Dietary magnesium


DarkChocolateMagnesium is the fourth most abundant mineral in the body and is essential to good health. Approximately 50% of total body magnesium is found in bone. The other half is found predominantly inside cells of body tissues and organs. Only 1% of magnesium is found in blood.

Biological roles in the body: Magnesium helps to maintain normal muscle and nerve function, keeps heart rhythm steady, supports a healthy immunity, as it is needed to make the anti-oxidant enzyme glutathione, and helps keep bones strong. Dietary magnesium also helps regulate blood sugar levels, promotes normal blood pressure, and is known to be involved in energy metabolism and protein synthesis. Magnesium is involved in the bioactivity of vitamin D and other vitamins.

Deficiency: Specific deficiency syndromes are rare in humans but lower than normal levels are commonly seen on micronutrient testing. Low levels can be an indicator of chronic poor intake of green vegetables, nuts, beans and fish unless it is caused by recent illness or medical treatments such as diuretics, antibiotics, painkillers and steroids, which can impair absorption or increase renal excretion. Serum levels (measured routinely) are not as good an indicator as red cell magnesiums which is included in the cancer risk nutritional profile. Magnesium deficiency can impact on vitamin D function. number of chemotherapy agents can deplete magnesium (mg) but particularly cisplatin, oxaliplatin and erbitux (cetuximab) – if you are receiving these drugs, it’s advisable to make an extra effort to eat more Mg containing foods. Very low levels can cause fatigue, insomnia, poor memory, muscular cramps, tremor, fasciculation’s, muscle weakness and an increased risk of nausea, low mood and peripheral nerve damage during chemotherapy. Severe deficiency can cause an abnormal heart beats (arrhythmia), prolongation of the QT interval, muscle spams, delirium and hallucinations.

The RDA is between 320 – 420 mg/day. Optimal serum levels are between 0.7-1.0 micromols/l and the more relevant red cell magnesium levels are between 2.1-3.0 mmols/

What foods provide magnesium? Real chocolate is one of the best sources of magnesium. The problem is that most chocolate products have harmfully high sugar content so not recommended. Even dark chocolate varieties have a lot of added sugar but there are some 100% chocolate brands available with no added sugar which as be bought on the internet from single plantations. These are very bitter but to make them palatable hey can be broken up and mixed with fruit making them both delicious and healthy. Fish such as halibut and other seafood are good sources. Green vegetables such as spinach, kale, seaweed and spirulina are rich in mg because the center of the chlorophyll molecule (which gives green vegetables their color) contains mg. Some legumes (beans and peas), nuts and seeds, and whole, unrefined grains are also good sources of magnesium. Refined grains are generally low in mg as when white flour is refined and processed, the mg-rich germ and bran are removed so bread made from whole grain wheat flour provides more than bread made from white refined flour. Tap water can be a source of mg, particularly if from a “Hard” water area contains more magnesium than “soft” water). In general, eating a wide variety of green vegetables, legumes, nuts, whole grains, and sea foods will easily help you meet your daily dietary mg.

In summary common sources of dietary magnesium include:

  • Dark chocolate, no sugar please (100g)- 150mg
  • Swiss card, spinach (one cup) – 150mg
  • Pumpkin seeds (1/8th cup) – 150mg
  • Almonds and cashews nuts (30g) – 80mg
  • Halibut cooked (60g) – 75mg
  • Soybeans, mature, cooked (30g) – 75mg
  • Beetroot and   rocket salad leaves (30g) – 75mg
  • Black-eyed or black beans (½ cup) – 60mg
  • Kale, dark green cabbage (1 cup) – 60mg
  • Shredded wheat (2 biscuits) – 55mg
  • Yogurt, Kefir – one cup – 50mg
  • Oatmeal, instant, fortified (1 cup)-  50mg
  • Potato, baked with skin, (1 medium) –  50mg
  • Peanuts (30g) –  50mg
  • Baked Beans, Kidney Beans ( ½ cup) – 50mg
  • Broad beans or peas (½ cup) – 50mg
  • Whole wheat cereal, branflakes (1 cup) – 45mg
  • Lentils, mature seeds, cooked (1 cup) – 40mg
  • Long grain rice (1 cup) – 35mg
  • Wheat germ, crude, (2 tablespoons) – 30mg
  • Avocado   (1 medium) – 30mg
  • Banana (1 medium) – 30mg