Health Supplement Corner
Magnesium is involved in numerous physiological and biochemical reactions in the human body. Magnesium deficiency can lead to problems in the nervous system, muscles, heart, or neurological function. Adequate magnesium intake is even associated with blood pressure and blood sugar regulation, which is why magnesium-related health supplements have grown increasingly popular. What types of magnesium supplements are available, which is most effective, and what are the risks of excessive intake? Registered dietitian Yi-Ting Wu from Heho summarizes everything you need to know.
High-Magnesium Foods in the Diet
Food and water are the primary sources of magnesium intake, including nuts and seeds (cocoa, pumpkin seeds, flaxseeds), whole grains (whole-wheat bread, brown rice), leafy green vegetables, meat, seafood, and soy products. Cocoa has the highest magnesium content. Magnesium levels decrease significantly after food processing and cooking. Today’s refined dietary pattern, combined with illness, medication, and alcohol consumption, increases the risk of magnesium deficiency.
According to the Nutrition and Health Survey in Taiwan (2013–2016), adults aged 13–44 consume only about 60–80% of the recommended daily intake, with deficiency more severe in women than in men.
Forms of Magnesium Supplements
Magnesium absorption is affected by many factors. The average absorption rate is about 30–50%; absorption decreases as more magnesium ions are ingested and increases when the body is deficient. Among different magnesium supplements, organic forms such as magnesium chloride and magnesium aspartate have higher bioavailability.
Common magnesium supplement forms and their potential therapeutic uses based on research:
- Magnesium chloride & magnesium aspartate: Higher bioavailability
- Magnesium hydroxide: Lower absorption rate; commonly used in antacids or laxatives
- Magnesium citrate: Highly water-soluble; better absorption than magnesium oxide. High doses may help prevent migraines.
- Magnesium oxide: Lowest bioavailability; effervescent tablets absorb better than tablets.
- Magnesium orotate: May benefit heart failure patients
- Magnesium glycinate or magnesium taurate: Used in depression management
Magnesium Oil & Magnesium-Containing Creams: Topical Use Not Confirmed Effective
A 2017 study published in PLOS One (n=20) suggested magnesium-containing creams might increase serum magnesium levels through skin absorption. This led to market claims that magnesium oil and magnesium creams can boost magnesium via the skin and even regulate blood pressure. However, scientific evidence remains weak.
A 2017 paper in Nutrients titled Myth or Reality—Transdermal Magnesium? challenged this hypothesis:
Intracellular magnesium exists in ionic form and cannot penetrate the skin’s lipophilic layer. Magnesium absorption relies on specific transporters rather than diffusion. No magnesium transporters have been found in epithelial cells, only in small areas of sweat glands and hair follicles. Existing transdermal magnesium studies have very small sample sizes and require further validation. Topical magnesium absorption is not recommended.
Note: Magnesium oil is not oil containing magnesium but a magnesium chloride solution with an oil-like texture.
Recommended Daily Magnesium Intake & Overdose Toxicity
Based on Taiwan’s Dietary Reference Intakes (DRI):
- Adults aged 19–50+: 380 mg/day for men, 320 mg/day for women(requirements vary by age group)
Magnesium is the second most common deficient mineral in Taiwan (after calcium). Overdose from natural food sources is almost impossible. Hypermagnesemia is more likely in people with kidney dysfunction, those receiving magnesium sulfate therapy, hypothyroidism, or those taking certain medications.
Symptoms of Excessive Magnesium Intake
- Diarrhea
- Decreased blood pressure, dizziness
- Muscle weakness
- Severe back and pelvic pain
- Confusion
- Difficulty breathing
- Arrhythmia
- Others: drowsiness, mental disorientation, worsening kidney function
For mild overdose: discontinue magnesium supplements, magnesium-containing laxatives, or antacids, and monitor for kidney damage.
For severe magnesium toxicity: emergency treatment such as intravenous fluids or diuretics is required.