Abstract: Magnesium is a very important mineral that is responsible for many enzymatic reactions in the body - creating biologically active ATP (cellular energy) among many other functions. Magnesium is associated with stress, leg cramps, and insulin resistance, leading to the development of metabolic syndrome. The need for magnesium increases during pregnancy and inadequate intake is associated with various complications, including preeclampsia. Even though magnesium is found in a lot of different foods, deficiency is common, due to modern dietary habits. Supplements can be very useful and certain forms (magnesium glycinate and magnesium malate) are shown to be highly bioavailable and typically not associated with any gastrointestinal side effects. 

What is Magnesium? Why Do I Need It? 

Magnesium is everywhere (the fourth most abundant element in the human body); it is involved in practically every significant metabolic and biochemical process within the cell and is responsible for numerous functions in the body. 

• Bone Development "Calcium Helper" 
• Neuromuscular Function "Nature's Muscle Relaxer" 
• Signaling Pathways (Nerve Impulse Conduction)
• Energy Storage and Transfer
• Glucose, Lipid, and Protein Metabolism
• DNA/RNA stability
• Activation of the Immune System
• Regulation of Cardiac Rhythm (Blood Pressure Regulation)

Magnesium is highly involved in many cellular processes, and scientific research has cataloged  magnesium as a cofactor for over 600 enzymes. Habitually low intakes of magnesium induce changes in biochemical pathways, leading to an increased risk of illness over time. 

Where is magnesium kept? More than 99% of the total body magnesium is located in the intracellular space, mainly stored in bone but also muscle, soft tissues, and organs. Magnesium, calcium, and phosphorus make up our skeleton. Less than 1-2% of total body magnesium is in blood and extracellular fluids. 

Have you heard of the ever-important ATP? ATP is the cell's energy and needs to be bound to magnesium to be biologically active. Magnesium is required for energy production and glycolysis, the process by which glucose is turned into energy. Magnesium is necessary to synthesize DNA, RNA, and the antioxidant glutathione. 

Signaling Pathways - magnesium is an  essential component of the central nervous system's extracellular and cerebrospinal fluid. Magnesium enters the brain through the blood-brain barrier, which maintains the passage of nutrients and electrolytes for the homeostasis of extracellular fluid. 

Deficiency is common and an issue; however, our body helps us out by trying to keep magnesium levels stable. Magnesium homeostasis is tightly regulated and relies on the dynamic balance between intestinal absorption, kidney excretion, and storage in bones. Magnesium in bones serves as a reservoir to maintain equilibrium with its extracellular concentration. 

Magnesium and Stress

Can magnesium levels impact stress? Yes, magnesium plays an inhibitory key role in the regulation and neurotransmission of the normal stress response. 

What came first? The chicken or the egg? Stress can increase magnesium loss, causing a deficiency. However, magnesium deficiency can also enhance the body's susceptibility to stress, resulting in a magnesium and stress vicious cycle. Lower magnesium levels are associated with depression, post-traumatic stress disorder, anxiety disorders, attention deficit hyperactivity disorder, and bipolar disorder. A causal factor between mental disorders and magnesium deficiency is not confirmed, but stress appears to be a key component in the relationship between mental health illness and magnesium deficiency. Magnesium promotes GABA activity, resulting in a mostly inhibitory effect. The progressive loss of magnesium from the reservoir in bone can eventually compromise its physiological inhibitory action and lead to an over-action of the HPA axis and neuronal hyperactivity. 

Magnesium supplementation has shown some promising results in research in connection to symptoms of daily psychological stress. 

• 250 mg/day in male students experiencing sleep deprivation, malnutrition, and a lack of physical activity showed an increase in erythrocyte magnesium and a reduction in serum cortisol. 
• 400 mg/day in subjects partaking in moderate muscle endurance training each week experienced a significant improvement in heart rate variability, an indicator of the parasympathetic nervous systems' response to stress. 
• 300 mg/day in subjects reporting severe stress levels experienced a 45% reduction in Depression Anxiety Stress Scale scores. 

Why is Magnesium Important During Pregnancy? 

Magnesium is beneficial for both you and your baby during pregnancy. Pregnancy demands more magnesium, so once you are pregnant, you are at a higher risk of developing magnesium deficiency - this can lead to maternal, fetal, and pediatric consequences. Magnesium deficiency during gestation may interfere with fetal growth and development and may lead to adverse neurodevelopmental outcomes. A deficiency can also lead to premature labor. Preterm delivery is due to uterine hyperexcitability caused by chronic maternal magnesium deficiency and is intensified in situations of maternal stress. Gestational magnesium deficiency may induce significant maternal, fetal, and pediatric effects, which could last throughout life. 

The research says…

• Randomized control trial involving three groups of 60 pregnant women over the pregnancy term: Experiment demonstrated that pregnancy outcomes such as preeclampsia, intrauterine growth restriction, leg cramps, preterm birth, low birth weight, maternal body mass index, neonatal weight, and gestational diabetes were all significantly better in the group that received Magnesium supplementation (300 mg/day) versus the control group. 
• Another study utilizing a group of over 500 women demonstrated that 300 mg/day of magnesium was associated with optimum birth weight, length, and head circumference. 
• One study evaluated maternal magnesium status during gestation concerning cognitive outcomes of neonates. Magnesium serum levels were measured at 26-28 weeks of pregnancy, and the infants' mental development was evaluated at four years of age. Higher maternal magnesium serum levels were associated with higher scores in letters and writing identification, suggesting the existence of long-term influences of maternal magnesium on a child's cognitive development. 

Low magnesium levels during pregnancy are associated with the onset of various diseases throughout life. Maternal hypomagnesemia has been related to the insurgence of metabolic syndrome later in life. Fetal hypomagnesemia has been associated with restricted fetal growth, which many epidemiological studies have linked to an increased risk of insulin resistance. This hypothesis states that severe magnesium deficiency in pregnant women might program the insurgence of insulin resistance in newborns, leading to the onset of metabolic syndrome in childhood and beyond. 

At the level of only very sophisticated speculation, magnesium status could potentially be linked to sudden infant death syndrome (SIDS). Low magnesium intake during gestation might lead to impaired control of thermoregulation mechanisms of the infant, which is a simplified description of the scientific connection to SIDS. 

Magnesium and Leg Cramps 

As confirmed by multiple studies, low serum magnesium level (hypomagnesemia) is associated with leg cramps during pregnancy. Magnesium has a muscular relaxation effect on the neuromuscular junction and is related to the release of acetylcholine, the chief neurotransmitter of the parasympathetic nervous system. 

Am I Getting Magnesium From Food? 

Many naturally grown foods contain magnesium. Foods containing dietary fiber generally provide magnesium, as well. However, consumption has declined over the years due to changes in dietary habits (higher consumption of processed foods rather than whole foods), soil quality, and food processing. Soil depletion has caused magnesium levels to decline in certain foods. Organic and biodynamic farms typically have higher magnesium in the soil, which the crops take up, creating more magnesium-rich produce.

Foods high in magnesium include almonds, bananas, black beans, broccoli, brown rice, cashews, flaxseed, green vegetables (spinach and seaweed), nuts, oatmeal, seeds (pumpkin, sesame, sunflower, chia), avocados, sweet corn, tofu, and whole grains. 

• • • 1 ounce of pumpkin seeds (156 mg)
    • 1 ounce of chia seeds (111 mg)
    • 1 ounce of almonds (80 mg)
    • ½ cup of cooked spinach (78 mg)
    • 1 ounce of cashews (74 mg)
    • ½ cup of black beans (60 mg)
    • 2 tablespoons peanut butter (49 mg)
    • 1 cup of cubed avocado (44 mg)
    • ½ cup of brown rice (42 mg) 
    • 1 packet of instant oatmeal (36 mg)
    • 3 ounces of chicken breast (22 mg)

Other good sources include unsweetened cocoa powder (dark chocolate), bone broth, wheat germ, bran cereal, quinoa, soybeans, baked potato, yogurt, and green herbs including chives, cilantro, parsley, mint, dill, sage, and basil. 

Magnesium also has a relatively high absorption rate, with approximately 30% to 40% of dietary magnesium absorbed by the body. 

Who Is At Risk For a Deficiency? 

Research, including a great number of epidemiological, clinical, and experimental studies, has demonstrated the significance of low magnesium over the last 20-30 years. Scientific literature highlights the association between low dietary magnesium intake and a higher risk of type 2 diabetes, cardiovascular disease, gastrointestinal diseases, osteoporosis, metabolic syndrome, and alcohol dependence. Since magnesium is so important to the functioning of many human body reactions, a deficiency increases the risk of physical and mental health issues over time. 

Despite its prevalence in various foods, subclinical magnesium deficiency is not uncommon among the general population. Studies estimate that approximately 50 percent of the American population does not meet the recommended dietary allowance of magnesium. Young adults, those over 70 years of age, and women are the most at risk for inadequate nutritional intake of magnesium. A low dietary intake can cause deficiency, but many lifestyle factors also play a role. Poor nutrition, excess alcohol intake, use of diuretics, oral contraceptives, antibiotics, and lower mineral content in commonly eaten foods makes subclinical magnesium deficiency not uncommon. Over the past 60 years, intensive farming practices have caused a significant depletion of the mineral content of the soil, leading to a decrease in magnesium within many fruits and vegetables. Dietary habits that consist heavily of refined processed foods, where magnesium is depleted up to 80-90%, contribute to the prevalence of deficiency. A diet high in sodium, calcium, protein, and caffeine/alcohol can also lower magnesium retention. Intense physical activity, poor sleep quality and quantity, and psychological stress induce magnesium loss. Lastly, physiological conditions such as pregnancy, menopause, and aging are all associated with changes in the need for magnesium. Magnesium deficiency is even more common during pregnancy. Research has found that magnesium depletion, especially in the presence of calcium excess, can predispose women to vascular complications (such as preeclampsia). Women with gestational diabetes are also commonly deficient in magnesium. 

Most women will not have obvious symptoms of magnesium deficiency - however, symptoms of magnesium deficiency and stress are very similar, the most common being fatigue, irritability, and mild anxiety. Early signs of magnesium deficiency include weakness, loss of appetite, fatigue, nausea, muscle cramps, and vomiting. 

Groups that need to be most aware of their magnesium intake include those who have: 

• Gastrointestinal Diseases - Crohn's disease, Celiac Disease 
• Type 2 Diabetes
• Alcohol Dependence 
• Are Pregnant 

What About Toxicity? 

From food? Not a risk of toxicity. 

From dietary supplements or medications? High doses can result in diarrhea, nausea, and abdominal cramping. Forms of magnesium most commonly reported to cause diarrhea include magnesium carbonate, chloride, gluconate, and oxide. 

However, overall, magnesium supplementation is considered well-tolerated. The upper limit for magnesium supplementation in healthy adults is 350 mg/day. An increased renal filtration can reverse a wide range of serum magnesium concentrations to normal levels. However, serious adverse effects have been reported for a serum magnesium concentration exceeding 1.74-2.61 mmol/L. 

Do I Need A Magnesium Supplement? Which Form Is Best? 

Magnesium is a bulky ingredient, making it harder to include in prenatal formulations, increasing the cost and capsule quantity. However, the importance of magnesium makes its inclusion often necessary. A daily supplement of 200 mg of chelated magnesium is suggested to be likely safe and sufficient to increase serum magnesium concentration to levels >0.85 mmol/L but <1.1 mmol/L. A steady-state is usually achieved in 20-40 weeks of supplementation and is dependent on the dose. Appropriate dosing typically ranges from 100-300 mg/day. 

As with most supplements, form does matter. Magnesium glycinate is a highly bioavailable and well-tolerated form of magnesium. And one of the least likely to cause GI side effects. Magnesium citrate is a good choice if you can benefit from faster transit time (dealing with constipation). Small studies have found that magnesium in the aspartate, citrate, lactate and chloride forms is absorbed more completely and is more bioavailable than magnesium oxide and magnesium sulfate. 

One form chelated dimagnesium malate is a molecule with magnesium salts on both ends. It has a high potency of magnesium, which is also bioavailable. Other forms are more bioavailable but can cause GI issues. Several human studies have shown that magnesium chelates are more bioavailable than magnesium oxide, despite its potency. Chelated minerals mimic the forms minerals take when inside cells (which are many and ever-changing) and have been demonstrated to be easier on your GI system. 

Another way to get magnesium is through your skin by taking Epsom salt baths or foot soaks (Epsom salt is magnesium sulfate).  

How Much Magnesium Do I Need? 

• • • RDA for Women 19-30 years old 310 mg | Pregnancy 350 mg
    • RDA for Women 31-50 years old 320 mg | Pregnancy 360 mg

How Do I Know If I Am Getting Enough Magnesium? 

In clinical practice, serum magnesium levels are considered a Mg marker. Magnesium status is hard to determine because most magnesium in the body is in cells or bone. However, the most commonly used and readily available method for assessing magnesium status is a measurement of serum magnesium concentration, even though serum levels have little correlation with total body magnesium levels. 

The estimation of the mean normal magnesium value in an average person is about 0.9 mmol/L Mg (2.1 mg/dL). Anything less than that and symptoms associated with magnesium deficiency may appear. 

Magnesium homeostasis is related to calcium and potassium status and should be evaluated in combination with these two cations. Emerging evidence suggests that serum magnesium/calcium quotient is a more practical and sensitive indicator of magnesium status than the serum magnesium level alone. Lastly, red blood cell magnesium levels could better reflect body magnesium status than blood magnesium levels. When the magnesium concentration in the blood is low, magnesium is pulled out from the cells to maintain blood magnesium levels within the normal range. Therefore, in a deficient state, a blood test of magnesium might show normal levels, while a RBC magnesium test would provide a more accurate reflection of the magnesium status of the body. 

Prenatal Vitamin Brands: What's the Magnesium Amount and Type in Popular Prenatal Brands?

Prenatal Analysis: 

Dimagnesium malate and magnesium glycinate forms have both been studied to be effective, bioavailable, and digestively harmless. Magnesium oxide is the most common and the least expensive form; it is not the most bioavailable and is also connected to loose stools or diarrhea. A dose of less than 50 mg of magnesium might not do much. Particularly if there is a deficiency, magnesium supplementation dosing should be between 100-300 mg/day. 

Resources: 

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