Few people are aware of the enormous role magnesium plays in our bodies. Emerging evidence confirms that nearly two-thirds of the population in the western world is not achieving the recommended daily allowance for magnesium, a deficiency problem contributing to various health conditions .
Deficiencies also impact kids and even kids with obesity who may consume an excess of energy but still not be meeting all of their micronutrient needs’ .
Magnesium is the fourth most common mineral in the human body after calcium, sodium, and potassium and is the second most common intracellular cation after potassium.
Magnesium is an essential element required as a cofactor for over 300 enzymatic reactions and is thus necessary for the biochemical functioning of numerous metabolic pathways, including energy production, protein synthesis, muscle contractions, nerve function, blood glucose control, synthesis of our DNA .
Magnesium is required for conversion of vitamin D into its active form which, in turn, supports calcium absorption and metabolism, as well as normal parathyroid hormone function.
Recommended Daily Allowance (RDA) of magnesium is 400-420 mg/day for adult males, 310-320 mg/day for non-pregnant adult females, and 350 mg/day for pregnant females .
Many nutritional experts though feel the ideal intake for magnesium should be based on the body weight (e.g., 4–6 mg per kg/day).
Signs and Symptoms of low levels of Mg:
Low levels of magnesium have been associated with a number of chronic and inflammatory diseases, such as Alzheimer’s disease, asthma, attention deficit hyperactivity disorder (ADHD), insulin resistance, type-2 diabetes mellitus, hypertension, cardiovascular disease (e.g., stroke), migraine headaches, and osteoporosis 
Clinical signs of Mg deficiency are usually totally absent (chronic latent, intracellular deficit).
When present they can include anxiety, fatigue, body weakness, tremor; muscle twitch, difficulty in swallowing, poor memory, constipation, abnormal heartbeat, depression, agitation, psychosis, rapid involuntary movements of the eye, and seizures.
How to measure Mg level:
The most commonly used test to measure magnesium level is the total serum magnesium concentration (SMC). However with less than 1% of total body Mg found in the serum (53% in bone, 27% in muscle, 19% in soft tissues) and as the body tries to maintain a constant level of Mg in the serum, an individual can have a SMC within normal range and still be profoundly deficient.
Causes of deficiency:
Chronic diseases, medications, decreases in food crop magnesium contents, and the availability of refined and processed foods causes the vast majority of people in modern societies are at risk for magnesium deficiency.
Since 1940 there has been a tremendous decline in the content of magnesium in our foods. In the UK for example, there has been loss of magnesium in beef (−4 to −8%), bacon (−18%), chicken (−4%), cheddar cheese (−38%), parmesan cheese (−70%), whole milk (−21%) and vegetables (−24%) [6-7].
Refined foods are depleted of magnesium during their processing: white flour (−82%), polished rice (−83%), starch (−97%) and white sugar (−99%).
Since 1968 the magnesium content in wheat has dropped almost 20%, which may be due to acidic soil, yield dilution and unbalanced crop fertilisation (high levels of nitrogen, phosphorus and potassium, the latter of which antagonises the absorption of magnesium in plants). [7-8] Also the expansion of monoculture agricultural techniques consuming specific nutrients and usage of pesticides have the propensity to chelate minerals also contribute to the decrease of content of Mg in soil and some crops.
Cooking and boiling of produce result in a significant decline of the food's Mg content
Reduced gastrointestinal absorption of Mg occurs in the face of vitamin D deficiency, a common problem in western cultures.
Medications in common usage (e.g., some antibiotics, antacids, and hypertensive drugs) diminish absorption of Mg.
There is excess excretion of Mg with alcohol use and the presence of type 1 or type 2 diabetes.
Smoking cigarettes reduces plasma Mg concentration
Magnesium absorption is reduced with aging by as much as 30%
Excessive sweating, vomiting or chronic diarrhea
Increased requirements (pregnancy, stress)
Food rich in Magnesium :