The Digestive System

Numbers 1-6 show the sequence of events in the digestive tract when we eat a meal.

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Food is vital for life. It is the source of energy that fuels chemical reactions in every bodily cell, muscle contraction and nerve impulse.

The digestive system comprises the digestive tract (alimentary canal) together with its associated organs; the liver, gallbladder and pancreas.  The digestive tract begins with the mouth and continues through to the oesophagus; intestines and terminates at the anus.  Along its winding course food is broken down and nutrients extracted, while waste materials are disposed of.

We can summarise the job of the digestive tract as follows:

(a)        To take in food

(b)        To break it down so nutrients can be extracted, absorbed and converted to energy; and

(c)         To eliminate the waste.

Let’s take a closer look at the different parts of the digestive system starting with:

Mouth and Teeth

In the mouth food is chewed; crushed and ground down by the teeth and mixed with saliva until it becomes a moist ball (bolus) of food.

Salivary Glands

Saliva is produced by three pairs of salivary glands; the parotids the sub-mandibulars and the sub-linguals, in addition to numerous glands in the mucous membranes lining the mouth and tongue.  Saliva contains 99.5% water as well as amylase, a digestive enzyme that starts the breakdown of starches, and salts. Once swallowed the bolus moves down the throat (pharynx) through to the gullet (oesophagus) on to the stomach.

In the stomach, food is churned and mixed to a paste called chyme to allow further breakdown by the digestive juices which contain hydrochloric acid (HCl). In the stomach mucus secretions prevent the acid damaging the stomach lining. The stomach wall moves in rhythmic contractions called peristalsis, mixing food with digestive juices.  The stomach is where protein digestion begins and where sugars are directly absorbed into the bloodstream providing fuel for energy.

The Small Intestine

The small intestine is made up of the duodenum, jejunum and ileum. In the first part, the duodenum, chyme is broken down further by pancreatic juices, bile and the intestine’s own secretions.  The nutrients from the chyme can then be absorbed into the bloodstream and lymph circulation.

The Liver, Pancreas & Gallbladder

In your small intestine, digestion of starches, proteins and fats occurs with secretions from your liver, gallbladder, pancreas and intestines.  About 90% of nutrient absorption takes place in your small intestine.  Each day, the liver manufactures anywhere from a pint to a quart of a bitter alkaline substance known as bile is stored in the gallbladder.  Bile is released into the small intestine and, with the help of enzymes, breaks down fatty substances.  The pancreas, located behind your stomach to the left of the abdomen, is an important organ secreting enzymes and hormones – including insulin, needed for digestion and absorption of food.  Daily the pancreas produces around 1.5L of digestive juice containing enzymes that break down lipids, proteins and carbohydrates, emptying the juice into the duodenum.

Large Intestine

Digested food that is not absorbed in the small intestine, passes through the ileocaecal valve into the caecum. From there it reaches the first part of the colon, the ascending colon. The large intestine is the final part of the digestive tract and comprises three main regions – the caecum, colon and rectum. The caecum is a short pouch linking the small intestine to the colon, which is around 1.5m (5 ft) long. The main function of the colon is to convert liquid chyme into semi-solid faeces as nutrients and water are absorbed for storage and disposal.  Sodium, chloride and water are absorbed through the lining of the colon into the blood and lymph and the faeces become less watery.  The colon secretes bicarbonate and potassium in exchange for sodium and chloride.  Solid waste then moves into the rectum.

Rectum, Anus & Defaecation

The rectum is around 12cm (5in) long, and it is normally empty except just before and during elimination (defecation).  Below the rectum lies the anal canal, which is around 4cm (1½ in) long.  The walls of the anal canal contain two strong sets of muscles – the internal and external anal sphincters.  During elimination, peristaltic waves in the colon push faeces into the rectum, triggering the defecation reflex.  Contractions then push the faeces along; and the anal sphincters relax allowing them out of the body through the anus.

How to care for your Digestive System

 There is much that that you can do to take care of your digestive system.  Here are a few tips:

  1. Cut out or reduce the amount of processed food in your diet.  Processed foods not only lack enzymes necessary for digestion, but also lack the fibre necessary for elimination.  Dietary fibre is essential for colon health, as it helps to quickly move waste through the colon and out of the body for elimination. Without enough fibre, solid waste can build up and stagnate, creating numerous problems in the colon and eventually the whole body.  Poor fibre, consumption is linked to nearly all diseases of the colon and many forms of cancers.
  2. Eating too quickly and not chewing your food is a prime cause of bloating and stomach discomfort after eating. Failure to chew food well, results in the food not being saturated by enzymes in saliva by the time it reaches the stomach. Not chewing well is a common cause of burping, bloating, gas and indigestion.
  3. Stress affects digestive secretions and the contractions of the stomach and intestines.  It is best not to eat when you are excessively stressed.  If you must eat, eat lightly, until you feel better.
  4. Lactose intolerance is difficulty digesting milk sugars. Try switching instead to rice or nut milks.
  5. A healthy intestine is home to trillions of beneficial bacteria that assist in the absorption of nutrients and the manufacture of vitamins including vitamin K and the B-complex family.  They also help keep harmful bacteria at bay.  Antibiotics kill beneficial bacteria along with harmless ones, allowing yeasts and other harmful organisms to flourish. This can make you prone to food allergies, digestive problems and infection from harmful micro-organisms.  As much as 60% of your immune function comes from beneficial bacteria in your intestinal tract.  Probiotics are a useful supplement of friendly bacteria.  The most common strands are Lactobacillus and Bifidobacterium.
  6. Useful herbs with antibiotic activity are Garlic, Echinacea and Goldenseal.  Propolis is a natural product made from bees.  Bees make Propolis to protect the  hive from any infections. Propolis is a powerful natural antibiotic with wide range    of activity against bacteria, viruses and fungi.
  7. Dehydration can cause constipation, as well as premature aging. Make sure you take in enough water. Try making a daily smoothie with linseed (flaxseed) oil, which is a stool softener.  Try switching to a water-rich, enzyme-rich raw food diet for a few weeks, which will also greatly increase your fibre content.
  8. Do not overuse laxatives, as this may damage the colon’s ability to work for itself and lead to dependency.  There are some gentle herbs that work on the liver, stimulating bile flow and easing constipation. Try using Dandelion Root and/or Yellow Dock.  They are gentle, effective and non-habit forming.
  9. Herbal treatment of the digestive system is more successful if combined with a temporary change to your usual way of eating.  Eat easily digestible foods; plain digestible foods.  Sometimes a day of fasting with just water or diluted fruit juice is a good option.

Some common digestive problems include

  • Allergies
  • Constipation
  • Diarrhoea
  • Flatulence
  • Gastric Reflux
  • Gastroenteritis
  • Heartburn
  • Indigestion
  • Irritable Bowel Syndrome
  • Peptic Ulcers

How Herbs can help

Broadly speaking, the actions of herbs used in digestive disorders, either stimulate or relax the digestive system, as well as kill bacterial growths.

Stimulating Herbs are used to encourage or increase activity in various parts of the digestive tract. Examples are (a) increasing appetite and improving digestion by promoting the flow of saliva; (b) stimulating bile production for fat digestion; and (c) stimulating the large intestine to encourage bowel movements in constipation. An example of a stimulating herb is Peppermint.

Relaxing Herbs are used when there is tension or pain. Examples are when there is inflammation or ulceration when herbs can be used to soothe, coat and protect the digestive tract. Many herbs are rich in volatile oils, ideal for helping the gut relax, release and disperse trapped gas to ease painful spasms, griping or colic. Other herbs will tone and firm the lining of the intestine, preventing the looseness we associate with diarrhoea and leaky gut. Examples of relaxing herb are German Chamomile and Marshmallow Leaf, which is both relaxing and soothing.

Anti-microbial herbs act against harmful microbes that can affect the intestinal tract. A good example is Goldenseal.

For advice or a consultation on managing digestive problems please fill in a consultation form or call 0845 468 0823.

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