by Jesse Davis, DC
The role of nutrition in cardiovascular health has long been dominated by the topic of cholesterol, and what foods to avoid. However in research circles that has changed and a broader view of cardiovascular health and nutrition has emerged. One important nutrient that may not be a top choice in a word-association game on heart-healthy nutrition is magnesium. But after reading this you’ll likely agree that it should be.
Here is an overview of magnesium’s relation to heart health from a review article in Current Opinion in Lipidology:
“Increased dietary magnesium intake confers protection against the incidence of diabetes, metabolic syndrome, hypertension, and cardiovascular disease. It ameliorates insulin resistance, serum lipid profiles, and lowers inflammation” 
Magnesium acts as a mild calcium antagonist on vascular smooth muscle tone, and on postreceptor insulin signaling; it is critically involved in energy metabolism, fatty acid synthesis, glucose utilization, ATPase functions, release of neurotransmitters, and endothelial cell function and secretion.” 1
What Does Magnesium Do in the Body
As mentioned, a vast number of biological functions include magnesium, using it in two primary ways, as a cofactor and an electrolyte. Magnesium interacts with ATP while burning calories and generating energy as a cofactor in glycolysis.  DNA replication for dividing cells is another example of magnesium as a cofactor. Protein synthesis utilizes magnesium, so that includes things like building muscle tissue, enzyme manufacturing, and creating endogenous antioxidants like glutathione.
As an electrolyte, it affects fluid dynamics and cell membrane functions.This explains magnesium’s influence on processes like speed and fluidity of digestion in the intestines (too much leads to diarrhea), ion transport in and out of cells, and the conduction of nerve impulses.
Mg and Cardiovascular Health
In cardiovascular functions, magnesium is particularly important. Since magnesium is involved in nerve conduction, magnesium levels play a role in heart rhythm. Low blood levels of magnesium may be associated with cardiac arrhythmias. Magnesium is even given in clinical settings as part of some arrhythmia treatments.
In patients with chronic heart failure, low serum magnesium populations had a greater mortality rate than those with a normal blood magnesium level. There have also been “small, clinically significant reduction(s) in blood pressure” found in the most recent meta-analysis of the topic of magnesium intake and hypertension. Magnesium acts by de-constricting blood vessels by slowing calcium’s depolarization of the vessels’ smooth muscle fibers. 
Mg in Metabolic Syndromes
Metabolic syndrome (formerly called syndrome X) is a combination of the following: high blood sugar, high blood pressure, high triglycerides, abdominal obesity, and low HDL cholesterol. A combination of three or more of these is called metabolic syndrome and is a sign of impending cardiovascular disease, prediabetes or diabetes. Some estimates have placed one third of American adults as having metabolic syndrome.
It turns out that magnesium has been found to be related to metabolic syndrome in several ways. As mentioned above, healthy magnesium levels support proper blood pressure*. In addition, magnesium is involved in insulin sensitivity helping shuttle glucose into cells*. A report from Northwestern School of Medicine had this to say about magnesium and Metabolic Syndrome:
“A magnesium rich-diet may help reduce the risk of metabolic syndrome and, perhaps, a heart attack or diabetes, Northwestern University researchers report in Circulation: Journal of the American Heart Association.
Previous studies indicate that magnesium can reduce the risk of the individual components of metabolic syndrome, but scientists lacked evidence of its efficacy against the syndrome.
‘As far as we can determine, this is the first prospective evidence that shows magnesium intake provides a beneficial effect in the syndrome,’ said Ka He, M.D., lead author of the study and assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine.
He also noted that a higher intake of magnesium was associated with beneficial support for healthy blood pressure, healthy weight and healthy glucose levels.
Magnesium is present in relatively smaller amounts in many different types of foods. Spinach, avocado, almonds, peanuts and cashews are examples of foods that have high amounts of magnesium per serving size, though no single food has very high levels relative to the RDA. Even mineral water high in magnesium can be one of the dietary sources of the mineral.
Intake levels are such that 60% of adults are not receiving the RDA. Around 1% of magnesium in the human body is in the blood, which makes a blood test for magnesium levels not highly sensitive unless there is a severe deficiency. Around 50% of the body’s stores are in the bones, while the rest is housed in other tissue types, primarily muscle. Intakes are typically in the 50-90% range compared to the RDA total, which are described as mild to moderate deficient intakes.7
Taking all of this together, it’s time to update our thinking on cardiovascular health and nutrition. And one nutrient that researchers are looking at more and more is magnesium. For people that are concerned with cardiovascular health, optimizing magnesium levels is an important step.
Dr. Jesse Davis has been a practicing doctor of chiropractic in the greater Boston area since 2006. He is a post-graduate instructor for the Gonstead Methodology Institute focused on specific chiropractic adjusting. He is a strong believer in the power of a healthy lifestyle including nutrition for achieving and maintaining health. Previously Dr. Davis was a molecular genetics researcher, published in BMC Genomics and Nucleic Acids Research, and has always enjoyed teaching and writing.
 Adv Nutr May 2013 Adv Nutr vol. 4: 378S-383S, 2013
 Paolisso G, Barbagallo M. Hypertension, diabetes mellitus, and insulin resistance: the role of intracellular magnesium. Am J Hypertens. 1997;10:346–55.
 Ford ES, Giles WH, Dietz WH (2002). “Prevalence of metabolic syndrome among US adults: findings from the third National Health and Nutrition Examination Survey”. JAMA 287 (3): 356–359
 Nielsen FH. Magnesium, inflammation, and obesity in chronic disease. Nutr Rev. 2010;68:333–40.