Effect of Magnesium Supplementation on Sleep Quality and Cognitive Function in Saudi Adults

Participants were instructed to take magnesium citrate supplements daily for 90 days and were provided with a diary to record their supplement intake and adherence throughout the study period. Any unconsumed capsules were left in the original bottle and returned during the follow-up visit to assess compliance. Participants were also asked to report any symptoms experienced during the intervention period. In addition, participants received reminders every two weeks via WhatsApp to encourage adherence to supplement intake.

Randomization codes were generated in advance using the RAND function in Microsoft Excel (Microsoft Corporation, Redmond, WA, USA). Following confirmation of eligibility at the screening visit, participants were sequentially assigned to the next available intervention based on the pre-generated allocation list.

At baseline and after the intervention, participants completed a comprehensive assessment that included dietary intake using a Food Frequency Questionnaire (FFQ) and physical activity using the short form of the International Physical Activity Questionnaire (IPAQ). All questionnaires were administered in English. Anthropometric data, including weight and height, were self-reported by participants. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI), and cognitive function was assessed using the Trail Making Test Parts A and B. Blood pressure measurements were also recorded using standardized procedures.

Blood samples were collected at baseline (prior to the intervention, during the second visit) and again after 3 months (at the final visit). Participants were instructed to fast for 8 hours before both visits, with only water permitted, to standardize conditions and minimize the influence of dietary intake on serum magnesium levels.

Approximately 10 mL of blood was drawn via venipuncture by a qualified laboratory specialist using red or yellow-top tubes. The collected samples were processed and stored at -80°C for subsequent analysis of nutritional biomarkers, including serum magnesium and HbA1c.

Inclusion criteria

• Adults aged 18 years and above
• Poor Sleep Quality (>5 PSQI score)
• Living in Saudi Arabia

Exclusion criteria

• Children less than 18 years old
• Good Sleep Quality (5 or less PSQI score)
• Pregnant or breastfeeding
• Current smoker
• History of sleep disorder
• History of cognitive impairment
• Diagnosed with a disease (e.g. diabetes, hypertension, celiac, psychiatric disease)
• Acute phase of diseases (e.g. cardiovascular)
• History of head injury (e.g. accident) or neurological disorders (e.g. seizures)/neurodevelopment disorders
• Use of prescribed medications within the past 3 months that may influence sleep
• Current use of hormone therapy (e.g. thyroxine, insulin, growth hormone, contraceptives)
• Use of dietary supplements within the previous 3 months (e.g. vitamin D, omega-3..etc)
• Food allergies/intolerances (e.g. eggs, nuts, milk)
• Excessive caffeine consumption (>450 mg/day, more than 4 cups)
• Shift worker or work schedules that cause irregular sleep patterns
• History of travel to a different time zone in the previous month
• Experiencing events that may cause severe stress for the previous 6 weeks from baseline (e.g. divorce or death or acute illness of a family member)
• Has children between 0-2 years