Benefits of taking magnesium: what it does in your body and how to choose the right one

Magnesium is an essential macromineral, meaning a mineral the body needs in relatively large amounts to function properly. It's the fourth most abundant mineral in the human body: the adult body contains approximately 25 grams of magnesium, of which between 50 and 60% is concentrated in the bones, 30% in the muscles and the rest in organs, the nervous system and the immune system.

What makes magnesium especially important is the breadth of its biological role. According to the National Institutes of Health (NIH) in the United States and the Harvard School of Public Health, magnesium takes part in more than 300 different enzymatic reactions. Some more recent sources raise that figure to around 600 reactions, which makes this mineral a central player in practically every system in the body.

Its main functions include: energy production at the cellular level, muscle contraction and relaxation, transmission of nerve impulses, DNA and protein synthesis, blood glucose balance and the maintenance of bone and cardiovascular health.

Before talking about the specific benefits of taking magnesium, it's important to understand how this mineral acts in the body:

• ATP production: Magnesium is needed to activate ATP (adenosine triphosphate), the main energy molecule of cells. Without magnesium, energy production is compromised.

• Muscle function: It acts antagonistically to calcium. While calcium triggers muscle contraction, magnesium induces relaxation. A proper balance between the two is essential to avoid cramps and spasms.

• Nervous system: It regulates the transmission of nerve signals and modulates the receptors of the neurotransmitter GABA, which has a calming effect on the central nervous system.

• Bone health: Magnesium helps regulate calcium metabolism and contributes to bone mineralisation, being as important as calcium itself for bone density.

• Glycaemic regulation: It improves insulin sensitivity and contributes to controlling blood sugar levels.

• Cardiovascular health: It regulates heart rhythm, relaxes the walls of blood vessels and helps keep blood pressure within healthy ranges.

Magnesium is essential for muscles to be able to relax after contracting. Low levels of this mineral are directly associated with muscle cramps, spasms, chronic muscle tension and even restless legs syndrome. This is especially relevant for athletes, people who spend many hours sitting or older people.

Although calcium usually takes all the spotlight when we talk about bones, magnesium is equally indispensable. Several studies have shown a direct relationship between magnesium intake and bone mineral density, in both men and women. Magnesium helps regulate calcium metabolism and takes part in the formation of tooth enamel, which makes it a key mineral for bone and dental health, especially in women from menopause onwards.

Magnesium has a clearly calming effect on the nervous system. It's involved in regulating neurotransmitters such as GABA (with an inhibitory effect) and partially blocks the activation of the NMDA receptor, which helps reduce neuronal over-excitation. This action is associated with a greater sense of calm, reduced anxiety and better stress management. Some studies suggest that magnesium levels may be related to the risk of depression, although research in this field is still advancing.

Magnesium regulates GABA and takes part in the production of melatonin, two key players in the sleep-wake cycle. Observational studies show a correlation between higher magnesium intake and better sleep quality. In addition, by relaxing the muscles and calming the nervous system, it eases the transition into deep sleep. People with a magnesium deficiency often report greater difficulty falling asleep and frequent night-time awakenings.

Magnesium acts on the heart muscle and blood vessels. It relaxes the arterial walls, which helps reduce blood pressure. It also has a stabilising effect on heart rhythm, to the point that in some clinical contexts it's used to treat certain arrhythmias. It's also associated with a reduction in triglycerides and cholesterol, and with a lower risk of metabolic syndrome.

Magnesium contributes to normal energy metabolism and improves insulin sensitivity, that is, the ability of muscles and the liver to absorb glucose from the bloodstream. Prospective studies show that adequate magnesium intake is associated with a lower risk of type 2 diabetes and metabolic syndrome.

Patients with frequent migraines tend to have lower magnesium levels in blood and tissues than the general population. Magnesium can influence neurotransmitters and the constriction of cerebral blood vessels, two mechanisms directly related to migraine episodes. Some clinical guidelines already consider magnesium supplementation as a preventive option in people with chronic migraine.

Magnesium boosts what is known as brain plasticity, that is, the brain's ability to form new neuronal connections. It has been observed to contribute to memory and learning, and its deficiency is associated with greater brain fog and difficulty concentrating.

Women can benefit from magnesium in an especially significant way at different stages of life:

During the menstrual cycle: Magnesium can relieve abdominal cramps and premenstrual discomfort, since it acts directly on muscle relaxation and hormonal regulation.

During pregnancy: Magnesium needs increase, reaching 350-360 mg per day according to the NIH. Magnesium contributes to proper fetal development, muscle balance and blood pressure stability.

In perimenopause and menopause: Magnesium has especially relevant effects at this stage, as it contributes to bone health (preventing osteoporosis), can relieve certain symptoms related to stress and anxiety, and supports the balance of the nervous system.

Magnesium deficiency is more common than people think, especially in diets rich in ultra-processed foods and low in fresh vegetables. Some signs that may indicate low magnesium levels:

• Frequent muscle cramps

• Chronic tiredness with no apparent cause

• Difficulty sleeping or poor-quality sleep

• Irritability, anxiety or mood swings

• Frequent headaches or migraines

• Chronic muscle tension

• Palpitations or mild arrhythmias

• Difficulty concentrating or brain fog

Certain groups are at higher risk of deficiency: older people, athletes, people with high stress levels, those who follow diets rich in alcohol or ultra-processed foods, and people with gastrointestinal diseases or type 2 diabetes.

The first line of action to maintain optimal magnesium levels is always diet. The main food sources of magnesium are:

Source: Academy of Nutrition and Dietetics of the United States / Harvard Health Publishing

A varied diet with leafy green vegetables, legumes, nuts, seeds and whole grains can provide a sufficient amount of magnesium. However, factors such as chronic stress, intense exercise, age or certain conditions increase needs beyond what diet can cover.