Lactose is a disaccharide of β-Dgalactose and β-D-glucose in β(1,4)
 Human milk contains 200mmol/lit of
 It is digested by enzyme lactase to
form glucose and galactose in the
brush border of the intestine.
3. Lactose containing food stuffs
Fresh, skimmed , non fat and
 Processed foods
 Salad dressings etc.
4. Lactose intolerance
Lactose intolerance, also called
lactase deficiency or hypolactasia,
is the inability to digest and metabolize
lactose, a sugar found in milk.
 Lactose intolerance is not an allergy
because it is not an immune response
but caused by lactase deficiency.
5. Lactose intolerance
Lactose intolerance can occur in any
age group or population.
 However, people of
African, Jewish, Hispanic, Asian, Middl
e Eastern and Native American
descent, Caucasians are at risk for
developing lactose intolerance.
7. Types of lactase deficiency
Primary lactase deficiency is a
genetically determined absence or
decrease in the enzyme is noted.
 Jejunal morphology is normal.
 In non caucasian groups, primary
lactase deficiency is abnormal in
8. Secondary lactase deficiency
Secondary, acquired, or transient
lactase deficiency is due to the small
disease, abnormalities of brush border
cells and transport processes.
 It is often associated with celiac sprue.
9. Congenital lactase deficiency
Congenital lactase deficiency is a
very rare, autosomal recessive genetic
disorder that prevents lactase
expression from the first feed.
 Congenital lactose intolerance is
serioue disorder in which the infants
may fail to thrive unless given lactose
free formula feed.
Dietary history of the patient who are
complaining flatulance , abdominal
pain , diarrhoea.
 Familial history of the patient.
 Check whether the patient has
underwent partial gastrectomy and
other related procedures.
 Tests – stool acidity test, hydrogen