Just for numbers sake 1 measuring cup (237 ml) of regular coffee typically contains between 95 and 200 mg of caffeine, as a point of comparison.
Calcium
Caffeine causes calcium to be excreted in the urine and feces. For every 150 mg (1 cup) of caffeine ingested, about the amount in one cup of coffee, 5 mg of calcium is lost. This effect occurs even hours after the consumption of caffeine. One study of postmenopausal women found that those who consumed more than 300 mg (2-3 cups) of caffeine lost more bone in the spine than women who consumed less!!
Caffeine also inhibits the amount of calcium that is absorbed through the intestinal tract and depletes the amount retained by the bones. Studies have shown that women with high caffeine intake (over 2 measuring cups a day) suffer more hip fractures than those who avoid caffeine or drink in moderation.
Vitamin D
Caffeine inhibits vitamin D receptors, which limit the amount that will be absorbed. Because vitamin D is important in the absorption and use of calcium in building bones, this could also decrease bone mineral density, resulting in an increased risk for osteoporosis.
Iron
Caffeine interferes with the body’s absorption of iron, which is necessary for red blood cell production. Drinking caffeine at the same time as an iron source can reduce absorption by up to 80% (wow that's a lot), according to the Nutrition Desk Reference. Any beverage containing caffeine should be separated from iron-containing foods or supplements by at least one hour.
B Vitamins
Caffeine has a mild diuretic effect, which increases urination. Water soluble vitamins, such as the B-vitamins, can be depleted as a result of the fluid loss and dehydration. In addition, it interferes with the metabolism of some B-vitamins, such as thiamine (vitamin B1). The one exception to this rule appears to be vitamin B12. Caffeine stimulates the production of stomach acid, which actually helps the body absorb B12. B12 is great at boosting energy.
Other Vitamins and Minerals
Caffeine may reduce the absorption of manganese, zinc and copper. It also increases the excretion of the minerals magnesium, potassium, sodium and phosphate. There is also evidence that caffeine interferes with the action of vitamin A.
So the moral of my research is, if you drink caffeine beverages best to do so an hour before you eat anything, drink plenty of water as it will dehydrate you. And don't drink more than 2 measuring cups a day!