Mental health disorders are another possible consequence of magnesium deficiency.
These include apathy, which is characterized by mental numbness or lack of emotion. Worsened deficiency may even lead to delirium and coma (5Trusted Source).
Additionally, observational studies have associated low magnesium levels with an increased risk of depression (9Trusted Source).
Scientists have also speculated that magnesium deficiency might promote anxiety, but direct evidence is lacking (10Trusted Source).
One review concluded that magnesium supplements might benefit a subset of people with anxiety disorders, but the quality of the evidence is poor. Higher quality studies are needed before any conclusions can be reached (11Trusted Source).
In short, it seems that a lack of magnesium may cause nerve dysfunction and promote mental health conditions in some people.
3. Osteoporosis
Osteoporosis is a disorder characterized by weak bones and an increased risk of bone fractures.
Numerous factors influence the risk of developing osteoporosis. These include:
- aging
- lack of exercise
- poor dietary intake of vitamins D and K.
Interestingly, magnesium deficiency is also a risk factor for osteoporosis. Deficiency might weaken bones directly, but it also lowers the blood levels of calcium, the main building block of bones (12Trusted Source, 13Trusted Source, 14Trusted Source, 15Trusted Source).
Studies in rats confirm that dietary magnesium depletion results in reduced bone mass. Although no such experiments have been done involving humans, studies have associated poor magnesium intake with lower bone mineral density (16Trusted Source, 17Trusted Source).
4. Fatigue and muscle weakness
Fatigue, a condition characterized by physical or mental exhaustion or weakness, is another symptom of magnesium deficiency.
Keep in mind that everyone becomes fatigued from time to time. Typically, it simply means you need to rest. However, severe or persistent fatigue may be a sign of a health problem.
Since fatigue is a nonspecific symptom, its cause is impossible to identify unless it is accompanied by other symptoms.
Another more specific sign of magnesium deficiency is muscle weakness, also known as myasthenia (18Trusted Source).
Scientists believe the weakness is caused by the loss of potassium in muscle cells, a condition associated with magnesium deficiency (19Trusted Source, 20Trusted Source).
Therefore, magnesium deficiency is one possible cause of fatigue or weakness.
5. High blood pressure
Animal studies show that magnesium deficiency may increase blood pressure and promote high blood pressure, which is a strong risk factor for heart disease (21Trusted Source, 22Trusted Source).
While direct evidence is lacking in humans, several observational studies suggest that low magnesium levels or poor dietary intake may raise blood pressure (23Trusted Source, 24Trusted Source, 25Trusted Source).
The strongest evidence for the benefits of magnesium comes from controlled studies.
Several reviews have concluded that magnesium supplements may lower blood pressure, especially in adults with high blood pressure (26Trusted Source, 27Trusted Source, 28Trusted Source).
Put simply, magnesium deficiency may increase blood pressure, which, in turn, increases the risk of heart disease. Nevertheless, more studies are needed before its role can be fully understood.
6. Asthma
Magnesium deficiency is sometimes seen in people with severe asthma (29Trusted Source).
Additionally, magnesium levels tend to be lower in individuals with asthma than in people who do not have the condition (30Trusted Source, 31Trusted Source).
Researchers believe a lack of magnesium may cause the buildup of calcium in the muscles lining the airways of the lungs. This causes the airways to constrict, making breathing more difficult (7Trusted Source, 32Trusted Source).
Interestingly, an inhaler with magnesium sulfate is sometimes given to people with severe asthma to help relax and expand the airways. For those with life threatening symptoms, injections are the preferred method of delivery (33Trusted Source, 34Trusted Source).
However, evidence for the effectiveness of dietary magnesium supplements in individuals with asthma is inconsistent (35Trusted Source, 36Trusted Source, 37Trusted Source).
In short, scientists believe severe asthma may be a symptom of magnesium deficiency in some people, but further studies are needed to investigate its role.
7. Irregular heartbeat
Heart arrhythmia, or irregular heartbeat, is among the most serious symptoms of magnesium deficiency (38Trusted Source).
The symptoms of arrhythmia are mild in most cases. Often, it has no symptoms at all. However, in some people, it may cause heart palpitations, which are pauses between heartbeats.
Other possible symptoms of arrhythmia include:
- lightheadedness
- shortness of breath
- chest pain
- fainting
In the most severe cases, arrhythmia may increase the risk of stroke or heart failure.
Scientists believe that an imbalance of potassium levels inside and outside of heart muscle cells may be to blame, a condition associated with magnesium deficiency (39Trusted Source, 40Trusted Source).
Some people with congestive heart failure and arrhythmia have been shown to have lower magnesium levels than people who don’t have the condition.
Treating those with magnesium injections significantly improved their heart function (41Trusted Source).
Magnesium supplements may also help reduce symptoms in some people with arrhythmia (42Trusted Source).
How to get enough magnesium
The table below shows the recommended daily allowance (RDA) or adequate intake (AI) for men and women in the United States (43Trusted Source).
| Age | Male | Female | Pregnancy | Lactation |
| Birth to 6 months | 30 mg* | 30 mg* | ||
| 7–12 months | 75 mg* | 75 mg* | ||
| 1–3 years | 80 mg | 80 mg | ||
| 4–8 years | 130 mg | 130 mg | ||
| 9–13 years | 240 mg | 240 mg | ||
| 14–18 years | 410 mg | 360 mg | 400 mg | 360 mg |
| 19–30 years | 400 mg | 310 mg | 350 mg | 310 mg |
| 31–50 years | 420 mg | 320 mg | 360 mg | 320 mg |
| 51+ years | 420 mg | 320 mg |
*Adequate intake
Although many people don’t reach the RDA for magnesium, there are plenty of magnesium-rich foods to choose from.
It is widely found in both plants and animal-sourced foods. The richest sources are seeds and nuts, but whole grains, beans, and leafy green vegetables are also relatively rich sources.
Below is the magnesium content in 3.5 ounces (100 grams) of some of the best sources (44):
- almonds: 286 mg
- pumpkin seeds: 535 mg
- dark chocolate: 152 mg
- peanuts: 168 mg
- popcorn: 144 mg
For example, just 1 ounce (28.4 grams) of almonds provides 20% of the RDA for magnesium.
Other great sources of magnesium include:
- flaxseeds
- sunflower seeds
- chia seeds
- cocoa
- coffee
- cashews
- hazelnuts
- oats
Magnesium is also added to many breakfast cereals and other processed foods.
If you have a health condition that causes your body to lose magnesium, such as diabetes, it’s important to eat plenty of magnesium-rich foods or take supplements.
Talk with your doctor about creating a plan to increase your magnesium intake that works well for your needs.
The bottom line
Magnesium deficiency is a widespread health problem.
Some studies suggest that 75% of Americans do not meet their dietary requirements for magnesium (1Trusted Source). However, true deficiency is much less common — less than 2%, according to one estimate (45).
The symptoms of magnesium deficiency are usually subtle unless your levels become severely low.
Deficiency may cause:
- fatigue
- muscle cramps
- mental health conditions
- irregular heartbeat
- osteoporosis
If you believe you may have a magnesium deficiency, your suspicions can be confirmed with a simple blood test. You should speak with your doctor to rule out other possible health problems.
Whatever the outcome, try to regularly eat plenty of magnesium-rich whole foods, such as nuts, seeds, grains, or beans.
These foods are also high in other healthy nutrients. Including them in your diet not only lowers your risk for magnesium deficiency, but it also supports your overall health.
