3 Things to Know Before You Buy Vitamins

A vitamin supplement can be a great way to fill in nutrition gaps. But before you spend your money, there are three questions to answer.

How much should you spend? What's the best form to take? And when should you take it? The answers are not much, small doses, and whenever, according to Elizabeth Somer, RD, author of Eat Your Way to Happiness.

Vitamins on the cheap: Somer says you can get just as much bang for your vitamin buck with cheaper pills. A good strategy for reducing cost: Avoid vitamin ingredients that tend to add cost without any real additional benefits -- like lipoic acid, enzymes, and primrose oil. And don't forget that you can lower your unit price per pill by buying in bulk. (Learn which cheap foods can make you healthier.)

Time-released and chelated: Time-released supplements actually dissolve so slowly that they're usually not totally absorbed, according to Somer. A better strategy? Split up your multivitamin into smaller doses throughout the day. There's also no proof that chelated or colloidal minerals are absorbed any better than regular mineral supplements. (Find out what the YOU Docs recommend for supplements.)

When to pop your pill: Morning, afternoon, or evening -- it doesn't really matter, Somer says. But to absorb as much of your vitamins or supplements as possible, take them with food, and spread them out throughout the day. Also keep in mind that calcium supplements and multivitamins with iron compete for absorption and should be taken separately. (Here's more advice on how and when to take calcium.)

Don't overdo it! Find out why too much vitamin A can be dangerous.