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Patients with gastro-oesophageal reflux (GORD) are usually advised to modify their dietary habits.1 Among the most popular beliefs is the recommendation to avoid fatty foods which are thought to be detrimental in GORD for several reasons, including reduced lower oesophageal sphincter tone2 and delayed gastric emptying. This latter effect may, in turn, result in an increase in the number of transient lower oesophageal sphincter relaxations (TLOSRs) elicited through a vago–vagal reflex originating in the mechanoreceptors located in the subcardial area.3TLOSRs are considered to be the main motor mechanism associated with the occurrence of reflux episodes both in asymptomatic subjects and reflux patients with or without oesophagitis.
With regard to the therapeutic benefit of a low fat regimen in GORD, a review of the literature has shown that there is a paucity of data to support the effectiveness of such a recommendation and no controlled trials.1 However, early studies attempted to find a rationale for reduced fat regimens by measuring postprandial oesophageal pH after a fatty meal in normal subjects and patients with GORD.4 ,5 As shown in table 1, the results of studies conducted in normal asymptomatic volunteers were quite conflicting, showing either an increasing effect of fat on upright (but not supine) acid exposure4 or exactly the opposite.5 However, as far as pathological reflux is concerned, Becker et al had already failed to show the deleterious effect of a high fat meal in patients with GORD,4 a result now confirmed by Penagini et al in this issue (see page 330). Indeed, after a solid/liquid meal with a high fat content (compared with an equivalent caloric load provided by a balanced meal), these authors observed no significant changes in oesophageal acid exposure during the three hour postprandial period in sitting or recumbent patients, whatever the conditions of pH monitoring. This study also provides interesting new information regarding the motor mechanisms underlying the pathogenesis of reflux—that is, the basal resting pressure of the lower oesophageal sphincter, the rate of TLOSRs and the number of TLOSRs associated with reflux episodes. Again, no statistical difference was detected relative to the fat content of the meal in both normal controls and patients with reflux (table 2). These results seem at variance with those recently reported in this journal by Holloway et al,6 who showed that intraduodenal infusion of fat increased the rate of reflux episodes and the incidence of reflux during TLOSRs, a variable which has been reported to be significantly higher in patients with pathological reflux (GORD) than in normal controls. Methodological differences, especially the short duration of recording and the rather unphysiological meal (100% fat) tested in the study by Holloway et al (table 2), may easily account for such discrepancies. Moreover, neither study conducted precise investigations of some key parameters—for example gastric tone or the role of cholecystokinin, which is released on contact of the duodenal mucosa with fat and which increases the number of TLOSRs in different species including humans.7-9 Finally, regarding the association of TLOSR with reflux, it is noteworthy that other oesophageal motor events could be involved—for example, the, oesophageal body muscular response normally following a TLOSR,10 which may be a protective mechanism and which may be impaired in GORD.
Is advice concerning fatty foods still justified in clinical practice? In my opinion, as potent and safe antireflux drugs become increasingly available, there will be less and less room for lifestyle recommendations which may, by themselves, impact the quality of life of patients with reflux without providing any significant benefit. However, clinical experience suggests that fatty foods may be poorly tolerated in some individuals, especially those with dyspeptic symptoms or those with severely delayed gastric emptying, or both, two conditions that are found in a substantial proportion of patients with GORD. In such patients, recommending a low fat diet may be reasonable. In the absence of clear clinical benefit from the patient’s point of view, there is no further justification for the doctor to recommend that patients alter their diet.
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