OLFO-FOOD: OLFactory Odour Stimulation and FOOD Preferences

Sponsor

University Hospital, Basel, Switzerland (Other)

Overall Status

Recruiting

CT.gov ID

NCT05869110

Collaborator

(none)

Enrollment

Location

Arms

11.4

Anticipated Duration (Months)

2.1

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The aim of the present "OLFO-FOOD" clinical trial is to investigate, if olfactory stimulation impacts food choice, reference and calorie intake in humans with obesity assessed using a test buffet.

Condition or Disease	Intervention/Treatment	Phase
Obesity	Other: Effects of odours on calorie intake, food choice and metabolic parameters	N/A

Detailed Description

Overweight study participants will be included in this study. For the participants the study consists of the screening visit and main visit 1 and 2. In between the main visits there is a wash-out period of 1 week (7 days ± 3 days). In total, participants will have 3 visits. After the screening visit and before the main visit 1, odours will be assigned in a randomized order. Each participant will receive both odours. The two visits (main visit 1 and 2) will have the exact same procedures except for the olfactory odour.

Hunger, appetite, thirst, food perception, nausea, headache and mood will be assessed and the first blood samples will be collected. The participants will receive the aspUraclip® filled with 50 μl of either olfactory stimulation or placebo (propylene glycol), due to the computer-generated randomization order. The "aspUraclip®" will be clipped to the nasal septum for 15 minutes. After olfactory stimulation, vital parameters will be measured and blood samples will be taken. Participants will rate hunger, appetite, thirst, nausea, headache, mood, as well as local nose irritation, odour intensity and odour perception. Directly afterwards, the participants choose food ad libitum from a test-buffet. Participants will have 2 hours to eat from the buffet, but can finish earlier if they wish. Eating time will be recorded. After finishing their meal, vitals will be measured, blood samples will be collected and the participants will rate hunger, appetite (general, carbohydrates, meat, dairy foods, vegetables, fruits, sweets, salty foods), thirst, nausea, headache, mood, food taste, food taste intensity, food scent intensity and food scent perception on a 10-point VAS (visual analogue scale). 2 hours after the start of the test-buffet, patients will rate the same questions on a VAS again, vitals and blood samples will be taken. If the participants eat throughout the 2-hour-timespan of the test-buffet and don't stop early, there will be only one measurement (vitals, VAS, BS) after 2 hours, when the test-buffet ends. Food intake will be measured by weighing the food before and after consumption. Following the test-buffet, patients will have a resting phase of 2 hours. During this phase, patients are free to read, listen to music or similar. After the 2 hour resting phase, vitals will be measured, blood samples collected and VAS-questions asked.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

24 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Intervention Model Description:

Randomized, placebo-controlled, single-blind, cross-over, single-centre trialRandomized, placebo-controlled, single-blind, cross-over, single-centre trial

Masking:

Single (Participant)

Masking Description:

Study participants will not be informed which substances are investigated

Primary Purpose:

Treatment

Official Title:

OLFO-FOOD: OLFactory Odour Stimulation and FOOD Preferences

Actual Study Start Date :

Apr 20, 2023

Anticipated Primary Completion Date :

Mar 31, 2024

Anticipated Study Completion Date :

Mar 31, 2024

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Experimental Intervention Olfactory stimulation	Other: Effects of odours on calorie intake, food choice and metabolic parameters Evaluation of the effects of olfactory stimulation compared to placebo on calorie intake and preference of food during a test-buffet. Odours will be assigned in a randomized order. Each participant will receive both odours, in between there will be a wash-out period of 1 week.
Placebo Comparator: Placebo Propylene glycol	Other: Effects of odours on calorie intake, food choice and metabolic parameters Evaluation of the effects of olfactory stimulation compared to placebo on calorie intake and preference of food during a test-buffet. Odours will be assigned in a randomized order. Each participant will receive both odours, in between there will be a wash-out period of 1 week.

Arm

Intervention/Treatment

Experimental: Experimental Intervention

Olfactory stimulation

Other: Effects of odours on calorie intake, food choice and metabolic parameters

Evaluation of the effects of olfactory stimulation compared to placebo on calorie intake and preference of food during a test-buffet. Odours will be assigned in a randomized order. Each participant will receive both odours, in between there will be a wash-out period of 1 week.

Placebo Comparator: Placebo

Propylene glycol

Other: Effects of odours on calorie intake, food choice and metabolic parameters

Outcome Measures

Primary Outcome Measures

Change in calorie intake after olfactory stimulation [two time assessment at baseline and after 1 week]
Olfactory stimulation compared to placebo in participants with obesity with a BMI ≥30 kg/m2 assessed by a test-buffet.

Secondary Outcome Measures

Change in food preference after olfactory stimulation [two time assessment at baseline and after 1 week]
Olfactory stimulation compared to placebo in participants with obesity with a BMI ≥30 kg/m2 assessed by a test-buffet. Proportion of carbohydrates, fat and protein of the chosen food products (processed foods, warmed-up ready-to-eat meal, fresh fruits and vegetables)
Change of hunger assessed via VAS (Visual Analogue Scale) upon olfactory stimulation [up to eight time assessment from baseline till day 7]
Hunger will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Change of appetite assessed via (Visual Analogue Scale) VAS upon olfactory stimulation [up to eight time assessment from baseline till day 7]
Appetite will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Change of thirst assessed via (Visual Analogue Scale) VAS upon olfactory stimulation [up to eight time assessment from baseline till day 7]
Thirst will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Change of nausea assessed via (Visual Analogue Scale) VAS upon olfactory stimulation [up to eight time assessment from baseline till day 7]
Nausea will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Change of headache assessed via (Visual Analogue Scale) VAS upon olfactory stimulation [up to eight time assessment from baseline till day 7]
Headache will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Change of mood assessed via (Visual Analogue Scale) VAS upon olfactory stimulation [up to eight time assessment from baseline till day 7]
Mood will be assessed via 10-point VAS Score (0= not at all, 10= maximum)) upon olfactory stimulation compared to placebo before and directly after olfactory stimulation, before and after exposure to a test-buffet.
Change in plasma glucose Level (mmol/L) [up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)]
Up to 5 blood samplings will be collected during each main visit, depending on the individual endpoint at the test-buffet: 4 blood samplings (60.8ml) if the participant eats the full 2 hours from the test-buffet, 5 samplings (76ml) if the participant stops eating from the test-buffet early. Before olfactory stimulation (OS), (Baseline) After OS, before the test-buffet (TB0) After individual endpoint at the test-buffet (TBX) After 2 hours of test-buffet (TB2) After 2 hours of resting phase (TBR)
Change in plasma insulin Level (pmol/L) [up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)]
Up to 5 blood samplings will be collected during each main visit, depending on the individual endpoint at the test-buffet: 4 blood samplings (60.8ml) if the participant eats the full 2 hours from the test-buffet, 5 samplings (76ml) if the participant stops eating from the test-buffet early. Before OS (Baseline) After OS, before the test-buffet (TB0) After individual endpoint at the test-buffet (TBX) After 2 hours of test-buffet (TB2) After 2 hours of resting phase (TBR)
Change in serum cortisol Level (nmol/L) [up to 10 time assessment at visit one (Baseline, TB0, TBX, TB2, TBR) and after 1 week at visit 2 (Baseline TB0, TBX, TB2, TBR)]
Up to 5 blood samplings will be collected during each main visit, depending on the individual endpoint at the test-buffet: 4 blood samplings (60.8ml) if the participant eats the full 2 hours from the test-buffet, 5 samplings (76ml) if the participant stops eating from the test-buffet early. Before OS (Baseline) After OS, before the test-buffet (TB0) After individual endpoint at the test-buffet (TBX) After 2 hours of test-buffet (TB2) After 2 hours of resting phase (TBR)

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 60 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Age 18-60 years
Written informed consent
BMI ≥30 kg/m2
Normosmia (as defined by Sniffin' Sticks Test)

Exclusion Criteria:

Known allergy to olfactory stimulation substance, citrus fruits, citrus flavours, citrus food products
Lactose-intolerance, celiac disease or non-celiac wheat sensitivity
Diet other than omnivore or vegetarian
Eating disorder (now or in the past)
Dysphagia
Acute disease affecting food intake
Acute upper respiratory tract infection, acute or chronic sinusitis
Severe visual impairment (vision <10%)
Surgical intervention of the nasal cavity or the paranasal sinus
Current illicit drug abuse including daily marijuana and CBD (Cannabidiol) consumption (alcohol ≤2 drinks per day allowed)
Any kind of severe chronic disease (e.g. severe heart failure, active cancer disease)
Type 1 and 2 diabetes mellitus
Treatment with insulin-sensitizing drugs within the last 3 months
Treatment with Glucagon-like Peptide 1 (GLP1)-analoga
History of neurodegenerative diseases, severe head trauma
Severe renal impairment (e.g. estimated glomerular filtration rate <30 ml/min/m2)
Known liver cirrhosis or other severe liver impairment
Use of any kind of decongestant more than twice a week
Uncontrolled dysthyroidism
Uncontrolled hypertension
Regular use of psychopharmaceutic drugs
Study participants aims to start a new diet or exercise program during the study
Bariatric surgery
Pregnancy/Lactation
Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc.
Participation in an interventional study within the last 3 months