Good health is not just about the foods we choose to put on our forks. Rather than “we are what we eat” in fact, our health greatly depends on how well we digest and absorb our food.
How good is your digestion?
If you answer yes to several of the following questions it could suggest that your digestion is not up to scratch:
- do you have diarrhoea or constipation that occurs most of the time?
- are you often bloated, especially after a meal?
- do you frequently have heartburn, excessive belching, or food that “repeats”?
- do you ever have stomach pain or abdominal cramps after eating?
- is there much undigested food in your stool?
- do you frequently have flatulence?
- do you feel discomfort on the right, upper abdomen, just under the ribs, especially after eating fatty foods?
- do you often feel nauseous?
- do you suffer from rectal itching?
- do you have the sensation that food lingers in your stomach?
- do you suspect that certain foods are the cause of your symptoms?
Apart from signs and symptoms from the digestive tract, problems with digestion can also cause symptoms elsewhere in the body, for example in the skin. Psoriasis, acne and eczema are typical examples where the underlying cause can often be problems with digestion.
The importance of good gut health and digestion is a central focus in ancient traditions of medicine. And, over the last couple of decades scientific research has confirmed the role that gut health can have on many diseases, including those outside of the digestive system. It seems that Hippocrates may have been right when he said “All disease begins in the gut.”
The digestive tract
Briefly the digestive tract is a long hollow tube extending from the mouth to the anus. However, rather than being a neat and simple tube, in fact it’s shape is complicated and it’s workings complex. For ease of describing the different areas we can break down the parts of the digestive tract into the mouth, throat, oesophagus, stomach, small intestine, large intestine, rectum and anus. Plus, there are several ancillary organs that are not part of the digestive system, but have important roles in the digestive process, such as the salivary glands, pancreas, liver and gallbladder.
The gut is richly supplied with a network of nerves, often called the enteric brain. This gut-brain connection explains a lot about why emotions can affect our digestion. In fact, in terms of health and function this also is a good example of why the body should be viewed as a whole rather than as individual parts. Traditional medicine systems have always known the importance of considering a holistic view of health, rather than focussing on one part of the body.
There is a great deal of communication that needs to happen within the digestive system so that the process goes smoothly. Many of these processes are controlled by hormones, secreted within the digestive tract and also by ancillary organs.
While the digestive process itself can be explained quite easily as the process by which the food we eat is broken down into nutrients that our bodies can use. The digestive tract is also a major barrier that protects us from ingested foreign invaders and chemical substances that could potentially be harmful.
The digestive process
The process of digestion actually begins before we put food in our mouths. Have you ever noticed that just thinking about food starts your mouth watering? Saliva production is increased in readiness for the arrival of food. Saliva is full of enzymes that start the process of breaking down your food. Adequate chewing is probably the best thing you can do to help your digestion as it mashes up the food and mixes it with saliva.
Once the food is swallowed it travels down the oesophagus to the stomach. Here it is mixed with more enzymes as well as hydrochloric acid. This acidic environment is very important to the digestive process as it help the enzymes to work properly to break down your food.
The stomach churns the food with the digestive juices, breaking it down into a semi-liquid consistency. But, its not just the consistency of the food that is changing, the particles that make up the food are being broken down into smaller and smaller particles.
When food leaves the stomach it enters the small intestine, the major site for digestion and absorption of nutrients. Digestive enzymes from the pancreas and bile from the liver and gallbladder enter the small intestine on cue and help to further break down food particles for absorption. This part of the intestine is lined by specialised cells with frond-like projections called microvilli. The presence of large numbers of microvilli creates a huge surface area, and provides the opportunity for the tiniest particles to be absorbed through the gut lining and into the bloodstream.
Food is moved through the intestines with a wave like motion, maintained by the nervous system. Until what remains of the food, mainly fibrous material, enters the large intestine. Not so long ago we thought that the large intestine was there to simply absorb water from the gut back into the body. Now we know that there is a huge colony of microbes that turn this fibrous material into beneficial substances for themselves and for us. In fact, we are learning a lot about the importance of the role that a healthy and diverse population of gut microbes has on our health. For instance we know that there are at least the same number of microbes in our gut as the number of cells that form our body, and their collective number of genes vastly outnumber ours.
Find out more: What is a microbiome
The final part of the healthy digestive process is the evacuation of the stool, at least on a daily basis. Ideally this should be a smooth and easy elimination, but all too often it is not.
So, what can go wrong?
Inadequate digestion is incredibly common and probably underlies many of the modern, common chronic inflammatory conditions.
Generally speaking problems with digestion can occur due to issues with the function of a part of the digestive system such as production of adequate amounts of digestive juices. Or, there can be structural problems causing an issue, such as a hiatal hernia that allows stomach contents to enter the oesophagus causing burning pain.
Functional problems might be caused by eating meals too quickly, and not taking the time to chew food properly. This makes the whole process of digestion more difficult and can often lead to indigestion. I can’t emphasise enough the importance of taking your time with meals, savouring the thought of the meal to come, and chewing food properly.
Eating in a stressful environment can wreak havoc on digestion. Not only does this translate into reduced production of digestive juices but the smooth and rhythmic movement of the gut that transports food through the intestine can be disrupted, leading to constipation or diarrhoea.
Digestion can also weaken with age, primarily due to a reduced production of digestive juices. But, medications can also play a part in this.
In Chinese medicine regularly eating cold foods like salad and ice cream is not advised. The stomach should be thought of as a cauldron, with a gentle fire, cooking and breaking down the food. Cold foods can dampen this fire and impede the digestive process. It’s certainly true that cold, raw food is harder to digest than cooked food, as the cooking process itself helps to start the breaking down of food.
The gut as a barrier
As well as digestion, the other important function of the digestive tract is to provide protection from harmful microbes or noxious substances that might enter the body with food. So, the lining of the digestive tract has to be able to allow the passage of nutrients through, whilst keeping out anything that might cause harm. The one cell think lining of the digestive tract is designed to do just that. Particles can travel through the cells or between the cells, and the body has ways to regulate each route.
However, the incredibly thin lining of the digestive tract is vulnerable to damage. Loss of microvilli greatly reduces the absorptive capacity of the gut, which can result in nutrient deficiencies. Damage to individual cells means that narrow spaces between cells can turn into relatively large gaps making the gut lining more ‘leaky’ than usual.
In fact there are many factors that can increase a leaky gut, otherwise known as increased intestinal permeability. Large gaps between cells means the body is less able to regulate the passage of particles from the gut to the bloodstream. With larger gaps between cells, larger particles or food fragments can penetrate the lining and surrounding tissues.
The immune system is our inbuilt defence mechanism against foreign or harmful material. So, to protect the body from potential harm via the digestive tract, a large proportion of immune system tissue lies between the gut barrier and the bloodstream. The immune cells ’sample’ the flow of particles from the gut and can respond to perceived threats by triggering an inflammatory reaction.
If the gut is often damaged and leaky, the inflammation can become a chronic situation and may lead to inflammation in other parts of the body. This process is believed to play a role in many, if not all autoimmune conditions.
What can be done?
For healthy digestion we need to ensure we have the optimal level of stomach acid, digestive enzymes and other secretions. Herbalists in particular pay attention to liver health, and adequate production of bile.
The good news is that most common problems of digestion are easily resolved by changes in diet, lifestyle and/or habits.
Common culprits that can be addressed include alcohol, tobacco and stress. Alcohol is an irritant to the digestive system and should be kept to a minimum. Likewise, the tar in tobacco is an irritant, and nicotine can promote ulceration of the digestive tract or slow healing of the gut lining.
Stress and anxiety can have a huge impact on digestion via the gut-brain axis. Learning ways to manage stress can make a tremendous difference to digestive conditions.
Age related changes in production of digestive juices, especially reductions in stomach acid production, all too often lead to symptoms that are very similar to having too much stomach acid. This is a common reason for taking medication for suppressing stomach acid when in fact the opposite might be more appropriate.
If a leaky gut is suspected we can take steps to heal and strengthen the intestinal lining. We can also improve the balance of microbes in the gut.
See my series of posts on improving digestion, starting with Optimise your digestive health.
There are also some ways to improve digestion with herbal remedies.
Probiotics, prebiotics and gut health
Our intestines contain trillions of microbes. Research shows us that our health and wellbeing relies on these microbes. In fact the greater the number and diversity of species of microbes the better.
However, not all gut microbes are friendly. Some microbes can cause disease, whilst other species of microbes can be harmful if their numbers are not kept in check by friendly species.
We can temporarily influence the balance of our gut microbes by taking probiotic supplements or by eating fermented foods. However, research shows that once we stop taking a probiotic supplement our gut microbe population returns to it’s previous state. In fact, there are only two ways to permanently improve the balance of the gut microbe population – by feeding your microbes with prebiotic foods, or by having a faecal transplant.