Magnesium is regarded by scientists as essential to life, playing a fundamental role in living cells. Magnesium is a crucially important mineral for optimal health throughout the body. A surprisingly large proportion of people do not get enough magnesium: At least 57% (some say 80%!) of the US population does not meet the US RDA for dietary magnesium intake!
Calcium tends to be taken in high quantities – which can cause more harm than good, as it’s very important to have a proper balance between these two minerals. This is the reason why they are sometimes seen paired together in “cal-mag” supplements. Magnesium is critical for heart healthand excessive amounts of calcium without the counterbalance of magnesium can lead to a heart attack and sudden death. 
Early signals of magnesium deficiency include: Appetite loss, headaches, nausea, tiredness and weakness. Ongoing or more severe magnesium deficiency can lead to more serious symptoms, such as numbness and tingling, cramps, seizures, behavioral changes, abnormal heart rhythm and coronary spasm.
One of the great challenges of testing your own body’s magnesium levels is that only around 1% of the body’s magnesium is in the blood, making the magnesium readings from a serum magnesium blood test inaccurate.
One of the best food sources of magnesium is pumpkin seeds – of which a quarter cup contains almost 50% of the RDA of magnesium! I would suggest to go for the organic ones – typically darker in color because of their higher mineral content. There are numerous other food sources of magnesium and we have listed them here.
Note that calcium and magnesium also need to be balanced with vitamin D and vitamin K2. In other words, any time you’re taking any of magnesium, calcium, vitamin D3, or vitamin K2, you need to take all four into consideration, since they all work synergistically. 
Magnesium Link For Further Study:
 Full Report On Magnesium and Health From Eat Local Grown:http://eatlocalgrown.com/article/12423-magnesium-the-missing-link-to-better-health.html