Recent studies have disproved the benefit of taking many vitamins.
Internist Matthew Mintz goes over the data, and finds that vitamin E has not been shown to improve dementia, and vitamin C does not prevent colds.
Some, like increased doses of vitamin A, can be even dangerous and increase the risk of death.
This is what works: i) folic acid for pregnant women, which prevents neural tube defects; ii) calcium for adult women, which can prevent osteoporosis; and, iii) vitamin D, where low levels increase the the fracture risk in women, and recently, have been associated with cognitive impairment.
Here’s Dr. Mintz’s bottom line: “If you are a women of child bearing age, you should probably take calcium and folic acid. If you are a senior, you should probably take calcium and vitamin D. If you want to take a multi-vitamin, a generic, inexpensive, once daily mutli-vitamin should be fine. I would not take extra doses of other vitamins or supplements, especially vitamins A, C, or E.”
Sounds reasonable to me.