This is the form of calcium most often recommended by doctors, chiefly because it is the most easily absorbed. This claim to fame may not apply to you since it is older  women who tend to have more problems with digestion as their stomach acid production goes down, not women in their 20s and 30s.

But if you have any problems with digestion — or just want a calcium that isn’t hard on your stomach, calcium citrate probably makes sense. There is one drawback to this type of calcium: it contains only about 21% elemental calcium, so to get enough calcium, you usually have to take more tablets… which winds up costing more.

In addition, in spite of its stomach-friendly reputation, it may cause stomach upset or diarrhea. If you choose this type of calcium, you should take it between meals or just before bedtime.

This is the other most widely-used form of calcium. It is not as easily absorbed as calcium citrate, but is the most concentrated form of calcium with 40 percent  elemental calcium (which usually makes it the best value option!)

In other words, if you take a 1250 mg of calcium carbonate tablet, you’re getting 500 mg of elemental calcium. This is also the form of calcium that has been studied the most — and there’s another side benefit: It also can act as an antacid.

On the negative side, though, it can cause constipation and bloating. If you take this, it’s a good idea to drink more water than usual — and take it in two or more doses, rather than all at one time. You may also want to chew it to make it more easily absorbed into your system. Unlike calcium citrate, you should take this with  (not between) meals.

This contains roughly 39% elemental calcium — and is another easily digested form of calcium. It’s also the type of calcium used to fortify many foods such as orange juice and soy milk. The only problem? It’s among the most expensive forms of calcium.

Like calcium citrate, Calcium Lactate and Calcium Gluconate are less concentrated forms of calcium (containing about 15 percent elemental calcium), and are similar to calcium citrate in terms of absorbability and lack of side effects.

But they usually cost more than calcium citrate — as much as three to ten times more — so you’re typically better off avoiding these and opting for another form of calcium.

Finally, there are calcium-based antacids — products like Tums and Rolaids Calcium Rich, which are probably one of the cheapest ways of getting calcium. These contain calcium carbonate, so usually offer you about 40% elemental calcium.

For example, if you chew a regular Tums tablet (which contains 500 mg of calcium), you’ll get about 200 mg of elemental calcium. Many women like them because you can chew them instead of swallowing. If you opt for this form of calcium, you should take them between meals. Also be sure to read the label carefully. You don’t want to get an antacid that includes aluminum because that can leach calcium from your system.

Vitamin D is essential for helping your body absorb calcium. While you can get Vitamin D from the sun, it’s not always considered the best way since you can’t be sure you’re getting enough (and it’s tough to get if you live in a very cloudy area or use sunscreen.)

In fact, according to one study, Vitamin D deficiency is much more common than previously thought. Most interestingly, thirty-seven percent of the women in the study who had low Vitamin D levels mistakenly thought  that they were consuming at least the minimum requirement of Vitamin D.

Since Vitamin D is so vital in the fight against osteoporosis, it’s probably best to take supplementation, then, to be sure you’re getting what you need. Nowadays, most doctors agree that you need at least 1000 to 2000 IU of vitamin D3.

You can also get Vitamin D in your diet from fatty fish (salmon, sardines, herring); fortified milk and other dairy products; egg yolks; and fortified cereals and breads.

Magnesium — which is very commonly found in calcium supplements — is also crucial for optimum skeletal health. In addition, it appears to hep fight fatigue and boost energy levels, as well as helping protect against heart disease.

Generally, you should take a dosage equal to half of the calcium dosage you’re taking. The usual dosage is about 200 to 750 I Us depending on how much calcium you take.

Some good natural sources of magnesium include: whole grains; dark-green leafy vegetables; milk and dairy products; nuts; meat and fish; and dried cooked beans, especially soy beans.

Boron is another mineral that helps prevent bone loss and it is often included in calcium supplements.

It’s generally recommended you get about 3 to 6 mg of boron daily. Good natural sources of boron include fruits (including apples and pears); green and dark-yellow vegetables (including broccoli and carrots); and nuts (including almonds and hazelnuts).

Vitamin K is another key player where bone health is concerned. Most women, however, get enough Vitamin K through their diet — since it’s found in many vegetables.

You also need trace amounts of the following minerals: copper, zinc, manganese and silicon (all of which are usually included in multi-vitamins or multi-mineral supplements).