|Year : 2015 | Volume
| Issue : 2 | Page : 315-318
Lactose intolerance among pediatrics: systematic review
Ali Mohamed ElShafie1, Hala Mohamed Shaheen2, Eman Shabaan Abd El bary Ebrahim MBBch 3
1 Department of Pediatric, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Family Medicine, Faculty of Medicine, Menoufia University, Menoufia, Egypt
3 Resident of Family Medicine at Ministry of Health, Kotor-Gharbiya, Egypt
|Date of Submission||13-May-2014|
|Date of Acceptance||07-Oct-2014|
|Date of Web Publication||31-Aug-2015|
Eman Shabaan Abd El bary Ebrahim
Resident of Family Medicine at Ministry of Health, Kotor-Gharbiya, Postal code 31726
Source of Support: None, Conflict of Interest: None
The aim of the study was to perform systematic review to summarize the investigation and management of lactose intolerance among children.
Medline, articles in Medscape, AAFP, and PubMed were searched. The search was performed on 1 April 2014 and included all articles with no language restrictions.
The initial search presented 320 articles. The number of studies that met the inclusion criteria was 15. The articles included lactose intolerance and health common clinical presentation, investigation to confirm the diagnosis, dietary modification and its impact on bone health, supplementation using different formula, and manifestation of lactose intolerance.
Data from each eligible study were independently abstracted in duplicate using a data collection form to capture information on study characteristics, interventions, and quantitative results reported for each outcome of interest.
There was heterogeneity in the collected data. It was not possible to perform meta-analysis. Significant data were collected. Thus, a structured review was performed.
Five articles were review articles and one systematic review summarized the clinical presentation, investigation, and management. Two studies showed the effect of lactose intolerance on bone and serum calcium and zinc as lactose intolerance prevents the achievement of an adequate peak bone mass; calcium absorption was significantly greater from the lactose-containing formula than from the lactose-free formula, whereas zinc absorption showed no difference. Six studies showed the relationship between ingested formula and clinical manifestation and relationship with methane production, which recommended the supplementation using small frequent doses or gradual increasing dose to produce adaptation. One study showed that the LCT(T/C-13910) polymorphism was associated with subjective milk intolerance and reduced bone mineral density (BMD) that may predispose to bone fractures.
Keywords: diagnosis, lactose, lactose intolerance, therapy
|How to cite this article:|
ElShafie AM, Shaheen HM, Ebrahim EA. Lactose intolerance among pediatrics: systematic review
. Menoufia Med J 2015;28:315-8
| Introduction|| |
Lactose intolerance is the clinical syndrome that occurs when the inability to digest lactose results in gastrointestinal symptoms. It is estimated that around 70% of the world population are deficient in lactose  . Both male individuals and female individuals are affected equally. Lactose intolerance is not a milk allergy. A milk allergy is related to the protein in milk rather than the lactose  . Lactose digestion takes place in the small intestine by the work of lactase-polarizing hydrolase, a protein expressed on the brush border of intestinal villi. The enzyme lactase has two active sites: the first hydrolyzes lactose in the two monosaccharides glucose and galactose, making them absorbable by the intestinal mucosa, and the second hydrolyzes phlorizin  . There are three causes of lactose intolerance: primary, secondary, or congenital lactase deficiency  . Symptoms usually occur between 30 min and 2 h after ingestion of lactose  . Lactose intolerance can be suspected in people who exhibit gastrointestinal symptoms following ingestion of milk or milk products  . The typical symptoms of lactose intolerance include abdominal pain, bloating, flatus, diarrhea, borborygmus, and on some occasions, nausea and vomiting. In a few cases, gastrointestinal motility is decreased and individuals can present with constipation  . Initial treatment of lactose intolerance is to minimize or avoid lactose-containing foods. However, it is important to retain an adequate calcium intake, including actual dairy products  .
| Materials and methods|| |
The guideline for conducting this review was according to guidance developed by the center for review and dissemination. It was used to assess the methodology and outcome of the studies. The study was approved by the ethical committee.
Search was performed in several database. It included Medline, articles in Medscape, AAFP, and PubMed. The search was performed on 1 April 2014 and included all articles published. There was no restriction according to language.
All studies were assessed to include in the review by three researchers. They were included if they fulfilled the following:
Participants included the pediatric age group with lactose intolerance.
- Lactose intolerance.
- Lactose intolerance among children.
- Clinical presentation of lactose intolerance.
- Management of lactose intolerance.
- Investigation to confirm lactose intolerance.
- Bone health and lactose intolerance.
Intervention was lactose reduction.
Comparative: using enzyme substitute.
Outcome was proper child health.
Articles in non-English language were translated. The article title and abstract were initially screened. Then the selected articles were read in full and further assessed for eligibility. All references from the eligible articles were reviewed to identify additional studies.
Data from each eligible study were independently abstracted in duplicate using a data collection form to capture information on study characteristics, interventions, and quantitative results reported for each outcome of interest. Conclusion and comments on each study were made.
There was heterogeneity in the collected data. It was not possible to perform meta-analysis. Significant data were collected. Thus, a structured review was performed with the result tabulated.
| Result|| |
The selected studies were 16 in number. The studies were deemed eligible by fulfilling the inclusion criteria. There was a high degree of heterogeneity regarding investigation and management of lactose intolerance and dietary restriction and its drawback.
| Discussion|| |
Heyman  defined lactose intolerance as a clinical syndrome of one or more of the following: abdominal pain, diarrhea, nausea, flatulence, and/or bloating after the ingestion of lactose or lactose-containing food substances. According to Wilt et al.  , lactose intolerance is caused by a low or absent activity of the enzyme lactase. According to Gremse et al.  , symptoms of lactose intolerance are independent of the cause of lactose malabsorption and are directly related to the quantity of ingested lactose. These symptoms are not necessarily correlated with the degree of intestinal lactase deficiency. Pimentel et al.  stated that, in a few cases, gastrointestinal motility is decreased and individuals can present with constipation possibly as a consequence of methane production. According to Wilt. et al.  , the origin of symptoms of lactose intolerance is due to lactose that is not absorbed by the small bowel passes rapidly into the colon as a consequence of the high osmolality of the intraluminal disaccharide. In the colon, lactose is converted to short-chain fatty acids and gas. Other factors related to the severity of symptoms include the rate of gastric emptying, fat content of the food in which the sugar is ingested, the individual sensitivity to intestinal distension produced by the osmotic load of unhydrolyzed lactose in the small bowel, and the response of the colon to the carbohydrate load. According to Heyman  , resolution of symptoms with elimination of lactose-containing food products and resumption of symptoms with the reintroduction are findings suggestive of lactose intolerance. According to Waud et al.  , breath hydrogen test, a noninvasive, easy-to-perform test (with high sensitivity and specificity), is the diagnostic test of choice. If lactose intolerance is suspected, this should be the initial test, with other tests to exclude a differential diagnosis or an underlying related condition causing secondary disease  . Lomer and colleagues stated that treatment is indicated only when lactase deficiency manifests as a clinical syndrome of lactose intolerance. The threshold for lactose varies between people. Most patients can tolerate a glass of milk (240 ml = 11 g lactose) a day, whereas others develop symptoms with just 2-3 g lactose from a chocolate bar (Eadala et al., 2008). According to Heyman  , managing the condition consists of minimizing the occurrence and severity of symptoms. Heaney  recommended that treatment of primary lactase deficiency consists of limitation of lactose-containing foods, use of lactase-treated dairy products, oral lactase supplementation, or elimination of dairy and nondairy lactose. Di Stefano et al.  stated that the common therapeutic approach tends to exclude milk and dairy products from the diet, leading to reduced intake of substances such as calcium, phosphorus, and vitamins, and may be associated with decreased bone mineral density. To overcome these limits, several studies have been carried out to find alternative approaches. Montalto et al.  recommended exogenous β-Galactosidase, yogurt, and probiotics for their bacterial lactase activity, pharmacological and nonpharmacological strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation. Jδrvine et al.  recommended that, beyond infancy, substitutes for cow milk based on rice, soy, or other proteins are readily available and are generally free of lactose, although the nutrient content of most of these milks is not equivalent to cow milk. Vonk et al.  recommended that chronic consumption of milk seems to be useful to favorite the adaptation. Considering the dose-dependent lactose absorption, the distribution of the daily milk amount in small meals was suggested. According to Obermayer-Pietsch et al.  , lactose intolerance (and lactose-free diets) theoretically may predispose to inadequate bone mineralization, a problem now recognized in many other disorders affecting pediatric patients. The effects of lactose-free diets in childhood on long-term bone mineral content and risk for fractures and osteoporosis with aging remain to be clarified. Calcium homeostasis is also affected by protein intake, vitamin D status, salt intake, and genetic and other factors, making long-term studies essential to determine the risks for each or all of these to bone health. Studies suggest that genetic testing may be useful for identifying individuals at increased risk for lactase deficiency and consequent diminished bone mineral density, potentially allowing early intervention with dietary manipulation or nutrient supplementation. In contrast, Greer and Krebs  reported that lactose malabsorption does not predispose to calcium malabsorption; avoidance of dairy products may be problematic for optimal bone mineralization. When there is elimination or significant reduction of dairy products, reduction in calcium intake should be compensated with other calcium-rich foods or calcium supplementation. The evidence given by Abrams et al.  indicates that dietary lactose enhances calcium absorption and, conversely, that lactose-free diets result in lower calcium absorption. Heyman  recommended that the American Academy of Pediatrics supports the use of dairy products as an important source of calcium for bone mineral health and of other nutrients that facilitate growth in children and adolescents. Abrams et al.  recommended that vitamin D supplementation and monitoring of vitamin D status every 6-12 months should also be provided for patients who restrict milk intake. Heyman  agreed that supplements and adjunctive treatments may be necessary for patients who reduce their lactose intake significantly.
| Conclusion|| |
Evaluation for lactose intolerance can be achieved relatively easily by dietary elimination and challenge. More-formal testing is usually noninvasive, typically with fecal pH in the presence of watery diarrhea and hydrogen breath testing. Treatment consists of limitation of lactose-containing foods, use of lactase-treated dairy products, oral lactase supplementation, or elimination of dairy and nondairy lactose. Lactose-intolerant patients need to know clearly that ingestion of dairy and nondairy lactose-containing products resulting in symptoms generally only leads to transient symptoms without causing harm to the gastrointestinal tract, and there are no long-term complications if good intake of calories, proteins, calcium, and vitamin D is maintained.
Development of guideline for management of lactose intolerance and increasing people awareness that the manifestation after ingestion of dairy product is transient, not harmful, and dairy product is essential for bone health are recommended.
| Acknowledgements|| |
The authors thank those who provided instruction and advice on search strategy.
Conflicts of interest
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