The brain processes emotions, stores memories, coordinates movement, and serves as the communication center for all our body’s systems. All these functions make it imperative that we make positive lifestyle choices to keep our brains healthy and strong. A key component in a brain-healthy lifestyle is eating a diet with sufficient magnesium.
Magnesium is one of the most abundant minerals in the body. This essential mineral plays an important role in promoting brain health and other bodily functions. This includes maintaining the health and proper functioning of the nervous system.
How is magnesium absorbed by the body?
An adult human body contains approximately 22-26g (1,000 mmols) of magnesium (2). After eating, magnesium is absorbed in the duodenum and ileum in the small intestine.
Around 60% of magnesium in an adult body is stored in the bones (2). Another 30% is found in the skeletal muscle and soft tissues, while the remaining 10% is present in fluid in the blood, lymph, and spinal cord (2).
Some micronutrients also affect how the body absorbs magnesium. For instance, when a person consumes 40-50g of fibre a day, this can reduce magnesium absorption. High zinc intakes of 142 mg/day can also affect absorption (3).
Not getting enough protein can affect your small intestine’s ability to absorb magnesium. However, too much protein can have undesirable effects. If your protein intake is more than 94g per day, the amount of renal magnesium passed through the body may also increase (3).
The good news is that the body can adjust its ability to absorb necessary minerals like magnesium depending on your daily food intake. Magnesium absorption through the gut can increase by up to 75% for a person who is not getting enough magnesium from diet. This amount reduces to 25% on high-magnesium diets.
Benefits of magnesium for brain
The nervous system requires sufficient amounts of key minerals like magnesium to keep it working efficiently. This is due to the fact that it comprises a complex network of the brain, spinal cord, and nerves.
Here are the benefits of magnesium for brain and nervous system health.
Maintains nervous system function
Magnesium plays an important role in the normal functioning of the body’s cells. This includes the nerve cells or neurons that carry messages from the brain to all our organs and body parts (4).
Magnesium is involved in neural processes like cellular respiration, protein synthesis, membrane stability, and regulation of vascular tone (5), among many other functions. When all these processes run smoothly, the nervous system performs its job with ease. One way to ensure the efficiency of these processes is by consuming sufficient magnesium.
Glutamate sends signals in the brain and throughout the body. It can be found in different types of food and is popularly known as monosodium glutamate (MSG). Having too much of it can damage nerve cells and the brain (6). Magnesium guards the nervous system against overactivity that can be caused by excessive glutamate (6).
Magnesium relaxes the vascular smooth muscle, causing blood vessels to expand. This process is known as vasodilation (7) and it increases blood flow to the brain. Vasodilation allows more oxygen and nutrients to reach the brain to keep it healthy.
Supports cognitive function
A growing body of scientific evidence suggests that magnesium can maintain and promote cognitive health (5). Cognitive health refers to the ability to think, learn, and remember.
Magnesium, especially when paired with zinc, has positive effects on academic performance (5). Specifically, magnesium therapy has shown promise in improving working memory and reference memory (5). Doctors continue to study how vital nutrients and minerals interact with each other to enhance learning and memory-related benefits of magnesium.
Researchers are also studying how magnesium may speed up recovery after a traumatic brain injury and hasten the recovery of parts of the brain that control senses, memory, and language (5). It has been suggested that magnesium stimulates strong biological activity that crosses the blood-brain barrier and improves cognitive performance (5). Clinical studies are also exploring the benefits of magnesium for brain-related disorders.
Maintains nerve conduction and neural health
Nerve cells are important parts of the nervous system. They convey information from our brain to different organs and body parts and vice versa in a process called nerve conduction.
Neurons are crucial in this process as the messenger of information or signals. Magnesium helps smooth the process of information transfer of neurons through the axon (2). The axon is a fibre-like part of the neuron that carries information to other neurons. When magnesium levels are low, the effectiveness of the axon can be compromised. At the same time, the speed in which information is transferred increases (2). A combination of these conditions triggers a release of information through the neurons and can affect muscle function.
Helps prevent dietary magnesium deficiency
Stress and certain health conditions may cause magnesium deficiency. They can affect the body’s ability to modulate stress response and emotions (8).
While the body is built to withstand a degree of stress, extended activation of the stress response and overexposure to stress hormones can be harmful. These affect your ability to think clearly and put you at increased risk of developing other health complications.
When your body is under stress, the adrenal glands release hormones to help you respond to a perceived threat. However, stress hormones, though essential, can deplete magnesium levels in the body by increasing the amount that is passed in urine (8).
Low magnesium levels also stimulate the release of catecholamines, a group of stress hormones that deplete magnesium levels further (8). Since hypomagnesemia, or magnesium deficit, often goes undetected (2), some doctors suggest that magnesium tests be carried out routinely on acutely ill patients.
Long-term stress may also result in hypomagnesemia9. Hypomagnesemia together with chronic stress can aggravate the symptoms of both conditions (8).
Studies have also pointed out that magnesium plays a role in modulating the hypothalamic-pituitary-adrenocortical (HPA) axis, our central stress response system (8). It interacts directly and indirectly with neurotransmitters and neurohormones involved in the stress response. Over 325 enzymes dependent on magnesium are enzymes from the nervous system (8), pointing to the potentially significant role of magnesium in modulating the stress response.
With regard to mental health and mood disorders, doctors are studying the potential effects of magnesium for the brain (7). In experimental studies, the mineral was found to affect how the serotonergic system functions (7). This system is a vital resource of serotonin, an important neurotransmitter that modulates higher brain functions, including emotional behaviour.
Supports healthy neuromuscular functioning
The neuromuscular system is made up of the muscles and nerves that enable you to move (10). Under normal conditions, the nerves and muscles work together to generate movement without issue. However, the neurons that instruct muscles and nerves to work together can become compromised. It is a problem that can be remedied by getting enough magnesium for brain health.
Some studies have revealed that the neuromuscular system may be the first system to show signs of a magnesium deficiency (2). The effects of hypomagnesaemia on the neuromuscular system may include (2):
- Muscle cramps
- Muscle weakness and tremors
- Irregular and involuntary movements
The normal range of serum magnesium concentrations is 0.75-0.95 mmol/L (9). If it falls past the 0.75 mmol/L mark, hypomagnesemia sets in and may cause neuromuscular problems (9).
What are magnesium-rich foods?
While the body is able to produce magnesium, you can ensure sufficient intake of the mineral by consuming magnesium-rich foods. Australians can get most of the magnesium they need from green leafy vegetables, nuts, seeds and whole grains as well as fibre-rich foods (1).
Here’s a list of magnesium-rich foods (1) that you can consider adding to your diet:
- Pumpkin and chia seeds
- Brown rice
It would be worth noting that processing and refining of foods during manufacturing or cooking can cut magnesium content by as much as 85% (2). For example, boiling can result in a significant loss of magnesium (2). To maximise your intake of this mineral from food, you can put together a meal containing as much unprocessed magnesium-rich foods. A salad of green, leafy vegetables is a good example. You can also snack on almonds and peanuts that haven’t been blanched or roasted.
How much magnesium should I get daily?
According to healthdirect.gov.au, the recommended daily intake for magnesium (11) is 400mg for men under 30 years old and 420mg for those aged 31 and above. Women aged 30 and below need 310mg of magnesium each day and 320mg by the time they turn 31.
Signs of magnesium deficiency
Despite the clear benefits of magnesium for brain health, more than one in three Australians are not getting enough of this key mineral (1).
Magnesium deficiency may or may not come with symptoms (9). However, persistently low magnesium levels may cause visible symptoms among certain individuals.
If you’re falling short of the recommended daily intake of magnesium, you may experience headaches and migraines. Magnesium deficiency is linked to factors that may contribute to these severe headaches, like vasoconstriction (9). It causes blood vessels to narrow and limits blood flow to the brain. Doctors have found that people who experience migraines have lower levels of serum and tissue magnesium than those without (9).
Other symptoms of magnesium deficiency may include:
- Loss of appetite
- Muscle weakness
If left untreated, these symptoms can interfere with day-to-day living and sleep. In severe cases of magnesium deficiency, you may experience the following symptoms (3):
- Weight loss
- Muscle cramps or muscle spasms
- Seizures or convulsions
- Abnormal heart rhythm
On its own, magnesium deficiency poses health problems, but it can also result in imbalance of its associated minerals over time.
For instance, magnesium plays a role in the metabolism of calcium and contributes to the structural development of your bones. This is why severe magnesium deficiency can also cause low calcium in the blood (9). In some studies on animals (12), it was observed that restricting magnesium in diets can reduce bone density. Low bone density increases the risk of injuries brought about by weakened bones.
Additionally, extreme magnesium deficiency may cause potassium levels to drop and cause worryingly low calcium in the blood (9). This condition can develop because magnesium contributes not only to the transport of calcium ions but also carries potassium ions across cell membranes.
How do I know if I have a magnesium deficiency?
Your healthcare provider may order a series of tests to discover if you are getting enough magnesium. These tests analyse your body’s serum magnesium concentration (2).
Your healthcare provider may opt to analyse intracellular magnesium in your red blood cells, mononuclear blood cells, and skeletal muscles (2).
Some experts also recommend looking at the amount of magnesium in your urine after a non-oral means of drug administration. Although it is more invasive, a magnesium tolerance test usually paints a fair picture of magnesium levels in adults.
Here are other procedures that may be used to assess a person’s magnesium status:
- Metabolic balance studies
- Magnesium loading test
- Fluorescent dye
- Nuclear magnetic resonance spectroscopy
- Magnesium balance
- Isotope studies
- Hair or tooth tests
- Functional assays
Is there such a thing as too much magnesium for the brain?
Doctors believe that excessive magnesium intake from food does not pose a health risk among healthy individuals. This is not a concern since kidneys can eliminate excess magnesium by passing urine (9).
However, some medications like laxatives and antacids may contain high amounts of magnesium. Diarrhoea and abdominal cramping are the first signs of excess intake (9). The laxative effects of magnesium are caused by the activity of unabsorbed salts in the intestine and colon.
The Australian National Health and Medical Research Council set an upper intake level (3) or the maximum level that is likely to cause negative health effects. Adult men and women are encouraged to keep magnesium supplements to 350mg/day to prevent any unintended side effects (3).
Should I take magnesium supplements?
As we age, the amount of magnesium absorbed by the gut decreases (9). Over the course of a lifetime, the magnesium stored in bones is cut by nearly half, even as the excreted amount increases. This makes older adults more vulnerable to magnesium deficiency, especially if they have pre-existing health conditions. If those in this group are taking medications, the risk of magnesium depletion increases.
If you are one of these at-risk groups or feel that you’re not getting enough magnesium from your diet, it may be worth looking into supplements. Magnesium supplements come in several forms, including magnesium oxide, citrate, and chloride. Vitable’s magnesium citrate is highly bioavailable, which means your body can absorb the mineral and extract the benefits faster.
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Learn more about other areas that magnesium can help you with, plus other supplements that can benefit in different ways:
*Always read the label. Follow the directions for use. If symptoms persist, talk to your health professional. Vitamin and/or mineral supplements should not replace a balanced diet.
1. Healthdirect. Foods high in magnesium. https://www.healthdirect.gov.au/foods-high-in-magnesium Accessed August 14, 2021
2. National Institutes of Health (2003). Magnesium Metabolism and its Disorders. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1855626/ Accessed August 14, 2021
3. Nutrient Reference Values – Magnesium. https://www.nrv.gov.au/nutrients/magnesium Accessed August 14, 2021
4. National Institute of Child Health and Human Development. What are parts of the nervous system? https://www.nichd.nih.gov/health/topics/neuro/conditioninfo/parts Accessed August 14, 2021
5. National Institutes of Health. (2011). The role of magnesium therapy in learning and memory. https://www.ncbi.nlm.nih.gov/books/NBK507270/ Accessed August 14, 2021
6. National Institutes of Health. (2018). The role of magnesium in neurological disorders. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024559/ Accessed August 14, 2021
7. National Institutes of Health. Magnesium. https://www.ncbi.nlm.nih.gov/books/NBK209305/ Accessed August 14, 2021
8. National Institutes of Health. (2011). Magnesium and stress. https://www.ncbi.nlm.nih.gov/books/NBK507250/ Accessed August 14, 2021
9. National Institutes of Health Office of Dietary Supplements. Magnesium Fact Sheet. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/ Accessed August 14, 2021
10. Healthdirect. Neuromuscular system. https://www.healthdirect.gov.au/neuromuscular-system Accessed August 14, 2021
11. Healthdirect. Magnesium. https://www.healthdirect.gov.au/magnesium Accessed August 14, 202112.
12. National Institutes of Health (2013). Magnesium and Osteoporosis: Current state of knowledge and future research directions. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775240/ Accessed August 14, 2021