21 mg iron pill???
Due to my problem of eating nuts due to my oversensitivity I lack in iron, I got suppliments today, tough it says that one pill contains 21 mg of iron, when i read that the daily dose of iron for women is 14 mg ( or was it 15? ) but then I guess that should be taken with a pinch of salt since some women are bigger and some are smaller, which means some need less and some need more, I would guess.
Tough the body only takes 10% of the nutritients you eat, so I am confused here.
If I take one pill, will my body take about 2 mg of iron from it? and the rest I have to eat? However with that logic, if the body need 14-15 mg of iron that would mean I have to eat 140-150 mg iron a day, which I question if even a meat eater can achieve 
But that sounds slightly insane, but 21 mg would be an overdose? These pills are made for vegetarians and vegans, but whatever you're veg or meateater, you still only need 14 mg of iron? So why 21 mg of iron in one pill? Is it to "fill up the storage" of iron in your body if you don't get enough from other sources of food?
I actually i think that a dietitian could better to answer.
I have some knowledge but i can't be 100% sure they re accurate and i would not lead you in error.
@Ladypearl
I agree with Tortue in that consulting with a dietician about your specific nutrient needs would be a great move and I also agree with you when you came to the conclusion that eating 140-150 mg of iron a day would ridiculous even for a meat eater as well as being slightly insane to boot. :p
That being said, I'm not sure where you got the 10% nutrient intake idea from since supplements, while in a concentrated form, have an identitcal effect to nutrients received from natural food sources. This means that since your supplement is 21mg worth of pure iron you would be receiving an estimated 140% daily value (116% DV once you reach the age of 19 and over according to the NIH) from the supplement alone.
Additionally, as a rule of thumb, our bodies do a thorough job of expelling any excess nutrients that we don't need, so barring extreme cases of overdose, you should be fine even though you'd already be exceeding the daily value with one singular pill of iron.
In any case, I wish you best of luck in remedying the lack of iron in your diet. Cheers!
@Ladypearl
I'd be very careful in making sure you seek advise from dietician with a diploma as such or books published by someone with that level of experience. Iron is one of those vitamins that don't flush through extra like vitamin C so too much of it can be very dangerous. Never eat polar bear meat because it's iron content will be far too high. Filling up storage in the body is less of a problem once you've made sure your intake is at the right level (meaning what's put into your mouth probably which is how I measure most vitamins but I'm not a dietician).