Digestive System 101: What’s really going on in there?

How else could I begin my Sidebar Nutrition Blog without diving into an ‘Essential’ topic of nourishment: Digestion! already feeling the excitement! This is part of my ‘Essential’ nutrition series where we will catch a basic understanding of nutrition and the role it plays in our bodies. Let’s jump in.

What is Digestion?

Digestion is the action of breaking down food both mechanically and chemically in order to provide our body with essential nutrients. Begins in your mouth with mechanical digestion (oral cavity) where food is chewed. This is digestion tip number one: when your grandma told you to chew each bite 22 times, she hit. Okay so I don’t know about the 22 times part, but chew eat bite well and take your time. Chewing physically breaks apart the food. The larger the food particles are when they leave your mouth and travel down the pharynx to the esophagus, the more work the other organs (stomach, small intestine) have to do to digestion them. Smoothies/juices are no exception, make sure you swoosh and swallowing verse glugging them down, this (and chewing) will help to activate salivary glands in our mouth that begin the digestion process releasing ENZYMES (amylase and lingual lipase) the initiation of the chemical digestion of food. Enzymes are amazing little buggas. There are numerous enzymes that all have their very own function in breaking down different types of food throughout the G.I. Tract (Gastrointestinal Tract). **We will talk more about specific enzymes when we discuss macronutrient (carb, protein, fat) digestion.

MOVING ON…

Now that we have chewed our french fry, the food bolus moves down the esophagus. The simple act of swallowing stimulates our parasympathetic nervous system to move in a wave like motion called peristalsis, this is a form of mechanical digestion and it is what carries the food bolus through the esophagus and into the stomach.

F.Y.I.

The stomach is super strong. It has three layers of muscles that force muscle contractions on the bolus allowing it to mix with gastric juice (water, electrolytes, HCL, enzymes, intrinsic factor, mucus) to form what we call chyme- chyme= partially digested food. The chyme is released out of the opening between the stomach and small intestine (pyloric sphincter)- into the beginning of the small intestine, called the duodenum. Digestion tip number two the rate at which chyme enters the duodenum depends on the type of foods we eat some foods hang around longer in the stomach (making us feel fuller longer) When food is slower to move from the stomach to the small intestine we call it- ‘delayed gastric emptying’. It could take anywhere from 2-6 hours after completion of a meal, (depending on the size of the meal and the type of food eaten) to empty the stomach.

Who claims the title POWERHOUSE for digestion and absorption?

Small intestine takes the kale, it is the main site for nutrient digestion and absorption. On the surface of the small intestine there are fingerlike bulges that contain hundreds of absorption cells called enterocytes. Each enterocyte has microvilli designed to maximize surface area and therefore maximize absorption of nutrients. Think small intestine = absorption of nutrients.

What are the accessory organs?

The pancreas, liver and gall bladder are what we call accessory organs to the digestive system meaning they contribute by sending the G.I. tract gifts like hormones and peptides assisting with digestion by transporting the nutrients to where they need to go.

What can disrupt our digestion?

In a perfect world, this digestive process would occur very smoothly. Meaning you would digest and absorb your nutrients and have no adverse symptoms- such as diarrhea, bloating, vomiting, cramps, constipation, skin rash etc. For some,  a happy tummy is not always. For those with allergies, sensitivities, intolerances, over indulges or poor food quality, these not so fun side effects can occur.

Even though the G.I. tract provides defense, against virus, bacteria and other foreign substances that may have been ingested with our food, this defensive barrier can be broken by pathogens causing damage to the layers of the digestive tract resulting in illness, injury, starvation. Long duration with out food intake can also lead to bacteria and their toxins moving from our gut to the blood or lymph exemplifying how our gut can play into the health of all our body systems including muscular, skeletal, integumentary, circulatory etc. 

What’ Next?

More post to come on our gut and what happens when we eat specific nutrients like proteins, fats and carbohydrates. 

Like this post comment below and tell me what you think. Happy eating.

With Gratitude, 

Jamie