When most people think of digestion, they immediately think of the stomach. When a patient comes in and says they have a stomachache and I ask where, they usually point to their lower abdomen. The stomach is actually much higher – just under the left lower rib and diaphragm, crossing over the midline toward the right. The stomach is one of the major centers of the digestive tract. As we will see, this is where the next stage of disassembling the food starts. The giant food processor that is your stomach is quite a bit different than the one you might have on your kitchen counter, because, unfortunately it doesn’t have a blade. This means that it can’t break down large food particles that might have been impatiently swallowed too soon by the mouth. In fact, it is more like a cement mixer. This mixer is a strong, elastic, and muscular sack, which has the ability to change size and shape depending on the need. This mixer is not a namby-pamby sack; it is really quite tough, with ridges that are several millimeters thick.
Back to your journey, so far you remember going through the journey of chewing and swallowing – being carried down a canyon by Peristalsis. You remember approaching a gateway and it opening for you. You now remember moving through it and as you do, the ground disappears beneath you. You find subway falling into what appears to be a great cavern. Once you land on the concave ground of the cavern you look around and realize that you are in the middle of some sort of cosmic-looking amusement park. You look out through the thick glass windows of the subway, happy that you are not exposed to the strong acids in this amusement park. Then the walls move and you start moving rapidly from side to side while it turns in circles. It seems to you that part of the ride must involve a water feature because you are constantly sprayed with acid liquid of some sort. But unlike water which is neutral, this liquid is highly acidic. The ride is so thrilling, that part of you wishes it would never end. But then an hour goes by. Then two hours. You are starting to get really tired of this ride. By hour three you have almost nothing left in you to even keep yourself upright anymore. Hour four rolls around and you collapse, completely incoherent and then you faint.
What you are remembering is your experience of being in your stomach. The average stomach can hold approximately 1 quart (950 ml), but can hold much more if you force it too. It secretes a stream of gastric acids powerful enough to burn your finger if you were to touch it, and digestive enzymes strong enough to rip apart the first bonds of proteins and fat. As we will see later, we need this strong acidic environment in the stomach. Its robust muscular action bounces the food from side-to-side, banging it against the stomach wall to assist with mixing in the juices and to break down the food as much as possible.
As exciting and fun as this part of the journey might be, the stomach is quite hard at work with three major tasks:
- Storing the swallowed food and liquid.
- Being a mixing machine to stir up food, liquid, and the digestive juices the stomach produces.
- Emptying its contents slowly into the small intestine.
The average time you should expect this stage to take to be completely finished is about 4 hours. This can vary quite a bit. The time it takes is determined by many factors, but some of the most significant ones are:
- The size of the meal ingested.
- How thoroughly the food is chewed.
- The contents of the food ingested.
- The amount of gastric juice available.
- How much the acids are diluted with other liquids while eating
- The amount of stress a person is under.
- How long ago, and how much, you ingested in your last meal.
- The motility (speed) of the digestive tract in general.
The first point, “eating until you are full” is a relatively modern occurrence and a product of Western culture. In Ayurvedic medicine – a Tradition from India, it is suggested that it is best to only eat until you are two-thirds full. The Okinawans (from a small island in southern Japan and considered to have one of the best life expectancy in the world) have a very specific diet. They use a principle called hari hachi bu, which translates to mean, “eat until you are 80% full”.
These simple ancient rules can be scientifically supported. As you most likely already know, it is better to leave some space in your blender. Think about when you make a smoothie, it always works better if you leave some space and not fill it to the top.
If the stomach is too full, you will end up with large undigested food particles travelling into the small intestine and we have already seen what that means. Eating too much, or even too near bedtime, can put pressure on that esophageal sphincter, possible to end up with that reflux we saw earlier. By eating smaller amounts and giving enough time between eating and lying in bed, can dramatically reduce the reflux.
I really like the old adage:
- Eat breakfast like a King
- Lunch like a Prince
- And suppers like a university student that is coming the end of the month and is wondering how they are going to pay rent.
OK, I put a bit of a modern twist on the old adage.
The second factor also plays a huge role in digestive health. Various foods digest at different speeds. For example, simple carbohydrates move through the stomach relatively fast, while proteins and fats take a much longer time. This is very simple to understand, as simple carbohydrates only have one bond to break and can even be broken down in the mouth if you chew long enough. It takes only 15 – 30 minutes for these simple carbohydrates to be ready to leave the stomach.
Complex carbohydrates are, well much more complex to digest and thus take longer, but proteins and fats take the longest. It can easily take 3 – 6 hours before they are ready to be released from the stomach. This contributes to the reasoning of one of the basic concepts of food combination. If you combine simple sugars with proteins or fat, the sugars will have enough time to start fermenting in the stomach, while waiting around for their slower partners to be ready to leave. Consider how exhausting the amusement park ride was for you, and imagine what it would have been like with young children with you, anxious to go on even more rides when you just want to take it slow and even just sit down for a minute to catch your breath. You can imagine that this might irritate and agitate you. In the case of the simple carbs and proteins, this agitation creates gas, putting pressure on that esophageal sphincter again, and we already know were this is going – up the reflux road. So, it is better to eat your simple carbs 30 minutes before the proteins, or three hours after. So, growing up, this is probably the only time your mother was wrong and you were right. It actually is best to eat your dessert first, or maybe three hours later – but what kid has that kind of patience?
The third factor of digestive processing – the amount of gastric juices – can be equally as important to many people’s familiar friend – well, acquaintance – reflux. If you do not have enough gastric juices, of course, it is going to take longer for the stomach to do its job, thus slowing the whole process down. This lag period in the stomach can be caused by many factors, some of which are eating too fast, stress, age and taking antacids. Yes, that last one is quite interesting, because if you watch TV, or even worse, go to your medical doctor and complain about reflux, they will suggest an antacid, or even a proton pump inhibitor (PPI). It doesn’t take a medical degree to understand that this is not very productive for you. If the problem is already one of too low a level of gastric acids, how could lowering it make the problem better? The thing is that it relieves the symptoms, but makes the problem worse in the long run. When I said this wasn’t very productive, I was not telling the whole truth, because it is very productive – for the pharmaceutical companies and the visits to the doctor to get the prescriptions. This, of course, assures more significant health issues in the gastrointestinal tract (GIT) later on down the road. The first one to be seen is usually irritable bowel syndrome (IBS). There is a long list of health issues that can occur from too many large food particles getting into the small intestinal tract. The major ones include:
- Candida (yeast infection)
- Chronic fatigue syndrome
- Cirrhosis of the liver
- Irritable bowel syndrome (IBS)
- Migraine headaches
- Rosacea or other skin conditions
- Restless leg syndrome
- Rheumatoid arthritis
- Nutrient deficiencies
- Food intolerances
- Immune imbalances
Back to the theme park in the cavern that is the stomach. You remember starting to regain consciousness and feeling completely limp, just as your subway comes away from the ride and, on a wave of liquid, takes you to another gateway. Above the gateway, you remember noticing a sign that says ‘Pyloric Gateway – Authorized Chyme Only’.
What happens when the stomach has broken food down as much as it can, the pyloric sphincter opens at the bottom of the stomach and lets what is called ‘chyme’ pass into the first stage of the small intestine. Chyme is the food broken down into a consistency of toothpaste, mix with digestive enzymes. This stage is called the duodenum (“doo-wah-de-num”).
As you pass through the gateway, you recall arriving into a long cavernous tunnel with spectacular stalactites and stalagmites. The subway keeps moving you along, with some of the liquid from the stomach cavern pooling on the ground around you. You tried to look down the tunnel, but could not look far because not only does it apparently twist and turn, but its walls also seem to constantly fold inward. You remember looking around, and feeling an enormous sense of awe as you observed the wonderland full of marvelous flora (plants) that live amongst the magnificent magnificent stalactites. When you looked closer the stalactites, they even have what look like smaller stalactites on them! Wait, on second look they seem much more flexible, almost like a 1970’s shag carpet. These formations and microorganisms, along with a host of digestive enzymes, are what help to break down the proteins, fats and complex sugars to be absorbed into the body.
Suddenly you feel a vibration under your feet and a tidal wave of greenish-yellow liquid comes surging in. This juice is full of bile and pancreatic enzymes to aid in the next stage of digestion. Again you are happy to have those thick windows to observe through, as the environment is changing rapidly from acidic to alkaline.
The next blog is the adventures of the Small Intestine . . .