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United States Department of Agriculture

Agricultural Research Service

Research Project: MICRONUTRIENT ROLES IN PHYSIOLOGY AND HEALTH Title: Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep

Authors
item Nielsen, Forrest
item Johnson, Luann -
item Zeng, Huawei

Submitted to: Magnesium Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 26, 2010
Publication Date: December 10, 2010
Repository URL: http://handle.nal.usda.gov/10113/58074
Citation: Nielsen, F.H., Johnson, L.K., Zeng, H. 2010. Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep. Magnesium Research. 23(4):158-68.

Interpretive Summary: People older than age 50 years often have poor sleep quality. Disrupted sleep and sleep deprivation have been associated with chronic low-grade inflammation, which is a stress response in the body that occurs without the need to fight infection or injury. Limited studies have indicated that magnesium deprivation may contribute to the occurrence of poor sleep quality and may affect the severity of the associated chronic low-grade inflammatory stress, which can lead to unwanted attacks on healthy tissue. Thus, an experiment was performed with 100 adults older than 51 years with poor sleep quality revealed by a subjective questionnaire called the Pittsburg Sleep Quality Index (PSQI). The PSQI generates seven component scores for sleep quality, latency, duration, efficiency, disturbances and medication use, and daytime dysfunction. An overall PSQI score of greater than five indicated poor sleep quality. After baseline assessment (week one) of body mass index (BMI), diet, blood and urine biochemical variables, and sleep quality, 50 subjects were supplemented with 320 milligrams of magnesium per day as magnesium citrate and 50 subjects were given a sodium citrate placebo for seven weeks. Final assessments were made at five and seven weeks after starting the supplements. Based on food diaries, 58% of the participants were consuming less than the U.S. Estimated Average Requirement (EAR) for magnesium. Consuming less than the EAR was associated with significantly higher BMI (more overweight and obese) and plasma C-reactive protein (an indicator of inflammatory stress). Only 40 participants had plasma C-reactive protein concentrations higher than 3.0 milligrams per liter, which was considered the threshold for chronic low-grade inflammation. Overall PSQI scores improved (10.4 to 6.6) and red blood cell magnesium increased regardless of magnesium or placebo supplementation. When only the 37 participants with serum magnesium concentrations less than 1.8 milligrams per 100 milliliter (indication of deficient magnesium status) were analyzed, magnesium supplementation, but not the placebo, increased serum magnesium concentrations. Magnesium supplementation compared with the placebo also decreased plasma C-reactive protein in participants with baseline values higher than 3.0 milligram per liter. The findings show that many individuals have a low magnesium status indicated by low dietary intakes and serum concentrations of magnesium. The low magnesium status was associated chronic inflammatory stress, which could be alleviated by magnesium supplementation. Another factor (possibly supplemental citrate affecting dietary magnesium use) in addition to an apparent placebo effect that improved sleep quality and increased erythrocyte magnesium concentrations prevented the determination of whether magnesium deficiency contributes to poor sleep quality. The findings, however, suggest an association between magnesium status and sleep quality that needs further study.

Technical Abstract: Low magnesium status has been associated with numerous conditions characterized as having a chronic inflammatory stress component. Some animal findings indicate that a moderate magnesium deficiency, similar to which apparently commonly occurs in humans, may enhance inflammatory or oxidative stress induced by other factors, including disrupted sleep/sleep deprivation. Thus, an experiment was performed with 100 adults (22 males and 78 females) older than 51 years with poor sleep quality revealed by a Pittsburg Sleep Quality Index (PSQI) score higher than five. The participants were randomly assigned to two groups matched by gender, age, and overall PSQI score. After baseline assessment (week one) of body mass index (BMI), diet, blood and urine biochemical variables, and sleep quality, one group was given a 320 mg magnesium/day supplement as magnesium citrate and the other group a sodium citrate placebo for seven weeks. Final assessments were made five and seven weeks (which were combined for statistical analysis to reduce intra-individual variation) after supplement initiation for the 96 participants that completed the study as designed. Based on food diaries, 58% of the participants were consuming less than the U.S. Estimated Average Requirement (EAR) for magnesium. Consuming less than the EAR was associated with significantly higher BMI and plasma C-reactive protein (CRP) concentration. Only 40 participants had plasma CRP concentrations higher than 3.0 mg/L (an indication of chronic inflammatory stress). Overall PSQI scores improved (10.4 to 6.6, p<0.0001) and erythrocyte magnesium increased (4.75 to 5.05 pg/cell, p = 0.01) regardless of magnesium or placebo supplementation. Magnesium vs. placebo supplementation did not significantly affect serum magnesium when all participants were included in the analysis. When only the 37 participants with serum magnesium concentrations <1.8 mg/dL (indication of deficient magnesium status) were analyzed, magnesium supplementation, but not the placebo, increased serum magnesium concentrations. Magnesium supplementation vs. placebo decreased plasma CRP in participants with baseline values >3.0 mg/L. The findings show that many individuals have a low magnesium status associated with increased chronic inflammatory stress that could be alleviated by increased magnesium intake. Another factor (possibly supplemental citrate affecting dietary magnesium use) in addition to an apparent placebo effect that improved sleep quality and increased erythrocyte magnesium concentrations in all participants prevented the determination of whether magnesium deficiency contributes to poor sleep quality. The findings, however, suggest an association between improved magnesium status and sleep quality that needs further study.

Last Modified: 4/18/2014
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