Why So Much Calcium?

I'm sure this was explained to me by my NUT at some point... but I have the world's worst memory.  Why do we take so much Calcium in a day?  In looking at my suppliment package, 500mg is 63% of the daily requirement, yet I am to take 1500-2000mg per day.

Thanks. :)

Government RDA's are generally set up as minimums to avoid deficiency disease rather than to ensure optimum health (and most date back to the 1950's) so we will often see recommendations for higher amounts of various nutrients based upon more recent research, medical practicianers' philosophy and individual needs. 1000mg of calcium is the RDA and generally accepted minimum amount to maintain bone density in sedentary adults (along with a whole host of other nutrients that are involved in the various cycles). Exercise can make more demands on our calcium supplies, and lots of us are exercising as part of our weight loss and maintenance efforts. Also, many or the PPI meds that many are taking for controlling acid reflux reduce the absorption calcium and other minerals, so more is required to get the proper amount absorbed. There is also a factor of most who are on the typical American diet are deficient from the start so there is some to be made up for there as well. It's a bit of a guessing game with all of the variables involved, but a moderate excess is better than a deficiency so that's why we normally see recommendations in the 1500-2000 mg range for us. RNY and DS patients, since they specifically malabsorb minerals to varying degrees will have higher recommendations.

As with all of our supplements, these are just starting points and future labwork will suggest adjustments up or down for many of these initial recommendations.