The Digestive System
Digestion begins with ingestion of food. The processes of digestion can be either mechanical or chemical. Mechanical digestion are the propulsion processes that move food through our digestive tract, and chemical digestion refers to the secretion of enzymes and chemicals that break down food into smaller molecules that can be more readily absorbed by our body.
Starting at the top, when we ingest food, our mouth’s salivary glands secrete saliva, which works to break down and moisten our food. Even before ingestion, saliva production begins when we smell appetizing food. In the mouth, we begin the mechanical process of digestion by chewing our food. This, combined with the secreted salivary enzymes, starts to break down our food. Swallowing our food moves it to our oesophagus, which massages our food and uses propulsion to move it to our stomach.
At the stomach, gastric juices (chemical) and muscular churning actions (mechanical) continue the process of breaking down our food for absorption, and ease of movement through the remainder of the digestive tract. The food in the stomach is then squeezed into the small intestine. The pancreas is responsible for creating digestive juices as part of chemical digestion for the small intestine. It also produces insulin in response to sugar in the blood after the breakdown of carbohydrates.
In the small intestine, enzymes are secreted, and bile, which is produced by the liver and stored by the gall bladder, mixes with the food. It is in the small intestine that most nutrients are absorbed and make their way into the bloodstream. Our liver also has the role of breaking down fats, processing proteins and carbohydrates, and filtering toxins from our body (including alcohol).
Once our food is broken down and nutrients absorbed in the small intestine, the remaining waste is moved mechanically through the large intestine. Here, water is absorbed. The remaining waste is now stored first in the descending colon (until full) before moving to the rectum. This is when we get the urge to defecate. The final step in the process is elimination of this waste via the anus. This process is called defecation.
The Excretory System
It is important that we maintain a balance of oxygen, water, and nutrients in our bodies. Our body maintains this balance by removing waste and harmful by-products via the excretory system. It’s helpful to think of our body needing inputs (e.g., food, air, water) for specific processes, but then waste and by-products are produced as part of these processes that need to be taken care of. Substances that are in excess to our needs are also eliminated through the excretory system as part of maintaining a balance of nutrients for cell development.
Many organs are involved in the excretory system. The lungs take in air, and excess carbon dioxide (and other unnecessary gases) are a byproduct released by exhalation. This maintains a balance of oxygen and carbon dioxide in the body. Excess salt is eliminated by the body through urination, tears, and as a secretion by the skin’s eccrine glands, as sweat. Urination is the final step in the kidney’s job to regulate sodium levels in the body. The kidneys also act to filter other wastes in the blood from food and cell production. Their processes also support our body to stay hydrated.
gut health and the microbiome
Our gut contains a colony of beneficial and harmful bacteria. What we eat affects the healthy balance of these bacteria, impacting how healthy our gut is. When our gut health is poor, this can result in digestive problems and malabsorption. Signs of malabsorption can include (but are not limited to); diarrhea and digestive discomfort, fatigue, weight loss, muscle wasting, anaemia, and poor immune health. A healthy gut microbiome that is well supported, helps to digest certain types of food through fermentation, manufactures specific vitamins (K and B) that are essential to health, and support the health of the gut as an important immune barrier, protecting us from pathogens, and helping to process toxins. We need a diversity of good bacteria to maintain digestive health. If there is an imbalance, and our gut health is poor then the it is less able to perform it’s duties leading to malabsorption of vital nutrients. Poor gut health can also result in intolerances to some foods such as dairy. There are many factors that can weaken our gut health, such as alcohol consumption, stress, specific medications, and specific medical conditions. Supporting our gut by providing it with food that supports the diversity of good bacteria leads to improved health outcomes. We can do this by eating a greater variety of fruits and vegetables, eating beans and pulses that include digestable fibre, taking a probiotic, and managing stress better.
Signs & symptoms of malabsorption, inflammation and poor gut health
General indigestion symptoms can be the first sign of malabsorption, inflammation and poor gut health. These symptoms include:
- Abdominal pain
- Abdominal distension
- Bloating
- Gas
- Nausea and vomiting
- Diarrhea
- Steatorrhea (fatty stools)
Malnutrition occurs as a result of malabsorption and can result in the following symptoms.
Macronutrient undernutrition can look like:
- Unintentional weight loss.
- Muscle wasting.
- Frequent infections.
- Bruising easily.
- Dry skin and skin lesions.
- Dry hair and hair loss.
- Dehydration.
- Edema (swelling with fluid).
- Anemia (weakness, lightheadedness).
- Irritability, apathy and fatigue.
- Amenorrhea (skipped periods) in women.
- Growth delays in children.
Micronutrient undernutrition can appear as:
- Night blindness (vitamin A deficiency).
- Weak bones and bone pain (vitamin D deficiency).
- Bleeding gums and nosebleeds (vitamin K deficiency).
- Sore, red tongue (vitamin b12 deficiency).
- Paleness, weakness and dizziness (vitamin deficiency anaemia).
General signs of poor gut health include:
- digestive symptoms – such as gas, bloating, constipation, diarrhoea and heartburn
- sleep issues or fatigue
- emotional issues – high stress, low mood or anxiety
- increase of infectious illnesses such as the common cold.
Inflammation in the gut can also result in bleeding and incontinence.
If you have these symptoms, seek help from a medical professional who may uncover the underlying cause and advise on nutritional support options and treatment.
Diet can be a cause but there may underlying factors also including coeliac disease.
sources:
https://my.clevelandclinic.org/health/diseases/22722-malabsorption
https://www.betterhealth.vic.gov.au/health/healthyliving/gut-health
https://www.hopkinsmedicine.org/health/conditions-and-diseases/inflammatory-bowel-disease