**Question:** What is not given in fructose intolerance patient:

A. Glucose tolerance
B. Glucose absorption
C. Lactose tolerance
D. Galactose tolerance

**Core Concept:** Fructose intolerance is a rare genetic disorder characterized by impaired fructose absorption and subsequent adverse effects on liver, brain, and bone health.

**Why the Correct Answer is Right:** In fructose intolerance patients, fructose is not absorbed properly from the gastrointestinal tract due to the absence or dysfunction of the enzyme aldolase B. As a result, fructose remains in the gut, leading to its degradation by bacteria, which generates toxic compounds such as glycerol and sulfur-containing compounds. These substances cause liver dysfunction, brain fog, and bone abnormalities.

**Why Each Wrong Option is Incorrect:**

A. Glucose tolerance: Fructose intolerance primarily affects fructose absorption, not glucose tolerance. Glucose tolerance remains normal or only slightly impaired in these patients.

B. Glucose absorption: Fructose intolerance is specifically related to fructose absorption, not glucose absorption. Glucose absorption remains normal or only slightly affected.

C. Lactose tolerance: Fructose intolerance and lactose intolerance are separate conditions with distinct etiology and clinical features. A fructose intolerant patient may or may not have lactose intolerance.

D. Galactose tolerance: Similar to glucose absorption, galactose tolerance is unrelated to fructose intolerance. Galactose is another sugar not affected in fructose intolerance.

**Clinical Pearl:** In clinical practice, it is essential to differentiate fructose intolerance from other carbohydrate malabsorption disorders, such as lactose intolerance, when assessing a patient's dietary needs and potential interventions. Misdiagnosis can lead to inadequate dietary advice or potentially harmful high-fructose diets, which can exacerbate liver dysfunction, bone abnormalities, and neurological symptoms in fructose intolerance patients.