Balanced diets can give us enough magnesium, but as we age we become more susceptible to conditions of the body that create deficiencies and/or are a result of deficiencies.
Magnesium deficiency leads to pathological changes int he immune system that are related to the initiating of an inflammatory response. There is evidence linking low magnesium to aging and age-related diseases due to the lack of sufficient magnesium in Western diets. Diseases of the bowel like Crohn’s and celiac are triggered by low magnesium. Also long-term use of diuretics and other medications can leech magnesium from the body.
The DV for magnesium is 400 mg although specific conditions would warrant increased dosage. Conditions helped by adequate levels of magnesium include, constipation, diabetes, hearing loss, kidney stones, migraines, mitral valve prolapse, osteoporosis, PMS, Hypertension, leg cramps, restless legs, cholesterol levels, and C-reactive protein levels (inflammation). As for supplementation, magnesium citrate seems to have the best absorption, but magnesium oxide is a close second and action gets more of the magnesium into the body per percent absorbed than the citrate. It is also important to note that is is prudent to take calcium with magnesium to facilitate proper utilization. At least 1:1 or 2:1 (mag/cal) ratio.
For a good Cal/Mag supplement see http://bit.ly/13pPgMQ