One study reviewed 63 controlled trials where multivitamins did not help prevent heart disease or cancer.
Another study looked at 160,000 post-menopausal women who supplemented multivitamins for 10 years, and it also concluded their multivitamin did not prevent heart disease and cancer.
Experts from Tufts, Yale and National Cancer Institute confirm the findings.
"One pill a day isn't going to all of a sudden ward off heart disease and cancer and even the common cold, because when you look at the nutrients that we really need, they're big," said nutritionist J.J. Virgin.
Virgin said we might not be able to eat all the vitamins and minerals we need each day, but eating foods that naturally contain these elements continues to be the best way to go, although she does feel there are a handful of supplements worth taking.
"Start with great healthy food, then let's look at those things that are naturally deficient in our diet that we really do need more of," Virgin said.
Many people lack calcium with magnesium. We do OK with calcium, but magnesium is a mineral most people don't get enough of.
There's also vitamin-D deficiency. But we can't get much from food sources, or even the sun, due to cancer risk.
Many don't like fatty fish, so getting omega-3 fatty acids from a DHA, EPA supplement is a good rule of thumb.
There are those with special needs, such as women who are pregnant, vegans and those on a very low controlled calorie diet.
Pregnant women might consider a multivitamin that contains vitamin C, folic acid, B vitamins and iron. A prenatal vitamin should have at least 600 mcg of folic acid and 27 milligrams of iron.
Vegans lack B12, as it is normally found in animal products that they do not consume. Try 25-50 mcg. They should consider also calcium and iron as well.
For those under 50 who need calcium, try 1,000 milligrams and iron at 18 milligrams for women (under 50).
Those on a very low-calorie diet might also add a multivitamin, as anything under 1,200 calories could indicate a lack of many vitamins and minerals generally coming from food.
Most experts suggest at least 800–1,000 international units of vitamin D and 1000 milligrams of omega-3 fatty acids coming from DHA and EPA.
For more information, visit www.prevention.com, or check out the November issue of Prevention magazine.