In this A Single-center, Prospective, Self-controlled trial, subjects should avoid a high-magnesium diet for 1-3 weeks and take magnesium supplements for 4-6 weeks.

Investigational drug# Oral magnesium Study title# To explore the regulatory effect of magnesium on intestinal flora in healthy adults # A Single-center, Prospective, Self-controlled trial.

Principal Investigator# Professor Yu Chen, Department of Gastroenterology, The Seventh Affiliated Hospital, Southern Medical University.

Professor Peng Chen, Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University.

Study subjects# Healthy adult, Age 20-30 years Study phase# Investigator Initiated Trial(IIT) Study objectives# The objective of the study is to explore the regulatory effect of magnesium on intestinal flora in healthy adults Study design# A Single-center, Prospective, Self-controlled trial. Medication method# Subjects should avoid high magnesium diet for 1-3 weeks, and take magnesium supplement (food grade magnesium citrate: three capsules a day, after meals, 400mg magnesium) in 4-6 weeks. Peripheral blood and stool samples were collected from 60 subjects on day 0, day 21, and day 42 of the study period for routine blood tests, blood biochemical tests, and 16s rDNA sequencing analysis of gut microbiota.

Course#42days Sample size#60.

Inclusion Criteria:

• Healthy adults aged 20-30 years in the general community
• Without gender or ethnic requirements, who did not participate in other trials at the same time, volunteered to participate in this study
• No underlying diseases.

Exclusion Criteria:

• (1) Patients who have taken antibiotics orally in the past 3 months or have acute or chronic inflammation;
• (2) Those who have taken hormones within 3 months;
• (3) Those who have taken drugs that may interfere with glucose and lipid metabolism (such as insulin, glyburide, indomethacin, phentolamine, fuuside, phenytoin sodium, cortisone, etc.) and those who have taken probiotics within 1 month;
• (4) smokers and drinkers;
• (5) Uncontrollable mental disorders (including hospitalization history of mental illness);
• (6) Currently attending a weight loss or weight management course;
• (7) prescribed diet for specific or other reasons (e.g. celiac disease);
• (8) pregnant or lactating women;
• (9) Patients with cardiac and renal insufficiency;
• (10) Long-term constipation.

since some data may involve subject's privacy #we have no plans to share data so far# and some data may be shared later depending on the subjects's wishes.