 May 2010 (UTC)

Edit request from Compgenius, 10 July 2010

{{editsemiprotected}} Spelling/grammar error in the "Creation" section
"It is requies one atom of Argon plus one atom of Helium."
It needs replaced with:
"It requires one atom of Argon plus one atom of helium." Compgenius (talk) 04:29, 10 July 2010 (UTC)

Fixed, thank you. Materialscientist (talk) 04:39, 10 July 2010 (UTC)

Edit request from 85.127.250.72, 15 July 2010

{{editsemiprotected}} Correct "Calcium (Latin word calcis meaning "lime") was known as early as the first century when the Ancient Romans prepared lime as calcium oxide."

Etymology of "calcium": Latin calx, calcis ("calcis" is just the genetive case, roughly translatable to "lime's"; "calc-" is the root, "-ium" the suffix added to identify most elements) Greek χάλιξ, χάλικος (chalix, chalikos) ("lime"), not to be confused with χάλυψ (kalyps) = "steel" or κάλυξ (kalyx) = "capsule, goblet" cf. English derivative "chalk" 85.127.250.72 (talk) 09:55, 15 July 2010 (UTC)

I am missing what is proposed to correct to what? Materialscientist (talk) 10:07, 15 July 2010 (UTC)

Ignition

This originally read that calcium was hard to ignite, somewhat like magnesium. This was changed to "UNLIKE magnesium". The problem is: "how hard is magnesium to ignite?" The answer is mostly in what form it's in. Shavings are easy, ribbon is semi-easy, and peices are difficult (you couldn't do it with a match). Calcium comes in pieces, and you never see it in ribbon, and very rarely in the high surface area forms. So comparison with magnesium isn't easy. Calcium turnings require a torch to light (but then go like magnesium and are difficult to put out). But magnesium peices of that size wouldn't be easy to light, either. They're thicker than ribbon, and again are not something you could do with ordinary materials, like a match. A candle would take some time. Anyway the point is that both these metals are difficult to light in chunks or chips. That's the oxide coating protecting them. S B H arris 02:21, 20 August 2010 (UTC)

Nutrition Criticism

I think it might be good for this article to include some of the criticism that has been leveled at the conventional wisdom about calcium consumption. In particular, see the comments about calcium in the Wikipedia article on "The China Study" http://en.wiki.x.io/wiki/The_China_Study Including these criticisms might result in a more balanced view of what scientists currently think about calcium and nutrition. --Westwind273 (talk) 18:54, 31 August 2010 (UTC)

The China Study is not widely regarded as credible.Struvite (talk) 00:27, 11 November 2010 (UTC)

Your comment conflicts with this section of the China Study article: http://en.wiki.x.io/wiki/The_China_Study#Reception Can you provide sources for your claim that The China Study is not credible? --Westwind273 (talk) 22:37, 25 September 2011 (UTC)

Nutritional proselytizing

I have removed the following sentence from the nutrition section: "Research has found an association between diets high in animal protein and increased urinary calcium loss from the bones.[24][25][26]" The sentence is misleading and, as it stands, tendentious. Moreover, the references cited are old, and two of the three do not actually make the claim attributed to them: ref 25 (Kerstetter and Allen, 1990) and 26 (Hegsted et al., 1981) deal with Ca loss and TOTAL protein intake, not animal vs plant protein specifically.

Some proteins (especially those rich in proline) produce acidic metabolites while other proteins do not. Animal proteins tend to fall into the former category and vegetable proteins into the latter. Common sense suggests that diets with a high ratio of acid-producing to base-producing proteins might contribute to Ca loss from bone, and there is some clinical evidence suggesting that this is true. But this is very different from the claim made in the deleted sentence. First, it is the RATIO of different proteins that is important, not the absolute amount of either. Negative effects of acid protein consumption can be offset by increasing base protein consumption. Second, the acid protein/base protein distinction does not neatly separate animal and vegetable proteins. Proteins in grains also are acid producing.

I originally intended to modify the sentence to make it true, but decided not to. The whole discussion is only tangentially related to calcium in the first place, and an accurate presentation of it would contribute little to the article. Struvite (talk) 00:27, 11 November 2010 (UTC)

No, but the whole calcium in nutrition thing needs to go into one of the two subarticles, and neither one has been particularly chosen for it, yet. Meanwhile it sits mostly here, where it's over-detailed (as you note). There should be a place where readers can go to read the sort of thing you just wrote, as also an explanation of the association between milk-drinking and osteoporosis (if you control for other variables, for example in controlled experiments, milk deposits calcium in the bones of adults, which means the calcium supplement effect more than compensates for the proline load). Milk has gotten a bad rap due to uncontrolled epidemiology (I sound like a National Dairy Council plant, now).

Similarly, recently in the news has been a cohort study suggesting that calcium supplements may increase cardiac event risk. However, again, it's not as well controlled as a randomized study, and the supplementing women (even though in the same study, so a good cohort) were a self-selected group. Most milk-drinking epidemiological studies show fairly broad and robust negative-correlation between milk consumption and coronary events, soemthing that isn't expected from the saturated fat (and actually, whole milk seems to have the same effect as non-fat). And it may not be the calcium, either. The vitatmin D? Who knows what it is. There's an interesting mystery there, waiting to be worked out. S B H arris 04:05, 11 November 2010 (UTC)

Mystery solved?

Milk contains monounsaturated fat which include Omega 6 and 9 which promote healthy hearts.Mr 63547828 (talk) 21:47, 2 March 2011 (UTC)

"Hazards and Toxicity"

What about kidney stones?..... Does too much Calcium give you Kidney Stones? — Preceding unsigned comment added by Mr 63547828 (talk • contribs) 21:28, 2 March 2011 (UTC) Mr 63547828 (talk) 21:35, 2 March 2011 (UTC)almost forgot...Thanks Sinebot. Better late than never albeit a bit superfluous.

Most kidney stones are calcium oxalate, and if you eat a lot of calcium this tends to bind oxalate in your diet so it doesn't get into your urine. Thus, calcium intake may actually help prevent this type of stone (since the extra calcium in your urine is not as imporant as the decrease in oxalate). Most of the rest of the types of stones are prevented by trying to keep urine from becoming too acidic, and any base consumption helps there. Since most calcium products are bases (calcium carbonate = TUMS) they help to keep urine acid down. Lower soda pop consumption is the major easily fixed intervention that does this also, as is a diet with less meat. In addition to calcium, there are many other effective supplements to decrease urinary acid, and either potassium citrate or magnesium citrate are appropriate. A few people have struvite stones, and they should probably not take magnesium supplements. However, in humans, struvite stones are associated with infections, so can sometimes be prevented with antibiotics. For all stones, increasing water/juice intake (but not soda intake!) dereases risk. Apparently, even though high in protein and phosphate, a cup of milk per day can be substituted for juice without increasing renal stone risk. [2], so you can't always figure this out from first principles. In general, calcium is a good thing, although it's probably more effective at preventing osteoporosis if you get a vitamin D supplement with it.[3]. Warning-- this should not be interpreted as specific medical advice. See a urologist if you have this problem. S B H arris 22:31, 2 March 2011 (UTC)

Notable Characteristics

Hey, don't any of you think that the "Notable Characteristics" section should have two subsections (not including the H and K lines), Labled physical and chemical properties? I think that it would help the article a lot and, anyway, it has those two sections in almost all the other articles. I mean, even the really radioactive and the synthetic elements' articles, like ununoctium, which has only been known because we have detected around 5 atoms of it, was able to put a section labled "Physical" and "Chemical" properties. And it's now a Featured article! That's just my opinion, though. --Geo7777 (talk) 05:37, 14 May 2011 (UTC)

Factor 4

A query for "Factor 4" now redirects here. Why is that? I recall an article on the Report to the Club of Rome entitled "Factor 4". How can that article be reached? --Lbeaumont (talk) 20:03, 17 December 2011 (UTC)