If a person has difficulty falling asleep, difficulty staying asleep, or early final awakening for a considerable time, then this person is experiencing insomnia. Insomnia is a condition of unsatisfactory quantity and quality of sleep, and its prevalence increases with age. Individuals who suffer from insomnia show memory weakness, increased reaction time, short-term memory problems, and lowered efficacy levels. Insomnia is more problematic in the elderly because it puts them at higher risk for falling, cognitive impairments, weak physical function, and mortality (from 1.3 to 3 times higher risk). Sleep disorders are also related to decreased quality of life and general health and increased health costs, stress, and depression symptoms (1).

    Many dietary supplements claim to help with sleep on the market; some contain mineral magnesium. What is the role of magnesium in health and would dietary supplementation of magnesium improve sleep?

    Magnesium is an essential element that is crucial to hundreds of physiologic processes in humans. Inadequate intake of magnesium has been linked to various adverse health outcomes, including sleep disorders. Epidemiologic surveys showed that the dietary intake of magnesium is inadequate in various populations. Some population groups, such as the elderly, have particularly lower magnesium intake than reference groups and aging is a major risk factor for magnesium deficiency (1).

    Numerous changes occurred in magnesium status in the elderly. Its total level reduces due to a decrease in bone mass which is the most important magnesium source in the body. The magnesium metabolism is also compromised due to reduced intestinal uptake, increased urinal, and fecal excretion, and drug-induced loss of magnesium.

    The most important factor resulting in age-related magnesium deficiency is probably the reduced dietary intake of magnesium. The lower magnesium intake may occur due to the inability in using magnesium sources or the tendency to consume more processed food and less whole grains and green leafy vegetables. Nuts, seeds and beans, whole grains, and fish and seafood are the best sources of magnesium in the diet. In addition to these foods, dark green leafy vegetables are good sources of magnesium. The effect of age on dietary habits may be chewing problems, which may have a large influence on food choice and, as a consequence, on nutrient intake. Older people chose different foods, suggesting that older persons tend to adapt their diet to the functional difficulties that often occur during the aging process. These factors may lead elderly persons to have a monotonous and energy-restricted diet, which easily results in an inadequate intake of nutrients (1).

    In a double-blind randomized clinical trial, 43 elderly subjects (21 men and 22 women, 65 ± 4.6 years old), were randomized to receive 500 mg magnesium or a placebo daily for 8 weeks. Magnesium was administered as magnesium oxide tablets twice a day (each tablet containing 414 mg magnesium oxide as 250 mg elemental magnesium). Questionnaires on insomnia severity index, physical activity, and sleep log were completed at baseline and after the intervention period. Anthropometric factors, daily intake of magnesium, calcium, potassium, caffeine, calories from carbohydrates, and total calorie intake, were obtained using 24-h recall for 3 days. Blood samples were taken at baseline and after the intervention period (1).

    As compared to the placebo group, dietary magnesium supplementation resulted in statistically significant increases in sleep time (+14% vs -2.7%, p = 0.002), sleep efficiency (+9.6% vs 0.1%, p = 0.03), the concentration of serum renin (+36.7% vs -5.9%, p < 0.001), and melatonin (+35% vs -1.1%, p = 0.007), and also resulted in a significant decrease of insomnia severity index score (-14.4% vs -2.7%, p = 0.006), sleep onset latency (-14% vs +3.7%, p = 0.02) and serum cortisol concentration (-8.2% vs +3.5%, p = 0.008). Supplementation also resulted in a marginally between-group significant reduction in early morning awakening (-3% vs -1%, p = 0.08) and serum magnesium concentration (+4.2% vs -1.3%, p = 0.06). Although total sleep time (+3% vs -0.19%, p = 0.37) did not show any significant between-group differences (1).

    Supplementation of magnesium appeared to improve subjective measures of insomnia such as insomnia severity index score, sleep efficiency, sleep time and sleep onset latency, early morning awakening, and likewise, insomnia objective measures such as concentration of serum renin, melatonin, and serum cortisol, in elderly people. It is believed that increased plasma renin level is associated with deeper sleep, and decreased renin level is concurrent with lighter sleep. So the magnesium supplementation seemed to improve the sleep quality with deeper sleep with better recovery power, thus less stress.

    Another study examined the effect of magnesium in 12 elderly subjects (age range 60-80 years) on the sleep electroencephalogram (EEG) and nocturnal hormone secretion. A placebo-controlled, randomized cross-over design with two treatment intervals of 20 days duration separated by 2 weeks washout was used. Magnesium was administered as tablets in an increasing dose of 10 mmol and 20 mmol each for 3 days followed by 30 mmol for 14 days. At the end of each interval, a sleep EEG was recorded from 11 p.m. to 7 a.m. after one accommodation night. Blood samples were taken every 30 min between 8 p.m. and 10 p.m. and every 20 min between 10 p.m. and 7 a.m. to estimate ACTH, cortisol, renin, and aldosterone plasma concentrations, and every hour for arginine-vasopressin (AVP) and angiotensin 11 (ATII) plasma concentrations (2).

    Magnesium supplementation led to a significant increase in slow wave sleep (16.5 ± 20.4  vs. 10.1 ± 15.4 minutes, p ≤ 0.05), delta power (47128.7 ±21417.7 microV(2) vs. 37862.1 ± 23241.7 microV(2), p ≤ 0.05) and sigma power (1923.0 ± 1111.3  vs. 1541.0 ± 1134.5 microV(2), p ≤ 0.05 ). Renin increased (3.7 ± 2.3 vs. 2.3 ± 1.0 ng/ml x min, p < 0.05) during the total night, and aldosterone (3.6 ± 4.7 vs. 1.1 ± 0.9 ng/ml x min, p < 0.05) in the second half of the night, whereas cortisol (8.3 ± 2.4 vs. 11.8 ± 3.8 pg/ml x min, p < 0.01) decreased significantly and arginine-vasopressin (AVP) by the trend in the first part of the night. ACTH and ATII were not altered. These results suggested that magnesium supplementation partially reversed sleep EEG and nocturnal neuroendocrine changes occurring during aging. The similarities between the effect of magnesium and that of the related electrolyte Li+ furthermore supported the possible efficacy of magnesium as a mood stabilizer (2).

    The process of normal aging is accompanied by changes in sleep-related endocrine activity. During aging, an increase in cortisol at its nadir and a decrease in renin and aldosterone concentration occur. In aged subjects, more time is spent awake and slow-wave sleep is reduced. Magnesium supplementation appeared to improve sleep quality and help with deeper sleep for the elderly.

References:

 

1. Abbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B. (2012). The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial. J Res Med Sci.17(12):1161-9.

2. Held, K., Antonijevic, I. A., Künzel, H., Uhr, M., Wetter, T. C., Golly, I. C., … Murck, H. (2002). Oral Mg2+ Supplementation Reverses Age-Related Neuroendocrine and Sleep EEG Changes in Humans. Pharmacopsychiatry, 35(4), 135–143. doi:10.1055/s-2002-33195
   
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