Chyle

Chyle is a fluid produced in your small intestine during digestion. It’s made up of lymph and fats. It’s one way that your body absorbs the fats in your food through your intestinal wall. After the fats have broken down, special lymph vessels in your small intestine take them up and transport them as chyle through your lymphatic system. These vessels will carry the chyle to your bloodstream so your body can use it.

Chyle can become a medical issue if it leaks from one of your lymph vessels into your chest cavity or abdominal cavity. This can happen if a lymph vessel has a defect or gets injured. A chyle leak can cause uncomfortable swelling in your body. It also prevents the chyle from getting to your bloodstream and the rest of your body, where it’s needed. This can affect your nutrition, hydration and immunity.

What does chyle do?

Chyle transports fats from the food you eat to your bloodstream through your lymphatic system. It does this by packaging the fats into lipoproteins called chylomicrons. Lipoproteins are like protein carriers for large fat molecules that your intestine can’t take directly into your bloodstream. They’re too big for the narrow capillaries in your intestine, and they don’t dissolve, so they need to be carried another way.

Chyle also contains lymph fluid that’s making its way through your lymphatic system. The lymph carries fluids, proteins and immune cells that need to return to your bloodstream. During circulation, small amounts of fluids and proteins leak from your blood vessels. Your lymphatic system collects and returns them. Immune cells circulate continuously between your lymph stream and your bloodstream.

Where is it located?

Chyle forms in your small intestine. This is where most of the nutrients in your food get broken down and absorbed. After fats break down and your intestinal lining absorbs them, cells in the lining (called enterocytes) repackage them into chylomicrons. Then, tiny lymph vessels in your intestinal lining (called lacteals) take the chylomicrons to your lymph system. There, they mix with lymph, forming chyle.

The chyle travels through your lymph vessels toward the center of your abdomen. Here, they connect with your thoracic duct, the main trunk of your lymphatic system. The thoracic duct runs from the middle of your abdomen up to your collarbone, where it connects with your jugular veins. So, chyle travels upward through your abdominal and chest cavities before returning to your bloodstream.

What does chyle look like?

Chyle is often described as “milky-looking.” While normal lymph fluid is clear, chyle has tiny particles of fat that make it look cloudy and whiteish. This helps in identifying a chyle leak. If a leak occurs during surgery, or it comes through a surgical wound or a surgical drain, healthcare providers can easily recognize chyle by its appearance. They can also draw and test a sample of the fluid to identify it.

What is chyle made of?

Chyle is made up of lymph and lipoproteins. Together, these include:

• Fats like triglycerides
• Fat-soluble vitamins (although very little)
• Fluids
• Proteins like albumin
• Immune cells

If chyle leaks and doesn’t make it to your bloodstream, you’ll be lacking in all these things.

What medical conditions and disorders involve chyle?

A defect or injury to a lymph vessel can cause a chyle leak in either your abdomen or chest cavity. As fluid builds up, it can cause swelling, discomfort and other issues, like compressing your lungs or heart.

The buildup of chyle is known as either:

• Chylous ascites: Ascites is a buildup of fluid in your abdomen that causes swelling. Chylous ascites, from a chyle leak, is one type.
• Chylothorax: Chylothorax is a buildup of chyle in your thoracic cavity (chest). It’s a type of pleural effusion, a buildup of fluid around your lungs. It’s also called a chylous effusion.

A chyle leak can also lead to deficiencies in your blood over time. When not enough chyle makes it back to your bloodstream, you lose some of the nutrients, fluids and cells that make up your blood plasma.

This can lead to:

• Hypoproteinemia: This is when your blood lacks important proteins, especially albumin. Low albumin levels cause general swelling (edema), poor wound healing and muscle wasting.
• Low fluid levels: Lost fluids in chyle can result in dehydration and electrolyte imbalances. In severe cases, it can cause low overall blood volume (hypovolemia) in your circulatory system.
• Lymphopenia: Having low levels of immune cells called lymphocytes in your blood weakens your immune system. You may get frequent infections that last longer and are more severe.
• Malnutrition: A chyle leak can leave you low in fats, causing low energy and weakening your immunity. Over time, you may start to get low in fat-soluble vitamins (vitamins A, D, E and K).

Fortunately, chyle leaks are treatable. Your healthcare provider will work to replace your missing nutrients and fluids. The leak may heal on its own, or you might need a small procedure to repair it.