QUOTE(Neilmanello @ Dec 13 2007, 06:58 PM)

Does it matter what your source of caffeine is? I very rarely drink coffee or tea. I may have coffee once a week and tea once a month. But I do drink energy drinks. They are sugar free with no carbohydrates and their main source of energy is B vitamins and aptogenic herbs. I also take a rhodiola supplement about twice a week for an energy burst, and that contains 75 mg of caffeine. I don't drink milk anymore, but I get my calcium from multi-vitamins, a vitamin C supplement, protein shakes, protein bars and a decent amount in food. Is my calcium consumption sufficient compared to the amount of caffeine I consume on a weekly basis?
Hmmm, that's an interesting question Neil. Off the top of my head I would say the source is irrelevant in terms of how your body absorbs caffeine and the metabolic effects that result. Caffeine is caffeine no matter the source and it is absorbed very easily.
As to your Ca consumption, it shouldn't be a problem with moderate intakes of caffeine. Studies typically find intakes of caffeine to be a potential issue in persons who drink >4 cups per day. (~400mg of caffeine) How much do you drink on average? Further, the recommended requirement of Ca is 1000mg/d (I am assuming you are btw the ages of 19-50?). Do you think your shake, bars etc reach this? If you don't drink milk you should ensure your Ca supplement(s) include vitamin D. Ca is relatively poorly absorbed by the body and so to get the most of your intake you need vitamin D to help absorb it.
In summary, if you are consuming less than 400mg of caffeine a day and your Ca/Vit D intake is acceptable then you "should" be ok... but I must say it not the ideal nutritional situation. Just curious, why do you not drink milk? Allergy?