Introduction
Magnesium is an essential mineral which plays a key role in many functions in the body, being involved in over 350 enzymatic reactions which influence various aspects of health such as energy metabolism, hydration, muscle function, performance and recovery.
It is known that having adequate magnesium levels in the body contributes to normal nerve transmission, cardiac excitability, neuromuscular conduction, muscular contraction, vasomotor tone, blood pressure, and glucose and insulin metabolism, all of which are essential to optimise for athletic performance (Volpe, 2013).
Additionally, magnesium supports efficient energy metabolism, which ensures that cells in the body can produce and utilise energy effectively, which is required for all daily activities as well as performance in intense physical exercise (Nielsen & Lukaski, 2010). Magnesium also facilitates hydration by supporting both electrolyte and fluid balance. Its anti-inflammatory properties may also help reduce oxidative stress and exert a protective effect on muscle damage, supporting faster recovery from exercise (Córdova et al., 2017).
Data from both the World Health Organisation and National Health and Nutrition Examination Survey in the USA suggest that 75% of the US adult population may not meet the required daily intake of magnesium. Reports from the UK suggest that figure is around 12% and in Europe inadequate magnesium intake ranges from 10-30% at the population level. This is likely the result of a major shift in dietary intake, away from wholefoods towards ultra processed food. Magnesium deficiency can also go undiagnosed as serum concentrations (eg. measurable magnesium) does not reflect intracellular concentrations. Magnesium deficiency is considered a major concern and potential contributing factor to a number of modern ailments (DiNicolantonio et al., 2018).
This article will review the research on magnesium with respect to health, sleep and exercise performance. It will dig into the studies for each respective aspect, as well as discuss the dosage recommendations for magnesium supplementation based on research data.
The Impacts of Magnesium Intake in Humans
Magnesium has numerous impacts in humans: on our general health, our sleep, and our athletic performance. We'll now break down the research, and present the data and discussions surrounding how magnesium effects these aspects.
Magnesium’s Effects on General Health
Research has investigated the role of magnesium status on various health markers for a number of years now, with evidence indicating that magnesium deficiency may be damaging to health. Much of the research supports the idea that magnesium supplementation may have significant benefits. Specifically, a meta-analysis of observational and intervention studies from Veronese et al (2020) found strong evidence for magnesium supplementation reducing the risk of hospitalisation in pregnant women and the frequency and intensity of migraines. Additionally, the meta-analysis of the body of research found that higher magnesium intake is associated with a 10-30% reduced incidence of type 2 diabetes and stroke.
Magnesium may also play an important role in maintaining good mental health. Moabedi et al. (2023) produced a systematic review and meta-analysis of randomised clinical trials regarding the effects of magnesium supplementation on depression. The meta-analysis included seven clinical trials with dosages ranging from 248 mg to 500 mg per day of magnesium. The findings indicated a significant reduction in depression scores, which highlights magnesium's potential in alleviating depressive symptoms.
The impact of magnesium status on metabolic health and insulin sensitivity has also been researched. Insulin resistance is a problem in the body which is highly correlated with the risk of potentially developing type 2 diabetes and other chronic diseases. Simental-Mendía et al. (2016) published a systematic review and meta-analysis to look at the impact of various magnesium dosages on insulin sensitivity, with significant findings showing that magnesium supplementation (≥4 months) significantly improved the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) index and fasting glucose levels. This suggests magnesium's potential as a beneficial supplement in managing blood sugar and metabolic disorders.
Improvements in metabolic health and insulin sensitivity are likely to also benefit body weight and composition too, long term. Research has explored the impact of magnesium status on anthropometric measures and obesity, with some very interesting findings. A meta analysis by Rafiee et al. (2020) analysed the outcomes of 28 clinical trials with dosages ranging from 168 to 625 mg per day of magnesium. Overall, magnesium supplementation did not significantly affect body weight or BMI. However, it did show a significant reduction in waist circumference by 2.09 cm specifically only in obese subjects (BMI > 30 kg/m²), indicating its potential in managing abdominal obesity, which is a marker of improved metabolic health.
Research has also confirmed the beneficial effects of magnesium on inflammation and key inflammatory markers such as C-reactive protein. Chronic inflammation is associated with a number of disease states and impaired recovery. A meta-analysis of randomised controlled trials published by Veronese et al. (2022) included 17 trials with dosages ranging from 250 mg to 450 mg per day. Results showed significant reductions in serum C-reactive protein (CRP) levels and increases in nitric oxide (NO) levels.
Magnesium’s Impact on Sleep
Magnesium has also been shown to support sleep, although the mechanisms of action are still unclear, it is likely related to improved relaxation, reduced stress and neurotransmitter regulation. Magnesium deficiency is commonly associated with sleep disorders (Nielsen, 2015). Arab et al. (2022) published a systematic review of the current research in this space. The review included studies with magnesium dosages ranging from 250 mg to 500 mg per day. Results indicated that magnesium supplementation improved sleep quality, particularly in individuals with magnesium deficiency. One study noted a 17% improvement in sleep efficiency, while another reported a significant reduction in sleep onset latency and nighttime awakenings.
Magnesium’s Effects on Exercise Performance
Beyond its impact on health, magnesium has also been researched in the area of exercise, performance and recovery. A meta-analysis published in 2017 reviewed 14 randomised clinical trials with a total of 542 participants, including athletes, untrained healthy individuals, and the elderly or alcoholics (Wang et al., 2017). Dosages of magnesium ranged from 250 mg to 500 mg per day. The results showed no significant improvements in isokinetic peak torque extension, muscle strength, or muscle power in the overall population. However, they did conclude that magnesium supplementation can be beneficial for elderly and individuals with magnesium deficiency, such as alcoholics, rather than athletes or physically active individuals who already had adequate magnesium levels.
That said, a study published by Bohl and Volpe (2002) reviewed various trials where participants received magnesium doses ranging from 250 mg to 500 mg per day. Results indicated improvements in muscle strength, power, and endurance, particularly in individuals with magnesium deficiencies.
In another meta-analysis the authors found that higher magnesium intake could improve muscular performance and reduce exercise induced muscle damage. For instance, one of the trials highlighted a 10-15% improvement in muscle strength and a notable decrease in muscle soreness post-exercise. Again, the authors do go on to conclude that magnesium supplementation didn’t have an impact on most athletes and physically active individuals who already have a relatively high magnesium status. However, magnesium supplementation may benefit individuals with a deficiency, such as the elderly and alcoholics (Wang et al., 2017).
The findings really highlight the fact that magnesium deficiency may significantly compromise exercise performance. The prevalence of deficiency and insufficiency at the population level was discussed earlier in this article. In such cases supplementation is likely to improve efficiency of metabolism, and both aerobic and anaerobic performance (tested by muscle performance, including factors such as grip strength, lower leg power, knee extension torque, ankle extension strength, maximal isometric trunk flexion, rotation, and jumping performance) (Zhang et al., 2017). Please also remember that a simple blood test is not enough to determine magnesium status and confirm deficiency or insufficiency.
Magnesium Considerations for Athletes
Athletes often require higher magnesium intake due to increased losses through sweat and urine, as well as the greater demand for this mineral to support muscle function and energy metabolism. A review by Nielsen and Lukaski (2006) suggests that athletes may need an additional 10-20% magnesium compared to non-athletes, as a result of strenuous exercise increasing urinary and sweat losses. This 10-20% increase in magnesium requirement translates to a daily intake of about 400-500 mg.
Data published by Killer el al., (2017) also suggests that pre-exercise magnesium supplementation might help offset the decline in magnesium which occurs during exercise in athletes, supporting metabolism, muscle function and recovery.
An 8 year long study of magnesium status on elite track and field athletes published in 2020 found that 22% of athletes were clinically deficient in magnesium. They went on to report that deficiency was more prevalent amongst female athletes as well as those with Black or Mixed Race ethnicity. Low magnesium levels were associated with increased tendon pain and muscle injuries (Pollock et al., 2020).
Magnesium Dosages & Forms
Studies suggest that the optimal daily dosage of magnesium for adults ranges from 300 to 500 mg. Research has shown that supplementation within this range may significantly improve health outcomes. Nielsen et al. (2010) demonstrated that 300 mg of magnesium per day reduced inflammation markers by 22% and improved overall health. Similarly, a study by Volpe (2013) found that 400 mg of magnesium daily improved muscle function and reduced cramps by 15-20%. Another study by Barbagallo & Dominguez (2020) highlighted that magnesium supplementation of 500 mg per day significantly improves hydration status by optimising fluid balance and reducing dehydration symptoms. With that being said, the best dosage is highly individual at a supplement level, ultimately depending on the initial magnesium status and intake from diet.
Another key consideration when thinking about the optimal dosage is the form of magnesium used in the supplement. Bioavailability refers to how well and how quickly a nutrient or medication is absorbed and utilised by the body. Simply, it measures the extent and rate at which an active ingredient or nutrient becomes available in the bloodstream and is able to have an effect where it's needed. As an example, if you consume a magnesium supplement, bioavailability would indicate how much of the magnesium is actually absorbed into your bloodstream and used by your body versus how much is excreted without being utilised.
Research by Blancquaert et al. (2019) investigated dosages of 300 mg of elemental magnesium from different salts such as magnesium oxide, citrate, and chloride. The results showed that magnesium citrate had the highest bioavailability, with a significant improvement in serum magnesium levels compared to magnesium oxide and chloride. Specifically, magnesium citrate showed about a 24% higher absorption rate than magnesium oxide, making it the most preferred choice for supplementation.
Further research published in BMC Nutrition (2017) investigated 20 healthy male participants who received single doses of magnesium citrate and magnesium oxide in a randomised cross-over design. The study found that magnesium citrate resulted in significantly higher urinary magnesium excretion and serum magnesium levels compared to magnesium oxide, with a 24-hour renal excretion difference of 0.565 mmol, which indicates a superior absorption and retention of the citrate form (Kappeler et al., 2017).
A study by Walker et al. (2019) also compared the bioavailability of different magnesium formulations. Magnesium citrate and magnesium chloride showed higher bioavailability compared to magnesium oxide, with a relative improvement in absorption of about 24% and 50%, respectively.
Dietary Sources of Magnesium
As previously discussed in this article, the prevalence of magnesium deficiency across the globe ranges from 10% to as much as 75% due to inadequate dietary intakes and significant changes to the habitual diet across the globe.
Dietary sources high in magnesium include dark leafy green vegetables, nuts, seeds, whole grains, and legumes. A single serving of spinach (1 cup cooked) provides about 157 mg of magnesium, almonds (1 ounce) provide 80 mg, and black beans (1 cup cooked) provide 120 mg. The recommended dietary allowance (RDA) for magnesium is 400 - 420 mg per day for men and 310 - 320 mg per day for women. If you’re an athlete partaking in strenuous exercise, as discussed in the article, there may be a requirement for more due to losses through urine and sweat. For specific advice on magnesium supplementation, you should always consult your healthcare professional.
Another consideration when considering dietary sources of magnesium is the other factors that both influence and inhibit the absorption of magnesium. Phytates and oxalates, found in foods like grains and spinach, can bind magnesium and reduce its absorption. High doses of zinc and calcium can also compete with magnesium for absorption. Additionally, gastrointestinal issues such as Crohn's disease or celiac disease can impair magnesium uptake. Certain medications, including diuretics and antibiotics, can also decrease magnesium levels. Conversely, vitamin D enhances magnesium absorption, making it beneficial to maintain adequate levels of this vitamin alongside magnesium intake.
Conclusion
To conclude, magnesium intake shows a broad impact on health, sleep, athletic performance and recovery. As discussed in the article, magnesium deficiency is widespread due to modern dietary habits coming away from a whole food diet and more towards ultra processed foods. Much of the research presented in this article showed beneficial impacts of magnesium supplementation specifically in those who are considered deficient in this mineral. If you are looking to increase your daily intake of magnesium, then you may want to consider our electrolyte hydration drinks, which contain 295mg of magnesium. If you’re unsure about your required intake of magnesium, or you think you may have a deficiency, you should always discuss it with a medical professional.
Frequently Asked Questions (FAQs)
How does magnesium affect athletic performance and recovery?
Magnesium plays a key role in exercise performance and recovery by supporting muscular function, energy metabolism and electrolyte balance. The studies presented in this article show that in those deficient in magnesium such as the elderly, alcoholics, or those who partake in strenuous exercise thus excreting 10-20% of their magnesium levels through sweater and urine can benefit from magnesium supplementation, potentially improving muscular strength and recovery from exercise induced muscle damage.
Can magnesium improve sleep quality?
Magnesium supplementation has been shown to improve sleep quality, particularly in individuals with a deficiency. It may reduce sleep onset latency (the time it takes to get to sleep) as well as decrease night time awakenings, and increase sleep efficiency. It is theorised that this may be due to its role in neurotransmitter regulation and muscle relaxation.
What is the recommended daily intake of magnesium for adults?
The best daily dosage of magnesium typically ranges between 300mg to 500mg, absolutely depending on individuals’ needs and their daily dietary intake. It has been found that athletes may require a higher dose due to increased losses through sweat and urine. We advise that if you have questions regarding your intake of magnesium, you should consult a medical professional.
What are the best dietary sources of magnesium?
Foods high in magnesium include dark leafy greens, seeds, nuts, whole grains and legumes. For example, one cup of cooked spinach delivers around 157mg of magnesium, whilst one ounce of almonds provides 80mg. One cup of cooked black beans has around 120mg. It is important to note that it is absolutely possible to acquire your recommended daily intake of magnesium from diet alone.
References
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