Which part of the small intestine is primarily responsible for folate absorption?

• A. Proximal small intestine (duodenum/jejunum)
• B. Ileum
• C. Folate is absorbed mainly in the ileum via active transport
• D. Stomach

Answer: (A)

Folate is absorbed mainly in the proximal part of the small intestine—the duodenum and jejunum—where active transport systems, such as the proton-coupled folate transporter, actively move folate from the lumen into enterocytes. This region provides the primary uptake machinery for folate, especially under physiological conditions.

The ileum is the main site for vitamin B12 absorption with intrinsic factor, not folate, so it’s not where folate absorption is concentrated. The stomach does not play a role in folate absorption. Some absorption can occur passively at very high luminal folate levels, but physiologically the proximal small intestine is the key site.