How effective are multivitamins?

Poorly effective. In general unless there is an obvious deficit of a particular vitamin it is difficult to associate symptoms to a deficit. Exceptions are vitamin B12 and vitamin d deficits which are common. If a person has access to a diet that is varied is unlikely to have a deficit unless pt has malabsorption .
Questionable. Multivitamines are compounds that contens multiple vitamines the value of multivitamines are questionable because most of the food and nutricional suplements are packed with vitamines. Beside studies done in specific vitamines such as vitamin e, a, c demostrate no evident beneficial efects but they also can acelerated certain type of cancers. The benefit as antioxydants is also questionable.
Proven effective. There is a large body of research showing that that taking a multivitamin can help prevent heart disease, strokes, cancer, osteoporosis & degenerative neurological diseases like parkinson's & alzheimer's. Even the conservative mainstream ama advises all adults take a multivitamin! it's important to choose a good one-see http://www.Multivitaminguide.Org/ see my comment for jama's research summary:.

Related Questions

How effective is a multivitamin?

Vitamins. If you eat poorly or are malnourished it can be effective in reversing hypovitaminosis. If you are normal and eat properly there may be only a limited value since it is not always possible to eat perfectly. Read more...
Well. Multivitamins are effective in making the vitamin company, distributor and retail seller wealthy. Unless you have a known vitamin deficiency or are eating a very restrictive diet, these multivitamins effectively drain your wallet, and not much more. Better to save your money and go to the gym more often. Read more...