Finally, the digested material reaches the large intestine (colon, anus and rectum). It enters the colon as a wet bulky mass consisting mainly of fibre (see here for information about fibre). This part of the gut has modified villi that absorb water and leave the faeces or stool (bowel motion). But the colon contains something more: it contains millions – perhaps billions – of bacteria that help this final stage of digestion by breaking down fibre. (More is said about gut bacteria under the section on Probiotics in the next chapter.)
Like all other good ‘systems’, the digestive system is no better than any one of its parts. For example, at the start of the digestive tube, teeth are used to tear and crush food to facilitate its chemical breakdown in the stomach and gut. If food is not crushed and mixed properly – perhaps because of ill-fitting false teeth, or a rushed meal eaten under stress – the chemical processes that occur further along the tube will be less effective. If the chemical processes are less than effective, absorption of nutrients will be incomplete. When nutrients do not reach the body in quantities needed to keep tissues healthy because of a failure in the digestive process, a potentially dangerous condition called malabsorption occurs.
A fully functioning digestive system is needed to reap maximum benefit from a healthy diet. As noted above, the normal flow of nutrients from the gut into the body through the bloodstream is called absorption. When this process fails, malabsorption results. If malabsorption becomes severe, malnutrition sets in. Malnutrition destroys the body. It lowers resistance to infection, stunts physical and mental growth in children, causes infertility, and is to blame for the slow degeneration of bones, muscles and other organs. Many scientists believe that borderline nutritional deficiencies (in which the body receives smaller quantities of vital nutrients than are required by normal body functions) are at the root of heart disease, arthritis and possibly certain forms of cancer.
Symptoms of malabsorption are variable and may include weight loss, fatigue and foul-smelling, bulky diarrhoea. If untreated, malabsorption leads to illnesses as diverse as peripheral nerve damage and anaemia. Causes of malabsorption usually involve inflammation of the gut and include food sensitivities, Coeliac disease, Crohn’s disease, chronic pancreatitis, advanced diabetes mellitus and cystic fibrosis. Left untreated, parasitic infection of the gut can also block the passage of nutrients.
There is evidence that a genetic factor contributes to the development of illnesses leading to malabsorption.
The largest organ in your body – the liver – deserves special attention. Protected by the ribs and tucked under the diaphragm, it contributes to the metabolism of fats and proteins, helps maintain normal blood sugar levels, is responsible for the formation and storage of energy as glycogen, and secretes bile to aid the digestion of fat. Of equal importance to its various roles in metabolism, the liver is the body’s great detoxifier. It neutralizes alcohol, nicotine, drugs and poisons, and stores toxic substances that have no means of being excreted from the body. It is responsible for at least 22 chemical functions on which life depends.
You obviously need your liver, but how do you care for it? Unlike the muscular parts of the digestive system, which quickly let us know when something is wrong, the liver is a quiet organ that gives little trouble unless it has suffered serious damage. Here are some basic tips.
• Avoid recreational drugs!
• Avoid heavy drinking and excessive intake of spicy foods.
• Restrict intake of saturated fats from dairy products and fatty meats.
• Limit caffeinated drinks, such as coffee, tea and cola.
• Reduce your intake of refined sugar.
• Enjoy foods high in vitamin C. (Vitamin C may help the liver cope with detoxification, so enjoy strawberries, blackcurrants, green peppers, spinach and citrus fruit whenever possible.)
• Eat liver! It is a rich source of folic acid and vitamin B12. (These nutrients are needed for normal liver function. Other sources of folate include wheatgerm, nuts and green leafy vegetables. Vitamin B12 is found in lean red meat, eggs and fortified cereal.)
• Include oily fish in your diet at least once a week.
• Enjoy foods from plants, especially green leafy vegetables, artichokes and beetroot (see Chapter 4).
The liver regenerates itself to a certain extent, but will fail when overtaxed by alcohol or drug abuse, poor diet, infections or illnesses. Signs of chronic liver disease include yellowing of the whites of the eyes and skin (jaundice), loss of body hair, distended abdomen and fever.
three maintaining a healthy gut
Few people blessed with a healthy gut know how to maintain and protect it. If the gut was a very expensive car, a fine camera – or even a top-of-the-line washing machine – we would take out the instruction book, read it from cover to cover, and make sure we followed the instructions to get the best possible service from our investment. The digestive system deserves the same care.
This chapter covers a range of topics that shed light on how to maintain a healthy gut, including how to eat, a modern approach to a balanced diet, and what you should look for on a yoghurt pot.
How you eat your food helps determine whether or not you have a healthy gut.
Modern lifestyles – TV dinners, dependence on takeaway food, and a different social schedule for everyone in a household – work against healthy eating habits. We live in a rush-rush world where consuming food has become a necessity, rather than a source of pleasure and relaxation. Gulping down half-chewed food, overeating, washing everything down with fizzy drinks, and failing to relax during a meal can lead to indigestion, bloating and uncertain bowels. Can we doubt that bad eating habits contribute to the epidemic of gastric and bowel conditions plaguing most of Western society?
What is the basic rule of good gut health? Meals should be eaten slowly at a table in a peaceful environment, taking time to enjoy both the food and the company of others. This may seem simplistic, but the belief that how you eat is as important as what you eat has been taught for thousands of years. Wise men advised us not to think only about how we eat, but also how the food is prepared. The ancient Indian healing practice of Ayurveda tells us to prepare food while in a peaceful state of mind. It claims that the cook’s mood enters the food, which in turn influences the mood of those who eat it. In other words, if you are tense and nervy when you poach the fish or season the Bolognese, those you feed will soon become tense and nervy, too.
There is some