With a well-crafted diet you can—and should—be getting almost all of the vitamins and minerals you need from foods. But if you prefer to have a little extra insurance, a multivitamin is probably your safest bet.

About one-third of all Americans take multivitamin/mineral (MVM) supplements. But not all MVMs are created equal. Here are 10 tips for managing your multivitamin/mineral supplement use:

1. Go generic. Consumer Reports found that store brands test as well as brand name or national brands. Their biggest winner? Costco’s Kirkland Signature, whose regular MVMs cost less than 5 cents per day.

2. Avoid megadoses. If you think 1000 percent of a vitamin is 10 times better than 100 percent, you are wrong when it comes to MVMs. Look for no more than 100 percent of the FDA's Daily Value (DV) for vitamins and minerals. One exception is vitamin D, where the DV is 400IU and should probably be higher for most populations.

3. You may not need one. A number of large-scale studies have shown that taking multivitamins does not mean you are any less likely to be diagnosed with heart disease or cancer than those who don’t take vitamins. There’s virtually no data to support this almost $5 billion industry. While MVMs in moderation are unlikely to do harm in most cases, they may be a waste of your money.

4. Lifecycle categories may matter. Multivitamins for older adults may contain greater amounts of certain vitamins that are more important with age, such as vitamins B12, D and calcium. Female-specific vitamins typically contain more iron, calcium and vitamin D, which some women may need.

5. High potency, prescription strength and pharmacy grade mean nothing – avoid flashy marketing terms. These are not backed up by any regulations and may result in you spending more money on a product that isn’t any better than a generic.

6. If you're pregnant you definitely need one. Women who are or might become pregnant should get 400 mcg/day of folic acid from fortified foods or a prenatal supplement to reduce the risk of neural tube defects such as spina bifida.

7. Keep your eye out for too much iron. Adult men and postmenopausal women are advised to avoid MVMs that have 18 mg or more of iron. Unless diagnosed with iron deficiency, too much iron can collect in body tissues and organs and cause damage.

8. Store supplements out of reach of your kids. Iron supplements are the leading cause of poisoning in children. Keep adult and children’s chewable vitamins and minerals away from kids, who may mistake them for candy.

9. A word of caution for Coumadin users. If you take warfarin (Coumadin) to reduce blood clotting, be careful about consuming added vitamin K, the fat-soluble vitamin responsible for clotting blood. Talk to your doctor about all supplement use, but especially as it affects prescription drug use.

10. Don't forget about fortified foods. In the United States, enriched grain products are fortified with iron, thiamin, niacin, riboflavin and folic acid. Your juice may have additional calcium, and your eggs can have added omega-3s. Don't forget that fortified foods also add vitamins and minerals and an MVM on top of that may be unnecessary.