Maintaining normal nutrient levels is imperative for good health, especially when it's a heavy hitter such as magnesium, which plays a number of essential roles in the body. In this article, we'll get into magnesium's many jobs; what magnesium levels are considered high, low, and normal; and what your magnesium level means to your overall health.
What Does Magnesium Do in the Body?
Magnesium is an important electrolyte (a mineral that carries an electrical charge). It functions as a cofactor for enzymes, binding with them and making it possible for them to regulate bodily systems. Magnesium is a cofactor in more than 300 enzyme systems, including those that manage:
- muscle and nerve function
- blood pressure regulation
- blood glucose control
- protein building
- nerve impulse conduction
- muscle contraction
- heart rhythm
- bone strength
There's a total of about 24 grams of magnesium in the body, with most of it located in the bones, muscles, and non-muscular soft tissues. The kidneys maintain the balance of magnesium, largely by excreting excess amounts in the urine. (Source)
How Are Magnesium Levels Tested?
There are two ways of assessing magnesium levels, which are usually tested when a health care provider suspects you have too much (hypermagnesemia) or too little (hypomagnesemia).
- serum magnesium test: This is a simple blood test, the most common method of evaluating the amount of magnesium in the body. (Source)
- urinary magnesium excretion: If serum magnesium is abnormal, urine is collected over a period of 24 hours and assessed for the amount of serum excreted. Comparing urinary magnesium excretion with the serum magnesium level will help determine if the problem is related to nutritional status or kidney function. (Source)
Most magnesium in the body is stored in bone, muscle, and soft tissue, with only 0.8% circulating in the blood. This makes it hard to accurately measure the body’s total magnesium levels through either a serum blood test or a urine sample. Depending on why your health care provider is investigating your magnesium levels, they might decide to do both tests. (Source)
What Are Normal Magnesium Levels?
The normal range of magnesium levels can vary from one lab to another, but for adults it is typically anywhere from 1.7 mg/dL (milligrams per deciliter) to 2.2 mg/dL. (Source)
Low Magnesium Levels (Hypomagnesemia)
The level of magnesium you have in your blood depends on how well your body is absorbing magnesium from food, as well as how appropriately your kidneys are excreting it. Normal serum magnesium levels vary from lab to lab, but generally speaking a level of less than about 1.7 mg/dL suggests hypomagnesemia or a magnesium deficiency. If your magnesium is low, but not low enough to indicate a deficiency, you have what's known as a magnesium inadequacy. (Source)
If your magnesium level is low enough to be considered hypomagnesemia, you may initially experience symptoms such as:
- loss of appetite
- muscle spasms
You might not experience any symptoms at the beginning of a magnesium deficiency, but if it continues, it may lead to:
- tingling or numbness
- muscle cramps or contractions
- personality or behavioral changes
- abnormal heart rhythms
- cardiac or heart muscle damage (also known as myocardial ischemia)
Causes of Hypomagnesemia
It's rare for magnesium levels to be detrimentally low in people who are generally healthy. Hypomagnesemia is more commonly seen in those who are hospitalized, especially those in intensive care. In fact, it's the most common electrolyte disturbance seen in ICU patients.
Hypomagnesemia in hospital patients may be due to diuretics (water pills, given to reduce blood pressure), aminoglycosides (a class of antibiotics used in the treatment of severe infections of the abdomen and urinary tract), as well as chronic diarrhea, pancreatitis, malnutrition, and hypoalbuminemia, a condition in which the body isn't producing enough of the protein that keeps water in the blood vessels. (Source, Source, Source, Source)
There are certain conditions that make low magnesium levels more likely, such as:
- gastrointestinal issues: Magnesium may be lost through acute or chronic diarrhea associated with conditions such as Crohn's, celiac disease, and irritable bowel syndrome. (Source)
- type 2 diabetes: Chronic magnesium deficiency is common in those with type 2 diabetes, since increased blood glucose levels can cause the kidneys to process more magnesium than it should. Insulin resistance, a feature of type 2 diabetes, causes a loss of magnesium in the urine, contributing to hypomagnesemia. (Source, Source)
- alcohol dependence: Alcohol is a diuretic, meaning the more you consume, the more you urinate, and the more magnesium you lose. Alcohol in excess also damages the liver, and as a result, inhibits the absorption of trace elements (minerals present in living tissue in small amounts, some of which are nutritionally essential), including magnesium. Magnesium deficiency aggravates liver disease, but increasing magnesium intake has been associated with a decrease in mortality due to liver diseases. (Source, Source, Source)
- malnutrition: Starvation and disordered eating conditions like anorexia, bulimia, and frequent vomiting can cause magnesium deficiency. (Source)
- pregnancy and breastfeeding: Both pregnancy and breastfeeding increase the need for magnesium. Pregnant women require 350 mg to 360 mg per day, as opposed to non-pregnant women, who need 310 mg to 320 mg. For breastfeeding women, the necessary amount is 360 mg. Magnesium deficiencies in pregnant people can result in adverse pregnancy outcomes. (Source, Source)
- aging: Elderly people are more susceptible to magnesium deficiency because they tend to experience increased urination and defecation, malabsorption of nutrients, and a lack of proper diet due to a decrease in appetite. Magnesium promotes bone density and elderly women with low magnesium levels are more likely to have osteoporosis. (Source, Source)
Diagnosis and Treatment of Hypomagnesemia
If you may have a magnesium deficiency, your health care provider will conduct a physical exam and run a blood test for confirmation. A 24-hour urine collection may be done as well, if the cause of the deficiency (for example, an underlying condition) is unclear. The treatment for magnesium deficiency depends on the reason for it, and how severe it is.
Treatment for Magnesium Inadequacy
If you don't have any other health problems and your levels of magnesium aren't low enough to constitute hypomagnesemia, your provider may recommend getting more magnesium from your diet. Magnesium-rich foods include:
- leafy greens (spinach and kale)
- nuts (almonds, cashews, Brazil nuts, pistachios)
- seeds (pumpkin, chia, sunflower)
- beans (black beans, edamame, kidney beans)
Treatment for Hypomagnesemia
When a magnesium deficiency is so profound that it's causing symptoms, you may be given magnesium intravenously (healthy kidneys are essential in order to receive this treatment). Magnesium salts are an option as well, if you can tolerate oral drugs. It's vital that the reason for the magnesium deficiency be pinpointed, so treatment has the best chance of being successful. (Source, Source, Source)
High Magnesium Levels (Hypermagnesemia)
A very high level of serum magnesium of 2.6 mg/dl or above indicates hypermagnesemia. Hypermagnesemia is actually very rare, and symptomatic hypermagnesemia is even more so. It occurs when the kidneys fail to process and excrete magnesium, causing the amount of magnesium in the body to build up.
Types of Hypermagnesemia
There are three categories of hypermagnesemia:
- mild (less than 7 mg/dL): May be asymptomatic or have very few symptoms, such as weakness, nausea, dizziness, and confusion.
- moderate (7 mg/dL to 12 mg/dL): Symptoms include more intense confusion, headache, constipation, blurred vision, and slow heart rate.
- severe (higher than 12 mg/dL): Symptoms include decreased breathing rate, slow heartbeat, and flaccid muscles. Coma and cardiac arrest can occur if levels are higher than 15 mg/dL. (Source, Source)
Causes of Hypermagnesemia
Kidney failure is the main cause of hypermagnesemia but it can also occur in people with healthy kidney function, who usually have mild symptoms. When those without kidney problems have hypermagnesemia, it may be due to:
- lithium, an oral medication used in the treatment of bipolar disorder, decreasing urinary excretion of magnesium for reasons that are unclear (Source, Source)
- hypothyroidism, or an underactive thyroid, increasing the amount of magnesium being absorbed by the kidneys, resulting in elevated levels of magnesium (Source, Source)
- drugs with magnesium in them, such as laxatives and antacids, inducing hypermagnesemia when taken by those with kidney problems (Source)
Diagnosis and Treatment of Hypermagnesemia
The sooner hypermagnesemia is diagnosed, the easier it is to handle. If a serum blood test shows high levels of magnesium, your health care provider will need to determine why. If it's because you're taking a medication that's spiking your magnesium levels, you'll likely be told to stop taking it.
Because symptoms of hypermagnesemia can be dangerous, it needs to be addressed quickly. This can involve:
- an infusion of IV calcium, which will normalize the heart rate and breathing
- diuretics, to rid the body of excess magnesium through increased urination
- dialysis, if neither of these options work. Dialysis can remove excess magnesium from the blood, and may become necessary if the kidneys are failing and unable to naturally excrete excess magnesium.
Magnesium and Autoimmune Diseases
Low levels of magnesium have been associated with increased levels of inflammation, which is associated with many autoimmune diseases. Since magnesium levels are associated with the healthy functioning of many systems in the body, knowing your magnesium status may benefit you as you manage your condition. Working with a WellTheory Nutritional Therapy Practitioner will allow you access to advanced testing to determine what your nutrient levels are, and to identify if you could benefit from more magnesium. (Source, Source)
The Bottom Line on Magnesium Levels
A 2013–2016 analysis of the National Health and Nutrition Examination Survey (NHANES) revealed that 48% of Americans do not get enough magnesium to meet their nutritional needs. While many people might be magnesium inadequate, it's rare for a healthy person to have a level of magnesium that's low enough to produce symptoms. Very high levels of magnesium are usually due to kidney failure. However, magnesium levels that are lower or higher than normal are treatable with the support of your health care provider. (Source, Source)
It's important to be in conversation with your health care provider about your nutritional needs and any concerns you might have about your magnesium levels. Being proactive and communicative is your best bet for feeling good, so don't hesitate to start a conversation and address your symptoms.