Lingual lipase is an enzyme found in saliva that begins the breakdown of fats. It initiates the digestion of dietary fats into smaller components, making them easier for the body to absorb.
Where Lingual Lipase is Found
Lingual lipase is produced by specialized glands located in the mouth, specifically the von Ebner’s glands. The enzyme is secreted along with saliva into the oral cavity.
Although released in the mouth, lingual lipase primarily becomes active in the acidic environment of the stomach. It travels with food from the mouth down into the stomach, where the low pH activates its fat-breaking capabilities. The enzyme’s optimal activity range is between pH 3.5 and 6.0, allowing it to continue working effectively in the stomach.
How Lingual Lipase Breaks Down Fats
Lingual lipase is a type of triacylglycerol lipase, meaning it acts on triglycerides, which are the main form of fat in our diet. Its specific action involves hydrolysis, splitting triglycerides into diglycerides and free fatty acids.
The enzyme typically targets the first or third ester bond of the triglyceride molecule. This action results in a partial breakdown of fats. Lingual lipase is particularly effective at breaking down short-chain and medium-chain fatty acids, making these smaller fat components more accessible for further digestion.
Why Lingual Lipase is Important
The action of lingual lipase holds particular significance for infants, especially newborns. Milk contains a high amount of fat, much of which is composed of short- and medium-chain triglycerides. Infants have underdeveloped pancreatic lipase activity, the primary fat-digesting enzyme in adults.
Because of this, lingual lipase plays a significant role in helping infants digest milk fat. Its ability to work in the stomach’s acidic environment and on milk fat globules makes it well-suited for nutrient absorption in newborns. The enzyme is present in fetuses as early as 26 weeks of gestation, highlighting its early developmental importance.
In adults, while pancreatic lipase performs the majority of fat digestion, lingual lipase still contributes to the overall process. For individuals with pancreatic insufficiency, where the pancreas does not produce enough digestive enzymes, lingual lipase can provide an initial breakdown of fats. This early action helps prepare fats for eventual absorption, even when other digestive enzymes are limited.
Lingual Lipase’s Role in Digestion
Lingual lipase sets the stage for subsequent breakdown by other enzymes further along the digestive tract. Although it begins working in the mouth, its primary digestive activity takes place in the stomach.
The partial breakdown of triglycerides by lingual lipase creates smaller fat molecules, such as diglycerides and free fatty acids. These products help to emulsify the remaining fats, meaning they disperse larger fat droplets into smaller ones. This emulsification increases the surface area of the fat, making it more accessible for other fat-digesting enzymes.
This initial step by lingual lipase is complementary to the actions of gastric lipase in the stomach and pancreatic lipase in the small intestine. By starting the digestion and increasing the fat’s surface area, lingual lipase contributes to the overall efficiency of fat digestion and absorption throughout the entire digestive system.