Vesanto Melina

Minerals are a vital part of these dynamic systems, and food is the

body’s source of minerals.

Of particular interest to vegans are calcium, iron,

zinc, and iodine. Following is a review of the functions of various minerals,

Calcium, copper, iron, magnesium, and zinc compete for absorption sites;

taking a single-mineral supplement may lessen the absorption of other

minerals. Thus, for example, calcium supplements should be taken between

meals by people who want to maximize their absorption of iron, magnesium,

and zinc from food.

• When a smaller quantity of calcium, iron, or zinc is consumed, the body

absorbs a higher percentage of the dose, compared to its absorption from a

large quantity. Thus, two 250 mg calcium supplements taken at different

times during the day deliver more calcium than a single 500 mg dose.

• Foods or beverages that accompany mineral intakes can affect absorption

negatively or positively. For example, the amount of iron absorbed can vary

sixfold or more, depending on whether factors that inhibit absorption (such

as cow’s milk, black tea, and wheat bran) or factors that enhance absorption

(such as vitamin C–rich foods) are part of a meal.