Hot flush relief with Mg

Hot flushes can cause great discomfort and disrupt sleep and daytime activities. They are particularly common in women who have taken chemotherapy for breast cancer, and there is a lack of safe and effective options to relieve hot flushes.

In this pilot study, 29 women (average age 54 years), who had breast cancer and at least 14 hot flushes a week, received one 400 mg tablet of magnesium oxide (250 mg of elemental magnesium) per day for four weeks. If after two weeks of taking magnesium the women still did not have adequate hot flush relief, they raised the dose to 400 mg of magnesium oxide twice a day. Women filled out questionnaires about the frequency and severity of their hot flushes before and after taking magnesium.

Results showed:

• Of 25 women who completed the study, 17 of them were raised to the higher 800 mg per day amount of magnesium oxide.
• Hot flush scores (based on hot flush frequency and severity) among women who had completed the study, were reduced by more than 50% in 14 participants (56%) and by more than 25% in 19 participants (76%).
• The average frequency among the women at the beginning of the study was 52 hot flushes per week, which decreased by 41% to 28 hot flushes per week after magnesium supplementation.
• Women also reported that symptoms such as fatigue, sweating, and distress were also significantly improved. No change in sleep disturbance was seen.
• Mild side effects occurred among four of the women and included headache, nausea and diarrhoea, which caused two of these women to stop the treatment.

The study authors comment, “Magnesium appears to be a safe and inexpensive therapy for those with bothersome hot flushes. The greater than 50% reduction in symptoms suggests that oral magnesium is likely more effective than placebo . . .” The authors add that they will now conduct a randomised, placebo-controlled trial to confirm these findings.

Magnesium facts and tips

• How does it work? It’s not yet well understood, but magnesium is known to affect the function of nerves and blood vessels and to influence neurotransmitters such as serotonin, according to the study authors—all of which may be involved in the development of hot flushes.
• How much is enough? The recommended dietary allowance of magnesium is 320 mg per day in non-pregnant women, and 420 mg per day in men over age 30, according to the National Institutes of Health Office of Dietary Supplements. But the amounts needed daily vary according to age, medical conditions, medications, and whether a woman is pregnant or breast-feeding. Talk with a doctor about how much magnesium is right for you, and if you are planning on taking a magnesium supplement talk with a knowledgeable healthcare professional about the risks and benefits.
• Food sources. Important food sources of magnesium include nuts, halibut, spinach, pulses, and whole grains. Eating foods rich in magnesium is important for creating a balanced diet and optimizing health.

(Support Care Cancer 2011;19:859–63)