## **Core Concept**
The resection of a significant portion of the ileum and jejunum can lead to malabsorption of nutrients, as these parts of the small intestine are primarily responsible for nutrient absorption. The ileum is crucial for the absorption of vitamin B12 and bile salts, while the jejunum is key for protein, carbohydrate, and fat absorption.

## **Why the Correct Answer is Right**
The correct answer, , implies that one of the options does not occur following the resection of 90% of the ileum and jejunum. Typically, such a resection would lead to malabsorption syndromes, including deficiencies in vitamins and minerals, especially those that are fat-soluble (A, D, E, K), and impairments in the absorption of proteins, carbohydrates, and fats. However, the specific effects can vary based on the segment and extent of resection.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Malabsorption of fat-soluble vitamins would indeed occur due to the reduced surface area for absorption in the jejunum, where most of the nutrient absorption takes place. This option is a consequence of such a resection.
- **Option B:** Malabsorption of vitamin B12 would occur because the ileum is the primary site for vitamin B12 absorption. This option is also a consequence.
- **Option C:** Impaired glucose absorption would occur because the jejunum is a major site for carbohydrate absorption. This is a consequence as well.
- **Option D:** Increased absorption of bile salts would not occur; instead, there would be a loss of bile salts due to the resection of the ileum, where bile salts are primarily reabsorbed. This leads to a decrease in the bile salt pool.

## **Clinical Pearl / High-Yield Fact**
A significant resection of the small intestine, especially if it involves the ileum, can lead to short bowel syndrome, characterized by malabsorption, diarrhea, and weight loss. Patients may require nutritional support and management of electrolyte imbalances.

## **Correct Answer:** . Increased absorption of bile salts