Magnesium reduces blood pressure
Up until now, evidence linking magnesium to better blood pressure has been inconclusive. Researchers in this review looked at all the magnesium studies to date and found 22 trials involving 1,173 people, who took 120 mg to 973 mg of magnesium per day for three to 24 weeks. Combining the data, doctors found that overall, magnesium reduced systolic blood pressure by 3 to 4 mmHg, and diastolic blood pressure by 2 to 3 mmHg, with the best results for doses over 370 mg of magnesium per day.
The blood pressure measurements, systolic and diastolic, relate respectively to when the heart contracts to pump blood out, and when it relaxes to refill. In discussing their findings, doctors said supplementing with magnesium appears to achieve a “small but clinically significant reduction in blood pressure”, and suggests larger controlled trials to confirm these results.
Vitamin C reduces high blood pressure
The evidence for the blood pressure benefit of vitamin C is also inconsistent. In this new analysis, doctors reviewed 29 placebo-controlled vitamin C supplement trials with 10 to 120 participants, average daily doses of 500 mg of vitamin C, and an average study period of eight weeks. Combining the data, researchers found that overall systolic blood pressure declined by 3.84 mmHg, and diastolic blood pressure declined by 1.48mmHg. The effects were greater in those with high blood pressure, with systolic and diastolic blood pressure declining respectively by an average of 4.85 mmHg and 1.67 mmHg.
In talking about their findings, researchers said doctors might eventually be able to recommend vitamin C to prevent or help treat high blood pressure, and suggested larger studies to confirm the blood pressure benefits of vitamin C.
Reference: European Journal of Clinical Nutrition; 2012, Vol. 66, No. 4, 411-8
From the July 2012 newsletter
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