However, data from studies including 3,487 individuals did not reveal a robust association between serum magnesium levels and the risk of metabolic syndrome, a condition characterized by central obesity, hypertension, and disturbed glucose and insulin metabolism. The syndrome has been linked to increased risks of both type 2 diabetes and cardiovascular diseases.
“The present systematic-review and meta-analysis showed a strong inverse association between Mg intake and MetS,” wrote the authors in Nutrition.
“Although we found the same association about the relationship between serum Mg, as a measure of body Mg, and MetS were highly heterogeneous. Therefore, our results should be discussed with more caution. Assessing the body Mg with better indicators of body storage such as magnesium retention test which shows the stored body Mg might reveal more accurate results.”
‘Necessary for over 300 biochemical reactions’
Data from population studies indicates that a large proportion of Americans is not making the recommendations for this essential nutrient. According to NHANES data, 60% of Americans are not hitting the Institute of Medicine’s intake recommendations for the mineral.
The National Institutes of Health (NIH) lists magnesium as being necessary for more than 300 biochemical reactions in the body, from helping maintain normal muscle and nerve function, to keeping heart rhythm steady, supporting a healthy immune system, and keeping bones strong. The mineral is also needed for blood sugar management, and healthy blood pressure.
In Europe, the difficult to please European Food Safety Authority (EFSA) has issued positive opinions on magnesium and the maintenance of normal bone, teeth, and protein synthesis; the reduction of tiredness and fatigue; electrolyte balance; normal energy-yielding metabolism; neurotransmission, and muscle contraction.
The authors of the new meta-analysis identified eight papers that met their inclusion criteria, and these provided data on almost 3,500 individuals with and without MetS. Crunching the numbers indicated that higher intakes were associated with a reduction in MetS risk of over 20%.
A significant association between serum magnesium and MetS was also observed, but this result was very heterogeneous.
Commenting on the potential mechanism(s) of action, the researchers noted that magnesium may help preserve pancreatic beta-cell function and therefore help with insulin action and secretion.
In addition, the mineral also plays a role in glucose metabolism via its role as a cofactor, they said.
“Similarly, Mg acts as a co-factor for several critical enzymes involving lipid metabolism,” they added. “Mg has been reported to raise HDL and reduce LDL cholesterol and triglycerides […] It has been assumed that Mg, in the intestine, by forming an un-absorbable soap with fatty acids and cholesterol, can decrease their absorption, reduce energy intake from the diet and may have advantages for weight maintenance because of this capability.”
In the US the overall prevalence of the metabolic syndrome has increased from 23.7% in 1988–1994 to 34.2% in 1999–2006 for adults aged over 20 – this breaks down to an increase from 24.8 to 34.9% for men and 23.4 to 33.3% for women.
A 2008 study entitled the “Metabolic Syndrome Pandemic” estimated about one-fourth of the adult European population has the condition.
According to the UK’s National Health Service, European men with metabolic syndrome tend to have a waist circumference of 37 inches or more and for European and South Asian women 31.5 inches or more.
Published online ahead of print, doi: 10.1016/j.nut.2015.09.014
“Magnesium status and the metabolic syndrome: a systematic review and meta-analysis”
Authors: N. Sarrafzadegan, et al.