Examples:
Life Extension Foundation: http://www.lef.org/Vitamins-Supplements/Item01335/Life-Exten...
NSI: http://www.vitacost.com/NSI-Synergy-Supreme-Multi-Vitamin-Ve...
Short version: I post a link to a NYT piece on the lack of medical evidence, someone eventually posts a link to a study which might show benefit. In the meantime, I think we don't know either way yet.
Here are some factors:
- Several studies have used no vitamins at all! (only surveys about "Do you take a vitamin?") They don't take account the frequency/consistency, quality, etc.
- Vitamin studies often focus on single vitamins in isolation. Nutrition doesn't work like that. You need the full range.
- Most studies involve really low end or even average vitamins, and I'm specifically suggesting very high end vitamins.
- There are plenty of studies that show the real benefits of high quality supplementation. LEF has cataloged and published many of these. So have countless others.
Nearly all vitamins sold in pharmacies, Walmart, etc. are poor quality. A Center for Nutritional Education study found that many low end child's vitamins are no healthier than candy.
You can always tell by reading the label. If B12 is packaged as "cyanocobalamin" it's an inferior vitamin. Look for B12 as hydrocobalamin instead (but you'll probably have to go to a health food store to find it.)
One time I saw a display of vitamins advertising heart-healthy Omega oils, however the vitamins also included hydrogenated oils (which promote heart disease.)
So, I don't doubt that average vitamins fewer benefits.
There's also the issue that too many people expect vitamins alone will solve their health problems, and disregard other important factors like having healthier meals, exercise, sufficient water and sunlight. Health involves the full package.
That page has 182 separate citations. Click the "References" link to see all of them.
That site looks like its primary purpose is to sell products, not dispense genuine medical advice. As such, I view it with extreme skepticism. In more blunt terms, that product looks like modern snake-oil.
Also, "These statements have not been evaluated by the FDA. These products are not intended to diagnose, treat, cure or prevent any disease."
Making it illegal for farmers to label their beef as mad-cow tested is one example of this. The way trans fats are labeled in the US compared to Canada/EU is another example. In fact, in most of EU trans fats are not acceptable food ingredients. In the US, they're acceptable ingredients for vitamins. A third example might be the silence regarding the importance of sunlight and vitamin D as a prevention for many forms of cancer.
Regarding "these statements have been evaluated by the FDA" -- it's actually illegal for supplement companies to make anything that resembles a health claim about their own products, even if it's demonstratively true.
In general, the big problem with health information in the US (as you've demonstrated) is that it's inaccessible. There's plenty of industry and financial interest in it remaining inaccessible. So, you'll have to do more than glance at a website for 30 seconds and drawing the fast and easy conclusions.
Finally, the Life Extension Foundation is a non-profit with a 30 year history, and one of the most respected health and wellness research organizations world wide. Googling around will demonstrate this.
Absolutely false. It is completely legal to make the claim as long as you demonstrate that it's true to the FDA and they accept your data. If the benefit were actually present, they could file safety & efficacy data with the FDA and on approval legally make the claim. The fact that they don't tells me that there isn't any benefit worth noting.