Data from 22 trials with magnesium supplements revealed that the mineral may reduce systolic and diastolic blood pressure by 4 and 3 mmHg, respectively, researchers from the University of Hertfordshire report in the European Journal of Clinical Nutrition.
Systolic function relates to the contraction of the heart, whereas diastolic relates to the filling of the heart with blood.
“Magnesium supplementation appears to achieve a small but clinically significant reduction in BP, an effect worthy of future prospective large randomised trials using solid methodology,” wrote researchers, led by Lindsy Kass.
Minerals and stroke
Diet is known to have an impact on a person's risk cardiovascular disease, and in particular a connection has been made between intake of sodium and hypertension. Conversely, more magnesium, potassium and calcium have been inversely linked to hypertension in some observational studies.
Dietary sources of magnesium include green, leafy vegetables, meats, starches, grains and nuts, and milk. Earlier dietary surveys show that a large portion of adults does not meet the RDA for magnesium (320 mg per day for women and 420 mg per day for men).
Recently, scientists from the Karolinska Institutet in Stockholm, Sweden reported that, data pooled from seven prospective studies revealed that, for every 100 mg per day increase in magnesium intake, the risk of stroke was reduced by about 9% (American Journal of Clinical Nutrition).
Meta-analysis
Kass and her co-workers analysed data from 22 trials involving 1,173 people. Magnesium supplementation doses ranged from 120 to 973 mg with trial duration ranging from three to 24 weeks.
The overall data indicated that magnesium supplementation was associated with a 3 to 4 mmHg reduction in systolic blood pressure and a 2-3 mmHg reduction in diastolic blood pressure, with the best results observed for doses over 370 milligrams per day.
Data from pharmaceutical trials has revealed that a reduction in systolic blood pressure of between 0.8 and 2 mmHg was “clinically significant in reducing the incidence of coronary heart disease, heart failure and stroke.
“The clinical significance in the reductions found from this meta-analysis is potentially very important,” said the researchers.
High blood pressure (hypertension),defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg, is a major risk factor for cardiovascular disease (CVD) - a disease that causes almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi:10.1038/ejcn.2012.4
“Effect of magnesium supplementation on blood pressure: a meta-analysis”
Authors: L. Kass, J. Weekes, L. Carpenter