Many people – biochemists, dietitians, and physicians as well as laymen – tend to think of vitamins and minerals as nutritional “carts and horses”, which is reasonable. They are both dietary essentials required in relatively small quantities when compared with such caloric nutrients as protein, carbohydrate, and fat; they pay important roles as co-enzymes in every living cell; and they lead to specific illness when in short supply. Yet there are important differences between these chemicals cousins.
Unlike vitamins, minerals easily survive extremes of chemical and physical processing, are obtained from drinking water as well as foods, and can easily accumulate in the body to cause severe poisoning. For this reason you are probably wise to adhere closely to estimated daily requirements and U.S. RDAs for minerals – unless otherwise directed by a qualified medical practitioner.
Despite their metabolic differences and because of metabolic similarities, there is good biochemical reason for taking many vitamins and minerals together in supplement form. For example, vitamins often work more efficiently in the presence of specific minerals, e.g. B6 with magnesium, pantothenic acid with calcium, E with selenium and manganese.
However, not all vitamin-mineral linkages are advantageous, e.g. vitamin E should not be taken at the same time of day as iron. Some minerals deplete your supplies of certain vitamins; e.g. the metabolism of iron requires vitamin C. For this reason iron supplements for women often contain additional C to protect their body’s supply of the vitamin.
Despite these exceptions it is a good general rule to take your vitamins and minerals together – preferably at meal times.