Low Dietary Magnesium Intake and Hypertension

Purpose: Magnesium (Mg) is a key factor in blood pressure regulation. However, only in recent years, magnesium dietary intake has been studied in relation to hypertension, with equivocal conclusions. Further no comparisons have previously been made between the UK general population and primary hypertensives, the UK RNI and the USARDA. Methods: Twenty-five hypertensives (HT) (mean age 63.4 y) and twenty-one normotensives (mean age 46.7 y) were recruited from the same geographical area. Food diaries were completed and analysed to determine average daily Mg intake. Mg intake was compared between the observed group (OB), normotensives (NT) and general population (GP) and both the UK RNI and the USA RDA. Results: Study participants had a significantly lower dietary Mg intake than the UK RNI (p < 0.05) and the US RDA (p < 0.05). Intake for HT males was significantly lower (p < 0.0001) than the external control (general population) and, for HT females, intake was significantly lower than the NT (p = 0.006). The findings also suggest that with ageing there is a reduction in daily dietary Mg intake. Finally, when UK external controls were compared to the USA RDA for both males and females they were found to be around 35% and 30% respectively below the recommended values. Conclusions: Daily Mg intake in hypertensives is lower than the general population, the UK RNI and the USA RDA. Daily magnesium intake reduces with age. These findings suggest that low Mg dietary intake increases the risk of hypertension.