title: Effect of drinking Arabian Qahwa on fractional exhaled nitric oxide levels in healthy nonsmoking Saudi adults.
abstract: OBJECTIVE
  Fractional exhaled nitric oxide (FENO) is an emerging marker of inflammation in respiratory diseases. However, it is affected by a number of confounding factors. We aimed to study the effect of drinking Arabian Qahwa on FENO in non-smoking Saudi healthy adults.
  
  
  METHODS
  We recruited 12 nonsmoker healthy male adults aged 36.6 ± 2.7 (21-50) years. All subjects were free from acute respiratory infections or allergies and had normal ventilatory functions and serum IgE levels. At 8 am in the morning, their baseline values of FENO were recorded. They had not taken tea or coffee in the morning and had taken similar light breakfast. They were given three cups of Arabian Qahwa to drink and then after every 30 minutes, serial levels of FENO were recorded.
  
  
  RESULTS
  Average FENO levels at baseline were 28.73 ± 9.33 (mean ± SD) parts per billion (ppb). The mean FENO levels started to decrease significantly after 30 minutes of drinking Arabian Qahwa (P=0.002). This decrease in FENO level was further observed till two hours after Qahwa drinking and then it started to increase in next 90 minutes but still was significantly lower than the baseline (P=0.002). The mean FENO level recorded after 4 hours was 27.22 ± 10.22 (P=0.039).
  
  
  CONCLUSIONS
  FENO levels were significantly lowered by intake of Arabian Qahwa and this effect remains for about 4 hours. Therefore, history of recent Qahwa intake and abstinence is essential before performance of FENO and its interpretation.
authors.affiliation: Department of Physiology, College of Medicine and King Khalid University Hospital, Kingdom of Saudi Arabia.
authors.forename: Syed Shahid
authors.initials: SS
authors.lastname: Habib
authors.forename: Shaikh Mujeeb
authors.initials: SM
authors.lastname: Ahmed
authors.forename: Ahmad
authors.initials: A
authors.lastname: Al Hadlaq
authors.forename: Amir
authors.initials: A
authors.lastname: Marzouk