Digestion

Digestion is a complex process involving the autonomic nervous system as well as the digestive system.

The autonomic nervous system controls our ‘automatic’ body functions such as temperature control, breathing, heart rate, blood pressure and digestion. 

This autonomic nervous system divides into the sympathetic and the parasympathetic systems; and, like the arms of a see-saw, only one arm can be up (active) at any one time.

When the parasympathetic system is active, the bowel receives good blood-flow and the glands all function well to secrete their various compounds.

When we are rushing in the morning, getting the kids to school or ourselves off to work, our body is in sympathetic ‘flight or fight’ mode.

In order to digest that breakfast that was eaten standing at the kitchen counter or that lunch that was grabbed to eat at the desk, the body requires parasympathetic mode.

Our modern lifestyle tends to cause continual sympathetic nervous system activation with very little opportunity for the parasympathetic nervous system to activate.  Absence of the autonomic parasympathetic activation leads to poor digestion.

In other words, the fast pace of day to day life is a factor in chronic digestive problems and the ‘flight or fight’ mode needs to be switched off in order for digestion to begin.  This doesn’t happen in an instant and requires time.  We need to sit down, relax and take time to smell the roses.

In our digestive system, digestion starts in the mouth and food needs to be well chewed for saliva to mix properly.  If food is eaten too quickly, this initial process is missed completely and the burden then falls on the pancreas alone with resulting bloating, flatulence and discomfort.

Saliva production reduces as we age and thus digestive problems become more common in the over- fifties.

Food proceeds from the mouth to the stomache where there is further enzyme activity.  Gastric juices contain hydrochloric acid and enzymes which work best in an acid envirronment.  The acid is concentrated enough to cause tissue damage but the stomache lining is protected by a special surface barrier.  This barrier may be disrupted by alcohol, aspirin and many anti-inflammatory medicines.

In the stomache, there may be a further problem for the over-fifties as acid production tends to fall with age and thus this stage of digestion may be inefficient.

The rate at which the stomache empties varies with the type of food ingested.  A meal rich in carbohydrates will result in gastric emptying in a few hours; a protein-rich meal is slower and a high fat meal slowest of all.

In the small intestine, the common bile duct drains from the liver and gall bladder and the pancreatic duct drains from the pancreas, bringing numerous enzymes into contact with food in the small intestine.  Different food types require a different set of enzymes; amylases for carbohydrates, proteases for proteins and lipases for fats.

In the large intestine, water, sodium and minerals are re-absorbed leaving semi-solid faeces for excretion.
Finally there is the influence of the bowel flora.  A healthy complement of intestinal organisms will assist digestion; whilst ‘dysbiosis,’ (an imbalance in these organisms,) can exacerbate symptoms such as constipation, diarrhoea, abdominal bloating and pain.

We have one hundred trillion micro-organisms in our intestinal tract weighing in excess of one kilogram.  There are four to six hundred different species and they make up forty per cent of our dry faecal matter each day.  Intestinal organisms, such as bifidobacteria and lactobacilli are present in the body from birth, having been acquired during vaginal birth.

Our bowel flora is positively influenced by a healthy fresh food diet and balanced life style.

Factors that can adversely influence the bowel flora include advanced age, a weakened immune state, psychological stress, physical stress, radiation, a diet high in sugar and the use of pharmaceuticals such as antibiotics, cortisone and oestrogen.

It is evident that digestion is a complex process with many influencing factors.  No wonder so many people today are troubled by bad breath, burping, bloating and biliousness.