Mineral Bioavailability
The degree to which the amount of an ingested nutrient is absorbed and available to the body is called bioavailability. Mineral bioavailability depends on several factors. Higher absorption occurs among individuals who are deficient in a mineral, while some elements in the diet (e.g., oxalic acid or oxalate in spinach) can decrease mineral availability by chemically binding to the mineral. In addition, excess intake of one mineral can influence the absorption and
metabolism of other minerals. For example, the presence of a large amount of
zinc in the diet decreases the absorption of
iron and copper. On the other hand, the presence of
vitamins in a meal enhances the absorption of minerals in the meal. For example, vitamin C improves iron absorption, and
vitamin D aids in the absorption of calcium, phosphorous, and magnesium.
In general, minerals from animal sources are absorbed better than those from plant sources as minerals are present in forms that are readily absorbed and binders that inhibit absorption, such as
phytates , are absent.
Vegans (those who restrict their diets to plant foods) need to be aware of the factors affecting mineral bioavailability. Careful meal planning is necessary to include foods rich in minerals and absorption-enhancing factors.
Read more:
http://www.faqs.org/nutrition/Met-Obe/Minerals.html#ixzz2PLcAHTe2