Magnesium deficiency…what foods are good sources of magnesium? Is magnesium important for training and racing, or for general health?
CHECK OUT what Dr. Marshall Porterfield from NASA says about magnesium.
Magnesium is an essential mineral that demands attention when it comes to health assessment. It is required by virtually every cell, and it’s vital in more than 300 chemical processes that sustain basic human health and function, including muscle contraction and relaxation, nerve function, cardiac activity, blood pressure regulation, hormonal interactions, immunity, bone health and synthesis of proteins, fats and nucleic acids. Magnesium is also crucial for energy metabolism by the activation of enzymes known as ATPases, which are needed to generate ATP (adenosine triphosphate).
When ATP is broken down, energy is released for all muscle contractions, and when exercising strenuously, this turnover is extremely high, meaning that ATP needs to be synthesized quickly. Thus a shortfall of magnesium can limit energy production, leading to fatigue, lethargy, reduced power, muscle twitches or cramps. Chronic deficiencies of magnesium are also implicated in reduced bone mineral density and increased risk of osteoporosis as well as anemia, depression and irregular heart rate. Virtually every body system can display symptoms because systems throughout the body rely on magnesium. Athletes in particular might find it easy to explain away fatigue or muscle cramps, lowered immunity, and even altered heart rates, and indeed these symptoms are common and multi-faceted in cause. However, a simple magnesium deficiency could also be the underlying factor.
There is emerging evidence that magnesium requirements are significantly elevated in athletes, and that performance might benefit from higher intakes. Aside from being used up in the production of energy, magnesium might also assist performance by reducing accumulation of lactic acid and reducing the perception of fatigue during strenuous exercise through its action on the nervous system. Magnesium is also lost through sweat, so athletes training hard in hot and humid environments might further increase demands.
Magnesium Depletion
The “Journal of Nutrition” reported on a study in 2002 that examined the effect of magnesium depletion on cardiac function and energy needs during exercise. Post-menopausal women were put on a diet supplemented with 200 mg of magnesium, followed by a non-supplemented diet. The restriction of dietary magnesium resulted in decreased magnesium concentrations in the body, which translated to poor cardiovascular function and poor energy during exercise, the study showed.
Effect of High Intensity Exercise on Magnesium Concentration
A 2006 review by Forrest Nielson and associates reported in the journal “Magnesium Research” stated that your body responds to exercise by redistributing its supply of magnesium. Concentration of magnesium in the blood increases by 5 to 15 percent after short bouts of high-intensity exercise. An increase is also seen after moderate exercise that is done over an extended period. This is a transient change, however, with plasma levels returning to normal within a day. Possible explanations put forward for this phenomenon include decreased plasma volume, muscle breakdown and transfer of magnesium out of the muscles during contractions.
Endurance Exercise and Magnesium
According to the Nielson study, there is evidence that cross country skiing, marathon running and other extended endurance exercises decrease plasma magnesium concentration. This may be the effect of increased loss of magnesium through sweat and urine, and the movement of magnesium into other areas of the body. The explanation seems to be that your body sends magnesium to the parts of the body with the greatest metabolic need, where increased energy production is required.
Magnesium is not produced by the body, so it needs to be ingested daily through the consumption of magnesium-rich foods such as whole grain cereals, leafy greens, nuts and seeds. Magnesium deficiency is actually quite common—dietary surveys indicate more than 70 percent of the population consumes insufficient magnesium. This is probably because our eating habits generally rely on processed, high-starch and refined foods, which are all poor sources of this vital mineral.
Eating a variety of food will help you meet and maintain magnesium requirements, and provide you with other essential vitamins and minerals.
Pumpkin seeds are one great source of magnesium and an easy addition to any diet—add them to cereal, salads, pasta and rice dishes for extra crunch or simply eat a handful as an afternoon snack. Spinach and kale are also rich in magnesium, but some magnesium is lost through the cooking process. Some common foods might also be magnesium fortified, and certain sports foods and supplements do recognize this important mineral by including it in significant amounts. All of these sources contribute to overall requirements, so check labels to gauge your intake before turning to a supplement.
The recommended daily allowance for the general population is a minimum of 300 to 350 mg for women and 400 to 450 mg for men. Research suggests that endurance athletes can safely consume 500 to 800 mg daily, and there is debate as to whether this amount should be higher still.
Aside from poor dietary intake, there are other potentially serious factors that may cause a magnesium deficiency, such as gastrointestinal absorption problems, physical stresses such as illness or even very cold weather, alcoholism and diabetes. Additionally, medications, prescription and non-prescription, and/or other supplements can interact with magnesium and its absorption or action within the body. So it’s important to first discuss with your doctor your own circumstances and any other medical issues that may be causing your low magnesium status and whether supplementation is required in addition to eating magnesium-rich foods.
Source: Triathlete, Pip Taylor Jan 14, 2015
Magnesium-Rich Foods
Brazil nuts225Sesame seeds200
| Pumpkin seeds (roasted) | 532 |
| Almonds | 300 |
| Peanuts (roasted, salted) | 183 |
| Walnuts | 158 |
| Rice | 110 |
| Whole-grain bread | 85 |
| Spinach | 80 |
| Cooked beans | 40 |
| Broccoli | 30 |
| Banana | 29 |
| Potato (baked) | 25 |
(Milligrams per 100 grams).
References
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- Office of Dietary Supplements: Magnesium
- “British Journal of Sports Medicine”: Oral Magnesium Therapy; R. Pokan; 2006
- “The Journal of Nutrition”: Dietary Magnesium Affects Metabolic Response; H. Lukaski; May 2002
- “Magnesium Research”: Relationship Between Magnesium and Exercise; F. Nielson; September 2006
- USDA nutrient database
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