title: Are people who have a better smell sense, more affected from satiation?
abstract: BACKGROUND
  The olfactory system is affected by the nutritional balance and chemical state of the body, serving as an internal sensor. All bodily functions are affected by energy loss, including olfaction; hunger can alter odour perception.
  
  
  OBJECTIVE
  In this study, we investigated the effect of fasting on olfactory perception in humans, and also assessed perceptual changes during satiation.
  
  
  METHODS
  The "Sniffin' Sticks" olfactory test was applied after 16h of fasting, and again at least 1h after Ramadan supper during periods of satiation. All participants were informed about the study procedure and provided informed consent. The study protocol was approved by the local Ethics Committee of Gaziosmanpaşa Taksim Education and Research Hospital (09/07/2014 no: 60). The study was conducted in accordance with the basic principles of the Declaration of Helsinki.
  
  
  RESULTS
  This prospective study included 48 subjects (20 males, 28 females) with a mean age of 33.6±9.7 (range 20-72) years; their mean height was 169.1±7.6 (range 150.0-185.0)cm, mean weight was 71.2±17.6 (range 50.0-85.0)kg, and average BMI was 24.8±5.3 (range 19.5-55.9). Scores were higher on all items pertaining to olfactory identification, thresholds and discrimination during fasting vs. satiation (p<0.05). Identification (I) results: Identification scores were significantly higher during the fasting (median=14.0) vs. satiation period (median=13.0). Threshold (T) results: Threshold scores were significantly higher during the fasting (median=7.3) vs. satiation period (median=6.2). Discrimination (D) results: Discrimination scores were significantly higher during the fasting (median=14.0) vs. satiation period (median=13.0). The total TDI scores were 35.2 (fasting) vs. 32.6 (satiation). When we compared fasting threshold value of >9 and ≤9, the gap between the fasting and satiety thresholds was significantly greater in >9 (p<0.05).
  
  
  CONCLUSIONS
  Olfactory function improved during fasting and declined during satiation. The olfactory system is more sensitive, and more reactive to odours, under starvation conditions, and is characterised by reduced activity during satiation. This situation was more pronounced in patients with a better sense of smell. Olfaction-related neurotransmitters should be the target of further study.
authors.affiliation: Turkish Ministry of Health, Gaziosmanpasa Taksim Education and Research Hospital, Department of Otorhinolaryngology, Istanbul, Turkey. Electronic address: seckinkbb@gmail.com.
authors.forename: Seckin
authors.initials: S
authors.lastname: Ulusoy
authors.affiliation: Turkish Ministry of Health, Gaziosmanpasa Taksim Education and Research Hospital, Department of Otorhinolaryngology, Istanbul, Turkey.
authors.forename: Mehmet Emre
authors.initials: ME
authors.lastname: Dinc
authors.affiliation: Turkish Ministry of Health, Gaziosmanpasa Taksim Education and Research Hospital, Department of Otorhinolaryngology, Istanbul, Turkey.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Dalgic
authors.affiliation: Turkish Ministry of Health, Gaziosmanpasa Taksim Education and Research Hospital, Department of Otorhinolaryngology, Istanbul, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Topak
authors.affiliation: İstanbul Kemerburgaz University, Faculty of Medicine, Bahçelievler Medical Park Hospital, İstanbul, Turkey.
authors.forename: Denizhan
authors.initials: D
authors.lastname: Dizdar
authors.affiliation: Turkish Ministry of Health, Gaziosmanpasa Taksim Education and Research Hospital, Department of Otorhinolaryngology, Istanbul, Turkey.
authors.forename: Abdulhalim
authors.initials: A
authors.lastname: İs
mesh_terms: D000328:Adult; D000368:Aged; D005215:Fasting / Q000502:physiology*; D005260:Female; D005502:Food; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D012527:Satiation / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D012903:Smell / Q000502:physiology*; D018709:Statistics, Nonparametric; D013997:Time Factors; D055815:Young Adult
keywords: Fasting period; Função do olfato; Humans; Período de jejum; Período de saciedade; Satiated period; Seres humanos; Smell function; Sniffin’ Sticks test; Teste de Sniffin’ Sticks