Assessment of a novel functional food modulating the microbiota-inflammation-brain axis in patients with heart failure and/or /atrial fibrillation patients (the AMBROSIA study): Protocol for a randomized controlled trial.

The AMBROSIA study targets a complex clinical triad of atrial fibrillation, heart failure, and undernutrition in older adults.

• AF, HF, and undernutrition represent a 'complex triad with major clinical and socioeconomic consequences in older adults, often predisposing to frailty'.
• Undernutrition often remains underdiagnosed due to reliance on weight-based measures and limited awareness of inflammation-related cachexia.
• The study aims to explore the microbiota-inflammation-brain axis in this population.

The trial is designed as a single-center, prospective, parallel-group randomized controlled trial enrolling 120 older adults with confirmed AF and/or HF.

• Participants are randomized 1:1 into an intervention group (n=60) or control group (n=60).
• All participants receive individualized dietary counseling.
• The intervention group additionally consumes one AMBROSIA nutritional bar daily for six months.
• Clinical, cognitive, and nutritional data along with blood, saliva, urine, and stool samples are collected at baseline, 3, and 6 months.

The AMBROSIA nutritional bar is a novel fortified functional food product with a specific composition targeting multiple physiological pathways.

• The bar contains hydrolyzed proteins, inulin, CoQ₁₀, and probiotics (L. rhamnosus IMC 501® and L. paracasei IMC 502®).
• The bar is delivered in a flavonoid-rich chocolate matrix.
• The intervention duration is six months with one bar consumed daily.

The primary endpoint of the AMBROSIA study is the change in skeletal muscle mass, physical function, and frailty.

• Secondary endpoints include changes in nutritional status, inflammation, gut microbiota, metabolomics, and quality of life.
• The study incorporates comprehensive outcome assessments alongside mechanistic/exploratory omics analyses and gut microbiota functional profiling.
• Multiple biological sample types (blood, saliva, urine, and stool) are collected to support omics analyses.

The study aims to uncover mechanisms driving undernutrition and identify biomarkers to support personalized interventions.

• The study integrates 'cutting-edge omics tools and a multidimensional nutritional strategy'.
• The goal is to 'uncover mechanisms driving undernutrition and identify biomarkers to support personalized interventions for older patients with AF and HF'.
• The study explores the microbiota-inflammation-brain axis as a mechanistic framework.