From the Guidelines
Daily magnesium intake should be initiated at the recommended daily allowance of 350 mg daily for women and 420 mg daily for men, and increased gradually as needed and tolerated. This recommendation is based on a recent study published in the Mayo Clinic Proceedings in 2023 1, which highlights the importance of gradual dose escalation to minimize potential side effects such as gastrointestinal tract intolerance, muscle weakness, and hypotension.
Key Considerations
- Magnesium supplements are available in various forms, including oral and intravenous formulations, with oral forms typically ranging from 600 to 6500 mg daily 1.
- Liquid or dissolvable magnesium products may be better tolerated than pills, especially for patients who experience gastrointestinal side effects 1.
- Intravenous magnesium administration is also an option, with a dosage of 2 g infused over 2 hours every 2 to 3 weeks, although data on its effectiveness is limited 1.
Potential Side Effects and Interactions
- High doses of magnesium can cause diarrhea, as reported in 2 patients in the TEA survey 1.
- Other potential side effects of magnesium supplementation include muscle weakness, flushing, hypotension, bradycardia, blurred vision, and cognitive effects 1.
Clinical Implications
- Magnesium plays a crucial role in various bodily functions, including muscle and nerve function, blood glucose control, and bone health 1.
- Deficiency in magnesium can lead to symptoms such as muscle cramps, fatigue, and irregular heartbeat, emphasizing the importance of adequate intake 1.
From the FDA Drug Label
DIRECTIONS Antacid Directions:■ take 1 tablet twice a day or as directed by a physician Magnesium Supplement Directions: ■take 1 to 2 tablets daily or as directed by a physician Directions shake well before using drink a full glass (8 ounces) of liquid with each dose may be taken as a single daily dose or in divided doses The daily magnesium dose is:
- 1 to 2 tablets for magnesium oxide (PO) 2
- A single daily dose for magnesium citrate (PO) with specific fluid ounce recommendations based on age 3
From the Research
Daily Magnesium Intake
- The daily magnesium intake is crucial for maintaining various bodily functions, including energy-requiring metabolic processes, protein synthesis, and anaerobic phosphorylation 4.
- Magnesium deficiency can lead to a range of health issues, including neuromuscular irritability, cardiac arrhythmias, and increased sensitivity to digoxin 4.
- Subclinical magnesium deficiency is a significant public health concern, as it can increase the risk of cardiovascular disease and other chronic conditions 5.
Factors Affecting Magnesium Levels
- Certain individuals, such as those with inflammatory bowel disease, are at a higher risk of magnesium deficiency due to decreased oral intake, malabsorption, and increased intestinal losses 6.
- Medications, such as loop and thiazide diuretics, aminoglycosides, and cisplatin, can cause renal magnesium wasting and subsequent deficiency 4.
- Dietary factors, including decreased food crop magnesium contents and the availability of refined and processed foods, can contribute to magnesium deficiency 5.
Bioavailability of Magnesium Compounds
- The bioavailability of magnesium compounds can vary significantly, with organic salts such as magnesium citrate and magnesium malate showing higher bioavailability than inorganic salts like magnesium oxide 7, 8.
- Magnesium citrate has been shown to have higher bioavailability compared to magnesium oxide, with significant increases in urinary magnesium excretion and plasma magnesium levels 7.
- Magnesium malate and magnesium acetyl taurate have been found to have high bioavailability and tissue penetration, with potential benefits for anxiety and other health indicators 8.