Magnesium is one of my favorite minerals. Might seem a funny thing to say, but magnesium is so important for our health, yet approximately 50% of us don’t get the recommended daily allowance (RDA) of it in our diet. This means that for many, a little supplementation can go a long way to quickly improve symptoms. Magnesium is involved with more than 350 different enzyme reactions in the body, and virtually every system in the body needs magnesium to function. 

As we saw in my previous post about minerals, magnesium deficiency is associated with 7 of the top 9 causes of death. Chronically low levels of magnesium have been linked to high blood pressure, heart disease, diabetes, sudden cardiac death, migraines, Alzheimer’s disease, menstrual cramps, depression, osteoporosis, asthma, and also cancer. Conversely, an adequate level of magnesium is linked to longevity.

Magnesium is the fourth most abundant mineral in our body. We have about 25g of magnesium in our bodies. It is distributed with ~55% stored in the skeleton, ~35%  in muscles and soft tissues, 6-7% inside cells, and the remaining ~1% or so in the blood. 

What does magnesium do?

With its involvement in over 350 different functions, magnesium does a lot of different things. These include:

  • metabolism of carbohydrates, proteins, and fats
  • energy production – ATP
  • maintains nervous system balance
  • enhances blood sugar control
  • cofactor in methylation
  • production of DNA, RNA and proteins
  • involvement in nerve impulses
  • muscle contractions
  • maintaining heart rhythm
  • synthesis of glutathione – key antioxidant and detoxifying chemical in our bodies.

Why don’t we get enough magnesium?

There are food sources of magnesium, but our intake levels have fallen because:

  1. Foods have reduced levels of magnesium due to processing. For example, refined grains have had  80-97% of magnesium removed; oil refining removes magnesium from seed oils. 
  2. Plants don’t make magnesium like they do some other micronutrients. The amount of magnesium in a plant is largely dictated by the amount of magnesium in the soil that the plant grows in. Because the levels of magnesium in our soils have reduced, even less magnesium gets into the plants we eat. Since 1940, the magnesium levels in vegetables have declined by 24%, in fruit by 17%, in meat by 15%, and in cheeses by 26%. Soil contains mineral-fixing bacteria. Pesticides reduce the level of this bacteria, which further impacts the magnesium level in the soil.
  3. Our eating habits have changed, and we have moved away from eating whole foods. 

Who is at particular risk for magnesium deficiency

As we’ve seen above, our intake of magnesium has lowered – and at least half of us are deficient in magnesium. To answer the question “who is at risk for magnesium deficiency?”  –  ALL OF US! 

But some parameters can increase our risk:

  • Some medications can affect our magnesium levels. These include:
    • diuretic drugs, often used for hypertension/high blood pressure
    • proton pump inhibitors used for heartburn/reflux
    • chemotherapies
    • immunosuppressive agents
    • antibiotics
  • Lifestyle and other factors can deplete magnesium:
    • alcoholism or long-term drinking
    • drinking dark colored sodas (these bind with magnesium and prevent absorption)
    • high calcium intake with a high salt diet (increases magnesium excretion)
    • age (as we age, we absorb less magnesium from the gut)
    • gastrointestinal diseases (such as Crohn’s disease)
    • diabetes
    • diarrhea
  • Stress in our lives can cause magnesium depletion and can lead to a deficiency. Any kind of prolonged stress, whether psychological or physical, can result in deficiencies. 

Recommended daily allowance for magnesium

The recommended daily allowance varies by age and gender:

  • Men aged 19-30 – 400 mg magnesium a day
  • Men aged over 30 – 420mg magnesium a day
  • Women aged 19-30 – 310mg magnesium a day
  • Women aged over 30 – 320 mg magnesium a day 
  • Different levels apply to pregnant and nursing women

These levels should come from food, water and any supplementation we might take. 

BUT, these levels don’t take into consideration if you have any risk factors for deficiency, e.g., if you have chronic stress, and are a woman aged 50, 320mg a day probably isn’t enough for you as you utilize more magnesium every day due to the stress. 

Signs of deficiency

Some of the signs of magnesium deficiency include:

  • fatigue
  • anxiety
  • migraines and headaches
  • menstrual cramps
  • leg cramps
  • tingling and numbness in arms and legs – restless legs
  • muscle weakness
  • tremors
  • elevations in blood pressure – hypertension

How do you test for your magnesium level?

To test for magnesium deficiency, you need to take a red blood cell magnesium test. This test looks at the magnesium levels inside the cells. You can request this test from your healthcare practitioner, or you can order the test yourself from one of the available direct labs or from Life Extension. Make sure the test says “red blood cell magnesium” or “rbc magnesium.” (Measuring plasma levels of magnesium is not a sensitive test for magnesium deficiency.)

Food sources of magnesium

“Excellent” and “very good” food sources of magnesium include pumpkin seeds, spinach, swiss chard, and summer squash. A family member of mine had restless leg syndrome at night and I suggested she eat a handful of pumpkin seeds before she went to bed. It solved the problem. 1/4 cup of pumpkin seeds contains 190mg of magnesium – more than half the daily requirement for women. Another example is one cup of spinach has ~150mg magnesium. 

Other “good” sources include black beans, sesame seeds, almonds, cashews, quinoa, soy beans, brown rice, tuna, oats, and dark chocolate. One cup of black beans has ~120mg of magnesium while 1/4 cup of cashews contains ~115mg magnesium.

However, for proper absorption of magnesium, you need to also have adequate protein intake. If your protein intake is less than 30g a day, your body can’t absorb magnesium very well. 

For more information on magnesium food sources, check out the website World’s healthiest foods (for more on that site, see our previous WHFoods blog post)

Supplementing with magnesium

If you are deficient in magnesium and need to supplement your intake, you have several options.  

Oral magnesium

There are many different types of oral magnesium capsules, but some of them can cause loose stools or diarrhea. The form that I recommend is magnesium glycinate. This is highly absorbable yet doesn’t tend to cause diarrhea.

Dermal magnesium

This is actually the form I recommend most, as magnesium is easily absorbed through the skin.  There are two main options:

a) Epsom salts. Have a regular Epsom salts bath or foot soak. Not only does this improve your magnesium levels, but laying in the bath or having your feet in warm water is relaxing too, and thus reduces your stress levels. Epsom salts are inexpensive and some are available with lavender or chamomile, or other scents to further the relaxation. Sprinkle one cup of salts in the bath or foot bath.

b) Magnesium “oil” spray. Although the name suggests that this is an oil, it feels just like water and isn’t oily at all. If choosing an oil, get one for sensitive skin, as some can cause tingling of the skin.  The best way to use these products is to spray your arms or legs just before you go to bed. As magnesium is relaxing to the body and muscles, it can help you sleep at night. However, you can use it at other times of the day, such as after a shower, and it won’t cause drowsiness. Here are a couple of versions I have used: in the US and Better for you magnesium oil in the UK.

These dermal products can be used when you feel specific symptoms of deficiency too. For example, if you have joint pain or a headache, soak in Epsom salts. Or if you have a headache, apply a little magnesium oil to your temples. If you have muscle cramps or joint pain, spray the muscle/joint. You might find rapid relief of your symptoms. 

Magnesium ‘partners’

Magnesium, calcium, vitamin D, and vitamin K2 all work together in the body so you need to ensure adequate levels of all of these, but not too high levels of any one, otherwise they will interfere with absorption.

Who should avoid supplementation?

If you have poor kidney function, it is much more difficult to excrete excess magnesium. However, supplementation might be very important for those of you with poor kidney function, so you should  supplement under the supervision of a healthcare provider. 

Take home message about magnesium

  • Magnesium is considered by some to be the ‘next vitamin D’ – meaning its value has been unrecognized until recently, it is low in cost, associated with many different health benefits, and many of us are deficient in it. 
  • Magnesium deficiencies are associated with many chronic diseases.
  • Stress increases our requirement for magnesium so prolonged stress may lead to deficiency.
  • Test your levels with a red blood cell magnesium test.
  • There are options for supplementing if you have a deficiency including relaxing Epsom salt baths/soaks and dermal magnesium sprays. These are particularly useful if you don’t like to take pills.

We’ll look at other important minerals in the next few weeks, but for now, go and take that Epsom salts bath and relaaaaaaax (or if you are at work, maybe wait until you get home!)

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