Magnesium: Do I need more?by Tina Greco, PharmD
How do I tell if my magnesium is low?
The majority of magnesium lies in our bone and muscle with less than 1% in the serum (or blood). Blood levels of magnesium are tightly controlled by the body (normal is 75-95 mmol/L). To assess your status, the total serum magnesium concentration is the most common test ordered by your physician. This blood test has limitations as it does not accurately reflect intracellular or total body magnesium stores- so a normal result may not be the whole story. Alternative tests do exist, but each have pros and cons.
What foods are magnesium rich?
Think of green leafy vegetables, nuts and seeds as your most powerful tools to increase magnesium levels. Whole grains including whole wheat bread and brown rice can also contribute magnesium to your diet. Thankfully, dark chocolate with greater than 70% cacao is also a good source. For more information check out this magnesium fact sheet from the National Institutes for Health.
Magnesium Supplements: How do I pick?
Magnesium products come in a variety of forms and it can be confusing. Magnesium salts with relatively good absorption, or bioavailability, include citrate, lactate and chloride. Chelated magnesium forms such as malate, lysinate, glycinate, orotate, and taurate also have good absorption profiles. How do you decide which is best for you? It depends on what you want to achieve.
- Magnesium chloride is best topical form of magnesium, and has good absorption rate. It is great for detoxing and metabolic function.
- Magnesium citrate can have more of a laxative effect than other forms, so it may be a better choice if regularity is important. However, it is not recommended to use long term as it may affect your levels of iron and copper in your body.
- Magnesium glycinate is great if muscle cramps, tightness or anxiety are of concern. This magnesium is bound to the amino acid glycine which itself is calming.
- If cramping or fatigue is an issue, magnesium malate is involved in ATP or energy production and supports proper muscle function. Thus, it is great for athletes. It’s also good for someone suffering with fibromyalgia.
- Magnesium oratate and taurate have good absorption rate and have a calming effect. They are good for cardiovascular health and athletic performance. Magnesium Taurate in particular is great for people who are troubled by insomnia.
- Magnesium sulfate is in the famous Epsom Salt. It is calming but does not have a lasting effect due to poor absorption. Great for achy muscles.
Regardless, the label should indicate the elemental magnesium -or actual amount of magnesium- in the product, but keep in mind that not all of the dose will actually be absorbed. To investigate a product, try Consumer Lab to see if it has been independently tested. The tolerable upper limit for supplementation or fortified food as set by the Food and Nutrition Board is 350 mg/day for both adult females and males. If you are deficient, your supplementation need may be higher. From your diet, the recommended dietary allowance (RDA) for magnesium is 320 mg for women and 420 mg for men. Often the first sign of magnesium excess is diarrhea (which is why it can be used as a laxative), so if you have loose stools decrease your supplement dose and/or rotate your food choices.
Think of green leafy vegetables, nuts and seeds as your most powerful tools to increase magnesium levels.
Magnesium L-Threonate: Is it just for the brain?
Magnesium l-threonate is a newer form that really deserves its own category. Developed at MIT, it has been shown in an animal models to enter the brain and enhance the neuronal networks needed for learning and memory. As a result, it is not the best choice for ensuring adequate body stores but a good one for those interested in potentially optimizing brain function and sleep quality.
Dean, Carolyn. (2014) The Magnesium Miracle. https://drcarolyndean.com/magnesium_miracle/
Oregon State University, Linus Pauling Institute: http://lpi.oregonstate.edu/mic/minerals/magnesium#RDA