Examine publishes rigorous, unbiased analysis of the latest and most important nutrition and supplementation studies each month, available to all Examine Members. Click here to learn more or log in.
Study under review: Long-term magnesium supplementation improves arterial stiffness in overweight and obese adults: results of a randomized, double-blind, placebo-controlled intervention trial
Introduction
Magnesium is an essential mineral that is used by the body in over 300 biological processes. The best dietary sources of magnesium are seeds and nuts, green leafy vegetables, and whole grains, though it’s also found in smaller amounts in meat and dairy products, as well as in some fortified cereals. Medications like laxatives and chewable antacids also contain magnesium.
Low dietary magnesium has been linked to a number of health risks, including heart disease[1], stroke[2], and type 2 diabetes[3]. One very large meta-analysis[4] of 16 trials surveying a total of 300,000 participants found that for each 200 milligram per day increase in dietary magnesium, there was an associated 30% decrease in heart attacks. In the same analysis, only circulating magnesium levels (not dietary consumption) were correlated with overall cardiovascular disease (CVD) risk, which includes not only heart attacks, but also stroke, arrhythmia, and heart failure. For each 0.2 mmol/L increase in plasma magnesium concentrations, a 30% reduction in risk for CVD was observed.
Increased arterial stiffness, or the reduced ability of an artery to contract and expand as blood moves through it, is independently linked[5] to increased CVD risk. You might remember reading about pulse wave velocity (PWV, which is depicted in Figure 1) analysis in “Blueberries every day keeps high blood pressure at bay” (Study Deep Dives #6, April 2015). This is a non-invasive way to measure arterial stiffness. It involves placing pressure catheters at two points on the body and then measuring the time it takes for the “wave” of the heartbeat to travel between those two points. Traveling faster between those two points means the arteries the wave is traveling through are stiffer.
Most prior studies on the role of magnesium in CVD have used blood pressure[6], lipid profiles[7], and inflammatory markers[8] as surrogates for cardiovascular events. These studies have shown mixed or inconclusive results. Only one study has used PWV analysis as the surrogate (and secondary) endpoint. The study[9] was completed in healthy young men over an eight-week period, and no improvement was found in the magnesium group. This study attempted to evaluate a more relevant population for CVD, and used a much longer study duration of 24 weeks in order to assess the effects of magnesium on arterial stiffness as a marker for CVD risk, which may overcome the limitations of the previous study.
Magnesium is a mineral that is essential to hundreds of biological functions in the body. Low magnesium levels have been linked to a number of health risks, including cardiovascular disease. Prior trials have attempted to assess the role of magnesium supplementation in CVD by using blood pressure or other biological markers as endpoints, with mixed results. This study examined pulse wave velocity as a measure of arterial stiffness linked with CVD.
Who and what was studied?
What were the findings?
What does the study really tell us?
The big picture
Frequently Asked Questions
What should I know?
Other Articles in Issue #19 (May 2016)
-
Training hot for performance gains
Athletes know all too well that sudden exposure to heat or altitude can severely impact performance, so acclimation is a good idea. And it turns out that exposure to one of these stressors may actually help the other one.
-
The art & science of evidence-based practice and elite performance By Craig Pickering
As one of the rare athletes to participate in both the Summer and Winter Olympic Games, Craig has a unique perspective on the intersection of optimal performance and evidence-based practice.
-
Beating “the burn” with baking soda
Can you believe that something as simple as baking soda may boost performance? While this fact has been known for a while, researchers didn’t know that people’s responses to different doses can vary quite a bit
-
A compound from beer may help fat loss
Bitter, hop-derived compounds found in beer may actually reduce body fat levels. Previously only shown in mice, this study tested the theory in humans
-
Sugar is the ultimate antioxidant and insulin will make you younger: Appreciating a few poorly recognized but critical contributions of carbohydrate
By Chris Masterjohn, PhD: Sugar is widely demonized in the media and medical establishment. Professor Masterjohn provides an eye-opening and detailed view on some potential protective roles of glucose.
-
Milk gone bad: A1 beta-casein and GI distress
Casein isn’t just the slowly digesting protein that helps prevent muscle breakdown. This study looked at possible negative effects of the most common type of casein in milk
-
Arsenic in rice: big trouble for little infants?
Depending on where it’s grown, rice can have rather high levels of arsenic. Especially brown rice. This may be important for developing infants
-
How much protein does grandpa really need?
One of the many downsides to aging is altered protein mechanics. Based on the theory that protein requirements for seniors may be pegged too low, this study quantified protein needs in older males.
-
Is resistance exercise the next frontier for nitrates?
Nitrate use for athletics has exploded in the past few years, but research typically focuses on aerobic activities like longer-distance cycling or swimming. Could nitrates also show benefit for weightlifting?
