CONDITIONS & DISORDERS
MALDIGESTION OR MALABSORPTION? THE DIFFERENCES EXPLAINED
Dr Mabel Blades Independent Freelance Dietitian and Nutritionist Mabel is a Registered Dietitian, a member of the BDA and NAGE, Food Counts, Older people Specialist Group and the Freelance Dietitians Group. All aspects of nutrition enthuse her and she is passionate about the provision of nutritional information to people in assisting their understanding of any diet.
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The terms ‘maldigestion’ and ‘malabsorption’ are often used incorrectly and the terms are often used as alternatives for each other. Malabsorption is the term most commonly used, but maldigestion may be a more physiological description in some situations. This article provides an overview, with some suggested resources. On scanning various medical, nursing and nutritional dictionaries, it was found that only the term ‘malabsorption’ appeared, with the term ‘maldigestion’ not being covered. Thus, it is not surprising that maldigestion is not so well known. Dietitians can help advise about all types of diet in order to assist with both of these conditions. DIGESTION AND ABSORPTION
Digestion is the breakdown of complex compounds into the constituent smaller molecules, which can be absorbed by various areas of the digestive tract. In the body the breakdown is due to the production of digestive enzymes. The process may also occur in the food industry where chemicals (as well as enzymes) are used to achieve such results. Absorption is the process whereby the smaller molecules of the nutrients resulting from the process of digestion, pass through the wall of the digestive tract and into the blood or lymphatic fluids. While the two processes are physiologically different, they are interdependent, with no absorption being possible unless there is first the stage of digestion which enables absorption to occur. However, it appears that the term malabsorption has taken prominence over maldigestion. Most of the digestion and absorption occurs in the small intestine, but other parts of the digestive tract can also be involved.
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RESULTS OF MALDIGESTION AND MALABSORPTION
Both maldigestion and malabsorption result in some form of undernutrition of various nutrients, plus energy, as well as additional adverse consequences of unpleasant symptoms. The symptoms include diarrhoea, bloating, pain and discomfort, plus nutritional issues of undernutrition, like anaemia, osteoporosis, poor growth, fatigue and weight loss, to name but a few. EXAMPLES OF MALDIGESTION
Lactose intolerance For the digestion of lactose from milk, the enzyme lactase must be produced by the brush border of the small intestine. Lactose is the main sugar found in cow’s milk and when it’s not fully broken down and absorbed by the body it can ferment in the gut and lead to pain and bloating. In order for lactose to be absorbed, it needs to be broken down by a special enzyme called lactase. Lactase is usually found naturally in the gut, but some people have very little lactase production and, thus, do not have enough lactase to digest lactose properly. There are two types of lactose intolerance, primary and secondary. Primary intolerance is when the body just doesn’t produce sufficient lactase. Around 70% of the world’s population has this type of lactose intolerance. It is most commonly found in certain ethnic groups, especially Asian, African and
Both maldigestion and malabsorption result in some form of undernutrition of various nutrients, plus energy, as well as additional adverse consequences of unpleasant symptoms.
Hispanic people. This is because their traditional diets over the years have not contained much lactose, so their digestive systems have lost the ability to produce much lactase once they are weaned. Secondary intolerance is when the lining of the gut is damaged and temporarily doesn’t produce enough lactase. This can be caused by any condition that damages and irritates the gut, such as gastroenteritis. More serious conditions, such as Crohn’s disease, coeliac disease and alcoholism, can also cause a secondary intolerance. In the UK, most cases of lactose intolerance are secondary and are as a result of another illness or condition and many people after a bout of gastroenteritis find that they are unable to tolerate milk until the lining of the gut recovers. The BDA produces useful information on lactose intolerance, which includes helpful advice on suitable milks and foods.1 Sucrase-isomaltase deficiency As occurs with lactose, the digestion of disaccharides and some oligosaccharides is undertaken by a number of small intestinal brush border enzymes and other forms of maldigestion of disaccharides occur, which require dietetic advice. Sucrase-isomaltase deficiency is a very rare congenital condition (except in Greenland) that requires the exclusion of sucrose from the diet.
Deficiency of pancreatic enzymes The lack of pancreatic enzymes responsible for the digestion of protein fat and carbohydrate are seen in pancreatic disorders, with a resultant deficiency in absorption of nutrients. The genetic disorder cystic fibrosis causes a defect in both the lungs and the pancreas, with the latter affecting the production of pancreatic enzymes. Treatment normally involves the prescribing of pancreatic enzymes as supplements, plus an appropriate diet.2 EXAMPLE OF MALABSORPTION
Coeliac disease This is a well-known condition requiring the avoidance of gluten. It is an autoimmune condition where the body reacts to gliadin in gluten causing the wall of the small intestine to become inflamed and the villi to be flattened. The villi increase the surface area of the gut and enable the correct absorption of nutrients so that the reduction in villi causes a reduced absorption of nutrients. Many sufferers present with weight loss, anaemia and osteoporosis. It is not known why some people develop coeliac disease, but the risk is increased in those with an established family history of the condition. It is also considered that giving gluten to babies before three months of age is associated with the later development of coeliac disease. Type 1 diabetes, itself an autoimmune condition, www.NHDmag.com February 2019 - Issue 141
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CONDITIONS & DISORDERS is also associated with the increased likelihood of the development of coeliac disease. Diagnosis is by examining a blood test for antibodies to gluten and the diagnosis is confirmed by a biopsy. For the biopsy to show clear results, sufferers are required to resume consuming gluten. However, due to adverse symptoms, many people prefer to simply continue a gluten-free diet. Treatment is by a lifelong gluten-free diet which needs to be rigorously kept to. Today, there are many glutenfree foods available, plus restaurants and other venues are well aware of the need to provide gluten-free food. Food labels are required by law to show food allergens including gluten.3 Crohn’s disease This is one of the inflammatory bowel diseases and causes inflammation at any point in the length of the digestive tract, which results in malabsorption and diarrhoea, as well as pain and discomfort.4,5 Pernicious anaemia Like iron deficiency anaemia, this condition results in symptoms of tiredness and lethargy, but is due to a lack of vitamin B12 needed for the formation of red blood cells that transport oxygen around the body. Vitamin B12 is absorbed in the ileum which is the final part of the small intestine. The stomach secretes a protein called intrinsic factor which binds with the vitamin B12 and enables its absorption. The secretion
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of intrinsic factor in the stomach ceases in some people as they get older due to an autoimmune condition which occurs often in women over the age of 60. Thus, vitamin B12 cannot be absorbed due to the lack of intrinsic factor and has to be provided by regular injections, usually given every three months.6 Short bowel syndrome Other forms of malabsorption include short bowel syndrome where the length of the small intestine is reduced so that the absorptive area is reduced. Some infants are born with this condition while other people develop it due to surgical removal of part of the small intestine after either an injury or illness. Such conditions require considerable nutritional support, including on occasions parenteral nutrition. BARIATRIC SURGERY
The surgical procedure called a Roux en Y Gastric Bypass is used as a method of managing morbid obesity. A small pouch is made from the top of the stomach and then connected to part of the small intestine. In doing so, the small size of the stomach means that people feel full quickly and that by attaching the stomach pouch to the ileum and thus bypassing the absorptive area, the upper part of the small intestine (duodenum) and, therefore, the nutrients are not so well absorbed and weight loss is promoted. Such procedures require lifelong supplementation with vitamins and minerals.
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