Magnesium is thought to combat fatigue because it helps release energy in the body. It also plays a role in the production of melatonin, which helps to regulate sleep; this production is disturbed when levels of magnesium are insufficient. As well as being helpful in treating fatigue and insomnia, magnesium plays a role in preventing and treating a host of other common ailments from the premenstrual syndrome (PMS) to heart problems.
Calcium is the principal mineral in bone, and if you don’t get enough calcium you either can’t make enough bone during growth or you tear down your bone as an adult in order to make up for what your diet doesn’t provide. Now vitamin D comes into the story, because vitamin D is necessary to help the body regulate calcium absorption so that you use your food calcium with maximum efficiency.