What are they? What do they each do? At which point of the digestive tract are they found? What is the significance of this?
Different digestive enzymes work on each of the macronutrients and other ingestible components. Each of these is found at varying points in our digestive tract.
As we age, our digestive enzymes get depleted through nutrient deficiencies and the decline in the integrity of organ function, with deficiency of Zinc being a key concern.
Let’s follow your food along the GI tract and help you understand what is happening and what may be missing.
The main ones you may already be aware of are:
- Lactase: breaks down lactose
- Lipase: breaks down lipids (fats)
- Protease: breaks down proteins
- Cellulase: converts cellulose into glucose.
- Amylase: hydrolyses starch into sugars
Where does Digestion start?
As you may have noticed, when watching or smelling something that makes your mouth water, the first instigator of digestion is our senses and our brain, activating the central nervous system to stimulate gastric activity.
Next, as food is ingested through the mouth, it is chewed and ground down by our teeth. Several processes take the stage with starches and fat hydrolysis via the release of lipase, amylase, and ptyalin.
As the food reaches the oesophagus, peristalsis occurs to transport it to the stomach.
In the stomach, churning instigates hydrolysis of proteins and lipids (fats). Multiple processes here synchronise the release of pancreatic enzymes and bile into the small intestines, including Hydrochloric acid, which in turn starts the process of breaking down minerals such as Iron and Calcium into more absorbable forms. Gastric Lipase further breaks down the components of lipids.
At the same time, off to the side of the digestive system, the liver, gallbladder, and pancreas play a vital supportive role for the liver. That which mainly impacts digestion is the synthesis and secretion of bile acids necessary for the absorption and utilisation of the fat-soluble vitamins A, D, K and E, as well as lutein and lycopene. The pancreas secretes bicarbonate, which is critical for neutralising stomach acids and minimising risks to the integrity of mucosal linings. The pancreas is also heavily involved in the secretion of proteases, lipases and amylases, further breaking the proteins, carbohydrates and fats for absorption.
Much of our absorption and assimilation occurs then in the small intestines with the aid of these enzymes, breaking down these components into absorbable and usable forms. Here also, other enzymes are produced and put into action. Hydrolytic enzymes (maltase, lactase, sucrase, etc.) further break down carbohydrates and amino acids from proteins to complete their digestion. These processes are critically inhibited where any form of gut damage or permeability is a factor such as leaky gut, Crohn’s Coeliac disease or food allergy.
Lastly, the large intestine is the organ responsible for water absorption and the last step of fermentation of carbohydrates, soluble fibre, and starch. Non-digestible carbohydrates and other insoluble particles are then sorted and utilised for transit mechanisms in the colon.
If you believe that you may have malabsorption or have abdominal pain, bloating, unusual faeces, nutrient deficiencies or excesses or quick transit of food from whoa to go, get it checked.
There are many reasons; some are reversible, some need quick attention, some are temporary, and some we need to find the best way forward …
Please value yourself enough to ask and expect investigation and help xo.