What is the recommended daily dose for all of these supplements?

The recommended dose for each supplement is listed on the product information page.

Is it possible to take too much Vitamin B12?

Vitamin B12 is generally considered safe, even in large doses.

What if I already take a multivitamin that contains any of these recommended products? Should I still consider a supplement?

The best source of vitamins and minerals is from a healthy diet. You can take a daily multivitamin as a bit of "insurance" in case your diet is not providing all of your nutritional needs. Multivitamins generally contain small amounts of many vitamins and minerals. If you have a deficiency, you may require a supplement in addition to your multivitamin to provide the nutrient in large enough amounts to correct the deficiency.

Is it true that the body needs magnesium and Vit D to absorb calcium. Should I be taking a supplement of these as well?

Calcium, magnesium and Vitamin D are all required for strong bones. You can take calcium alone, or you can take it in combination with other nutrients that help to build bone. In general, most North Americans have difficulty getting enough magnesium and Vitamin D from our diets.

What is the difference between Calcium citrate and Calcium carbonate and any others available?

Calcium carbonate should be taken with meals because it requires stomach acid to dissolve and absorb. Calcium carbonate has the most calcium per pill (40 percent), therefore fewer pills are needed. Some find calcium carbonate constipating.

Calcium citrate is well absorbed on an empty stomach and does not constipate. The downside is that it has less calcium per pill (20 percent). On the positive side, calcium citrate is less dependent on stomach acid for absorption. Older people often have decreased stomach acid, so the citrate form may be a better choice than calcium carbonate.

Calcium Gluconate and Calcium Lactate: These types of calcium pills contain low content of elemental calcium. Hence, one may need to take a larger number of tablets to meet the calcium requirement!