This study proposed to set the intervention doses at 6 mg/day and 12 mg/day, with an intervention period of 6 months. The intervention agent was Astaxanthin Capsules from Haematococcus pluvialis (containing 6 mg of astaxanthin per capsule) supplied by Astareal Corporation, Japan. The control group received placebo capsules identical to the intervention group in terms of color, shape, size, packaging, and quantity but devoid of astaxanthin. Prior to the experiment, random sampling was conducted on the intervention capsules to verify the effective content of astaxanthin, ensuring the accuracy of the intervention doses. During the intervention period, experimenters distributed the intervention and control capsules to the corresponding populations, along with a consumption record form. The dosage for each month was administered, and the capsule containers were collected at the end of each month. Daily text messages were sent to remind participants to take the capsules and check in, with compliance assessed based on the record form and check-in records.A self-designed questionnaire was used to conduct baseline surveys on the study subjects, covering demographic characteristics, lifestyle, and medical history. The demographic survey included gender, age, educational level, marital status, occupation, and housing conditions. Lifestyle factors were assessed through smoking, alcohol consumption, mental activity (e.g., reading, newspaper consumption, computer use, television viewing), physical activity, household chores, and dietary supplement use. Past medical history encompassed current illnesses, prior diseases, family genetic history, duration of illness, and medication regimens. Physical examinations were performed by community health center physicians, measuring routine parameters such as height, weight, waist circumference, and blood pressure, with calculation of body mass index (BMI).The dietary questionnaire designed by the research team was administered through face-to-face interviews by specially trained investigators.Cognitive function was measured before intervention (baseline), at 3 months of intervention, and at the end of intervention (6 months of intervention), including the following tests: 1) Tracking the changes in the brain's neural electrophysiology during cognitive processes using event-related potential (ERP) P300.2) The Montreal Cognitive Assessment (MoCA) was used to evaluate the cognitive function of the subjects.The Siemens Trio 3T MRI system was used to acquire imaging data, including T1-weighted structural and resting-state functional scans as well as T2w-FLAIR images.Fasting peripheral blood samples were collected at three time points (pre-intervention, 3 months, and 6 months), and after processing, underwent comprehensive laboratory analyses including routine metabolic panels, plasma astaxanthin, mitochondrial function, oxidative stress markers, and cognition-related neurobiomarkers.
