Vitamin supplements nearly always have no health benefits, are a waste of money and could even be harmful, a group of scientists said in a damning indictment of the industry.
Evidence from studies of almost half a million people suggested that "supplementing the diet of well-nourished adults... has no clear benefit and might even be harmful", despite one in three Britons taking vitamins or mineral pills.
The conclusions were drawn by academics from the University of Warwick and the Johns Hopkins School of Medicine in Baltimore, the US, and published in the Annals of Internal Medicine.
The scientists also suggested that companies selling supplements were fuelling false health anxieties to offer unnecessary cures, The Times said.
Three research papers helped inform their opinion.
One, analysing 24 previous trials involving 450,000 people, found no beneficial effect on mortality from taking vitamins.
Another examined 6,000 elderly men and found no improvement on cognitive decline after 12 years of taking supplements, while a third saw no advantage of supplements among 1,700 men and women with heart problems over an average study of five years.
The experts said most supplements should be avoided as their use is not justified, writing: "These vitamins should not be used for chronic disease prevention. Enough is enough."
They said that an average Western diet is sufficient to provide the necessary vitamins the body needs.
Edgar Miller, of the Johns Hopkins School of Medicine, said: "There are some that advocate we have many nutritional deficiencies in our diet. The truth is though we are in general overfed, our diet is completely adequate."
He added: "These companies are marketing products to us based on perceptions of deficiencies. They make us think our diet is unhealthy, and that they can help us make up for these deficiencies and stop chronic illnesses.
"The group that needs these is very small. It's not the general population."
Dr Miller continued: "There's something for everything: preventing joint pains, stopping heart disease. If you're going to spend your money on something every month, is this really the best option?"
The NHS advised recently that other than women taking folic acid to help them conceive and the elderly and children under five benefiting from vitamin D, supplementary vitamins would be surplus to that already gained through diet, The Times said.
The Health Food Manufacturers' Association said vitamin supplements provided people with "nutritional insurance".