Micronutrient absorption disorders -
Carbohydrates are ingested primarily in the form of starch or carbohydrates, sucrose table sugar , fructose fruit sugar and lactose milk sugar. Salivary and pancreatic amylase digestive enzymes break up the starch into long chains of sugars called oligosaccharides and shorter chains called disaccharides and trisaccharides.
Most starch hydrolysis breaking up a molecule into its smaller components occurs in the duodenum and absorption takes place in the duodenum and jejunum. Specific enzymes that hydrolyze disaccharides disaccharidases into their simplest forms or monosaccharides are located along the small intestine microvilli.
Once the sugar is in the form of a monosaccharide, it can then be absorbed into the blood. Carbohydrate malabsorption occurs in pancreatic disease, in selective deficiency of disaccharidases such as lactase digests lactose or sucrase digests sucrose , in disorders of small intestinal cell function such as sprue or regional enteritis, and in loss of intestinal mucosal surface which occurs after resection of bowel.
Abdominal distention, bloating and gas may be signs of carbohydrate malabsorption. Proteins are broken down into long chains of amino acids by pancreatic enzymes. Small intestinal enzymes activate the pancreatic enzymes so that digestion and absorption of protein can take place.
Absorption of amino acids and peptides occurs in the duodenum and jejunum. Dietary fat is normally absorbed in the duodenum and jejunum. Before fat can be absorbed, however, it must first be made into a water-soluble form. Broken down dietary fats combine with bile salts and phospholipids substances present in bile from the liver to form a packet called a micelle.
The micelle is water-soluble and is easily absorbed in the duodenum and jejunum. Large amounts of water are involved in digestion and must be recycled in order to prevent dehydration.
Water is reabsorbed in the large intestine. From the large intestine, water goes back into the bloodstream and the waste passes into the rectum and out the anus. These can be used to identify suspected malabsorption and are usually the first tests done.
They are not specific because low levels of certain substances could be due to disorders other than malabsorption e. an unusual diet.
Blood carotene levels are useful to screen for malabsorption. Low levels of carotene in the blood suggest deficient absorption of fat-soluble vitamins or dietary deficiency. Serum carotene levels are generally low in people with fat malabsorption. Vitamin B12 and folate levels may also be used to screen for malabsorption.
There are numerous causes of folate and B12 deficiency, and since the deficiencies often occur together and cause similar types of anemia, both must be measured to ensure proper diagnosis. Low calcium levels may result from either malabsorption of vitamin D or to binding of calcium to unabsorbed fatty acids.
Vitamin K deficiency resulting from malabsorption may cause bleeding disorders. Anemia due to iron deficiency may be caused by malabsorption of iron in the first part of the small bowel. Normal levels of carotene, vitamin B12, folate, iron, calcium, phosphorus, albumin, and protein suggest that malabsorption is not a significant problem.
Another type of blood sampling can be used to test absorption. A substance can be administered orally and its concentration is then measured in the blood to provide a measure of absorptive capacity. The most commonly used test is the D-xylose test.
A sugar called xylose is given orally and then measured in the blood 2 hours later. Tests of the fat content of stool may be used to determine if fat malabsorption is present. Stool is collected over a period of 72 hours with the person consuming a diet containing g of fat per day.
If the amount of fat in the stool is high, it suggests that the body is not absorbing fat. Breath tests are another method of detecting malabsorption. They are most often performed to test for lactose intolerance.
If lactose is being malabsorbed, colonic bacteria will work on the lactose to produce hydrogen gas which will be exhaled by the patient and measured in his or her breath. Tests such as biopsies of the small intestine usually performed using an endoscope passed through the mouth into the intestine are used to diagnose certain malabsorptive conditions.
Special tests to image organs such as the pancreas are also useful in some cases. Perhaps the most common malabsorptive state is due to lactose malabsorption. This is a genetically determined condition and affects many individuals of African or Asian descent.
In these persons, the body lacks an enzyme to digest lactose, a sugar present in milk, and bloating and diarrhea can result. The enzyme may be totally absent or present in reduced amount so that symptoms may vary depending on the amount of lactose ingested.
The amount of the enzyme decreases with age and some people first notice symptoms when they reach their twenties. Dairy products are an important source of calcium and this should be considered in planning diets for lactose-intolerant subjects. Lactose intolerance is widespread and under-diagnosed.
Recognizing this condition and using milk treated with enzymes to pre-digest the lactose or taking enzyme tablets with dairy products can correct symptoms related to this condition. Learn more about lactose intolerance. Surgical resection or diseases of the small intestine may result in varying degrees of malabsorption depending on the site of resection or disease.
Diseases involving the duodenum may be associated with lactose intolerance, poor tolerance of concentrated sugars, and decreased absorption of iron and calcium. Almost all nutrients are usually absorbed in the first three to five feet of the bowel. The absorption of most minerals especially iron, calcium and zinc, as well as most vitamins occurs in the upper part of the small intestine.
The ileum plays a major role in reabsorption of bile salts, substances produced by the liver to help digest fats that are recycled by the body for use with future meals. The ileum is also important in vitamin B12 absorption. If bile salts are not absorbed properly, the amount of these substances in bile falls and fats and fat soluble vitamins A, D, E, K , cannot be properly absorbed.
A further problem is that if bile salts reach the colon, they can cause large amounts of fluid to be secreted causing watery diarrhea. If large portions of the bowel are lost to surgical resection, rapid transit of nutrients through the remaining bowel occurs, causing malabsorption.
Learn about short bowel syndrome. Diseases of the pancreas can cause severe malabsorption of fats and carbohydrates. Symptoms depend on the severity of the condition but diarrhea with greasy, foul smelling stools is common and weight loss can be profound. In conditions when insufficient bile reaches the intestine, fats are not absorbed and again diarrhea and weight loss occur.
Vitamins that are absorbed with fats are also affected and vitamin D deficiency can occur. When the cause of malabsorption is treatable, the primary goal of treatment is to treat the cause.
In patients who cannot be completely restored to normal for example after extensive surgical removal of the intestine , special dietary measures need to be adopted. Dietary treatment will also depend on the site of malabsorption.
In another test, the person swallows a substance that requires pancreatic enzymes for its digestion. The products of digestion are then measured in the urine. Recently, doctors have been doing simpler and easier tests that measure levels of certain pancreatic enzymes in the stool.
Other diagnostic tests including culture of digestive bacteria, certain blood tests, or breath tests may also be done. Learn more about the Merck Manuals and our commitment to Global Medical Knowledge. Brought to you by About Merck Merck Careers Research Worldwide.
Disclaimer Privacy Terms of use Contact Us Veterinary Edition. IN THIS TOPIC. OTHER TOPICS IN THIS CHAPTER. GET THE QUICK FACTS. Causes Symptoms Diagnosis. Certain disorders, infections, and surgical procedures can cause malabsorption. Malabsorption causes diarrhea, weight loss, and bulky, foul-smelling stools.
Interferes with the digestion of food. Digestion of food can be affected by. Disorders that prevent adequate mixing of food with digestive enzymes and stomach acid.
Inadequate mixing may occur in a person who has had part of the stomach surgically removed. The Small Intestine. Absorption of nutrients into the bloodstream can be affected by.
Disorders that injure the lining of the small intestine. Chronic diarrhea. A doctor's evaluation of the person's history and symptoms. Tests to measure fat in stool. Drugs Mentioned In This Article.
Generic Name Select Brand Names lactase. All rights reserved. Was This Page Helpful? Yes No. To make a diagnosis of a malabsorption disorder, a doctor will ask a person about their symptoms. They might ask about when a person first noticed the symptoms, what makes these symptoms worse or better, and what types of medical conditions a person already has.
A doctor may also recommend an esophagogastroduodenoscopy upper GI scope or a colonoscopy lower GI scope to examine the intestinal lining and take tissue biopsies to diagnose certain conditions. For example, doctors will treat malabsorption caused by lactose intolerance in a different way to malabsorption due to liver disease.
Initially, a doctor may recommend that a person avoids the food type that is causing the malabsorption, such as lactose or gluten-containing foods. The doctor can evaluate the nutrients present in this food type and make recommendations on supplementation as a means of enhancing nutritional intake.
A doctor may also make recommendations for replacing missing enzymes or prescribing medications to enhance appetite. People may also choose to meet with a registered dietitian to establish a diet that is nutritious, but less likely to cause unpleasant symptoms associated with malabsorption.
A doctor will likely recommend frequent follow-up appointments to assess the effectiveness of the treatment and make new recommendations if necessary. The complications associated with malabsorption depend upon the severity of the underlying condition.
Malabsorption can lead to weight loss, malnutrition , and even failure to thrive in many people. A person can also experience impaired wound healing, a deficient immune system, and low energy levels.
Anyone who notices their symptoms become more frequent and less occasional should see a doctor as soon as possible. This way, they can receive treatment before they experience significant unwanted weight loss and other side effects.
Whipple disease is an infectious bacterial intestinal disease. It commonly causes diarrhea and weight loss. If the central nervous system is affected…. Anemia is the most common blood disorder. With anemia, the body does not have enough red blood cells and is unable to deliver enough oxygen around the….
Lactose intolerance happens when a person has too little lactase. Find out what it is, how to recognize and manage it, and what foods to eat and avoid. Dyspepsia or indigestion is a feeling of burning, pain, or discomfort in the digestive tract.
It can result from a medical condition or lifestyle…. My podcast changed me Can 'biological race' explain disparities in health?
Malabsorption Micronutrient absorption disorders a disorder that occurs when people are unable to Micdonutrient nutrients Books and literature collection their diets, such as carbohydrates, fats, minerals, disordera, or vitamins. Some commonly known Natural health products related to malabsorption are lactose intolerance Herbal natural remedies dosorders disease. People with a history of bowel or stomach surgery may also have malabsorption disorders. Enzymes continue to break down the food as it travels through the esophagus, stomach, and large and small intestines before it leaves the body as waste products. Malabsorption can occur if someone does not have enough digestive enzymes, bacteria or other foreign invaders are present, or movement in the small or large intestine is faster than usual. The sisorders role of your small intestine is Glucose levels Micronutrient absorption disorders nutrients from Herbal natural remedies food Hydration and sports drinks eat into your Micronutridnt. Nutrients that the small Micronurient often has trouble absorbing can be one or both of the following:. Abeorption things can lead to malabsorption syndrome, from certain diseases to infections or developmental issues. The syndrome may also be caused by digestive problems. Your stomach may not be able to produce the enzymes it needs to digest certain foods. Or, your body may not be able to mix the food you eat with the enzymes and acid produced by your stomach. There are also some uncommon disorders that can result in malabsorption.
Wacker, welche die nötige Phrase..., der bemerkenswerte Gedanke
der sehr gute Gedanke
Wacker, die ideale Antwort.
Sie lassen den Fehler zu. Ich biete es an, zu besprechen. Schreiben Sie mir in PM.