Combining supplements will not normally interfere with the way they work and in some cases may be beneficial, for example vitamin C helps iron absorption. However, certain supplements may interact with each other. There is competition within the gut for the absorption of different minerals and a large dose of one might decrease the absorption of another. Therefore a multivitamin and/or mineral product is best for all-round supplementation because it has been designed to deliver nutrients in the right balance.
Before combining supplements, people should consult a health care practitioner or the product manufacturer. It is also important to check that the daily amount taken of each particular nutrient does not exceed Safe Upper Levels. For more information about Safe Upper Levels see our Recommended Intake Guidelines.