What you need to know about your clients with lactose intolerance
Lactose intolerance is a common condition, in which symptoms arise following ingestion of the disaccharide sugar lactose, in an individual lacking the hydrolytic enzyme lactase. Lactose is
consequently unable to be absorbed across the intestinal wall into the bloodstream, and therefore remains in the lumen of the intestine to cause symptoms. Primary hypolactasia is common in most races, although rarer in Northern Europeans, and may be congenital, inherited in a recessive manner. Secondary hypolactasia follows damage to the intestinal mucosa (e.g. acute gastroenteritis, Crohn's disease, and Whipple syndrome) and is therefore potentially reversible following treatment of the initial insult.
Lactose is the carbohydrate component of milk. In higher mammals, lactase levels are highest at birth but decline gradually after weaning. In humans, however, a mutation on chromosome 2 has resulted in maintenance of pre-weaning levels of lactase and has, therefore, allowed our consumption of dairy products.
Lactose intolerance results from a deficiency in the enzyme lactase, usually found within the brush border of the intestine, especially in the jejunum. In a healthy individual, lactase would usually hydrolyze ingested lactose into glucose and galactose. With insufficient levels of the enzyme, lactose remains in the intestine and due to its osmotic potential draws fluid into the
lumen, causing symptoms.
In infants, lactose intolerance can sometimes present with vomiting or with failure to thrive. In adult patients, symptoms may include watery diarrhea, abdominal distension, abdominal discomfort, and excessive flatulence. Symptoms are similar to those of irritable
bowel syndrome and can, therefore, be misdiagnosed. Clinical examination is usually unremarkable.
Diagnosis is made by the presence of reducing sugars in a stool sample or by means of a hydrogen breath test. Hydrogen is produced when the incompletely hydrolyzed sugars are fermented in the bowel by normal colonic bacteria, and is detectable by a breath test.
Strict dietary control is sufficient to avoid the symptoms resulting from lactase deficiency. This includes avoidance of dairy products such as cheese, milk, yoghurt, and butter, and non-dairy foods that use lactose as an additive for texture, including processed meats and other foodstuffs, gravy, stock, sliced bread, potato chips, breakfast cereals, and some medications.
For primary hypolactasia, lactase supplements such as Lactaid are available for purchase over-the-counter. In cases of secondary hypolactasia, treatment of the underlying condition should