Lactose Intolerance

Question 1

What is lactose intolerance?

Answer 1

Inability to digest lactose due to shortage of lactase

Question 2

Which sugar is primarily found in milk/dairy products?

Answer 2

Lactose

Question 3

What is lactase?

Answer 3

Enzyme found in small intestine necessary for lactose digestion

Question 4

Levels of lactase at birth, childhood, and adolescence?

Answer 4

High at birth, steadily declines during childhood and adolescence due to diet changing/no longer being as milk dependent

Question 5

Is lactose intolerance the same as a milk allergy?

Answer 5

No, usually w allergy will have hives, respiratory involvement, angioedema, etc. rather than GI sx

Question 6

How many people in the US have lactose intolerance?

Answer 6

Approximately 50 million

Question 7

Who has higher prevalence of lactose intolerance?

Answer 7

Asian Americans, African Americans, Native Americans, Mexican Americans, Jewish Americans
Affects mostly those of non-European ancestry

Question 8

Etiologies of lactose intolerance?

Answer 8

Acquired/genetically regulated, secondary to GI disease or surgery affecting proximal SI mucosa (Crohn’s, celiac, trauma)

Question 9

Pathophysiology of lactose intolerance?

Answer 9

Malabsorbed lactose —> fermented by intestinal bacteria —> produces gas & organic acids, increase stool osmotic load —> diarrhea

Question 10

Symptoms of lactose intolerance can vary depending on what?

Answer 10

Severity of lactase deficiency, amount of lactose intake

Question 11

Clinical features of lactose intolerance?

Answer 11

Bloating, gas, diarrhea, cramping

Question 12

It’s a red flag if someone presenting with lactose intolerance symptoms also presents with what? What is this concerning for?

Answer 12

Red flag: losing weight
Needs more extensive work up, concerning for cancer, celiac, etc.

Question 13

Diagnostics for lactose intolerance?

Answer 13

Try lactose free diet
Oral ingestion of lactose/symptom survey
Hydrogen breath test

Question 14

What is a hydrogen breath test for lactose intolerance?

Answer 14

Patient ingests 50gm of lactose mixed in water
Positive: rise in breath hydrogen of >20ppm within 90 min (indicates bacterial carbohydrate metabolism)

*lactose goes to bacteria, bacteria release gas which is transferred/exhaled by the lungs

Question 15

Treatment goal of lactose intolerance?

Answer 15

Achieve patient comfort

Question 16

Is complete intolerance of lactose rare or common?

Answer 16

Rare, many patients can tolerate small intake of lactose

Question 17

How much milk can be spread out over the day and usually be well tolerated w no symptoms or need for lactase supplements in those w lactose intolerance?

Answer 17

8 oz per day spread out over the day

Question 18

Treatment options for lactose intolerance?

Answer 18

Lactose free diet, milk pre-treated w lactase, lactase enzyme replacement (lactaid), consider calcium & Vit D for patients w very lactose restrictive diet

Question 19

What is important to relay to patients who take lactaid?

Answer 19

It’s effects are very temporary/has a short window of being effective
Must take it just before eating, can take multiple if necessary (effects only last about 45 min - 1 hr)