Particular vitamins and minerals are purchased because they are believed to protection against heart disease and cancer. Only a few special groups of people need dietary supplements in addition to a balanced diet. Even though good, balanced diets contain needed nutrients, not everyone consumes a good and balanced diet. Taking a daily vitamin would help these groups. Although there are many strategies for fitting a healthy diet into a hectic lifestyle.
Some supplements rise and fall in popularity.
The great interest in antioxidant supplements during the early 1990s waned, for example, when studies showed that vitamins C and E and beta carotene were not good substitutes for the yellow, orange, and leafy green vegetables rich in these antioxidants. The idea that if a little amount of a vitamin or mineral is good, then a megadose ought to do wonders is not valid. There is no good evidence, for example, that megadoses of vitamin C can cure cancer, as was publicized by the Nobel prize winning scientist Linus Pauling 30 years ago. In fact, large doses of some vitamins can have serious toxic effects. The American Psychiatric Association and the National Institutes of Health have both warned against megadose therapies for the treatment of psychiatric diseases.