Observational epidemiologic studies have observed an inverse relationship between daily dietary magnesium intake and blood pressure (BP). Except for BP, magnesium may also beneficially affect other cardiovascular risk markers. Whether all these effects translate into improved vascular function is not known. Different vascular function markers at various stages on the pathway between diet and disease exist. One of these markers, vascular stiffness, is closely related to the process of atherosclerosis, an independent cardiovascular risk factor, and predictive of future cardiovascular events and mortality. To examine the integrated effects of interventions on cardiovascular risk, vascular stiffness may therefore serve as a marker at the later stage of cardiovascular disease development.

Therefore, it is imperative to examine in a 24-week, randomized, double-blind, placebo-controlled, two-way parallel-group human intervention study, the effect of magnesium on vascular stiffness. Focus will be on carotid-femoral pulse wave velocity (PWV), the gold standard for the evaluation of vascular elasticity, to quantify vascular stiffness. Urinary excretion of magnesium will be used to assess dietary magnesium uptake. Furthermore, time courses of an increased magnesium intake on changes in BP, other markers reflecting vascular function, and plasma biomarkers related to low-grade inflammation and vascular activity will be measured to unravel possible cause-effect relationships.

Inclusion Criteria:

• Aged between 45-70 years
• Women postmenopausal: two or more years after last menstruation
• BMI between 25-35 kg/m2 (overweight and slightly obese)
• Plasma glucose < 7.0 mmol/L
• Serum total cholesterol < 8.0 mmol/L
• Serum triacylglycerol < 4.5 mmol/L
• No current smoker
• No diabetic patients
• No familial hypercholesterolemia
• No abuse of drugs
• Less than 21 alcoholic consumptions per week
• Stable body weight (weight gain or loss < 3 kg in the past three months)
• No use of proton pump inhibitors or medication known to treat blood pressure, serum lipid or glucose metabolism
• No use of dietary supplements or an investigational product within another biomedical within the previous 1-month
• No severe medical conditions that might interfere with the study, such as epilepsy, asthma, kidney failure or renal insufficiency, chronic obstructive pulmonary disease, inflammatory bowel diseases, auto inflammatory diseases and rheumatoid arthritis
• No active cardiovascular disease like congestive heart failure or cardiovascular event, such as an acute myocardial infarction or cerebro vascular accident
• Willingness to give up being a blood donor (or having donated blood) from 8 weeks before the start of the study and during the study
• No difficult venipuncture as evidenced during the screening visit

Exclusion Criteria:

• High habitual dietary magnesium intake
• Plasma glucose ≥ 7.0 mmol/L
• Serum total cholesterol ≥ 8.0 mmol/L
• Serum triacylglycerol ≥ 4.5 mmol/L
• Current smoker, or smoking cessation < 12 months
• Diabetic patients
• Familial hypercholesterolemia
• Abuse of drugs
• More than 21 alcoholic consumptions per week
• Unstable body weight (weight gain or loss > 3 kg in the past three months)
• Use of proton pump inhibitors or medication known to treat blood pressure, serum lipid or glucose metabolism
• Use of dietary supplements or an investigational product within another biomedical within the previous 1-month
• Severe medical conditions that might interfere with the study, such as epilepsy, asthma, kidney failure or renal insufficiency, chronic obstructive pulmonary disease, inflammatory bowel diseases, auto inflammatory diseases and rheumatoid arthritis
• Active cardiovascular disease like congestive heart failure or cardiovascular event, such as an acute myocardial infarction or cerebro vascular accident
• Not willing to give up being a blood donor (or having donated blood) from 8 weeks before the start of the study and during the study
• Not or difficult to venipuncture as evidenced during the screening visit