A pilot phase II trial of magnesium supplements to reduce menopausal hot flashes in breast cancer patients

Via Supportive Care in Cancer:

Abstract


Background

We tested if magnesium would diminish bothersome hot flashes in breast cancer patients.

Methods

Breast cancer patients with at least 14 hot flashes a week received magnesium oxide 400 mg for 4 weeks, escalating to 800 mg if needed. Hot flash score (frequency × severity) at baseline was compared to the end of treatment.

Results

Of 29 who enrolled, 25 women completed treatment. The average age was 53.5 years; six African American, the rest Caucasian; eight were on tamoxifen, nine were on aromatase inhibitors, and 14 were on anti-depressants. Seventeen patients escalated the magnesium dose. Hot flash frequency/week was reduced from 52.2 (standard error (SE), 13.7) to 27.7 (SE, 5.7), a 41.4% reduction, p = 0.02, two-sided paired t test. Hot flash score was reduced from 109.8 (SE, 40.9) to 47.8 (SE, 13.8), a 50.4% reduction, p = 0.04. Of 25 patients, 14 (56%) had a >50% reduction in hot flash score, and 19 (76%) had a >25% reduction. Fatigue, sweating, and distress were all significantly reduced. Side effects were minor: two women stopped the drug including one each with headache and nausea, and two women had grade 1 diarrhea. Compliance was excellent, and many patients continued treatment after the trial.

Conclusions

Oral magnesium appears to have helped more than half of the patients and was well tolerated. Side effects and cost ($0.02/tablet) were minimal. A randomized placebo-controlled trial is planned.
 
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From Livestrong.org:

Magnesium, a mineral found in tofu, grains, nuts, potatoes, leafy green vegetables, chocolate and cocoa powder, has been found to decrease during menopause, according to the University of Maryland Medical Center. Natural-Approaches-to-Menopause.com cites a study in which patients who increased their magnesium experienced decreased symptoms and eventual elimination of hot flashes, so supplementing magnesium levels may decrease the severity and frequency of your hot flashes.

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From NaturalStandard.com (accessed Feb 1st/2011):

Brief Safety Summary:

Likely safe: When used orally, intravenously, or intramuscularly in people with normal renal function. Oral magnesium has been given in doses of 600-1,200mg daily for months without major adverse effects.

 
Interestingly:

"Hormonal effects: Oral magnesium has been reported to benefit mood changes associated with premenstrual syndrome (PMS) (6). Facchinetti et al. theorized that this effect may be due to raising intracellular magnesium levels."

 
Pharmacodynamics/Kinetics:

Magnesium is the second most abundant intracellular cation (positive ion) in the human body and is involved in more than 300 enzymatic reactions, including glucose use, the synthesis of fat, protein, and nucleic acids, the metabolism of adenosine triphosphate, muscle contraction, and some membrane transport systems (154). Magnesium is known to be essential for all ATPase activity, including its capability to facilitate movement of calcium across and within the cell membrane of cardiac and vascular tissues (155).

Absorption: Based on clinical review, 35-40% of ingested magnesium has been shown to be absorbed in the gastrointestinal tract (156). It has been found to reach steady-state after 2-3 hours and maximum concentrations at 4 hours (156). Magnesium is primarily absorbed in the small intestine (156).

Distribution: Normal serum magnesium levels are generally considered to be between 0.70 and 0.94mM/L; the average 70kg adult body contains approximately 24g of magnesium (60% is in the bone; 35% is in the muscles, particularly the heart and skeletal muscles; 1% is found in the extracellular fluid compartment). Approximately 35% of the body's magnesium is bound to albumin, with the rest primarily in ionized form (157).

Metabolism: Based on secondary sources, magnesium is not metabolized.

Excretion: Magnesium excretion is primarily via the kidneys and averages only 3-5% of the filtered load; excretion ranges from 10-5,000mg over a 24-hour period (156). Urinary magnesium and pH are known to modulate urinary calcium excretion; however, the underlying mechanism is unknown (158).

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