Lactose intolerance. Pinpointing the source of nonspecific gastrointestinal symptoms

Fermented foods and probiotics: An approach to lactose intolerance

The aim of this review was to present various topics related to lactose intolerance with special attention given to the role of fermented foods and probiotics in alleviating gastrointestinal symptoms. Lactose intolerance is a common digestive problem in which the human body is unable to digest lactose, known as milk sugar. Lactose intolerance can either be hereditary or a consequence of intestinal diseases. Recent work has demonstrated that fermented dairy products and probiotics can modify the metabolic activities of colonic microbiota and may alleviate the symptoms of lactose intolerance. We suggest that, lactose free dairy products could be recommended as alternatives for the alleviation of lactose intolerance and for the promotion of human health and wellness.

Use of a Novel Probiotic Formulation to Alleviate Lactose Intolerance Symptoms-a Pilot Study

Lactose intolerance is a common condition caused by lactase deficiency and may result in symptoms of lactose malabsorption (bloating, flatulence, abdominal discomfort, and change in bowel habits). As current data is limited, the aim of our study was to assess the efficacy of probiotics with a β-galactosidase activity on symptoms of lactose malabsorption and on the lactose hydrogen breath test (LHBT). The study group comprised eight symptomatic female patients with a positive LHBT. Patients were treated for 6 months with a probiotic formula with β-galactosidase activity (Bio-25, Ambrosia-SupHerb, Israel). All patients completed a demographic questionnaire as well as a diary for the assessment of symptom severity and frequency at entry, every 8 weeks, and at the end of the treatment period. Measurements of hydrogen (H₂) levels (parts per million, ppm) at each of these time points were also performed. End points were a decrease of 50% in symptom severity or frequency, and the normalization (decrease below cutoff point of 20 ppm) of the breath test. Mean age and mean body mass index (BMI) were 36.4 ± 18.6 years and 23.2 kg/m², respectively. Compared to baseline scores, the frequency of most symptoms, and the severity of bloating and flatulence, improved after treatment. Normalization of LHBT was obtained in only two patients (25%). In this pilot study, Bio-25, a unique formulation of probiotics with β-galactosidase activity, demonstrated symptom resolution in most patients with lactose malabsorption. A larger randomized trial is warranted to confirm these preliminary findings.

Lactose malabsorption and intolerance: a systematic review on the diagnostic value of gastrointestinal symptoms and self-reported milk intolerance

BACKGROUND

When lactose malabsorption gives rise to symptoms, the result is called 'lactose intolerance'. Although lactose intolerance is often bothersome for patients, once recognized it may be managed by simple dietary adjustments. However, diagnosing lactose intolerance is not straightforward, especially in primary care.

AIM

To summarize available evidence on the diagnostic performance of gastrointestinal symptoms and self-reported milk (lactose) intolerance in primary care, and the relationship between lactose malabsorption and intolerance.

DATA SOURCES

PubMed, EMBASE and reference screening.

STUDY SELECTION

Studies were selected if the design was a primary diagnostic study; the patients were adults consulting because of non-acute abdominal symptoms; the diagnostic test included gastrointestinal symptoms and/or self-reported milk intolerance. A total of 26 primary diagnostic studies were included in the review.

DATA EXTRACTION

Quality assessment and data extraction were performed by two reviewers independently. They adhered to the most recent guidelines for conducting a diagnostic review as described in the Cochrane Diagnostic Reviewers' Handbook.

RESULTS

The diagnostic performance of diarrhea, abdominal pain, bloating, flatulence and self-reported milk intolerance was highly variable. A non-Caucasian ethnic origin was associated with the presence of lactose malabsorption. Both lactose malabsorbers and lactose absorbers reported symptoms during the lactose hydrogen breath test.

CONCLUSION

Our review shows that high-quality studies on the diagnosis of lactose malabsorption and intolerance in primary care are urgently needed. An important prerequisite would be to clearly define the concept of lactose intolerance, as well as how it should be assessed.

Lactose digestion and maldigestion: implications for dietary habits in developing countries

Milk is an important source of high quality protein, energy, calcium, potassium, phosphorus and riboflavin. It also has good functional properties and a highly acceptable taste, making milk a good alternative for the nutrition of children and for food programmes in developing countries. However, in some instances it has been advocated that milk or milk based products might not be appropriate for nutritional support, given the high prevalence of lactose intolerance among populations in those countries. After reviewing studies in different regions of the world it is concluded that:

1. Prevalence of lactose maldigestion in children and adults is significantly reduced, to less than half in most studies, when assessed with a dose of milk similar to that normally taken in the diet, as distinct from a large dose of lactose used in the lactose tolerance test.

2. Lactose intolerance as a result of consuming a glass of milk occurs only in a small proportion (about 30% in most studies) of lactose maldigesters. Even this small group can ingest smaller amounts of milk without adverse symptoms and there is good evidence that colonic metabolism in these people adapts to the presence of lactose to reduce or eliminate adverse symptoms.

3. Lactose maldigestion and intolerance in children in developing countries is more likely to exist in association with gastrointestinal damage associated with diarrhoea, malnutrition and/or infection.

4. There is no evidence to support a reduction or elimination of milk intake for people in developing countries because of lactose maldigestion or intolerance.

Genetic testing improves the diagnosis of adult type hypolactasia in the Mediterranean population of Sardinia

OBJECTIVE

Recently, the C/T-13910 polymorphism on chromosome 2q21 in North-European populations has been found completely associated with lactase activity and its genetic typing proposed as first-stage screening test for adult hypolactasia. However, the C/T-13910 variant in some sub-Saharan African groups is not a predictor of lactase persistence. In this work, we wanted to verify if in the Mediterranean island of Sardinia, located in Southern Europe, the C/T-13910 polymorphism may be useful or not for the diagnosis of adult type hypolactasia.

DESIGN

Validation study of a genetic testing for adult type hypolactasia in Sardinians.

SETTING

Brotzu Hospital and Microcitemico Hospital, Cagliari, Italy.

SUBJECTS

The sample consisted in 84 Sardinian individuals (63 women and 21 men; range 20-73 years) selected from a group of 832 patients.

METHODS

Genetic testing was compared to an improved test obtained by a combination of different breath hydrogen tests and clinical assessment.

RESULTS

We found that all 49 individuals with lactose malabsorption, demonstrated by a combination of different breath hydrogen tests and clinical assessment, carried the C/C-13910 genotype associated with lactase non-persistence, 23 individuals with lactose normal absorption carried the C/T-13910 genotype associated with lactase persistence and only one person with the above phenotype showed a discordant C/C-13910 genotype. The genetic testing showed very high sensitivity, specificity, positive and negative predictive values of 100, 95.8, 98 and 100%, respectively.

CONCLUSIONS

Sardinians, unlike some ethnic groups in sub-Saharan Africa, show the same genetic association of hypolactasia with the C/T-13910 variant as other North-European populations. The genetic testing for the C/T-13910 variant may contribute to improving the diagnosis of adult type hypolactasia.

The effect of a lactose-restricted diet in patients with a positive lactose tolerance test, earlier diagnosed as irritable bowel syndrome: a 5-year follow-up study

DESIGN AND METHODS

Prospectively, the effect of a lactose-restricted diet was evaluated among irritable bowel syndrome patients with lactose malabsorption. Lactose malabsorption was defined by a positive hydrogen breath test and a positive blood-glucose test. An analysis of symptoms was completed before, during, 6 weeks after and 5 years after starting the diet. In addition, the number of visits made by the patients to the outpatient clinic was scored during 6 years.

RESULTS

In 17 out of 70 irritable bowel syndrome patients (24.3%), lactose malabsorption was detected. There was no difference in the symptom score between patients with a positive lactose tolerance test and patients with a negative lactose tolerance test. After 6 weeks of the lactose-restricted diet, symptoms were markedly improved in lactose malabsorption-positive patients (P < 0.001). After 5 years, one patient was lost for follow-up, and 14 out of the remaining 16 lactose malabsorption patients (87.5%) still had no complaints during the lactose-restricted diet. Two patients chose not to follow the diet continuously and accepted the discomfort caused by lactose intake. Only two out of 16 patients (12.5%) no longer experienced any benefit from lactose restriction. In the 5 years before their diagnosis of lactose malabsorption, these 16 patients visited the outpatient clinic a total of 192 times (mean 2.4 visits per year per person; range 1-7 visits). In the 5 years after diagnosis, they visited the outpatient clinic a total of 45 times (mean 0.6 visits per year per person; range 0-6 visits; P < 0.0001).

CONCLUSIONS

In a large majority of irritable bowel syndrome patients with lactose malabsorption, which was previously clinically unrecognized, a lactose-restricted diet improved symptoms markedly both in the short term and the long term. Furthermore, visits by all patients to the outpatient clinic were reduced by 75%. We conclude that diet therapy is extremely cost- and time-saving. Therefore, it is strongly recommended that lactose malabsorption, which is easily treatable, is excluded before diagnosing irritable bowel syndrome.

Irritable bowel syndrome: is the search for lactose intolerance justified?

OBJECTIVES

To determine if confirmation of hypolactasia offers any benefit to the dietary treatment of patients with irritable bowel syndrome (IBS).

METHODS

One hundred and twenty-two consecutive IBS patients (37 male, 85 female) were given lactose hydrogen breath tests (LHBT). Those with positive LHBT followed a low lactose diet for 3 weeks. Those improving on the diet were given double-blind, placebo-controlled challenges (DBPCC) with 5 g, 10 g and 15 g of lactose and a placebo, to confirm lactose intolerance. Those who did not respond to the low lactose diet followed either an exclusion or low fibre diet. Symptoms scores were kept prior to the LHBT, 8 h post-LHBT and daily whilst following any dietary change. Patients with negative LHBT returned to clinic and subsequent dietary interventions were recorded.

RESULTS

LHBT was positive in 33/122 (27%) IBS patients. Syrr otom scores prior to LHBT were not significantly different between the two groups, but after LHBT the symptoms in the positive group were significantly worse. Twenty-three patients followed a low-lactose diet of which only nine (39%) improved. Six who did not improve followed an exclusion diet, three improved and all were intolerant of milk. Three tried a low fibre diet with two improving. DBPCC were inconclusive. In the negative LHBT group 35 agreed to try a diet and 24 improved (69%). Eight were intolerant of cow's milk.

CONCLUSIONS

Use of a low lactose diet was disappointing in IBS patients with lactose malabsorption. Food intolerance was demonstrated in IBS patients with positive or negative LHBT and milk was identified as a problem in both groups. DBPCC were inconclusive. There appears to be little advantage in trying to separate patients who malabsorb lactose from others with IBS.

Lactose intolerance: problems in diagnosis and treatment

Lactose malabsorption and lactase deficiency are chronic organic pathologic conditions characterized by abdominal pain and distention, flatulence, and the passage of loose, watery stools. Though malabsorption of the sugar lactose is determinable by breath hydrogen test or jejunal biopsy, intolerance can only be confirmed by challenge with lactose-containing food, the response to which may not be immediate. The difficulty of making a positive diagnosis of these conditions has led to a proportion of lactose-intolerant patients being misdiagnosed with irritable bowel syndrome (IBS), which has a remarkably similar symptom complex and for which there is no current pathophysiologic marker. The incidence of the two disorders is approximately equal, but the actual proportion of patients with IBS incorrectly diagnosed in this way varies as a function of the methodology used. Once correct diagnosis is established, introduction of a lactose-free dietary regime relieves symptoms in most patients. Symptom similarity and the resultant incorrect diagnosis of IBS may explain the refractory nature of some patients labeled as IBS who remain largely unaware of the relationship between food intake and symptoms.

The evaluation of acute abdominal pain in children

The infant or child that presents with abdominal pain must be evaluated with a careful history, physical examination, and selective laboratory studies. There are a few diagnoses that the emergency physician should always consider as "life threatening." In the event of any uncertainty in the diagnosis of conditions like appendicitis, pyloric stenosis, or intussusception, the child or infant should be observed carefully over time with appropriate laboratory/radiologic studies ordered to further delineate pathology. Ultrasound evaluation of children with abdominal pain continues to be one of the most valuable tools to help diagnose different conditions.