Food Intolerance Flashcards
Define food intolerances
Non-immune adverse reactions to food and/or food additives that are distinct from food allergy
Which food intolerances are most common
Lactose (most common)
Wheat
What is the aetiology of lactose intolerance
Lactase enzyme not expressed on the microvilli of the intestine → lactose cannot be broken down into glucose + galactose → lactose ferments in the gut → waste gas
May be primary, congenital, secondary/acquired hypolactasia (gastroenteritis, giardiasis, coeliac disease)
What are the risk factors for food intolerances
Recent gastroenteritis (post gastroenteritis syndrome)
Irritable bowel syndrome (Crohn’s)
Family history (congenital lactose intolerance)
Coeliac disease
What are the symptoms of food intolerance
Symptoms arise with the consumption of lactose-containing products - Often a delay in onset (minutes to hours) and prolonged symptomatic phase
Often presents later in life than CMPA
GI symptoms: bloating, abdominal pain, vomiting, diarrhoea, constipation
Foul smelling ‘yeasty’ stool: Explosive, bulky, frothy, watery
Headache
Fatigue
Musculoskeletal symptoms
Failure to thrive, faltering growth
What are the signs of food intolerance on examination
Weight and height
Obs
Abdominal: Abdominal tenderness, Abdominal distension
What are the differentials for food intolerances
Coeliac disease
Sucrase-isomaltase deficiency
CMPA
Giardiasis
Irritable bowel syndrome
Tropical sprue
What investigations should be done for lactose intolerance
Clinical diagnosis → 2 week trial of dietary lactose elimination
If inconclusive:
Lactose hydrogen breath test
Stool for reducing substances and pH: +ve with low pH
FBC (anaemia from secondary lactase deficiency from coeliac)
Small bowel biopsy (persistent symptoms)
Lactose intolerance test: measures serum glucose after lactose administration
What is the management for lactose intolerances
- 2-week dietary lactose elimination trial followed by reintroduction
→ Resolution of symptoms followed by resumption after lactose is re-introduced is diagnostic
Dairy-free exclusion diet + referral to dietician
± Lactase supplements (although easily denatured by the stomach)
± lactase-treated dairy products
± calcium supplements
What are the complications of lactose intolerance
Osteoporosis
Rickets
Malnutrition
Faltering growth
What is the prognosis for lactose intolerance
Will resolve after several months of the dairy-free diet, when lactase starts to be expressed again
Excellent prognosis
Persistent symptoms in a small number of patients is due to ongoing inadvertent lactose exposure, IBS, or poorly controlled underlying disorders
Treatment is lifelong and adherence can be an issue, especially in children