Investigating the Feasibility of Krill Oil Intervention to Improve Muscle Function in Adults With Long-term Conditions

This study will recruit 30 adults (men and women, aged 18 years and over) who will be randomly assigned to one of two groups in a 12-week double-blind pilot trial. Participants will receive either: * Arm 1: Krill Oil group: 4 g/day of krill oil supplements (Superba™ Antarctic Krill Oil, 1000 mg capsules), or * Arm 2: Control group: 4 g/day of placebo (vegetable oil capsules). Participants will be instructed to maintain their usual diet and physical activity patterns throughout the study. Eligibility will be assessed using a health screening questionnaire, completed with the researcher's assistance, before obtaining informed consent. Habitual physical activity will be evaluated using the International Physical Activity Questionnaire (short form), and dietary intake will be assessed with the EPIC Food Frequency Questionnaire (FFQ) at both the beginning and end of the study. In addition, participants will record their fish consumption weekly using a dedicated logbook. Measurements will be taken at baseline and after 12 weeks, including: * Blood samples to assess inflammatory and metabolic markers. * Anthropometry and body composition, including weight, height, fat mass, fat percentage, and muscle mass (via ultrasound). * Muscle strength, measured using handgrip strength and maximal voluntary contraction (each performed three times with rest between attempts). * Physical performance, assessed with a 4-meter walk test at normal speed Upon completing the study, participants will receive a £50 voucher in appreciation of their contribution.