How Your Digestive System Works and How to Maintain It - Dr. Axe
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How Your Digestive System Works (+ How to Maintain It)

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How the digestive system works - Dr. Axe

The Western diet and lifestyle are linked to a growing number of digestive diseases. The health of your digestive system has a lot to do with lifestyle, since it’s in part determined by the food you eat, the amount of exercise you get and your stress level throughout the day.

By better understanding the digestive system process and learning some helpful tips, you can not only boost the health of your digestive system, but you can naturally help yourself to overcome many digestive issues.

What Is the Digestive System?

What are the four types of digestive systems? The four basic types of digestive systems in animals are monogastric, avian, ruminant and pseudo-ruminant.

The human digestive system is monogastric. A basic monogastric digestive system definition is a simple single-chambered stomach rather than a more complex multi-chambered stomach.

The digestive system is one of 11 major human body systems. It is a group of organs that work together to convert food into energy and basic nutrients that feed the entire body and the foundation of good health.

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This amazing system includes a combination of nerves, hormones, bacteria, blood and the organs of the digestive system that work together to complete the intricate task of digesting the foods and liquids that we consume every day.

What is the job of the digestive system? What is the process of digestion?

The digestive system interacts with all other body systems — this includes the nervous, endocrine and immune systems.

Did you know that digestion actually begins in the brain? The hypothalamus, which is involved in metabolic processes, stimulates appetite. When you eat, your brain decides how you will digest that food – it will respond with stress or ease, depending on the health of your organs and your state of mind.

How long does it take for your body to digest food? The time frame can vary from person to person, but typically it takes around six to eight hours for the food you eat to pass through your stomach and small intestine to the large intestine (colon).

Some studies have shown that this transit time tends to be shorter for men and longer for women.

There are a number of factors at play in the digestive system. We have digestive juices that contain enzymes that speed up the chemical reactions in the body and break down food into nutrients.

There are also cells in the lining of the stomach and small intestine. These cells produce and release hormones that stimulate digestive juices and regulate appetite.

We also have nerves that control the digestive system. They connect the digestive system organs to the brain and spinal cord as well as release chemicals that stimulate relaxing or contracting muscles.

We have nerves within the gastrointestinal tract that are triggered when there is food present, and this allows our digestive system to work properly.

Role of Digestive Organs

What are the body parts involved in the digestive system? If you look at a digestive system diagram, you’ll see that there are a lot of key parts.

Let’s take a look at the digestive system organs and functions:

Mouth — The simple act of chewing breaks food into pieces that are more easily digested, and saliva mixes with the food to begin the process of breaking it down into a form that the body can absorb and use. When you swallow, your food pushes into the esophagus, the muscular tube that carries food and liquids from the mouth to the stomach. Once swallowing begins, it becomes involuntary and proceeds under the control of the esophagus and brain.

Spleen — The spleen is a brown, flat, oval-shaped lymphatic organ that filters and stores blood to protect the body from infections and blood loss. The spleen is in charge of cleaning impurities from the blood, destroying old red blood cells and storing blood in case of emergency, such as an injury.

Stomach — The stomach acts as a storage tank for food so the body has time to digest large meals properly. This central organ not only holds the food, but it also works as a mixer and grinder. The stomach contains hydrochloric acid and digestive enzymes that continue the digestion of food that began in the mouth.

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Enzymes and acids mix with the food that has already begun to break down in the mouth and esophagus, and it turns into a liquid called “chyme.” The word “chyme” comes from the Greek meaning of juice. It’s a semi-fluid mass that is expelled by the stomach and sent to the intestines during digestion.

In the stomach, hydrochloric acid destroys harmful bacteria and alters enzymes to begin digesting protein.

Hydrochloric acid is a clear, colorless and highly pungent solution of hydrogen chloride in water. It’s a corrosive mineral acid that serves as a digestive fluid and breaks down unwanted bacteria.

After it does its job, food is the consistency of a liquid or paste, and it’s ready to move to the small intestine for the next step of this complex process.

Liver — What does the liver do? The liver is the second largest organ in the body, and it has many different functions.

The main function of the liver in digestion is the production of bile and its release into the small intestine. The liver makes and secretes bile, which helps enzymes in the body break down fats into fatty acids. The liver also cleanses and purifies the blood that is coming from the small intestine.

After you absorb nutrients through your small intestine, it then enters the bloodstream. This blood is sent to the liver for filtering and detoxification.

The liver has the amazing ability to break down and store amino acids, synthesize and metabolize fats and cholesterol, store glucose, detoxify the blood, and regulate internal functions.

Gallbladder — The gallbladder is a small, pear-shaped organ that is used to store and recycle excess bile from the small intestine so it can be reused for the digestion of future meals. The gallbladder sits just under the liver and stores bile that is made in the liver, which then travels to the gallbladder through a channel called the cystic duct.

The gallbladder stores bile between meals, and when we eat, the gallbladder squeezes bile through the bile ducts, which connect the gallbladder and liver to the small intestine.

Pancreas — The pancreas is a spongy, tube-shaped organ that is about six inches long. It secretes digestive enzymes into the small intestine, and this completes the chemical digestion of foods.

Pancreatic juice is capable of digesting lipids, carbohydrates (creating energy), proteins (creating amino acids for building) and nucleic acids.

Insulin is one of the hormones made by the pancreas and controls the amount of sugar in the blood. Both enzymes and hormones are needed to keep the body and digestive system working properly.

The pancreas connects to the liver and the gallbladder with the common bile duct. As pancreatic juices are made, they flow into the main pancreatic duct and then join the common duct, which allows the bile (which helps digest fat) break down food before it reaches the small intestine.

Small Intestine — The small intestine is a long, thin tube about one inch in diameter and about 20 feet long.

How does the small intestine function? When the chyme (our juices that are being digested) leaves the stomach, it enters the small intestine through the pyloric sphincter — a muscle that serves as a valve and prevents the regurgitation of food from the intestine back into the stomach.

What is digestion and absorption? The entire small intestine is coiled, and the inside surface is full of many folds and ridges.

Most of the digestion as well as the nutrient absorption occurs in the small intestine. It transforms from an acidic environment to an alkaline one, which means the acids are neutralized.

The small intestine is lined with very small protrusions that increase the surface area of the intestinal wall, which creates a larger absorption area. Each protrusion, called villi, is covered in smaller hair-like structures, which are called microvilli.

Enzymes exist on the villi, helping further break down nutrients into a readily absorbable form. It is the job of the villi to help prevent leaky gut.

Leaky gut is when the bowel lining is damaged. This is caused by poor diet, parasites, infection or medications, and it allows substances — such as toxins, microbes, undigested food or waste — to leak through the small intestine.

The folds in the small intestine are used to maximize the digestion of food and the absorption of nutrients. By the time food leaves the small intestine, around 90 percent of all nutrients have been extracted from the food that entered it. Once the nutrients have been absorbed, the liquid left over passes through the small intestine and goes to the large intestine, or colon.

Colon — The colon, or large intestine, is a long, thick tube that is about 2.5 inches in diameter and five feet long. It wraps around the border of the small intestine.

Colon or large intestine function is the final stage of the digestive process. Once the juices (that used to be your food) leave your small intestine, they enter your large intestine. At this point, most of the nutrient absorption has happened, but water, fat-soluble vitamins and minerals can be absorbed in the colon as well.

The naturally present bacteria in your colon will continue to help with digestion. These gut bacteria are called flora.

Flora break down waste and extract small amounts of nutrients (whatever is left). The waste that is left over will exit the body from the colon by means of peristalsis (peristalsis definition: contractions that move the waste to the anal canal).

At first the waste is in a liquid state, but as it moves through the colon, the water is removed and it becomes the solid form of stool.

The stool is mostly food debris and bacteria. The bacteria fuse vitamins, process waste and food particles, and protect us against harmful bacteria.

How long does it take to clean out your colon? It takes about 36 hours for stool to get through the colon, and when the colon becomes full, it empties its contents into the rectum, which begins the elimination process.

Western vs. Eastern Medicine

In Western medicine, the spleen is recognized for its production and destruction of red blood cells and storage of blood. However, in traditional Chinese physiology, the spleen takes a lead role in the assimilation of nutrients and maintenance of physical strength. It turns digested food from the stomach into usable nutrients and qi, which is our life energy force.

In China, entire schools of medicine were formed around this organ because it’s believed that all aspects of life depend on the functioning of this essential organ, which allows the body to receive its needed nutrients.

In Eastern medicine, fatigue and anemia are often recognized as a breakdown in the spleen’s ability to transform food into blood and energy. If the spleen is weak, then the colon, uterus, rectum or stomach can sag or weaken.

According to the ideas of Eastern medicine, exercise and a healthy diet can benefit the body only if the spleen is able to transmit nutrition and energy to the muscles, and a person with deficient spleen function will often experience weakness and fatigue.

In addition to its role in nutrition and blood production, the spleen is viewed as responsible for the transformation of fluids, as it assists in water metabolism, helping the body rid itself of excess fluid and moistening the areas that need it, such as the joints. It separates usable and unusable fluids that we consume daily.

The spleen has the power to transform food and liquids into energy, which is then transported to the organs and enables the proper function of the entire body. This is why the spleen is seen as playing a central role in nourishing our bodies and promoting development.

Digestive system organs like the spleen and the stomach work together and ensure each other’s functions. Because the spleen is where the energy of food and fluid is transformed, it’s the most essential of the pair.

In Traditional Chinese Medicine, the spleen is considered essential for healing because it not only affects the body’s immunity, but also the ability to maintain and heal itself. It’s also believed that the spleen influences our capacity for thinking, focusing, concentrating and memorizing.

Top 10 Healthy Tips to Improve Your Digestive System

The way we live and eat has a direct impact on the digestive system and how well it functions. By taking steps to improve your digestive health, your digestive system will function more efficiently, and this will improve your overall health.

1. Keep chewing

An easy tip that can have a huge impact on your digestive system is the simple act of chewing! Chewing is often underestimated, but it’s crucial for proper digestion.

The more you break down food in your mouth, the less work has to be done later. Your brain also needs some time to receive the signal that you are full, so take your time, and chew 20–30 times before swallowing.

Allow your stomach to prepare for the food it’s about to receive.

2. Eat plenty of fiber

It is important that you eat enough fiber to keep your food moving through your intestines easily. There are two types of fiber – soluble and insoluble.

Soluble fiber, like fiber in veggies and whole grains, draws in water and helps prevent stool from being too watery. Insoluble fiber helps add bulk to stool.

By pairing fatty foods with fiber, your body will be able to break down the fatty foods (which are usually hard to digestive) easily.

3. Drink water

Adding plenty of water to your diet will help digestion by dissolving fats and soluble fiber. This allows food to pass through your intestines more easily.

This is a simple tip that will have a big impact. Too little water will lead to a harder stool that is more difficult to pass through the colon. However, to promote optimal digestive health, some people find they do better to drink water apart from meals.

4. Exercise

Moving your body — taking walks or jogs, lifting weights or doing yoga – keeps food moving through your digestive system. Exercise increases blood flow to your organs and engages muscles in the GI tract. This is important because the walls of your colon need to contract when passing waste, and exercise can tone those muscles.

5. Reduce stress

Feelings of stress or anxiety can mess with your digestive system because your brain and digestive system are connected. Stress can lead to digestive problems like irritable bowel syndrome and ulcers.

To help control these digestive health issues, try stress-relieving exercises, getting more sleep or relaxation techniques, like steady breathing or meditation and prayer.

What is good for digestion after eating? Staying relaxed after eating is extremely helpful to promote optimal digestion of the food you just ate.
Digestive system tips

6. Eat warm foods

The spleen works best with the warmth and dislikes the cold, and our digestive enzymes require warmth to break down food properly. Too much cold food and drinks can impair spleen function, so eating foods that are warm makes the foods easier to digest. Try incorporating soups, cooked vegetables or teas into your diet.

7. Quit smoking

Smoking can have a seriously negative impact on your digestive system because it weakens the valve at the end of the esophagus, and this leads to acid reflux and heartburn. It also increases the risk of gastrointestinal cancers.

8. Drink less alcohol

Ever notice how your digestion is a little off after a night of drinking? Alcohol interferes with acid secretion, stomach muscles and nutrient absorption, so be careful not to drink too much.

Alcohol consumption also leads to heartburn, liver problems and diarrhea. It can wreak havoc on organ function and the success of your digestive system.

9. Lose weight

Being even a few pounds overweight can cause digestive issues. For instance, the valve between the stomach and esophagus sometimes won’t close completely, which allows stomach acid back into the esophagus.

By losing weight, you ease pressure and allow your digestive system to carry on properly.

10. Try probiotics

Besides fiber, one of the things missing from the Western diet is healthy doses of probiotics, which are beneficial bacteria that help the immune system. Probiotics compete for space with bad bacteria, promote the release of natural antibodies in the digestive tract and can even attack unhealthy bacteria directly in some cases.

Research has found that probiotics can ease irritable bowel syndrome, prevent allergies and infections, and even shorten the duration of the common cold. Cultured dairy is one of the best sources of probiotics. You can also try sourdough bread, pickled cabbage and fermented soybeans.

Digestive enzymes are another great daily supplement addition that can really boost digestive health.

Signs of Digestive System Issues and Causes

Digestive system diseases are disorders of the digestive tract, also known as the gastrointestinal tract (GI tract).

Initial warning signs and symptoms of issues involving the digestive tract often include one or more of the following:

  • Bleeding
  • Bloating
  • Constipation
  • Diarrhea
  • Heartburn
  • Incontinence
  • Nausea and vomiting
  • Pain in the belly
  • Swallowing problems
  • Weight gain or loss

Digestive diseases that can cause some of the symptoms mentioned above include:

  • Gallstones, cholecystitis and cholangitis
  • Rectal problems, such as anal fissure, hemorrhoids, proctitis and rectal prolapse
  • Esophagus problems, such as stricture (narrowing) and achalasia and esophagitis
  • Stomach problems, including gastritis, gastric ulcers usually caused by H. pylori infection and cancer
  • Liver problems, such as hepatitis B or hepatitis C, cirrhosis, liver failure, and autoimmune and alcoholic hepatitis
  • Pancreatitis and pancreatic pseudocyst
  • Intestinal problems, such as polyps and cancer, infections, celiac disease, Crohn’s disease, ulcerative colitis, irritable bowel syndrome (IBS), diverticulitis, malabsorption, short bowel syndrome and intestinal ischemia
  • Gastroesophageal reflux disease (GERD), peptic ulcer disease and hiatal hernia

Top Foods for Digestion

Are you wondering, “How can I improve digestion?” Start by choosing the right foods to eat on a daily basis:

  • Bone broth
  • Raw cultured dairy
  • Fermented vegetables and other probiotic foods — probiotics may help relieve leaky gut by enhancing the production of tight junction proteins that defend against intestinal permeability
  • Sprouted seeds (like chia seeds, flaxseeds and hemp seeds)
  • Foods high in omega-3 fatty acids like wild-caught fish
  • Herbs and spices
  • Coconut products
  • Other nutrient-dense, anti-inflammatory foods like grass-fed beef, lamb, other fresh veggies and most fruits, apple cider vinegar, sea veggies, and other superfoods

Worst Foods and Substances for Digestion

A poor diet is by far one of the leading causes of digestive system disfunction.

What’s a poor diet? One that includes allergens and inflammatory foods, such as unsprouted grains, added sugar, GMOs, refined oils, factory-farmed meat, processed foods, fast food, synthetic food additives and conventional dairy products.

There are also seven food additives that can trigger leaky gut and other digestive issues, including sugar, gluten, emulsifiers, sodium and “meat glue.”

Another thing that can lead to digestive issues is toxin overload, which includes a high consumption of alcohol and drugs. There are thousands of chemicals and toxins we come into contact with every single year, unfortunately, but some of the worst offenders include antibiotics, pesticides, tap water, aspirin and NSAIDS.

Healthy Digestion Recipes

Here are some healthy recipes that can help to boost digestion:

You can also use essentials oils like ginger, peppermint and lemon to support digestive health. As long as you have a 100 percent pure, therapeutic-grade, organic essentials oils, you can add a drop or two to tea, smoothies and other recipes.

Of course, check with your pediatrician if you’re looking to use essential oils internally to boost the digestive system for kids. Also check with your health care provider before using essential oils internally if you are being treated for a medical condition or are currently taking medication.

Precautions

If you have any signs of a digestive system disorder, see your health care provider. If you are pregnant, nursing, have an ongoing medical condition or are currently taking medication, talk to your doctor before making any dietary changes or adding any natural remedies to your diet.

Also, speak with a pediatrician if you suspect your child has a digestive system problem before trying any natural treatments.

Final Thoughts

  • In order to be in a state of generally good health, the health of your digestive system is of upmost importance.
  • There are many human digestive system parts and functions, which all must be in an optimal state in order for the entire digestive system to function as it should.
  • There are many symptoms that can indicate poor digestive health, including bloating, indigestion, diarrhea and stomach pain.
  • Unwanted digestive symptoms shouldn’t be ignored and can be the result of a leaky gut, an H. pylori infection or one of many other digestive diseases.
  • Your digestive system function can be enhanced by:
    • Eating a healthy diet, including lots of whole foods and healthy fiber
    • Chewing your food well
    • Reducing stress
    • Drinking enough water
    • Not eating problematic foods, like factory farmed meats, processed foods and fast foods
    • Avoiding excessive alcohol consumption and drugs like NSAIDS
    • Daily exercise
    • Losing weight if needed
    • Taking daily probiotic and digestive enzyme supplements

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