Magnesium is needed within the body for many different reasons – strong teeth and bones as well as a healthy cardiovascular and nervous system. Concern regarding magnesium status in the body is not often brought up to me by clients – with the exception of clients dealing with renal insufficiency. This is likely because when we get our annual blood work done, magnesium doesn’t seem to ever come up as a red flag for being “outside of the normal range”. This is due to the fact that 99% of magnesium is located in bone, soft tissues and muscles and these values are not accurately reflected in a blood test. Magnesium levels are best detected via a 24-hour urine analysis rather than a blood test.. and how many of us do 24-hour urine analyses on a regular basis? Not many.
Other factors that can lower magnesium levels include:
▪ Drinking too much coffee, soda, or alcohol
▪ Eating too much sodium (salt)
▪ Heavy menstrual periods
▪ Excessive sweating
▪ Prolonged stress
Symptoms of low magnesium levels are:
▪ Agitation and anxiety
▪ Restless leg syndrome (RLS)
▪ Sleep disorders
▪ Nausea and vomiting
▪ Abnormal heart rhythms
▪ Low blood pressure
▪ Muscle spasm and weakness
▪ Poor nail growth
Symptoms that I tend to see most frequently in my practice that are positively impacted by an increase in magnesium-rich foods of a magnesium supplement are: sleep disorders, muscle spasms, and restless leg syndrome. Magnesium citrate taken in the evening can also help with regularity of bowel movements.
I always recommend food first.. so let’s take a look at the daily magnesium recommendations some nutrient-dense foods that contain magnesium
▪ Males, 19 to 30 years of age: 400 mg daily
▪ Females, 19 to 30 years of age: 310 mg daily
▪ Males, 31 years of age and over: 420 mg daily
▪ Females, 31 years of age and over: 320 mg daily
▪ Pregnant females, 19 to 30 years of age: 350 mg daily
▪ Pregnant females, 31 and over: 360 mg daily
▪ Breastfeeding females, 19 to 30 years of age: 310 mg daily
▪ Breastfeeding females, 31 years of age and over: 320 mg daily
Food; Serving Size; Magnesium (mg)
Vegetables and Fruits
Spinach, cooked 125 mL (½ cup) 83
Swiss chard, cooked 125 mL (½ cup) 80
Potato, with skin, cooked 1 medium 47-52
Okra, cooked 125 mL (½ cup) 50
Quinoa, cooked 125 mL (1/2 cup) 47
Meats and Alternatives
Legumes (dried beans, peas and lentils)
Peas, black-eyed peas/cowpeas, cooked 175 mL (¾ cup) 121
Beans (black, lima, navy, adzuki, white kidney, pinto, Great Northern, cranberry, chickpeas), cooked 175 mL (¾ cup) 60-89
Lentils, split peas, cooked 175 mL (¾ cup) 52
Nuts and Seeds
Pumpkin or squash seeds, without shell 60 mL (¼ cup) 317
Brazil nuts, without shell 60 mL (¼ cup) 133
Sunflower seed butter 30 mL (2 Tbsp) 120
Sunflower seeds, without shell 60 mL (¼ cup) 119
Almonds, without shell 60 mL (¼ cup) 88-109
Cashews, without shell 60 mL (¼ cup) 90
Pine nuts, without shell 60 mL (¼ cup) 70-86
Cashew butter 30 mL (2 Tbsp) 84
Flaxseeds 30 mL (2 Tbsp) 78
Sesame seeds 30 mL (2 Tbsp) 56-68
Peanuts, without shell 60 mL (¼ cup) 65
Chinese chestnuts, without shell 60 mL (¼ cup) 54
Peanut butter 30 mL (2 Tbsp) 50-52
Hazelnuts, without shell 60 mL (¼ cup) 48-52
Fish and Seafood
Salmon, Chinook, cooked 75 g (2 ½ oz) 92
Halibut, cooked 75 g (2 ½ oz) 80
Mackerel, Atlantic, cooked 75 g (2 ½ oz) 73
Pollock, Atlantic, cooked 75 g (2 ½ oz) 64
Crab, Atlantic snow, cooked 75 g (2 ½ oz) 47
Meat and Poultry These foods contain very little of this nutrient.
There is quite a bit of concern regarding the magnesium content of our soil (or lack thereof) due to our current agricultural practices. Many experts say that magnesium is one of the most depleted minerals in farm soils today. Increased use of NPK fertilizers (NPK standing for nitrogen, phosphorus, potassium) has led to much of this controversy regarding the magnesium content of our soil. Potassium and phosphorus are antagonists of magnesium and as a result, can create magnesium deficiencies in the soil. Acid rain causes magnesium to leach from the soil and therefore, it is unavailable for the crop. Finally, genetically modified hybrid plants that are continuously being introduced to our food supply are bred to grow in soil that is depleted of these minerals making it less important that the mineral content of the soil is adequate. Your best bet to avoid purchasing fruits and vegetables that are depleted in these minerals is to talk to your local farmer about his/her soil replenishment practices.
If we decide that a supplement will be helpful – remember, the form of the supplement matters! I often look at nutrition supplement labels when I am browsing through the pharmacy and see “magnesium oxide” as the magnesium source of many multi-vitamin/mineral supplements. This is unfortunate, as magnesium oxide is poorly absorbed and utilized within the body, however many supplement manufacturers use it because it is less expensive than other forms of magnesium. The two that I tend to stick with, based on the success experienced with my clients are: magnesium glycinate (I typically only find this in health food stores) or magnesium citrate (this is commonly found in the pharmacy). I also really like the idea of using magnesium (in the form of salts or oil) topically to be absorbed through the skin.
According to Dr. Sealy “transdermal therapy creates “tissue saturation”, which allows magnesium to travel to the body’s tissues and cells at a high dose without losses through the gastrointestinal tract”.
Several commonly prescribed medications can cause us to lose more magnesium in our urine. Some of these medications include, but are not limited to, diuretics, insulin, birth control pills, corticosteroids, tetracycline and other antibiotics just to name a few.
You may notice if you’re shopping for a calcium supplement that they usually come in the form of calcium/magnesium. This is due the fact that magnesium helps prevent calcium from being deposited into the soft tissues in the body. Magnesium also assists with the conversion of vitamin D to it’s active form in the body, which also increases the absorption and utilization of calcium in the body. It is important to note that although magnesium assists with proper utilization of calcium within the body, calcium actually interferes with the absorption and utilization of magnesium. Therefore, magnesium in the form of a calcium/magnesium supplement is NOT a good source of magnesium.
Since the kidneys are responsible for excretion of magnesium, people with heart or kidney disease should not take magnesium supplements except under their doctors’ supervision.
So what can we do to increase our intake and absorption of magnesium from our food sources?
•Regularly consume foods higher in magnesium
•Consume nuts that are raw and soaked (to help reduce phytic acid content) rather than roasted (I will discuss this in a future post)
•Filter water to get rid of fluoride (check out reverse osmosis water filters – not all water filters filter fluoride)
•Decrease (or better, eliminate) intake of processed foods
•Be mindful of the amount of tannins, phytic acid and oxalates we are consuming – all of these compounds bind to magnesium in the body, making utilization difficult (again, we will talk more about this later)
•Talk to your local farmer at the market about soil replenishment practices
Hopefully this post shed some light on the importance of adequate magnesium status in the body. Please don’t hesitate to let me know if you have any further questions.
Yours in Health,