THE EFFECT OF DIET ON THE PATTERN OF GASTROOESOPHAGEAL REFLUX IN THE RURAL SETTING OF THE EASTERN CAPE

Abstract

Gastro-oesophageal reflux is the return of stomach contents back up into the oesophagus. Excessive reflux of acid content into the oesophagus can cause oesophageal disorders such as heartburn, gastro-oesophageal reflux disease and oesophagitis. The prevalence of oesophageal disorders appears to be high in North America, Europe, japan and China while epidemiology data from Africa, South America and Middle East are unknown. More data is required in Africa because population diversity in reflux symptoms may exist and it is important that standard reference ranges of reflux profiles are established for African countries. The aims of this study was to establish a data base of gastro-oesophageal reflux pattern in the Eastern Cape rural area, to compare our findings with similar western studies and to establish the effect diet, H. pylori infection, gender, weight and age on the observed reflux pattern. The reflux pattern was evaluated in healthy subjects for 24h using the newer technique involving the recording of eosophageal intraluminal impedance and pH simultaneously. The technique gives quantitative data on the frequency, nature, type, and duration, and correlates them to the pH of the reflux. The diet survey was done using the usual pattern diet questionnaire, the body mass index (BMI) was calculated and the quantification of H. pylori antibodies IgG was determined in the serum of each participant using an ELISA kit. In total, 77 participants including 48 females and 29 males were included in the study. The mean age was 35 (range 18 - 60) years for females and 37 (range 18 - 54) for males. The mean BMI was 29 (range 19 - 42) for females and 23 (range 18- ii 30) for males. The total number of refluxes recorded in 24h in this population was presented as median, 25th, 75th and 95th percentile corresponding to 49, 29, 65 and 97, respectively. Of these, 37 % were acidic, 43 % were weakly acidic and 20 % were non-acidic. In term of reflux composition 12 % were liquid, 24 % were gas (belches) and 64 % were mixed (gas and liquid). The oesophageal bolus clearance time was 18 s while the acidity of the reflux was completely neutralised 30 s after a reflux. The oesophageal bolus exposure time was 14 min/day and while acid exposure time was 15 min/day. More refluxes were found in upright position compared to supine position. They were a higher number of refluxes and a predominance of non-acid reflux in the present study compared to western countries. We found that most refluxes were postprandial and some parameters of the pattern of gastro-oesophageal reflux were significantly influenced by the traditional diet. Higher carbohydrate, protein and fat in the meal were associated with a high frequency of refluxes most of which were acidic and weakly acidic while higher fruit and vegetable consumption was associated with fewer refluxes. An increased number of non-acid refluxes were observed in high carbohydrate maize based diet. Nearly all participants of the present study were positive for H. pylori and those with a higher concentration of H. pylori IgG in the serum had less oesophageal acid exposure. Females, older and overweight participants presented with an increased frequency of reflux. This study provides normal references values for the pattern of Gastrooesophageal reflux in the rural population of South Africa. The observed pattern of reflux is positively influenced by the traditional diet which is mainly carbohydrate maize based and also by BMI, weight and gende