By Erin Stokes, ND
In the past century, intake of minerals like magnesium has declined to half what our great grandparents consumed. The causes for this decline overlap into farming, nutrition and lifestyle choices. They include reliance on high yield farming methods, low vegetable consumption in the American diet, and even increased prescriptions of proton pump inhibitors, which can reduce magnesium absorption.
The health implications are significant. According to the National Institutes of Health, habitually low magnesium intake can increase the risk of hypertension, cardiovascular disease, type 2 diabetes, osteoporosis, and migraine headaches.1
The question is: Can Americans consume enough magnesium in their daily diet to reach optimal intake levels? Experts believe it may not be possible without a concerted effort to raise the RDA, change farming practices, and help patients make dietary changes.
Role of Magnesium
Magnesium is a cofactor that plays several significant roles in more than 300 enzyme systems that regulate protein synthesis, blood glucose, blood pressure as well as muscle and nerve function.2  Proper bone development relies on magnesium, as does the synthesis of DNA, RNA and glutathione. Magnesium assists in the transport of potassium ions across cell membranes, which contributes to essential functions such as muscle contractions, nerve signals and regular heart rhythms.3
Approximately 50% of magnesium in the adult human body is found in the skeleton. It is an essential mineral for the development and maintenance of bones and teeth. In the past, most people placed the primary emphasis on the role of calcium in maintaining strong, healthy bones. Now many practitioners are realizing that magnesium and other nutrients are essential.4
After the skeletal system, the highest concentration of magnesium is found in our muscles. About 25% of magnesium is found in the muscular system.  Magnesium is absolutely necessary to maintain proper muscle function.5  In modern times, where many aspects of daily living such as stress, computer work and driving all lead to increased muscle tension, this is particularly relevant. In addition to the roles in the skeletal and muscular systems, magnesium activates various enzymes that are vital for providing energy. It assists with ATP production and helps the body to metabolize proteins, carbohydrates and fats.
Magnesium RDA
The RDA for Magnesium is age and gender specific.

Age Male Female Pregnancy Lactation
Birth – 6 mos. 30mg 30mg
7-12 mos. 75mg 75mg
1-3 yrs. 80mg 80mg
4-8 yrs. 130mg 130mg
9-13 yrs. 240mg 240mg
14-18 yrs. 410 mg 360 mg 400 mg 360 mg
19-30 yrs. 400 mg 310 mg 350 mg 310 mg
31-50 yrs. 420 mg 320 mg 360 mg 320 mg
51+ yrs. 420 mg 320 mg

Source: National Institutes of Health, Office of Dietary Supplements
Almonds, 1 oz                                      80mg              20% RDA
Spinach, ½ cup cooked                     78mg              20% RDA
Cashews,1 oz.                                       74mg              19% RDA
Peanuts, ¼ cup                                  63mg              16% RDA
Shredded Wheat Cereal                   61mg              15% RDA
Soy Milk, 1 cup                                  61mg              15% RDA
Black Beans                                       60 mg             15% RDA
Causes for Declining Intakes
Experts say that in the last century magnesium intake has declined by more than half, from 500mg per day to as low as 164mg in adolescents and adults.6 In NHANES data, magnesium intake levels are consistently below the RDA.7
Median Intake:
Caucasian men, 326 mg/d (mean 352 mg/d)
African American men 237 mg/d (mean 278 mg/d)
Mexican American men, 297 mg/d (330 mg/d)
Caucasian women, 237 mg/d (mean 256 mg/d)
African American women, 177 mg/d (mean 202 mg/d)
Mexican American women, 221 mg/d (mean 242 mg/d)
Why are we currently seeing such high rates of magnesium deficiency? Part of the answer may lie in the food sources that contain the highest levels of this mineral. Magnesium is found in particularly high concentrations in nuts, seeds, beans and leafy green vegetables, which are not a part of the daily diet for many people. In fact, the center of the chlorophyll molecule found in green vegetables contains magnesium, making green vegetables a reliable source of this mineral. In addition, magnesium deficiency may be related to more than just diet alone. Medications, physical and mental stress, poor digestive function, along with documented mineral content depletion of soil, have also been considered contributing factors.8
Studies show a strong inverse relationship between high plant yields and mineral concentration. It is called the “dilution effect.”  According to a study review by Donald Davis:9
“Three kinds of evidence point toward declines of some nutrients in fruits and vegetables available in the United States and the United Kingdom: 1) early studies of fertilization found inverse relationships between crop yield and mineral concentrations—the widely cited “dilution effect”; 2) three recent studies of historical food composition data found apparent median declines of 5% to 40% or more in some minerals in groups of vegetables and perhaps fruits; one study also evaluated vitamins and protein with similar results; and 3) recent side-by-side plantings of low- and high-yield cultivars of broccoli and grains found consistently negative correlations between yield and concentrations of minerals and protein, a newly recognized genetic dilution effect.” — Donald Davis, Declining Fruit and Vegetable Nutrient Composition: What is the Evidence?, Hort Science, 2009.
As Davis discusses, numerous studies and historical data, from the past 50 to 70 years, show that high-yields farming methods dilute mineral composition in fruits, vegetables and grains anywhere from 5% to 40%.10
Other factors outside farming that affect magnesium levels include commonly prescribed medications and conditions, such as the following:
Proton Pump Inhibitors: The FDA issued a Drug Safety Communication on March 2, 2011 regarding prescription proton pump inhibitor (PPI) because they may cause hypomagnesemia (low serum magnesium levels), if taken for longer than one year. The FDA reported that in 25% of the cases reviewed supplementation did not improve serum magnesium levels (PPI’s were discontinued).11
Diuretics: Commonly prescribed loop diuretics (furosemide, bumetanide and thiazides)  can increase the loss of magnesium in urine and lead to magnesium depletion.12
Gastrointestinal Diseases: Illnesses associated with chronic diarrhea and fat malabsorption, such as Crohn’s, celiac and inflammatory bowel disease, can reduce magnesium absorption or lead to increased losses.13

Health Implications of Low Magnesium Levels
The 2009 WHO report, Calcium and Magnesium in Drinking Water, looks at severe dietary magnesium deficiencies or profound hypomagnesaemia as compared to moderate deficiencies, which is more likely the case in general populations.14 The report identified a global problem with magnesium deficiencies and made recommendations for supplementation.
The study cites the global epidemic of health issues related to inflammation and loss of red blood cell glutathione as a result of moderate inadequate magnesium intake levels.
“Overall, these data suggest that magnesium deficiency causes systemic hyperactivation of the magnesium-gated NMDA receptor/channel complex, which leads to early release of the proinflammatory neuropeptide, SP, triggering a cascade of proinflammatory/pro-oxidative events in multiple tissues/organs and altering susceptibility to subsequent stresses.” – WHO, Calcium and Magnesium in Drinking Water, Magnesium Deficiency: Clinical and Experimental Aspects.15
Contributing writers to report also discuss the limitations in the reference intervals for magnesium, which may be too low. There is an absence in methodologies to measure free ionized magnesium rather than total magnesium in tissues, organic and body fluids. The report calls for better evidence based methods to measure serum deficiencies so that physicians could recommend changes to diet and possible supplementation when necessary.
Given that current magnesium intake is about 175-248mg/day, the WHO recommends that total magnesium intake must be at least 450-500mg/day.  Appropriate supplementation may be the answer to the gap between intake and ideal intake. Considering magnesium’s crucial role in bone health, muscular health, cognitive health, blood glucose regulation and energy levels, it is a mineral that cannot be overlooked.
The report concludes, to which I agree, “Corrections of these deficits should perforce lead to healthier bodies, less cardiovascular diseases and longer lifespans.” 16  As our farming methods rely more heavily on high-yield output and modern busy lifestyles lead to poor dietary choices, key minerals necessary for health and wellness may continue to be depleted from our patients’ diets. I believe it is imperative that  health providers seriously look at the growing problem of low magnesium intake levels when assessing patient’s overall health.
1 Institute of Medicine (IOM). Food and Nutrition Board. Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride. Washington, DC: National Academy Press, 1997.
2 ibid, IOM, 1997.
3 Dean, Caroline, MD., ND, The Magnesium Miracle, Random House Publishing, Ballantine Books, 2008, PART ONE, Ch 1. Case of Magnesium.
4 ibid, Dean, 2008.
5 National Institutes of Health, Office of Dietary Supplements, Magnesium, Fact Sheet for Health Professionals,
6 S Agarwal, et al. Comparison of Prevalence of Inadequate Nutrient Intake Based on Body Weight Status of Adults in the United States: An Analysis of NHANES, 2001-2008. J Am Coll Nutr. 2015 1: 1-9.
7 ibid, NHANES, 2015
8. ibid, Dean 2008.
9. D. Davis. Declining Fruit and Nutrient Composition: What is the Evidence? Hort Science, 2009, 44 (1): 15-19.
10. ibid, Davis, 2009.
11. FDA Drug Safety Communication: Low magnesium levels can be associated with long-term use of Proton Pump Inhibitor drugs (PPIs). March 2, 2011.
12. PA Sarafidis et al. Diuretics in clinical practice. Part II: electrolyte and acid-base disorders complicating diuretic therapy. Expert Opin Drug Saf 2010;9:259-73.
13. CC Booth, et al. Incidence of hypomagnesaemia in intestinal malabsorption. Br. Med J, 1963 Jul 20;2(5350):141-4.
14. World Health Organization, Calcium and Magnesium in Drinking Water, Public Health Significance, 2009.
15. ibid, WHO, 2009
16. ibid, WHO, 2009
Erin Stokes, ND is a Boulder-based Naturopathic Doctor and Medical Director at INNATE Response. This article was written with the assistance of Kimberly Lord Stewart. 

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.