Gastrointestinal Health and Nutrition Flashcards

Which probiotic strain has the most robust clinical evidence for preventing antibiotic-associated diarrhea?

Answer: Lactobacillus rhamnosus GG

Lactobacillus rhamnosus GG has the strongest and most consistent evidence across clinical trials for reducing antibiotic-associated diarrhea.

The primary site of vitamin B12 absorption in the gastrointestinal tract is the:

Answer: Terminal ileum

Vitamin B12 bound to intrinsic factor is absorbed exclusively in the terminal ileum via specific cubilin receptors.

Which dietary fiber type has the strongest evidence for lowering LDL cholesterol?

Answer: Soluble fiber (beta-glucan)

Soluble fiber, particularly beta-glucan from oats, forms a viscous gel that binds bile acids and reduces LDL cholesterol through enterohepatic recycling.

Increased intestinal permeability ('leaky gut') is primarily caused by dysregulation of:

Answer: Tight junction proteins

Leaky gut results from disruption of tight junction proteins (such as occludin and claudins) that normally seal the paracellular space between enterocytes.

Short-chain fatty acids (SCFAs) produced by colonic fermentation of fiber primarily serve as the main energy source for:

Answer: Colonocytes

SCFAs—especially butyrate—are the preferred fuel for colonocytes, providing approximately 70% of their energy needs.

Celiac disease causes malabsorption primarily by:

Answer: Autoimmune destruction of intestinal villi triggered by gluten

In celiac disease, gliadin peptides trigger an autoimmune response that destroys the intestinal villi, dramatically reducing absorptive surface area.

By definition, a prebiotic must be:

Answer: A non-digestible ingredient that selectively stimulates beneficial gut bacteria

Prebiotics are non-digestible food components that selectively feed and stimulate growth of beneficial bacteria, distinguishing them from probiotics (live organisms).