Where does fat digestion occur

Where does fat digestion occur ?

It is worth noting that fat digestion begins before food enters the stomach. Chemical digestion begins in the mouth, and the body continues to digest fats while food travels through the digestive system.

Unlike carbohydrates and proteins, triglycerides are insoluble in water, so they usually accumulate in large droplets when they are in an aquatic environment such as the digestive system, during digestion, these large drops of fat are broken down into tinier droplets, and then the fat molecules are digested by an enzyme known as the enzyme lipase, after which the products digest fats are absorbed into the circulatory system and transported to all parts of the body.

Fat digestion involves a series of steps, each of which occurs at a specific location in the digestive system :

Mouth

As mentioned earlier, the digestion process begins when chewing food, where the teeth cut food into small pieces, and saliva moisturizes food so that it is easy to move through the esophagus to the stomach, saliva also contains enzymes that help break down the fats in food.

The first step begins in the digestion of triglycerides and phosphorylated lipids (in English : Phospholipids) in the mouth, where fat faces saliva and chewing food helps to facilitate the digestion of fats, so the lipase enzyme combines with a small amount of them in the form of an emulsion; which is the first step to digest fats, and this procedure helps to facilitate the arrival of fats to digestive enzymes, and they become tiny droplets and separate from the aqueous components.

Stomach

The lining of the stomach produces acids and enzymes that help break down food better so that foods can travel to the small intestine. Including the enzyme lipase, which begins to break down triglycerides into double fats and fatty acids, approximately 30% of triglycerides are converted into double fats and fatty acids within two to 4 hours after a meal, and stomach ripples and contractions help disperse fat molecules, while derived bifats act in this process as other emulsifiers, however, fat digestion is very little in the stomach.

Small intestine

The bulk of fat digestion occurs once food reaches the small intestine, where most of the nutrients are absorbed in the small intestine, and when the contents of the stomach enter the small intestine, most of the dietary fat is undigested and collected in large droplets, after which the bile that is produced in the liver is released and stored in the gallbladder. In the duodenum, which is the first section of the small intestine, bile salts contain a hydrophobic and hydrophilic side, so they are attracted to both fat and water, making them effective emulsifiers in breaking down large fat globules into smaller droplets, and emulsifiers facilitate the work of digestive enzymes.

The pancreas also produces enzymes that contribute to the breakdown of fats, carbohydrates, and proteins, these enzymes include the enzyme lipase of the pancreas, which helps digest triglycerides enzyme, and triglycerides are divided into fatty acids, monounsaturated fats, and some free glycerol, and it should be noted that cholesterol and fat-soluble vitamins do not need to be digested enzymatically.

Time required to digest fats

Fat digestion is a complex process that takes time and requires a well-functioning liver, pancreas, stomach, and small intestine, in addition to many digestive enzymes, and people who are concerned about not digesting or absorbing fats properly should consult a doctor, as no home remedy can reliably improve fat digestion. It is worth noting that the amount of time it takes for fat to digest varies from person to person, and between men and women, but in general it can be said that the average time for food to pass through the mouth until it leaves the body is about 33 hours for men and 47 hours for women.

What happens to fat when it reaches the blood ?

Fats cannot move in the bloodstream freely, such as carbohydrates and proteins, because they are insoluble in water, so they combine with what is known as protein transporter to form lipoproteins, which carry both triglycerides, cholesterol, and phospholipids, as lipoproteins contain an inner nucleus consisting mainly of triglycerides, and cholesterol esters, which is cholesterol associated with a fatty acid, and the outer shell consists of phospholipids, They are interspersed with proteins and cholesterol, and together they form the chylomicron, a large lipoprotein that enters the lymphatic system, and then is released into the bloodstream, and the kilomicron transports dietary fats through the body’s aquatic environment to specific destinations, such as the liver and other body tissues.

If fat is not absorbed properly, as happens in some health cases, the person’s stool will contain large amounts of fat, and if fat malabsorption continues, the condition is known as steatorrhea, and fatty diarrhea can result from diseases that affect absorption, such as Crohn’s disease and cystic fibrosis.

Where is fat stored and broken down ?

Once fat is broken down during digestion, some of them are immediately used for energy, and the rest is stored, as the body transfers them to fat stores if they are not used to produce energy, and the kilo microns are responsible for transporting triglycerides to different sites, such as muscles, breasts, outer layers under the skin, and internal fat layers in the abdomen, thighs, and buttocks, and are stored by the body in adipose tissue, and once they enter the fat cells, fatty acids and glycerin are resynthesized to produce fat. When an individual’s energy requirements exceed the amount of energy available from eating a meal or if physical activity has depleted glycogen stores, fat reserves are recovered for use as energy.

When the body needs extra energy, such as when exercising or not eating enough food, adipose tissue responds by breaking down triglycerides and draining glycerol and fatty acids directly into the blood, and when receiving these substances, the energy-needed cells break them down into very small pieces, which go through a series of chemical reactions that produce energy, carbon dioxide, and water.

As mentioned earlier, fats take longer to digest compared to other foods, and the amount of time varies based on the type of fat, as dietary fats consist of :

Saturated fat.
Trans fats.
Monounsaturated fatty acids.
Polyunsaturated fatty acids, including omega-3 fatty acids.

Tips to facilitate the digestion of fats

Here are some tips that can help facilitate the digestion of fats :

Reduce fat intake : A 2018 study published in the journal Cell Host & Microbe suggested that a high-fat diet may promote the growth of bacteria in the gut, leading to increased fat absorption and, consequently, weight gain.
Eat healthy fats : it is recommended to include healthy fats in the diet, including avocados, nuts, coconut oil, and fish in the diet, and it is also recommended to reduce the intake of processed fats, red meat, and fried foods.
Treatment of health conditions that cause digestive problems : it is necessary to get treatment for any chronic or long-term medical condition, especially those that affect the liver and digestive system, as problems with these organs can lead to difficulty digesting nutrients, including fats.
Maintaining liver health : as mentioned earlier, the liver makes bile salts that play a key role in the digestion of fats, and liver health can be maintained by refraining from alcohol consumption.