Everything You Need to Know About Vitamins

New studies and claims about vitamins are published daily, and many seem to contradict each other. What does an average consumer really need to know about vitamins?

“The fairly simple answer is, not much,” says Paul Thomas, EdD, RD, scientific consultant with the National Institutes of Health Office of Dietary Supplements. Almost everyone can benefit from taking a supplement with calcium because most people don’t get as much as they need through their diets — 1,000 mg a day for adults, increasing to 1,200 mg after age 50. Thomas notes that some vitamins become especially important at certain times in a person’s life. Pregnant women or women who may become pregnant should be certain to get enough folate, or folic acid, a B-complex vitamin — 600 units a day, rather than 400. And as you age, you should probably take a daily supplement to get additional B12, he suggests.

“You don’t have to become an expert or learn all the intricacies of all the vitamins — because you can't,” adds Dr. Thomas. There’s simply too much information to try to remember.

What you need to do is eat a healthy diet, selecting recommended foods based on the USDA guidelines. Because few of us consistently eat a well-balanced diet, Thomas says taking an over-the-counter multivitamin, even a store brand, is a good idea. “It’s sort of like an insurance policy that covers all your bases,” he explains.

Vitamins and Healthy Living: Not as Easy as A, B, C, and D

Maintaining a balance of the vitamins we need is important yet tricky. While vitamins work together in the body to ensure our health — the most obvious being the way vitamin D aids in absorbing calcium — the interaction between vitamin supplements and prescribed medications can cause health problems. For example, calcium can interact with some pharmaceuticals, limiting the body’s ability to absorb the prescribed medication. So whenever your doctor gives you a new prescription or changes one, it’s important to discuss all of the vitamin and mineral supplements you’re taking to avoid any potential problems.

Vitamins and Healthy Living: Is Taking More Better

For people who have a healthy diet, taking a multivitamin according to package directions won’t trigger a vitamin overdose. But Thomas warns, “You run into trouble if you take vitamins and supplements where the dose is very large.”

Some people take large amounts of supplements — hundreds or thousands of times more than the recommended amount — to treat or prevent illnesses or diseases, in effect treating vitamin supplements like drugs. “That’s different from taking them to get the recommended amount,” Thomas cautions.

Using supplements as therapy should be done only with a doctor’s guidance, as side effects and complications can and do occur. As an example, Thomas points to niacin, or B3, which in very high doses can harm the liver. However, in many cases niacin is a good drug for reducing statin levels, he adds.

Even some very familiar advice isn’t yet proven medical theory, Thomas notes: “When you look at the use of large doses of vitamin C (to combat colds), the evidence to date is kind of murky.”

To evaluate any supplement as a medical treatment, consider the body of evidence supporting any health claims and seek information from a pharmacist, dietitian, or your family doctor. “The folks who sell supplements probably aren’t the best sources of information,” Thomas says.