But minerals and vitamins are not all benign. Some counteract the benefits of others. Some need to be taken with food, and others should be avoided when certain things are consumed. Here are some tips to get the most out of your supplements:

* Fat soluble vitamins need to be taken with food to be well absorbed. The fat soluble vitamins are vitamins A, D, and E

* Iron tablet are often poorly absorbed. Try taking them with vitamin C, or drinks or food rich in vitamin C, such as citrus fruits

* Tea and coffee impede the absorption of mineral supplements

* Time-released vitamins may actually provide better absorption

* Chelated minerals that are associated with organic compounds like amino acids, picolinates, or citrates are usually better absorbed than those bound with inorganic compounds like sulfates and phosphates

* There is no difference in the body's ability to use natural vitamin C and synthetic vitamin C

* Natural forms of vitamin E are generally better absorbed than synthetic vitamin E. Natural vitamin E is chemically known as d-alpha-tocopherol, and synthetic vitamin E is dl-alpha-tocopherol

* Vitamin E supplements should not be taken by people on anti-coagulant medications like warfarin.

* People with kidney stones or cancer should not take calcium supplements.

* Iron, zinc, and selenium can be toxic if taken in excess.

* Too much vitamin C can upset the stomach.

* Calcium supplements should be taken with magnesium. Most good calcium supplements already combine them.

* If you're taking a lot of zinc, you might need to take copper as well.

* Iron supplements can reduce the absorption of zinc, so they should not be taken together.

* High doses of iron supplements can reduce the absorption of vitamin E.

* Women on oral contraceptives may benefit from taking coenzyme Q10 and vitamin E supplements. A small study found that the sample group had lower blood levels of coenzyme Q10 (37% lower) and vitamin E (24% lower).

References: J Wills, The Food Bible