Magnesium-What You Need to Know


Often called the invisible deficiency, low magnesium (Mg) intake is a common problem. Estimates vary but somewhere between 50-80% of us don’t have enough. Scientists have theorized that since farmers do not replace Mg taken up by crops, the soil, over time has become depleted and therefore, the food we eat contains less magnesium with each harvest. Since Mg is involved in over 300 enzyme interactions in our bodies that regulate everything (including energy, digestion, RNA/DNA synthesis, neurotransmitter formation and muscle and nerve function), this is a mineral you want to keep topped up.

Detecting low magnesium levels is tricky. The common blood test only finds the most critically low individuals since a mere 1% of the mineral is found in blood. The truly interested can get a Mg RBC test at for $49 that is more reliable but there is little downside to increasing consumption of high Mg foods and, in most cases, supplementation.

Symptoms of mg. deficiency can include:
Weakness                         heart irregularity                      muscle spasm

nausea/vomiting           fatigue                                             personality change

eye twitches                     numbness                                     tingling

constipation                     insomnia

How much do you need? The RDA recommends a minimum of 320mg/day for adult women and 420mg for adult men over the age of 30 with supplement recommendations running 400 to 1000mg/day depending on your health status. Several conditions lead to Mg wasting including type 2 diabetes (diabetics excrete more Mg in their urine and bind more to the sugar in their blood making it unavailable for other interactions), Crohn’s disease, GI resection, celiac disease, alcohol use, heavy soda drinking, high salt or caffeine intake, heavy menses, high stress (physical as well as psychological) and use of any of these medications: diuretics, ACE inhibitors, statins, fluoride, cipro and antacids/acid blockers. Folks who should not supplement Mg until they talk to their doctor include anyone with kidney disease or severe heart disease.

A rule of thumb for supplementing Mg is that you know when it’s too much if you develop diarrhea. While that is largely true, there are several types of Mg supplementation and not all of them lead to loose stools. Magnesium cannot exist elementally by itself and must be bound to another molecule for stability. If considering a supplement, it could matter what form you take.

Magnesium Oxide: cheap, readily available, poorly absorbed, softens stool

Espsom Salts (Mg Chloride) or Mg oil: Well absorbed through the skin, used topically as a bath additive or massage oil, it is cheap, easy to get and harder to take too much. Should not cause GI symptoms

Magnesium glycinate: good absorption, least likely to cause diarrhea, has more of a calming effect as the Mg is bound to glycine which is a calming neurotransmitter

Magnesium sulfate: found in Milk of Magnesia, has a large laxative effect. Not recommended as a Mg supplement source

Magnesium Citrate: Laxative, well absorbed

Magnesium carbonate and gluconate both have poor absorption

Magnesium L-threonate: A new player in the Mg market. The only one to cross the blood brain barrier and show benefit to cognition (see this study if you want more info)


The safest, and best tasting, way to get your Mg fix is in food. 30-40%  of the Mg in food is absorbed. Foods high in Mg include:

Dark leafy greens                   nuts (brazils, cashews, almonds)

herbs                                              avocado                                        wheat/oat bran

sunflower seeds                      shrimp                                            beans

brown rice                                 artichokes                                     pumpkin seeds

garlic                                             dark cocoa powder

There are also several steps you can take to keep the Mg you have:

Don’t drink soda (the phosphates in the soda bind Mg)

avoid sugar and caffeine

limit alchohol to one drink per day

People who need more Mg, usually need more B6, Vitamin D and selenium to use it well. A good multivitamin should cover these bases. Magnesium is best taken on an empty stomach and not within 2 hrs. of taking a calcium supplement.

Want a recipe for a high magnesium smoothie? Thought so 🙂


Magnificent Magnesium Chocolate Smoothie

1 cup spinach leaves

1 tablespoon raw cashews

2 tablespoons unsweetened black cocoa powder ( I use Bloomers)

1 ½ frozen bananas

4 ice cubes

1 cup cold water

Add all ingredients to a blender and blend until smooth. Makes a bit more than 2 cups of smoothie. If you drink the whole thing, it will give you 279 mg of magnesium, 224 calories, 4.5 grams of protein, 23% of your potassium, 59% of your daily vitamin A and 12% of your daily iron requirements. Definitely a healthy chocolate fix!





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