The sources of magnesium include food, water, and supplements. While clearly a “good” source of magnesium is one that is readily available and easily absorbed, most experts recommend a combination of sources, taking advantage of both dietary magnesium and absorbable magnesium supplements.
What are the best sources of magnesium?
A “macro-mineral”, magnesium is one of the six essential minerals that the body needs in large quantities.
Yet currently less than 30% of Americans meet the recommended daily intake for magnesium in the diet. 1 2 3 4 And a stunning 19% of adults—one in five—consumes less than half of the US RDA for magnesium. 5
The articles in this section list common dietary sources of magnesium, and also explain how magnesium absorption affects the body’s ability to make good use of those sources.
Good Sources of Magnesium in Food: The Top 5
Traditionally, foods highest in magnesium content are green vegetables, whole grain cereals, nuts and beans, and seafood.
According to USDA food charts (see a complete chart of magnesium rich foods), the five foods with the highest magnesium per typical serving are:
- Boiled spinach
- Bran breakfast cereal
Foods with highest magnesium per milligram, regardless of typical intake, are:
- Bran breakfast cereal
- Pumpkin seeds
However, several factors can impair your ability to get magnesium from the foods you eat, including:
- Lowered magnesium availability in foods due to industrial farming practices
- Dietary habits leading to low magnesium uptake, such as consumption of sodas and carbonated beverages
- Excess stress or illness, which lowers the ability of the body to utilize magnesium
- Mineral imbalances, such as excess calcium, which blocks cellular magnesium activity
- Metabolic differences in individuals, such as excess magnesium excretion by the kidneys, sometimes resulting in magnesium losses and deficiency
What’s the best way to get adequate magnesium?
For most people, the best way to get magnesium is to ensure intake from a variety of sources, choosing a combination of:
Researchers have found average magnesium absorption by the digestive system to be 20 to 50%.
When magnesium is absorbed in the digestive system, a variety of factors can affect its intake.
This is why the amount of magnesium your body actually uses is different than the total amount of magnesium found in a food or supplement – in fact researchers have found that the average magnesium absorption by the digestive system is only 20 to 50%. 6 7 8 9
Those who are particularly vulnerable to magnesium deficiency may need to take extra steps due to the inability of their bodies to assimilate magnesium properly. They include:
- Those above the age of 55
- Those who regularly consume alcohol, caffeinated beverages or sodas
- Those taking certain medications such as diuretics, heart and asthma medications, birth control pills and/or estrogen replacement therapy
- Those undergoing significant psychological or physical stress, including surgery, burns and liver disease
- Those suffering from digestive disorders
Certain symptoms may also indicate the possibility of an existing magnesium deficit. These include:
- Muscle cramps and chronic pain
- Facial tics or muscle spasms
- Anxiety or hyperactivity
- Sleep problems
- High blood pressure
For people in these high-risk groups, increasing magnesium intake can be therapeutic. Dr. Mildred Seelig, magnesium researcher and author of The Magnesium Factor, has noted that supplementation is necessary when combating low magnesium:
If your health assessment leads you to believe that you may have been accumulating a magnesium deficit over some years as a result of a daily magnesium gap, recognize that you will first need to correct that deficit, most likely with magnesium supplements. 10
The best plan of action to correct a magnesium imbalance—or prevent future deficiencies—will likely include both increasing overall dietary intake and adding easily tolerated sources of magnesium supplements.
When choosing magnesium sources, it’s important to go beyond a generic list of the “best sources of magnesium”. Instead, recognize that certain sources may be better for certain people and certain lifestyles.
For example, many people experience poor magnesium tolerance leading to loose stools and other side effects of oral magnesium.
It’s important to know that other methods of delivery are now available that do not cause these side effects. These include intravenous magnesium and topical or “transdermal” magnesium. Transdermal magnesium therapy involves simply applying magnesium oil directly to the skin in a spray or lotion form, or by bathing in magnesium chloride salts, and can be done at home with products available for purchase.
Topical and transdermal preparations may also represent an appropriate adjunct therapy for those with poor magnesium absorption due to Crohn’s disease, IBS, celiac disease, or other digestive disorders.
When choosing magnesium rich food sources, the following factors come into play for each individual:
- What other foods or drinks do I choose regularly that may impair or improve my magnesium intake?
- How do I typically prepare foods containing magnesium?
- What vitamins and minerals do I take that could lessen magnesium absorption?
For example, when selecting foods for high magnesium bioavailability it is important also to consider the phytate and oxalate content of foods.
Phytates and oxalates, sometimes referred to as phytic acid or oxalic acid, are naturally occurring substances found in many different kinds of foods. Inside our digestive system, they can form bonds with magnesium that then prevent the magnesium from being absorbed, and cause it instead to pass out of the body as waste. While it is not recommended to avoid these foods entirely, as many are quite rich and valuable sources of nutrients, it can be prudent to preference high magnesium foods that are also low in phytates and oxalates.
The busy lifestyles common today can make meal planning a challenge, which is why it is especially uncommon for the average American to meet even the minimum daily requirements for magnesium. In fact, the average American diet provides barely over 50% of the U.S. RDA. 11
The average American diet provides barely over 50% of the U.S. Recommended Daily Allowance.
Convenience food choices that act as time-savers are commonly deficient in magnesium, so for many people magnesium supplementation becomes a natural choice to provide extra support for achieving adequate nutritional intake.
But even supplements can vary in absorption and bioavailability, and not all supplements are in fact “good” magnesium sources.
Magnesium oxide, for example, the most common magnesium supplement found in drugstores, has been found to have only a 4% rate of absorption, much lower than even the worst cases of magnesium absorption found in medical dietary balance studies. 12
When choosing magnesium supplements, consider:
- Which supplements have the greatest solubility and absorption?
- How should supplements be combined with food for maximum bioavailability?
- How well will my digestive system tolerate my chosen supplement?
How much magnesium do you need?
The current U.S. recommended daily allowance of magnesium for adults aged 31+ is:
- 420 mg per day for men
- 320 mg per day for women
- 360 mg per day for pregnant women 13
A number of medical experts dispute these amounts, believing they are insufficient to prevent some health problems. For example, many doctors and nutritionists recommend an intake of at least 500 mg per day for adults, 14 others recommend even higher amounts.
Certain individuals and those with certain conditions who are more prone to deficiency may also require additional intake and supplements to meet their bodily needs.
Conditions that may require greater magnesium intake include diabetes, frequent alcohol and/or drug consumption, and conditions that require use of certain medications such as diuretics and the anti-cancer drug cisplatin.
In addition, all forms of kidney disease can influence magnesium absorption. However, kidney patients are not advised to take supplements, due to problems with their ability to process minerals. Those with kidney disorders are advised to consult a qualified health practitioner for advice on managing proper magnesium levels.
Why are good magnesium sources so important?
The list of common health disorders related to magnesium deficiency is growing, and now more than ever it is important to build a diet and supplementation program that meets or exceeds recommended magnesium requirements.
In fact, the National Institutes of Health DASH diet plan (Dietary Approaches to Stopping Hypertension) includes 50% more magnesium than the US RDA. 15
Regarding the safety and use of magnesium supplements for health, Dr. Allan Magaziner has said:
Magnesium has so many beneficial effects, often patients will see other things improve such as muscle aches, general fatigue, and sleep. I find magnesium to be a very safe substance. 16
A solid combination of good sources of magnesium through diet and supplementation is a safe and effective way to combat deficiency and to ensure you get enough magnesium to stay healthy, before deficiencies arise.
Magnesium is a vital nutrient whose biochemical role in the body influences a vast array of the body’s systems. It deserves its place high in the list of nutrients of concern for those who wish to be healthy and stay healthy.
References [ + ]
|1.||↑||World Health Organization. Calcium and Magnesium in Drinking Water: Public health significance. Geneva: World Health Organization Press; 2009.|
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|10.||↑||Seelig M, Rosanoff A. The Magnesium Factor. New York: Avery; 2003.|
|11.||↑||Altura BM, Altura BT. Magnesium: Forgotten Mineral in Cardiovascular Biology and Therogenesis. In: International Magnesium Symposium. New Perspectives in Magnesium Research. London: Springer-Verlag; 2007:239-260.|
|12.||↑||Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research. 2001; 14: 257-62.|
|13.||↑||American Dietetic Association. Complete Food and Nutrition Guide. Hoboken, NJ: John Wiley and Sons; 2006.|
|14.||↑||Pressman A. Vitamins and Minerals. New York: Alpha Books; 2007.|
|15.||↑||U.S. Department of Health and Human Services, U.S. Department of Agriculture. Adequate Nutrients Within Calorie Needs. In: Dietary Guidelines for Americans 2005. 2005. Available at: http://www.health.gov/dietaryguidelines/dga2005/document/pdf/DGA2005.pdf. Accessed January 28, 2010.|
|16.||↑||Cohen JS. The Magnesium Solution for Migraine Headaches. New York: Square One Publishers; 2004.|