A Guide to Good Digestion. Part 2: The Stomach

A Guide to Good Digestion

Part 2: The Stomach

Welcome to the second part of my introductory guide to digestion. I hope you enjoyed Part One, I talked us through the beginning processes of digestion, everything to do with the mouth and the important role of saliva and chewing. If you missed it, catch up on my website or in the the previous Community Paper.

So, what happens next? After the mouth, food heads down to the stomach. The stomach is an organ located in the upper left of your abdominal area, protected by the bottom of your rib cage and below your left lung. The stomach is shaped like a rounded sack, and fits neatly between your oesophagus and duodenum.

Put simply, the stomach stores food and continues the process of converting food into chains of absorbable nutrients. Just like the mouth, it continues breaking down food through both mechanical and chemical breakdown processes.


While chewing is a pretty straightforward process, as teeth grind food into smaller parts, the stomach has a more complex mechanical method of breaking down food. The outer lining of the stomach comprises a series of muscles, known as bundle muscles, which are capable of contracting in multiple directions and angles. These contractions turn the stomach into a sort of washing machine, where food is tossed around the stomach from wall to wall. As the food gets thrown about, it breaks down into smaller and smaller pieces, ready for eventual entry into the small intestine. 

As food needs to be totally broken down by this process, the stomach has to hold the food for one or two hours while the process happens, which it does with the help of some chemicals I’ll discuss in a moment! The inner lining of the stomach helps with this, because wrinkled folds called rugae are capable of stretching the stomach into a size large enough to hold and move around all the food.

What not to do. 

What not to do. 


Your stomach is one of the scariest organs in the body because it contains some extremely powerful chemicals. If you think of the stomach as a ‘hot pot’, it would be something of a horror-movie-esque-death-acid-cooking-pot. If you dipped your hand inside that pot of chemicals, you would quickly be eaten by acids right through to the bone. Luckily, the rest of the body is protected from the powerful chemicals inside by a thick protective lining on the inside of the stomach. What a relief! 

The reason that the stomach contains such strong chemicals is that it has to break down all of the foods we eat before they reach the delicate small intestine, from thick steaks to fibers. To do this, the stomach is strongly acidic, with a pH ranging between 1.3-3.5. Where 7 is neutral and anything higher than 7 is basic or alkaline. The acid in the stomach is Hydrochloric Acid. 

To maintain a healthy digestive system, we should aim to keep our stomach very acidic, so the hydrochloric acid is strong and capable of breaking down foods before they reach the small intestine. If we fail to do this, pathogens can enter the small intestine, damaging the organ and stopping the body from absorbing vital nutrients. 

Another crucial reason to take care of stomach acidity levels is to control acid reflux. At the top of the stomach is a sphincter that opens up to the oesophagus. It’s ingeniously called the oesophageal! When the stomach is strongly acidic meaning a pH level of 1-2, it indicates to the sphincter to close off the pathway between the stomach and oesophagus. If our stomach isn’t acidic enough, or that ‘hot pot’ isn’t burning strongly enough, then the sphincter can remain open, allowing the contents of the stomach (food and acid) to enter the oesophagus. This causes the horrible sensation of acid reflux, which is actually the acid from the stomach burning the oesophagus. Ouch!

Sadly, most treatments for acid reflux like anti-acids or protein pump inhibitors don’t actually help the stomach to return to a pH of 1-2. They do the opposite, blocking the acid from being released into the stomach.  Consequently there is less acid to rise up and burn the oesophagus which is good for avoiding the pain. It is not so good for training that sphincter to shut and supporting the chemical breaking down of food. So don’t just reach for those medications to treat reflux, but investigate why you have reflux, and work on a nutritional plan to keep the stomach acidic strong!

To sum up so far: our stomach is a stretchy washing machine full of strong acid, which breaks down food over an hour or two. If the stomach isn’t acidic enough, we can get acid reflux. 


Another crucial chemical process to break food down happens through digestive enzymes. There are many different enzymes in the stomach and throughout the whole digestive tract. They have unique skills and specific roles! Typically, enzymes in the stomach help to convert foods into nutrient chains, such as amino acid chains or fatty acid chains. An example of this is one of the most important enzymes in the stomach is pepsinogen, which breaks down protein. Another example is called intrinsic factor, which helps to unlock B12 vitamins within food. 

Enzymes are produced in the lining of the digestive tract, and we can stimulate their production by eating specific foods. With a varied and healthy diet, we will produce a wide range of enzymes which can ensure that we are getting the most out of our food! However, if our diet isn’t varied enough, then production of specific enzymes will slow down. 

Equally, if we eat too much of a specific food, then the particular enzymes required to break down that food can struggle to keep up which can cause further problems. One example of this is lactose which is the type of sugar found in dairy products. In order to break down lactose, our bodies require the enzyme lactase, which many of us don’t produce enough of! 

We call this problem of not having the enzyme required to break down a specific food an intolerance. Some of the symptoms caused by having insufficient digestive enzymes include bloating, abdominal pain, and diarrhoea. If left untreated, food intolerances can cause a whole range of serious health concerns, from migraines to joint pain and eczema! These may be a result of undigested foods reaching the small intestine.

The good news is that there is highly specialised testing available for intolerances, which can test up to 350 different foods to figure out exactly what you’re intolerant to! With an effective, healthy nutrition plan, taking care of our stomach acid and enzymes, we can help our digestive system to function optimally. Keeping our digestive system in balance is essential to supporting a healthier life! 

I’ll be back soon with my next article, where we’ll follow the digestive journey into the liver, gallbladder and pancreas… See you soon!

Lydia Irving is a qualified Nutritionist Lydia Irving is a practicing nutritionist (BHsC) who consults clients in Forster and Taree. Through her business, Internal Instinct, Lydia also offers personalised supplement formulas, and sourdough and fermentation workshops. Lydia specialises in helping clients to understand their health concerns and looks for underlying causes of disease rather than just treating symptoms. For more information and enquiries contact Lydia.


For consultation enquiries in Taree

Lydia Practices out of Spectrum Natural Family Health Care in Taree on Monday afternoons.
02 6550 1223

For Forster consultations Lydia is located at Forster Yoga Studio, Forster Towers, Level 1

10-12 Wallis Street, Forster