Primary Motility  Disorders of the  Esophagus
 The Esophageal
 Esophagogastric  Junction

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Volume: Barrett's Esophagus
Chapter: Pathophysiology

Can liquid diet, avoiding food interference, be advised in duodenogastric reflux detection by Bilitec™?

K.-H. Fuchs, M. Fein, J. Maroske, S.M. Freys (Würzburg)

One major problem in studying duodenogastric reflux is the multifactorial process that determines this phenomenon in physiologic and pathologic circumstances [1-5]. Therefore, it is important to emphasize that duodenal juice refluxing into the stomach consists of mucosal secretions of the duodenal mucosa, pancreatic secretions, such as pancreatic enzymes, lysolecithin, and bicarbonate as well as bile as a composition of bile acids, pigments and bilirubin [6-8]. Little is known about the circadian variations of these different components in duodenal juice, however, the bicarbonate contents of duodenal juice substantially varies during a circadian rhythm, depending on the status of stimulation of the pancreatic and duodenal mucosa.

Therefore the question whether liquid diet can be advised in the assessment of duodenogastric reflux using the Bilitec™ device to avoid food interference does not have a simple answer. It depends heavily on what the focus of the study is. There are much more possible interferences in the assessment of duodenogastric reflux with measuring bilirubin than just food interference. The major restriction in the assessment of duodenogastric reflux by bilirubin monitoring is the variability in the composition of duodenogastric reflux and the lack of assessing the pancreatic component [8, 9]. As we have shown, bile reflux favorably occurs during the night hours while pancreatic juice is more frequently involved in duodenogastric reflux during day-time. Therefore, the misjudgment in describing semiquantitatively duodenogastric reflux by only bilirubin monitoring is by far larger than the influence and possible mistakes caused by different food regimens.

Reasons to use standardized liquid diet in bilirubin monitoring to avoid food interference

The primary investigator of this method Bechi pointed out in several publications that there is a documented influence of food on the bilirubin monitoring system [10-12]. Gastric as well as esophageal measurements can be influenced by the ingestion of some foods such as coffee or food impact at the probe tip. Food with an absorption value between 400 and 450 nm is especially involved. Therefore, this food should be avoided. With a large variety of different food around the world and different habits of different people it would be best, of course, for the precise measurement to suggest a worldwide standardization of food, since it is rather impossible to establish a complete list of food interfering with the measurement. For this reason a good alternative to the natural diet is a commercially available fluid with proper absorption characteristics. This is the vanilla or banana flavored drink by Nutritia, 1,000 ml of Nutridrink subdivided into 3 meals for a total of 1,500 calories as recommended by Bechi [12].

Reasons not to use liquid diet but suggesting a restricted diet

On one hand, it is obvious that a standardized liquid diet does not reflect a normal physiologic way of eating. On the other hand, by performing 24 hours functional studies, we would like to have a representative circadian course of activities of the investigated patients in order to be able to detect abnormalities in his individual situation. This requirement cannot be met by liquid diet. Several diets could have an influence on the pathologic situation of the patients especially on duodenogastric reflux. In general, the composition of food is related to regional habits. Therefore it is important, dependant on the aim of the study, to have these requirements included in the study.

There are several published lists of absorbing values of different food [12-14]. Bechi himself measured some food within the limit, such as skimmed milk, sugar, dry biscuits, white cheese, boiled chicken breast, boiled potatoes, pineapple, and apples. In our laboratory we evaluated several fluids and food with their absorption values demonstrated in Table I. Romagnoli et al. also published a list of several food stuffs demonstrated in Table II. Their absorbance value is within the limits. There is another major argument which emphasizes the point that there is no need in the routine investigation to avoid solid diet. This argument is based on a study performed in our laboratory.
1. We published normal values in 24 hours gastric bilirubin monitoring [13]. These values demonstrate that bilirubin

Table I. Absorption of fluids measured in a non transparent wall container. All tested fluids and food except for coffee have absorption values smaller than 0.25.

Table II. Percentage time of bile reflux for healthy volunteers (threshold of 0.25*).

exposure using a normal threshold of 0.25 is involved in 4.8% of the percentage of the time measured in theupright position, 10.5% during nighttime, and only 3.7% during the meal time. As shown for the median values, this is even more favorable for the argument that the bilirubin exposure during the prandial time doesn't play a major role in the assessment of total bilirubin exposure.
2. Romagnoli published a series of 25 healthy volunteers comparing several thresholds for the total upright and supine exposure in the gastric lumen [14]. These values (Table III) show that e.g. for the absorption value of 0.25, again, the bilirubin exposure during the upright measurement time is always lower than the supine time indicating that bilirubin exposure reflecting the measurement for bile reflux is much more involved during night-time than during the day, even though during the day the volunteers had 3 mealtimes with solid food involved. Therefore, a standardized absorption adapted solid diet does not interfere in an important level with bilirubin monitoring as assessed by Bilitec™ device.

Table III. Percentage time of intragastric bilirubin exposure in 25 healthy volunteers as measured above an absorption value threshold of 0.25 with a combination of solid and liquid diet (from Romagnoli et al. Surgery 1999;125:481-486).

3. In a study comparing liquid and solid diet in 14 volunteers we could document no significant difference between the 2 diet versions (unpublished data). In the solid version the absorbance value adapted diet was given using the food as recommended in Table I and II avoiding food with an absorption value above 0.2. Table IV demonstrates these values.

Table IV. Percentage total time of intragastric bilirubine exposure in 14 healthy volunteers as measured above an absorption value threshold of 0.25 (comparison of solid and liquid diet).


In summary, the above mentioned question can be answered in a differentiated way. If the Bilitec™ system is used in a study focussing on e.g. a medication study during day-time, minimal changes in absorption values need to be detected to prove or exclude the action and influence of medication, liquid diet is advised. If 24 hours bilirubin monitoring is used to assess functional abnormalities in patients with foregut symptoms the influence of a solid diet, standardized and adapted to some restrictions as pointed out above, is advisable to reflect normal eating habits of the patients and because the influence of the diet is neglectable compared to the influence of different pathophysiologic mechanisms involved in functional foregut disease. After all, it must he emphasized at last that the assessment of duodenogastric reflux by a 24 hours bilirubin monitoring probably has many more restrictions since only one marker is monitored with a lacking description of other components of duodenal juice.


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Publication date: August 2003 OESO©2015