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.
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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
24
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.
University Hospital Basel
Basel, Switzerland
Change in calorie intake after olfactory stimulation
Olfactory stimulation compared to placebo in participants with obesity with a BMI ≥30 kg/m2 assessed by a test-buffet.
Time frame: two time assessment at baseline and after 1 week
Change in food preference after olfactory stimulation
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)
Time frame: two time assessment at baseline and after 1 week
Change of hunger assessed via VAS (Visual Analogue Scale) upon olfactory stimulation
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.
Time frame: up to eight time assessment from baseline till day 7
Change of appetite assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
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.
Time frame: up to eight time assessment from baseline till day 7
Change of thirst assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
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.
Time frame: up to eight time assessment from baseline till day 7
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Change of nausea assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
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.
Time frame: up to eight time assessment from baseline till day 7
Change of headache assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
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.
Time frame: up to eight time assessment from baseline till day 7
Change of mood assessed via (Visual Analogue Scale) VAS upon olfactory stimulation
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.
Time frame: up to eight time assessment from baseline till day 7
Change in plasma glucose Level (mmol/L)
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)
Time frame: 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)
Change in plasma insulin Level (pmol/L)
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)
Time frame: 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)
Change in serum cortisol Level (nmol/L)
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)
Time frame: 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)