Lactose intolerance

Question 1

Lactose Intolerance OR Lactase Deficiency
The Facts

Answer 1

• Nr 1. Inborn Error of Carbohydrate Metabolism
• Extremely common in non-Caucasians, and it also occurs in some Caucasians.
• Lactase activity decreases after weaning;
• Ingestion of lactose in the form of milk and milk products by individuals with decreased amounts of small intestinal lactase activity may be associated with a range of gastrointestinal symptoms:
  including diarrhoea, cramps, and flatus, or with no discernible symptoms

Question 2

Factors affecting symptoms after ingestion of lactose:

Answer 2

• rate of gastric emptying
• transit time through the small intestine
• the ability of colonic bacteria to metabolize lactose to short-chain fatty acids, CO2, and H2.

Question 3

Treatment for primary lactase deficiency

Answer 3

1. reduction or elimination of milk and milk products or the use of milk products treated with a commercial lactase preparation.
2. No other defects in intestinal function or structure are associated with primary lactase deficiency.

Question 4

Case study 1

Answer 4

To guide you in applying facts gathered from a case study
Understand normal physiology and solidify the physiological facts
clear concise informative case study, straightforward questions
Prior learning

Answering QUESTIONS:
STEP 1: READ THE CASE STUDY
STEP 2: HIGHLIGHT FOCUS WORDS
STEP 3: PLAN YOUR ANSWER

Highlight the main points of the case & any issues that you can identify.
Read the case again, linking the information that is relevant
Use your knowledge of existing FACTS
Order your thoughts & flow of facts in a scientific story with facts & mechanisms

Lactose Intolerance
A 25 year-old college student who recently read about the health benefits of calcium, & decided to increase her intake of dairy products by drinking milk.
She experienced bloating, cramping, & gassiness.
her parents & sister complained of the same problem.
She consults you for guidance in incorporating the proper amount of calcium and vitamin D in her diet without gastrointestinal distress.
She has experienced no symptoms since discontinuing milk & is agreeable to trying new foods. Her medical history is negative for gastrointestinal disease

Question 5

Primary lactase deficiency
Testing the Facts

Control: Normal lactase activity
blood glucose levels rise after the ingestion of either glucose or lactose.
The small intestine can split the lactose into glucose & galactose and can absorb the two monosaccharides.
At the same time, H2 in the breath is low

Suspected diagnosis: Lactase deficiency
adult with low lactase activity, the rise in blood levels is less pronounced after ingesting lactose.
the rise is normal after ingesting glucose, thus the difference is due to lactase activity.
lactase deficiency excretes large amounts of H2 into the breath.
H2 = product of lactose catabolism by colonic bacteria.

Question 6

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