I don't recommend them, except in very specific cases. I don't believe they prevent chronic disease or will help to you live longer. I don't believe they're a targeted approach to your specific concerns. I do believe they can help, if slightly, make up for a nutrient gap caused either by widespread depletion from medications (such as oral contraceptives) or in cases where people, for whatever reason, refuse to eat real food or visit the produce section.
In the wake of a recent editorial in the Annals of Internal Medicine which was also a hot topic in the Toronto Star this week, I'm getting a fair number of questions about them. My approach has always been: there are about 20 things everyone can take just because they're 'healthy', but that doesn't mean they're therapeutic. Absorbing and assimilating large doses of the full nutrient spectrum in one shot isn't what we're built to do. We're built to get nutrients from food where there's enzymes and cofactors and a nifty little mix of nutrients that absorb really well. Plus, this just makes a healthy diet, which is a great foundation for health and longevity.
Multivitamins don't make up for a poor diet and a poor lifestyle. These things will make you sick eventually. We all fall off the healthy wagon at times (hellooooo December) but if we get back on in January and keep going as best we can until November, that's not too shabby. For people who are on the go, eating out, in court all day, running around a hospital all night, just forget to eat (?!), etc, there might be a case there if the diet doesn't stack up.
Wondering if your diet is good enough? Ask. Track it. Have someone who knows nutrition (wink, wink) take a peek and see if there's any gaps. Have someone evaluate how you're doing physically and mentally. Have someone take a look at your list of meds and figure out what might be dropping out and get some therapeutic advice.
If you make regular trips to the produce section and are otherwise healthy, save that money to invest in some more dark leafy greens. That's my two cents.