How much calcium can the body absorb in one meal?

Some foods are fortified with extra calcium - Total cereal, for example, contains 1000 mg of calcium in one serving. If you ate this, would you have fulfilled your calcium requirements for the day? Or, would your body be unable to absorb it all? (so there really would be no benefit in having so much of it at once)

It depends on the form of the calcium - it is bound to other elements, some of which are easier to absorb than others. It also requires Vitamin D to be aborbed and used.

Calcium and all the minerals also need a fairly acidic stomach to be absorbed. So if you're stomach acidity is low, or you have it with a big meal (which uses up the hydrochloric acid that makes your stomach acid) you may not absorb so much.

Women need about 2-3 gm (2,000 - 3,000 mg) of calcium. I don't think the value is too high in total, but the form in which it's present may or may not be readily aborbed. I would guess that Total also have vitamin D.

Your body is seldom able to absorb all of the vitamins or minerals you eat at once. A lot of it is lost, but the actual amount you need to be absorbed is less than the required daily intake. So, the RDA of 2,000 mg for a mineral is based on the expectation that you will only aborb say 20% of it, so your body's actual need would be 400 mg.

The best source for minerals in the most bioavailable form is broth - from beef, chicken, pork bones.