Ask most athletes to name some key minerals for human performance nutrition and you’ll probably find calcium, iron, zinc and even chromium popping up in their lists. They’re unlikely to mention magnesium. Despite this mineral’s pivotal role in energy production, many coaches and athletes remain unaware of its critical importance in maintaining health and performance. Indeed, dietary intakes of magnesium in the West have declined to less than half of those recorded 100 years ago and they are still falling. Many scientists believe that the amount of magnesium required for optimum health has been underestimated in the past. Recent research suggests that even small shortfalls in magnesium intake can seriously impair athletic performance. Clearly, magnesium nutrition is an area that no serious athlete can afford to overlook!
Roughly one quarter of this magnesium is found in muscle tissue and three-fifths in bone; but less than 1% of it is found in blood serum, although that is used as the commonest indicator of magnesium status. Magnesium is well supplied in unrefined whole grain cereals, such as wholemeal bread, and also in green leafy vegetables, nuts and seeds, peas, beans and lentils. Fruit, meat and fish supply poor levels, as do refined foods. Contrary to common belief, milk and dairy products are not particularly rich sources of magnesium.
Magnesium plays a number of roles in the body, being required for more than 325 enzymatic reactions, including those involved in the synthesis of fat, protein and nucleic acids, neurological activity, muscular contraction and relaxation, cardiac activity and bone metabolism. Even more important is magnesium’s pivotal role in both anaerobic and aerobic energy production, particularly in the metabolism of adenosine triphosphate (ATP), the ‘energy currency’ of the body. In normal adults, a magnesium deficiency results in altered cardiovascular function, including electrocardiographic abnormality, impaired carbohydrate metabolism, with insulin resistance and decreased insulin secretion, and high blood pressure!
