Spinach — the dark green leafy source of Popeye’s superhuman strength — is abundant in many nutrients, including magnesium. A new study suggests that diets higher in magnesium are associated with lower blood levels of glucose and insulin, which are often elevated in people with type 2 diabetes.
Research now shows that people with type 2 diabetes are at increased risk of certain cancers, including kidney, pancreatic and colorectal.
The study was published online last month in The Journal of Nutrition.
Study researchers analyzed data from approximately 53,000 non-diabetic European men and women from 15 studies who were part of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) study. The individual studies had collected dietary data through questionnaires, interviews, and/or food diaries along with glucose and insulin levels after participants had not eaten for at least 8 hours.
The participants were also genetically tested for 25 single nucleotide polymorphisms (SNP), a type of change where one letter – or nucleotide – in the DNA sequence differs. The SNPs had been previously associated with glucose, insulin or magnesium metabolism.
Study investigators found that every increase of 50 milligrams per day of magnesium intake was associated with decreasing levels of both fasting glucose (-0.009 mmol/L) and fasting insulin (-0.020 ln-pmol/L). This inverse relationship stayed true even after taking into account lifestyle factors such as age, gender, alcohol, calorie intake, BMI, smoking status, education, and physical activity.
One cup of cooked spinach contains about 150 milligrams of magnesium and 1 slice of whole-wheat bread has approximately 30 milligrams of magnesium.
The study did not see any significant effects between the genes studied and fasting glucose or insulin, suggesting that magnesium’s beneficial lowering effects on glucose and insulin may work independently of genetics, or as least the SNPs looked at in this study.
Magnesium is an essential mineral our body needs to contract and relax muscles, produce and transport energy, and make protein, among other important functions. Government recommendations for magnesium are 310-320 milligrams daily for women and 400-420 milligrams daily for men.
Dark green, leafy vegetables, whole grains, legumes and nuts are all good sources of magnesium. These foods are also all part of a cancer-protective diet, containing fiber, phytochemicals and numerous other healthful compounds.
Here’s a chart showing how much magnesium is in spinach, nuts, and other foods.