The popular brands won't help you live longer, and they don't protect against heart disease, say researchers from Johns Hopkins Medicine, who took a second look at 277 clinical trials of popular vitamins, minerals and nutritional supplements.
They certainly won't do you any harm, but with 52 per cent of Americans taking at least one vitamin a day and spending a total of $31bn a year in the process, it might be hoped they'd do some good as well.
Only omega-3 supplements had any health benefits, the researchers found, reducing the risk of a heart attack by 8 percent, and coronary heart disease by 7 percent.
The only problem is that the studies the researchers analysed came up with partial results, or had drug company funding, or there was a failure to understand nutrition. Plenty of independent studies have discovered the benefits of taking vitamins.
Nonetheless, the principle still holds: when you buy supplements, spend a little more and get nutraceutical-grade.