Ileum

Your ileum (pronounced “IH-lee-um”) is the final part of your small intestine. It connects the middle part of your small intestine (jejunum) to your large intestine.

Your ileum’s main job is to absorb certain nutrients from the food you eat. These nutrients include vitamin B12, fats and bile salts. They help your body further digest food and make energy.

Health conditions related to your ileum can lead to malabsorption of these nutrients. So, it’s important to keep this part of your small intestine healthy.

Ileum function

Your ileum has a few important functions. These include:

• Nutrient absorption: It absorbs specific nutrients your body needs, like vitamin B12, fats and bile salts. These help with digestion and keep you healthy.
• Digestion: It finalizes the process of breaking down food that comes from your stomach and jejunum. This ensures that your body can use it for energy.
• Immune protection: It contains clusters of lymphoid follicles called Peyer’s patches. These follicles help detect and fight harmful germs that enter your gut.

Ileum location

Your ileum is located in the lower right part of your abdominal cavity. It sits between the middle part of your small intestine (jejunum) and the ileocecal valve.

The ileocecal (pronunced “il-ee-oh-SEE-kuhl”) valve connects the end of your small intestine (distal ileum) to the first part of your large intestine (cecum). It helps control the flow of digested food. It also prevents bacteria in the large intestine from moving backward.

A fold of tissue called the mesentery attaches your ileum to the back of your belly (abdomen). This tissue holds your ileum in place. It carries the ileum’s blood vessels, nerves and lymphatic tissue.

What are the parts of the ileum?

There are a couple of distinct features along your ileum. The proximal ileum is closer to your jejunum. It has large folds and fewer lymphoid follicles.

The terminal ileum is at the very end of the distal ileum. It’s the closest part to your large intestine. It has smaller folds but more lymphoid tissue than the proximal ileum.

The terminal ileum plays a key role in absorbing vitamin B12 and bile salts. Problems here can affect how well your body digests food and absorbs nutrients.

Like the rest of your small intestine, your ileum has four layers. From the inside out, these layers are:

• Mucosa: Tiny finger-like projections called villi line this innermost layer. You’ll also find Peyer’s patches here.
• Submucosa: This layer is made up of connective tissue. It contains blood vessels, lymph nodes and nerves.
• Muscularis externa: Two layers of smooth muscle make up this layer. The inner circular muscle and the outer longitudinal muscle help move food along.
• Serosa: This layer is made of thin tissue. It covers and protects your ileum.

What does it look like?

Your ileum is a coiled, flexible, narrow tube. It looks like a loosely curled rope. Its diameter (width) is smaller than your jejunum (the middle part of your small intestine).

Your ileum is also lined with small circular folds. The folds are less noticeable than they are in your jejunum. So, they make the inner surface appear smoother.

What color is it?

Your ileum is usually a light pink color. That’s because it has a slightly lower blood supply than your jejunum (which is bright red). It also has a thinner wall.

How long is the ileum?

Your ileum is about 11.5 feet (3.5 meters) long. It makes up about 3/5 of the total length of your small intestine.

What are the common conditions and disorders that can affect the ileum?

Several health conditions can affect the ileum, including:

• Crohn’s disease: This is a type of inflammatory bowel disease. It causes swelling and sores in the lining of your ileum. This can lead to pain, diarrhea and problems absorbing nutrients.
• Celiac disease: This is an autoimmune disorder. When your body reacts to gluten, it damages the lining of your ileum. This makes it harder to take in nutrients.
• Ileal atresia: This is a rare condition present at birth (congenital). Part of your ileum is missing or blocked. This keeps food from passing through properly.
• Meckel’s diverticulum: This is a small pouch that forms in the wall of your ileum during fetal development. It can cause bleeding, infection or blockages later in life.
• Ileitis: This is a general term for ileum inflammation. It can cause stomach pain, diarrhea and poor nutrient absorption.

Signs/symptoms that something isn’t working right

If your ileum is inflamed, it can’t absorb nutrients properly. Because of this, you may feel weakness or discomfort. Signs that something may be going on in your ileum include:

• Stomach pain or cramps
• Diarrhea
• Bloating
• Unexplained weight loss
• Fatigue

How can I keep my ileum healthy?

To help keep your ileum healthy:

• Eat a variety of foods that contain fiber, lean proteins and healthy fats.
• Include foods rich in vitamin B12 (eggs, fish, meat).
• Avoid processed, fried and fatty foods.
• Try to avoid excess sugar and artificial sweeteners.
• Eat smaller meals more often, rather than very large meals.
• Drink plenty of water to stay hydrated.
• Stay physically active.
• Manage stress levels.
• See a healthcare provider on a regular basis.