Posts Tagged ‘Magnesium’

Magnesium Supplementation in Health and Performance
Section: Nutritional Optimization for Endurance and Functional Athletes
Subsection: Micronutrients — Magnesium

Overview
Magnesium is the second most abundant intracellular cation and plays a pivotal role in more than 300 enzymatic reactions. These include processes essential for:

Neuromuscular function

Skeletal and cardiac muscle contraction and relaxation

ATP synthesis in mitochondria

Bone mineralization and parathyroid hormone regulation

Glucose transport and insulin signaling

Regulation of systemic vascular tone and cardiac rhythm

Recommended Daily Intake (RDA)
Men (ages 19–70+): 400–420 mg/day

Women (ages 19–70+): 310–320 mg/day

Note: RDA reflects the intake needed to prevent deficiency, not to optimize performance or recovery.

Risk Factors for Suboptimal Magnesium Status
High sweat rate (endurance athletes, workers in heat)

Gastrointestinal disorders (Crohn’s, celiac, chronic diarrhea)

Chronic diuretic or proton pump inhibitor use

Diabetes mellitus (especially if uncontrolled)

Older age and low dietary variety

High alcohol intake

Inadequate intake due to dietary restrictions (e.g., vegan, low-calorie diets)

Clinical Signs of Potential Deficiency
Muscle cramps, tremors, or fasciculations

Fatigue, low-grade inflammation, or poor recovery

Sleep disturbances, including restless leg syndrome

Premature ventricular contractions (PVCs) or palpitations

Insulin resistance or elevated fasting glucose

Anxiety or mild neuromuscular irritability

Supplementation Guidelines
Indications for Trial Supplementation:

Confirmed low dietary intake

Belonging to high-risk groups (see above)

Unexplained fatigue or neuromuscular symptoms

Preferred Forms:

Magnesium glycinate (well tolerated, calming)

Magnesium citrate (well absorbed, mild laxative effect)

Avoid: Magnesium oxide (low bioavailability; often causes GI distress)

Dosing Strategy:

Start with 200–400 mg elemental magnesium/day

Administer with food to reduce GI side effects

Reassess symptoms and tolerance after 7–10 days

Dietary Sources
Food Source Magnesium (mg)
Pumpkin seeds (¼ c) ~190
Almonds (1 oz) ~80
Spinach (½ c cooked) ~75
Black beans (½ c) ~60
Dark chocolate (1 oz) ~65
Whole grain bread (2 slices) ~45

Precautions
Excessive supplementation may cause:

Diarrhea

Nausea

In high doses or in renal impairment: hypotension, bradycardia, cardiac arrest

Serum magnesium is a poor marker for total body stores. Consider clinical signs and dietary history first.

Clinical Note:
Endurance athletes, individuals with high-volume training, and those undergoing occupational thermal stress should be routinely screened for magnesium adequacy via diet recall and symptom assessment. Supplementation may improve recovery, neuromuscular performance, and cardiovascular stability in deficient or marginal populations.

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