CAUTION!!! Beware of taking supplements without talking to a doctor or dietitan first.
I'm in college studying to be a dietitian and have had to learn a lot about vitamins and minerals in the last few years. Therefore, I would caution against taking single vitamin supplements. Most multi-vitamins are able to provide you with an adequate, but safe, level of most of the vitamins the body needs.
Fat-soluble vitamins (like Vitamin A) are stored in the body and taking it by itself can cause it to build up in the body in toxic amounts. The RDA (recommended intake) for vitamin A is
700 μg/day. Taking as little as 10x more than the RDA of vitamin A can, over time, cause dry, itchy skin, alopecia (hair loss), bone and muscle pain (luckily it's reversible if you stop taking too much vitamin A). But too much vitamin A can also cause birth defects for pregnant women.
As for iron, taking too much of it can cause: liver damage, caidomyopathy (heart damage), endocrine dysfunction, pulmonary hypertension, and increase the risk of having an opportunistic infection. Also, zinc and iron kind of counteract one another when taking at the same time. So if you do decide to take a zinc and iron supplement they need to be taken at different times of the day (ex. take your iron supplement between meals and your zinc with meals).
Ladies, taking supplements (besides a multi-vitamin) can be very dangerous if you take more than you should. Be careful, whatever you decide to do.
I hope my post was helpful.
P.S.
For more reliable nutrition info. (from a registered dietitian) go to
www.dietitian.com (I can't help endorsing my future profession. I love it!
)