Nutrition: Phosphate vs. Phosphorus

[tcgirl]

I'm having trouble with an assignment for my nutrition class. I'm supposed to list the phosphate content in a renal menu I'm working on, but all I can find is the phosphorus content. I can't even find references to phosphates in my nutrition book, but I do have a big chart on phosphorus. I've tried using google, but the articles I'm finding are way over my head - they look like in-depth chem stuff, which is nowhere near where I am right now.

I'm beginning to think that they're sort of interchangeable... Can someone please steer me in the right direction?

[JROregon, ASN, BSN, RN]

Phosphorus is the element. According to wikipedia, phosphorus is never found as a free element because it is highly reactive. So it's always going to be connected to something as a phosphate. I would treat it as the same thing for your nutrition purposes.

[tcgirl]

Thank you for your quick reply. I'm going to go with that for now, and double check it with my teacher tomorrow.

[shaas, ASN, RN]

Addendum to JPOregon - Phosphorus (P) is an uncharged, neutral element (usually found as white solid). When this element gains electrons from a nearby oxygen that donates them to phosphorus ion because they are reactive together in proximity, they form a polyatomic ion (PO43- ). * 4 is a subscript and 3- superscript.

Phosphate is an anion (a polyatomic ion at that, too, with a -3 charge) that can biochemically be used in many reactions in organisms. The most common biochemical reaction using phosphate(s) in an organism is phosphrylation wherein a phosphate group is attached to an organic molecule for synthesis of various biomolecules.

Recall ATP (adenosine triphosphate)? Recall cell signaling pathway? Without these reactions, you basically....well, die. There are myriad uses for phosphate ion. This is just the tip of the iceberg. Very, very important and fascinating stuff.

Good luck.

[Dvldlphn32]

In Chemistry we learned about Phosphate and Phosphite. Remember Phosphate is PO4 and Phosphite is PO3. There is a difference in the amount of oxygen atoms and Phosphates and Phosphites are Polyatomic Ions. Like mentioned above Phosphorus is highly reactive and not found alone. I hope this helps you out, it is from my measly pre-req Chemistry class.

The phosphite ion is PO3 Charge of -3

The phosphate ion is PO4 Charge of -3

[shaas, ASN, RN]

great point made by dvldlphn32.

additionally, phosphate ion is what is found in you, me, and every other organisms in our internal environment (remember, most stuff exists as soluble ions in our body, not as pure elements). phosphite, however, is not a readily usable material for biosynthesis. rather, it is found in pesticides, including fungicidal agents.

the slightest differences in molecules make the scariest differences. :)

my bad...you probably wanted a list of foods that are rich in phosphorus (-ate). here they are:

all-bran cereal

almonds

beef

brazil nuts

cashew nuts

cheese

chicken

dried fruit

egg

garlic

halibut fish

hard potatoes

herring

kidneys

legumes

lentils

liver

meat

milk

peanuts

poultry

roe

salmon

sesame seeds

sunflower seeds

[color=blue !important]turkey

wheat bran

wheat germ

whole wheat bread

yogurt