The mineral Magnesium is best known as a counterpart to Calcium for improving bone
health but that is only a small part of the Magnesium story. The National Institutes
of Health lists Magnesium as being necessary for more than 300 biochemical reactions
in the body. It is necessary for protein synthesis and maintaining normal muscle
and nerve function, keeping the hearts rhythm steady and normal, and for energy
production. Magnesium is also needed for blood glucose control (blood sugar), and
blood pressure regulation.
The Recommended Dietary Allowance (RDA) refers to the average daily level of intake
sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals.
The RDA for Magnesium is 420mg a day for men over 30 and 320mg a day for women over
30. An adult body contains approximately 25 g magnesium, with 50% to 60% present
in the bones and most of the rest in soft tissues. Less than 1% of total magnesium
is in blood serum, and these levels are kept under tight control.
Assessing magnesium status is difficult because most magnesium is inside cells or
in bone. The most commonly used and readily available method for assessing magnesium
status is measurement of serum magnesium concentration, even though serum levels
have little correlation with total body magnesium levels or concentrations in specific
tissues.
Groups at Risk of Magnesium Inadequacy
The following groups are more likely than others to be at risk of magnesium inadequacy
because they have medical conditions (or take medications) that reduce magnesium
absorption from the gut or increase losses from the body:
People with gastrointestinal diseases or who have had surgical resection or bypass
of the small intestine, especially the ileum, typically leads to malabsorption and
magnesium loss
People with type 2 diabetes and increased urinary magnesium excretion can occur
in people with insulin resistance and/or type 2 diabetes
People with alcohol dependence
Older adults generally have lower dietary intakes of magnesium than younger adults.
In addition, magnesium absorption from the gut decreases and renal magnesium excretion
increases with age. Older adults are also more likely to have chronic diseases or
take medications that alter magnesium status, which can increase their risk of magnesium
depletion.
