[dwnielsen]

Hi, I have very little knowledge about biochemistry, but I am interested in which elements may be considered pretty much essential for life - especially animal life - especially high animal life - especially human life.

I have found a couple sources which give a pretty good idea.

They clearly agree on major elements
H C N O Na Mg P S Cl K Ca

They also clearly agree on transition metals
V Mn Fe Co Ni Cu Zn Mo

The elements that are left to interpretation are
Li B F Al Si Cr As Se Br Rb Sr Zr Cd Sn Sb I Ba W Pb

Of these, it seems the elements that might realistically be very important are
B F Si Cr Se I W
(ie, some halogens and metallics)

Can I get some advice on what elements are really important for living?

Boron, silicon, and arsenic do not seem important to human living. Neither do fluorine or tungsten. Chromium appears very important for insulin function. Selenium looks very important for health and immunity, though it is trace. Iodine looks to be essential for thyroid function.

That boils it down to
H C N O Na Mg P S Cl K Ca
V Mn Fe Co Ni Cu Zn Mo
Cr Se I

Does my list seem representative?

[Borek]

F for teeth.

[dwnielsen]

Good suggestion; that's a tricky one. F is an everyday element for us, and saves many mouths and lives. It's important for fighting bacteria, strengthening teeth when bonding with Ca. But is it essential? Before fluoridation, people who ate non-sugary foods and drank water before bed fared okay, didn't they?

[dwnielsen]

Another source lists the following "essential elements", citing Schwarz' work in the 70s:

Bulk
H C N O P S

Macrominerals and ions
Na K Mg Ca Cl PO(3-,4) SO(2-,4)

Trace
Fe Zn Cu

Ultratrace
Nonmetal
F I Se Si As B
Metal
Mn Mo Co Cr V Ni Cd Sn Pb Li

[dwnielsen]

Saved by Wikipedia!

[dwnielsen]

Okay, I'm back once again on this topic of essential trace elements.

What I have is..

Questionable trace elements
F V Sn W Br

Trace elements with no determined function
Rb Sr Pb Cd Ba Sb Zr

F is the most difficult for me right now; it is not generally considered an essential trace element, but there is a whole lot of it in the body, as far as trace elements go. Also, the Food and Nutrition Board has established Adequate Intake Levels and Tolerable Upper Levels. Fluoride is obviously considered important.

Could someone advise me on the Questionable Trace Elements? Are any essential?