The SAVOR Study: Appetite and Physiological Responses

Official title

Seniors' Appetite: Vibrant Opportunities for Revitalization (SAVOR)

Overview

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.

Detailed description

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.

Interventions

• Other Shredded Chicken Congee
  This is a mixed meal tolerance test intended to elicit gut hormone responses reflective of real-world dietary patterns.

Primary outcome measures

• Ad Libitum Lunch [Time frame: Participants will be given 30 minutes to consume the meal until they are comfortably full, 180 minutes after the start of the intervention.]

Secondary outcome measures (11)

• Palatability questionnaire [Time frame: Administered after consuming test meal and after consuming the ad libitum meal.]
• Appetite hormones [Time frame: Blood samples will be collected at timepoints (t = -15 minute (baseline), 30, 60, 90, 120 and 180 minutes)]
• Subjective Appetite Questionnaire [Time frame: Measurement is taken at t = -15 minute (baseline), 10, 30, 60, 90, 120 and 180 minutes]
• Gastric Ultrasound [Time frame: Measurements will be taken at t = -15 minute (baseline), 15, 45, 105 and 165 minutes]
• Stool collected using the OMNIgene and OMNImet [Time frame: Baseline stool sample will be collected once between screening and intervention day.]
• Olfactory Acuity (SCENTinel) [Time frame: Baseline measurement administered once during screening, takes approximately 5-10 minutes]
• Taste Acuity Test (WETT) [Time frame: Baseline measurement administered once during screening, takes approximately 10-15 minutes]
• Blood plasma (Cytokines) [Time frame: t = -15 minute (baseline), 30, 60, 90, 120, 180 minutes]
• Blood plasma (Bile acids and short-chain fatty acids profiling) [Time frame: t= -15 minute (baseline), 30, 60, 90, 120, 180 minutes]
• Bite Strength [Time frame: Baseline measurement that may be administered once during screening or test session, as schedule and equipment permits. Takes only a few minutes.]
• Tongue Strength (Tongue Pressure) [Time frame: Baseline measurement that may be administered once during screening or test session, as schedule and equipment permits. Takes approximately 5 minutes.]

Eligibility criteria

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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Other

Study locations

Singapore · 1 center

• Clinical Nutrition Research Centre — Singapore

Publications

• Sturm K, MacIntosh CG, Parker BA, Wishart J, Horowitz M, Chapman IM. Appetite, food intake, and plasma concentrations of cholecystokinin, ghrelin, and other gastrointestinal hormones in undernourished older women and well-nourished young and older women. J Clin Endocrinol Metab. 2003 Aug;88(8):3747-55. doi: 10.1210/jc.2002-021656. PMID 12915664
• Dagbasi A, Warner J, Catterall V, Smith K, Crabtree DR, Carroll B, Frost G, Holliday A. Augmented gut hormone response to feeding in older adults exhibiting low appetite. Appetite. 2024 Oct 1;201:107415. doi: 10.1016/j.appet.2024.107415. Epub 2024 May 16. PMID 38761969
• Atalayer D, Astbury NM. Anorexia of aging and gut hormones. Aging Dis. 2013 Oct 1;4(5):264-75. doi: 10.14336/AD.2013.0400264. PMID 24124632
• Dagenais S, Fielding RA, Clark S, Cantu C, Prasad S, Groarke JD. Anorexia in Medicare Fee-for-Service Beneficiaries: A Claims-Based Analysis of Epidemiology and Mortality. J Nutr Health Aging. 2023;27(3):184-191. doi: 10.1007/s12603-023-1882-4. PMID 36973924
• Morley JE. Peptides and aging: Their role in anorexia and memory. Peptides. 2015 Oct;72:112-8. doi: 10.1016/j.peptides.2015.04.007. Epub 2015 Apr 17. PMID 25895851

Identifiers

NCT: NCT07636369 · 2025-133

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗