Associations Between Dietary Intake and Cardiometabolic and Gut Microbiota Outcomes

Pittsburgh Sleep Quality Index Questionnaire (PSQI) will be used to assess the sleep quality. Overall score ranging from 0 to 21 points, where lower scores denote a healthier sleep quality.

Use Montreal Cognitive Assessment (MoCA) questionnaires to assess cognitive function. A score of 26 or above (out of 30) is generally considered normal, though adjustments may be made for educational level.

Skin carotenoid concentration: This can be measured by Resonance Raman Spectroscopy, the unit is skin carotenoid score, a higher score means optimal, lower score means poor condition of skin carotenoids.

Macular Pigment Optical Density (MPOD): A measurement of macular pigment of the eye using a heterochromatic flicker photometry device. The measurements are in arbitrary units.

The Global Physical Activity Questionnaire (GPAQ) will be used to assess physical activity levels in three areas: work, transport, and leisure. It measures activity in terms of frequency, duration, and intensity, generating a score in metabolic equivalents (METs). Higher MET values indicate higher levels of physical activity.

The Perceived Stress Scale (PSS-10) will be used to assess the level of perceived stress over the past month. The scale consists of 10 items scored on a 5-point Likert scale (0 = never to 4 = very often), with a total score ranging from 0 to 40. Higher scores indicate greater perceived stress.

The Beck Anxiety Inventory (BAI) will be used to measure the severity of anxiety symptoms. It consists of 21 questions scored on a 4-point Likert scale (0 = not at all to 3 = severely). The total score ranges from 0 to 63, with higher scores reflecting more severe anxiety symptoms.

The Beck Depression Inventory-II (BDI-II) will be used to assess the severity of depressive symptoms over the past two weeks. It contains 21 questions scored on a 4-point scale (0 = no symptoms to 3 = severe symptoms). Total scores range from 0 to 63, with higher scores indicating more severe depression.

Participants will read out letters on a ETDRS LogMAR chart at a fixed distance where letters becomes smaller as it goes down the chart. Tests results will be recorded in number of letters read, where the more letters the better the outcome.

A questionnaire to for participants to self-evaluate their perception of their current eye health based on general vision, ocular pain, near activities, distance activities, vision specific functions, driving, color vision and peripheral vision. The best possible score is 100 and worst possible score is 0.

Skin advanced glycation end products (AGE) levels: Measurement of skin advanced glycation end products level using a skin autofluorescence device, where participants wlll be instructed to place their forearm over the device and a light will be shone and a reading can be captured by detecting fluorescence. The results will be presented as arbitrary units.

The blood drawn will be processed and stored. Measurements will be done using ultra-performance liquid chromatography coupled with mass spectrometry techniques to determine the levels of advanced glycation end products. Units will be in μg/mL.

Participants will read out letters on a ETDRS LogMAR chart at a fixed distance, where the letters differs in lightness to test participants' sensitivity to contrast. Tests results will be recorded in number of letters read, where the more letters the better the outcome.

Untargeted metabolomics profiling of plasma will be conducted using ultra performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-QTOF-MS)