Intestinal fructose malabsorption is associated with increased lactulose fermentation in the intestinal lumen

Fructose malabsorption and fructan malabsorption are associated in patients with irritable bowel syndrome

BACKGROUND

Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT).

METHODS

We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm.

RESULTS

Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate.

CONCLUSIONS

Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.

[Benefits of using a recommended testing algorithm for the diagnosis and dietary-nutritional management of patients with chronic gastrointestinal disorders]

Introduction

Introduction and objective: chronic gastrointestinal disorders such as celiac disease and lactose or fructose intolerance in adulthood are becoming more frequent and are usually accompanied by symptoms that affect daily activities and greatly limit diet. The spectrum of symptoms manifested by those affected is heterogeneous and not very specific; in addition, there is no standardized and agreed protocol for dietary management, which makes a correct diagnosis and effective treatment difficult. Disorders related to malabsorption/food intolerance can originate from primary (genetic) or secondary causes (parasites, allergies, inflammatory bowel disease, drugs, etc.). Using genetic data makes it possible to rule out or confirm primary causes, and when necessary, focus the search on secondary ones. The objective of this algorithmic approach is to guide the dietary-nutritional management of the patient with chronic gastrointestinal disease to optimize the diagnostic process and nutritional treatment. Material and methods: after a review of the literature on the pathologies most frequently associated with these disorders, a testing algorithm is proposed and the successive steps to be followed depending on the results obtained, in order to determine the diagnosis and treatment. Results: the proposed algorithm aims to be a tool for health personnel (gastroenterologists, endocrinologists, nutritionists, etc.) who care for these patients. The aim is to guide the flow of diagnostic tests based on the information provided by the patient and the clinic at the beginning, as well as to recommend the most appropriate treatment (dietary-nutritional and/or pharmacological). Conclusions: the benefit of using an algorithmic approach is that it allows optimising the diagnostic process of primary and secondary causes, and with this, to prescribe a personalised nutritional treatment considering the origin of the disorder, to alleviate the intensity and frequency of the symptoms with the least amount of dietary restrictions possible and minimise the impact on the quality of life of the patients.

Fructose Malabsorption in Chilean Children Undergoing Fructose Breath Test at a Tertiary Hospital

Fructose is a highly abundant carbohydrate in western diet and may induce bowel symptoms in children as in adults. The main objective of this study is to describe the frequency of fructose malabsorption (FM) in symptomatic patients 18 years or younger undergoing fructose breath test in a single tertiary center between 2013 and 2018, and to evaluate whether certain symptoms are related to positivity of the test. Out of 273 tests 183 (67%) were compatible with FM. The most frequent pretest symptom in the overall study population was bloating (83%), followed by abdominal pain (73%). Patients with positive test were younger than those with a negative test (median 5 vs 8 years, P < 0.001). In multivariate analysis, which included age, sex, and symptoms (diarrhea, abdominal pain, bloating, nausea), only age <6 years (odds ratio 2.93, 95% confidence interval 1.64-5.23) and absence of nausea (odds ratio = 3.32, 95% confidence interval 1.56-7.05) were associated with FM.