Don't waste your money on "natural" vitamins - your body can't tell the difference between synthetic (man-made) vitamins and so-called "natural" ones, but synthetics are usually cheaper. The exception to this rule is vitamin E: your body absorbs the natural form better than the synthetic version, although vitamin manufacturers add enough synthetic vitamin E to make up for the difference (and it's still cheaper). Also remember that generic and other reasonably priced brands are just as good as more expensive ones.

Read the label to make sure the expiry date hasn't passed - like foods, supplements should not be used after their expiry dates. Look for the DIN (Drug Identification Number) or GP (General Product) number, usually on the front label.

Don't assume that more is better. In fact, vitamins A and D, iron, zinc and selenium can be toxic in high doses, while others can have unpleasant or serious side effects. Your safest bet is to look for supplements that provide no more than the recommended daily dose of each nutrient.

Keep supplements away from children. Those pills may look and taste like candy to a child - but they can be deadly. Iron supplements cause more poisoning deaths in children than any other substance.

Tell your doctor about all of the vitamins, minerals, and other supplements you're taking. Some vitamins and minerals can interfere with certain medications.