The body needs food for fuel, energy, growth, and repair. The digestive process breaks down food into a form the body can absorb and use for fuel. The broken-down food gets absorbed into the bloodstream from the small intestine, and the nutrients are carried to the cells throughout the body. Understanding how the organs work together to digest food can help with health goals and overall health.

The Digestive Process

The organs of the digestive system are the following:

• Mouth
• Esophagus
• Stomach
• Pancreas
• Liver
• Gallbladder
• Small intestine
• Large intestine
• Anus

The digestive process starts with the anticipation of eating, stimulating the glands in the mouth to produce saliva. The digestive system’s primary functions include:

• Mixing food
• Moving food through the digestive tract – peristalsis
• The chemical breakdown of food into smaller absorbable components.

The digestive system converts food into its simplest forms, which include:

• Glucose – sugars
• Amino acids – protein
• Fatty acids – fats

Proper digestion extracts nutrients from food and liquids to maintain health and function properly. Nutrients include:

• Carbohydrates
• Proteins
• Fats
• Vitamins
• Minerals
• Water

Mouth and Esophagus

• The food is ground up by the teeth and moistened with saliva to swallow easily.
• Saliva also has a special chemical enzyme that starts breaking down carbohydrates into sugars.
• Muscular contractions of the esophagus massage the food into the stomach.

Stomach

• The food passes through a small muscle ring into the stomach.
• It gets mixed with gastric chemicals.
• The stomach churns the food to break it down further.
• The food is then squeezed into the first part of the small intestine, the duodenum.

Small Intestine

• Once in the duodenum, the food mixes with more digestive enzymes from the pancreas and bile from the liver.
• The food passes into the lower parts of the small intestine, called the jejunum and the ileum.
• Nutrients are absorbed from the ileum, lined with millions of villi or thread-like fingers that facilitate the absorption.
• Each villus is connected to a mesh of capillaries, which is how nutrients get absorbed into the bloodstream.

Pancreas

• The pancreas is one of the largest glands.
• It secretes digestive juices and a hormone called insulin.
• Insulin helps regulate the amount of sugar in the blood.
• Problems with insulin production can lead to conditions like diabetes.

Liver

The liver has several different roles that include:

• Breaks down fats using bile stored in the gallbladder.
• Processes proteins and carbohydrates.
• Filters and processes impurities, medications, and toxins.
• Generates glucose for short-term energy from compounds like lactate and amino acids.

Large Intestine

• A large reservoir of microbes and healthy bacteria live in the large intestine and play an important role in healthy digestion.
• Once the nutrients have been absorbed, the waste is passed into the large intestine or bowel.
• Water is removed, and the waste gets stored in the rectum.
• It is then passed out of the body through the anus.

Digestive System Health

Ways to keep the digestive system and the digestive process healthy include:

Drink More Water

• Water helps the food flow more easily through the digestive system.
• Low amounts of water/dehydration are common causes of constipation.

Add More Fiber

• Fiber is beneficial to digestion and helps with regular bowel movements.
• Incorporate both soluble and insoluble fiber.
• Soluble fiber dissolves in water.
• As soluble fiber dissolves, it creates a gel that can improve digestion.
• Soluble fiber may reduce blood cholesterol and sugar.
• It helps your body improve blood glucose control, which can aid in reducing your risk for diabetes.
• Insoluble fiber does not dissolve in water.
• Insoluble fiber attracts water into the stool, making it softer and easier to pass with less strain on the bowels.
• Insoluble fiber can help promote bowel health and regularity and supports insulin sensitivity which can help reduce the risk of diabetes.

Balanced Nutrition

• Eat fruit and vegetables daily.
• Choose whole grains over processed grains.
• Avoid processed foods in general.
• Choose poultry and fish more than red meat and limit processed meats.
• Cut down on sugar.

Eat Foods with Probiotics or Use Probiotic Supplements

• Probiotics are healthy bacteria that help combat unhealthy bacteria in the gut.
• They also generate healthy substances that nourish the gut.
• Consume probiotics after taking antibiotics that often kill all the bacteria in the gut.

Eat Mindfully and Chew Food Slowly

• Chewing food thoroughly helps to ensure the body has enough saliva for digestion.
• Chewing food thoroughly also makes it easier for nutritional absorption.
• Eating slowly gives the body time to digest thoroughly.
• It also allows the body to send cues that it is full.

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How The Digestive System Works

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References

GREENGARD, H. “Digestive system.” Annual review of physiology vol. 9 (1947): 191-224. doi:10.1146/annurev.ph.09.030147.001203

Hoyle, T. “The digestive system: linking theory and practice.” British journal of nursing (Mark Allen Publishing) vol. 6,22 (1997): 1285-91. doi:10.12968/bjon.1997.6.22.1285

www.merckmanuals.com/home/digestive-disorders/biology-of-the-digestive-system/overview-of-the-digestive-system

www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works

Martinsen, Tom C et al. “The Phylogeny and Biological Function of Gastric Juice-Microbiological Consequences of Removing Gastric Acid.” International journal of molecular sciences vol. 20,23 6031. 29 Nov. 2019, doi:10.3390/ijms20236031

Ramsay, Philip T, and Aaron Carr. “Gastric acid and digestive physiology.” The Surgical clinics of North America vol. 91,5 (2011): 977-82. doi:10.1016/j.suc.2011.06.010