The SAVOR Study: Appetite and Physiological Responses

Seniors' Appetite: Vibrant Opportunities for Revitalization (SAVOR)

The study aims to identify key physiological factors that differentiate older adults with healthy appetites from those experiencing appetite decline. The investigators hypothesize that seniors experiencing appetite decline will exhibit distinct oro-sensory, gastrointestinal, and hormonal profiles compared to seniors with healthy appetites, suggesting underlying biological mechanisms contributing to reduced appetite.

Appetite decline in older adults, or anorexia of aging, is a prevalent geriatric syndrome associated with decreased quality of life, increased risk of malnutrition, and accelerated decline in health. While current nutritional guidelines often emphasize increasing nutrient density, these strategies often fail to address the root causes of diminished appetite. Emerging research highlights the critical role of age-related physiological changes, particularly dysregulation of the gut-brain axis, altered sensory perception, and hormonal imbalances, in suppressing appetite. Notably, existing evidence is largely derived from Western populations, which may not fully reflect the influence of cultural and lifestyle factors on appetite in Asian seniors. This leaves a significant gap in understanding and addressing appetite loss within this specific demographic. This study aims to address this gap by comprehensively investigating the physiological mechanisms underlying appetite regulation in Asian seniors, to identify key determinants that differentiate individuals with healthy appetites from those experiencing a decline. By assessing the relationships between oro-sensory function, gastric dynamics, neuro-hormonal regulation, gut microbiome composition and subjective appetite, this study seeks to provide a deeper understanding of the biological pathways driving appetite differences in this population. The findings of this study will lay the groundwork for future research aimed at developing culturally sensitive and effective interventions that can restore appetite, improve nutritional status, and ultimately enhance the health span and quality of life for older adults in Singapore and beyond. Furthermore, this work has the potential to drive innovation in the food and nutrition industry, leading to the development of tailored products and dietary strategies that effectively address the unique nutritional needs of aging populations, ultimately impacting public health recommendations and policies related to senior nutrition.

Inclusion Criteria:

• Postmenopausal female
• Aged 65-74 years
• Habitual breakfast consumer (consumes breakfast between 7am to 10am)
• Willingness to consume meals and follow intervention protocol
• English speaking

Exclusion Criteria:

• BMI ≥ 27.5
• Diagnosed with medical condition that may influence appetite or microbiome (e.g. diabetes, thyroid disorders, gastrointestinal diseases)
• Currently taking any medications or supplements that may influence appetite or the microbiome (e.g. probiotics, antibiotics, appetite stimulants/suppressants) one month prior to their first visit in consultation with study physician, PI and study team
• Following a special diet for weight management (e.g. low-calorie, low carbohydrate)
• History of bariatrics surgery
• Intentional attempt to change body weight or composition
• History of severe vasovagal syncope (blackouts or near faints) following blood draw
• Drug abuse within last 5 years
• Excessive alcoholic beverage consumption > 2 servings per day (1 serving defined as 360 mL beer, 150 mL wine or 45 mL distilled spirits)
• Smoking (cigarette, e-cigarette, cigar, pipe, vape)
• Engaging in habitual vigorous physical activity (as defined by physical activity questionnaire-PAQ)
• Loose teeth or jaw pain
• Not missing > 2 non-wisdom molars
• Involvement in other clinical studies that may influence the outcome of the study
• A study team member or their immediate family member