Probiotics: Manipulating Your Internal Ecosystem

The human body is an ecosystem harboring numerous different species living in delicate balance, well-adapted to each other and to their physical environment. The creatures that thrive on our skin and in our noses, mouths, urogenital tracts and guts are microscopic organisms – mainly bacteria, fungi and bacteriophages (viruses carried by bacteria). These organisms comprise the human “microbiome” and perform valuable services for us, breaking down food, making vitamins and other chemical compounds that we absorb, teaching our immune systems how to recognize invaders, and maintaining bowel health. Their genes interact with our genes, up-regulating and down-regulating them as we change our diets.

Research relating the the invisible world of the microbiome to physical states of health and illness is still in its infancy, but has produced interesting data and useful observations about attempts to restore microbiome composition after disruption by illness and antibiotics. Outside this world of esoteric research, entrepreneurs have leapt ahead of the facts, supplying millions of people who wish to better their health with supplements called probiotics, pills containing “living microorganisms, which when administered in adequate amounts, confer health benefits on the host.”

Not a new idea

The idea of manipulating the body’s microorganisms to improve health is not new. In 1908, Nobel prize winner Elie Metchnikoff, the “Father of Immunology,” theorized that the large intestine was a cesspool where putrefaction by bacteria produced autotoxins that aged the body. While some believers advocated removing the colon or administering repeated enemas to cleanse it, Metchnikoff thought that Lactobacilli, bacteria found in the yogurt consumed by long-lived Bulgarians, could battle the putrefactive bacteria, and that consumption of the yogurt, along with other ascetic practices like avoidance of alcohol and intoxicants, would prevent dementia, illness and premature death. Like yogurt, other fermented, bacteria-laden foodstuffs such as kefir and sauerkraut have long been advocated for general good health.

Experimental evidence?

There is tantalizing experimental evidence that the interior microbial world has previously unsuspected ties to overall health. For instance, in germ-free mice, introduction of specific bacteria into the gut will alter energy usage because the bacteria digest incoming food. The mice get fatter on the same amount of food they were fed in the germ-free state because they absorb more of it. Bacteria also produce substances which act like neurotransmitters and communicate with the brain via the gut’s neural network. And they modify the action of their genes to match the types of food we eat, which in turn modifies food absorption and immune system function.

Genetic tools speed modern microbiome research

High speed DNA analysis is the modern tool which drives microbiome research. No longer do scientists struggle with culturing and identifying the multitude of bacterial types that reside in the human body. Based on microbial DNA sequencing of samples from human bodies, we know that we carry over 3.3 million bacterial genes, vastly more than our own 22,000 genes). There is far more diversity between humans in terms of the genetics of the organisms they carry than there is in their genetic profiles – and enough stability in each person’s microbiome to create unique microbial DNA profiles, which can be identified like fingerprints on surfaces people touch. There are even identifiable differences between the fingerprint profiles from an individual’s right and left hands.

Fecal transplants: the ultimate probiotics

The best scientific information about manipulation of the microbiome in the quest for better health comes from the ultimate type of probiotic – the so-called fecal transplant. Transfer of fecal material from one person’s gut to another’s was first tried in the 1950s. In this experiment, a patient suffering severe colitis was spared surgical removal of the colon when restoration of a normal mix of bacteria, as well as everything else in contained in the stool sample used for the transplant, quelled the toxic bacteria eating away his colonic lining. Since that time, fecal transplantation has been 90% successful in treating the severe and often recurrent colitis and diarrhea produced by the bacterium clostridium difficile.

The complex nature of fecal material

Fecal material contains bacteria, viruses, bacteriophages – the viruses that bacteria can transfer among themselves and to the host, other types of microorganisms, and all the chemical products of the metabolic processes of all these living creatures. Each stool donor has a unique microbial profile, as does each fecal transplant recipient. Donor stool is screened for drug resistant and abnormal bacteria, prepared as a slurry and introduced into the colon via colonoscope, or into the stomach or small intestine via a tube. Capsules that resist the acid and enzymatic environment of the upper GI tract also show some promise.

Probiotics: less complex mixtures of living organisms than fecal transplants

Like fecal transplants, probiotics aim to create a healthier balance of bacteria in the gut, but they are capsules containing a few types of freeze-dried bacteria harvested from cultures in labs. When swallowed and exposed to the warmth and moisture of the body’s interior they spring to life. Sold as supplements, probiotics are not subject to FDA quality control.

Probiotics have been studied as treatments for antibiotic-induced diarrhea, allergies, autism, metabolic syndrome, autoimmune ulcerative colitis, Crohn’s, disease, infectious colitis, constipation, traveler’s diarrhea, periodontal disease, and more. The studies are fraught with problems that make most of them inconclusive at best. But as preventives for antibiotic0induced diarrhea and clostridium difficile diarrhea, probiotics may be helpful and are generally not harmful for otherwise healthy people. Theoretically, people with depressed immune systems could contract an infection from one of the organisms included in the product. There has been at least one neonatal death attributed to a contaminated probiotic.

Do the introduced bacteria survive?

A recent, carefully designed study from Israel assessed whether or not probiotic bacteria took up residence in the colon after ingestion. In some people, called persisters, the probiotic bacteria can be found in the recipient, but in others, called resisters, none of the probiotic bacteria survive. The type of bacterial populations already living in the gut make the difference. In addition, another good study demonstrated that probiotic use actually delayed the return of normal bacteria to the colon after a course of antibiotics.

Much work remains in the investigation of the human microbiome and in attempts to improve health by manipulating it. What is clear so far is that each person’s microbiome is unique and that success in understanding and manipulating it will require individualized evaluation. Most probiotic use at this time is a one-size-fits-all approach, done for non-specific reasons. Similar to Metchnikoff’s Bulgarian yogurt.*

*modern science shows that the lactobacillus in the yogurt does not survive the trip through the gut to the colon.

Posted by medical plaintalk

Physician turned medical writer.

Nausea and Vomiting: the Great Equalizers

In 1832, British scientist Charles Darwin, who is famous for his evolutionary theory of biology, wrote a letter to his father after having been at sea for more than a month, saying: “The misery I endured from sea-sickness is far far beyond what I ever guessed at.” Much later in the letter, Darwin goes on to make the following pronouncement: “If it was not for sea-sickness, the whole world would be sailors.”

In these statements, Darwin, is, of course, referring to the all-consuming symptoms of nausea and vomiting associated with seasickness. In Darwin’s case, these symptoms were particularly severe and continued to plague him even on land. Modern medical detectives theorize that he may have had a rare genetic problem called mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS) syndrome, which he would have inherited from his mother. One does not, however, need to have any experience with rare diseases to empathize with the misery he describes. Nausea and vomiting are the great equalizers of men, stripping all sufferers of energy, ambition, and desire. Virtually everyone has experienced both symptoms.

Why do we vomit?

Like diarrhea, nausea and vomiting are probably evolutionarily developed, protective mechanisms designed to rid the body of toxins. Why these symptoms spill over into motion sickness and inner ear problems is a mystery, but the answer may have something to do with the fact that many toxins affect the inner ear. Some scientists speculate that over eons of evolutionary time the ear came to use the same warning symptoms experienced with seasickness to alert the body to other problems, such as trouble controlling balance. Nausea and vomiting are universal symptoms. The threshold for their appearance is highly variable. While triggers are usually physical, the symptoms can also come from the mind itself. Vomiting can be triggered by great distress, and in some people undergoing chemotherapy, antianxiety agents can diminish “anticipatory” nausea.

The scientific literature devoted to studying nausea and vomiting is full of words like “probably,” “possibly,” and “perhaps,” which reflects the lack of full understanding of the subjects. Nausea is a subjective sensation, a queasy feeling, which seems to come from the stomach but is felt primarily in the head—a feeling that vomiting may soon occur, though not necessarily. Nausea is often accompanied by the need to lie down or even to sleep, by an inability to concentrate, and by lack of interest in one’s surroundings. In people suffering from nausea, the muscular activity of the stomach and intestines is slower than normal. As nausea progresses toward vomiting, sweating and increased saliva production occurs, the skin pales, and the heart rate increases.

Vomiting is an action

Vomiting is an action and is much better understood than the sensation of nausea. It begins with a masterfully coordinated sequence of muscular actions that are carried out by the upper portion of the gastrointestinal tract, working in reverse to bring stomach contents back up the esophagus to the throat and mouth. When a person vomits, the muscles are all recruited to expel the mess with great force. Once vomiting occurs, nausea often subsides, at least temporarily.

Nausea is a sensation

Nausea has many different causes, including the presence of drugs and toxins, primary gastrointestinal problems, inner ear problems, hormonal and other metabolic problems, and brain problems. In most circumstances of nausea and vomiting, the symptoms are acute (appearing suddenly in a previously stable individual) and self-limited, meaning that they get better on their own within hours to days. The most common causes of short-lived symptoms are side effects of medications, surgery when anesthesia is used, viral or bacterial toxins, motion sickness, and migraine headaches. The most common causes of longer lasting episodes are the hormonal changes that take place during pregnancy, the side effects of chemotherapy and radiation treatments used to treat cancer, and episodes of inner ear problems that provoke a severe, spinning dizziness that is triggered when a person changes head position.

Searching for the cause of nausea: pay attention to other symptoms

Nausea and vomiting may also be symptoms of more serious illnesses, particularly when the cause is not easily identified or the symptoms do not resolve in the usual few days of discomfort that are experienced with a stomach flu. Often other, associated symptoms point to the source of trouble. Primary stomach disorders, like ulcers, can produce nausea, particularly after eating, and abdominal pains or blood in the stool lead to the correct diagnosis. Other abdominal problems, like bowel obstruction, gall bladder disease, and pancreatic cancer, can cause significant abdominal pain along with nausea and vomiting. Nausea caused by liver disease might be associated with increased abdominal size or yellowing of the whites of the eyes. Severe headaches and lethargy are symptoms of increased pressure in the brain, which can cause what is known as “projectile vomiting,” – sudden, unexpected, and very forceful expulsion of the stomach’s contents. Dizziness and double vision along with nausea may point to an impending stroke in the brainstem.

Treatment

The stomach and the brain work together in normal digestion, and when something goes awry, the neurotransmitters in the brain play a role in producing nausea. This brain-gut connection is at the heart of attempts to treat the symptoms of nausea with drugs, which fall into two categories. The first category consists of drugs that increase normal gut muscle action; drugs in the second category act by blocking neurotransmitters in the brain and the nerves leading to the gastrointestinal tract.

Drugs from both of these categories are used in postoperative care and in cancer chemotherapy and radiation treatment, and drugs from one or both of these categories are often tried in cases of persistent nausea, while an attempt is made to discover the underlying cause of the symptom. Drugs that block histamine receptors, such as over-the-counter remedies containing dimenhydrinate and prescription patches containing scopolamine, are most helpful in cases of motion sickness.

All of these drugs have side effects, the most common of which are drowsiness and mood disturbances. The most troublesome possible side effect is involuntary, small, twitchy movements. In self-limited cases of nausea and vomiting such as stomach flus, it is probably safest to retreat to bed and sleep, without using pharmacologic interventions other than over-the-counter nausea and vomiting remedies. When suffering from an acute case of nausea and vomiting, remaining hydrated is important, but the stomach is likely to revolt against more than a tablespoon or two of water at a time until the vomiting has stopped completely. Ginger may have some value in calming the stomach; ginger ale is a good first beverage in recovery. Unlike Charles Darwin, who had more complex, chronic and undiagnosed bouts of vomiting, you will most likely recover and forget how miserable you felt.

Posted by medical plaintalk

Physician turned medical writer.

The Troublesome Appendix

“The modern king has become a vermiform appendix – useless when quiet, when obtrusive in danger of removal”
Austin O’Malley (United Irish leader, 1760-1854)

The vermiform (wormlike) appendix is narrow pouch, approximately a 2-4” long, that hangs off the colon, or large intestine, in the lower right side of the abdomen. Charles Darwin, who popularized evolutionary theory of human development, consigned the appendix to the lowly status of vestigial organ – a body part left over from the process of natural selection, but having no continuing function. Beginning in the 1700s though, doctors recognized the troublesome tendency of the appendix to become inflamed and rupture – an often fatal condition called appendicitis. Long before anesthesia and antibiotics had been invented physicians attempted surgical removal of the organ and results were generally poor.

Fortunately for us, modern surgery makes appendicitis a far less fearsome condition. Recent medical research also suggests that Darwin was wrong and that textbooks may need to be rewritten, striking out the vestigial label. Clinical and research trends are converging, and it is possible that we may soon see more attempts at preserving the inflamed appendix rather than immediately removing it.

Who gets appendicitis?

No one knows why appendices become inflamed. They do so far more often in developed countries with high levels of sanitation than in undeveloped countries where severe diarrhea frequently purges the intestines. They act up more in younger people, below age 30 but no age is immune, and, at least in Western countries, seven out of every hundred people will develop appendicitis at some point in their lives.

What are the symptoms?

Appendicitis usually begins with pain, which is often mild and located near the belly button. Over the next few hours, as inflammation progresses, the pain tends to migrate and settle in the lower right side of the abdomen. Other symptoms may or may not occur and include nausea, vomiting, fever, and poor appetite. Diarrhea or constipation may occur, or there may be no change in bowel habits. As with many illnesses, the most important things to note are changes from normal patterns, and persistence of symptoms despite attempts to make them better. Since appendicitis typically develops over 4-48 hours, abdominal pain that lasts more than 4 hours is reason enough to seek a medical opinion.

Rupture often relieves pain – temporarily

Because the appendix is a blind pouch, its opening into the colon can become obstructed by the swelling that comes with inflammation. When this happens, pressure builds within the appendix and its wall may rupture. Paradoxically, rupture often relieves pain, at least for awhile. But because the colon and appendix house bacteria and rupture spills these “dirty” contents into the normally sterile abdomen, the patient soon becomes desperately ill with a condition called peritonitis. The coronation of King Edward VII of England was delayed by just such a series of events in 1902. His initial symptoms seemed to improve, and he planned to go through with the scheduled ceremony, but when he worsened, his doctors told him that if he continued as planned he would “go as a corpse.” Instead of being crowned, he underwent surgery and an abscess around the appendix was drained. The appendix was not removed because it had decompressed and sealed itself. The lucky monarch survived the surgery and was crowned later.

Diagnosis is not always easy

Appendicitis has proved a vexing condition to diagnose. The clinical history brings the patient to the doctor, who examines the abdomen for tenderness, measures temperature, and draws blood to see if the white blood cell count is elevated. There are many organs in the abdomen, and many possible causes of abdominal pain. No single test proves the presence or absence of appendicitis. Abdominal X-rays and ultrasound tests are sometimes done, but the CT scan has proven best for the diagnosis of appendicitis. But the definitive test is still a direct examination of the appendix at surgery, where removal is done even if the appendix is normal in appearance, as it is in about 10% cases. Since failing to discover and remove an inflamed appendix can result in far greater illness and possibly death, a 10% rate of misdiagnosis is considered very acceptable. Removal of a normal appendix also prevents confusion if future episodes of pain occur.

A role for antibiotics

Since CT scanning has been helpful in showing which appendices have ruptured and absolutely require surgery, some studies have been done to see whether treatment of early, uncomplicated appendicitis with antibiotics alone can be safely accomplished. Four randomized trials in England suggest that this is possible and will reduce the need for appendectomy in over 60% of cases of early appendicitis. Adopting this approach means that all patients with suspected appendicitis require the X-Ray exposure of abdominal CT scanning and that 20 % of patients will have recurrent symptoms within the year. In addition, if antibiotics do not quell the inflammation, the delay in getting to surgery can result in more complications. If the appendix is an unnecessary organ anyway, is it worth the expense and radiation exposure of CT scanning, attendant risks of delaying surgery, and the risk of recurrent appendicitis? Possibly.

Not so vestigial after all?

Until recently it has been assumed that there is no real role for the appendix. People seem to do very well without them. But researchers have always wondered why the appendix contains tissue that produces immune cells. It now appears that the immune cells are there to protect the bacteria that live in peace in the large intestine and play a crucial role in its health. When diarrhea has emptied the colon of its all its contents, the appendix still contains normal bacteria which, researchers think, repopulate the colon and bring it back to a healthy state. It is also possible that the immune cells in the appendix recognize new proteins that come in through the intestines, and teach the body’s immune system what to tolerate. In the case of the appendix, vestigial may only mean that we have not previously understood its function and if it can be preserved perhaps it should be.

Posted by medical plaintalk

Physician turned medical writer.

From Heartburn to GERD

At my Grandmother’s house, there was little for children to do after dinner but play games and eavesdrop on the grownups who sat around the table for hours after the end of the meal. Back then, the adults seldom talked about “diseases,” but they did seem to think that bodies, like cars, had parts that could be relied upon to malfunction with age and abuse. Dining room table wisdom held that “heartburn” was the expected result of overindulgence in rich food, alcohol, coffee and cigarettes, and that Alka Seltzer was the best remedy. I can still recall the fizz of the tablets dissolving in water.

Renaming a symptom

Heartburn is a vivid word image for the most common gastric complaint – distressing, burning pain just beneath the breastbone. With time, technology, and advertising, heartburn has been replaced by the anatomically correct term gastro-esophageal reflux (GER), which accurately describes the source of the symptom: acid splashing up into the esophagus from the stomach. However, renaming a symptom, heartburn, with its cause, reflux, does not make it a disease, no matter how many TV commercials advertising drugs for GERD (gastro-esophageal reflux disease) say otherwise. Diseases are sometimes associated with GER, but they are diseases that promote reflux, diseases treated with medications that promote reflux, or diseases that result from stomach acid eating away the sensitive lining of the esophagus.

How the esophagus works

Stomach acid is potent stuff, necessary to break down food and to kill off the bacteria that come along with it. Acid also helps with the absorption of vital substances like calcium, iron and Vitamin B12. The stomach lining produces acid and is remarkably resistant to its corrosive effects, unlike the lining of the esophagus above. The job of the esophagus, a muscular tube, is to assist gravity in getting food from the mouth to the stomach via a series of coordinated contractions. In its lowest portion, the esophageal muscle works like a valve. It opens to let food into the stomach and closes to hold it there as digestion begins. The esophagus can also reverse its normal action, opening the valve and emptying the stomach in a hurry, propelling its contents back out the mouth. This very unpleasant action, called vomiting, is perceived mainly as a squeezing, muscular sensation rather than a burning pain, because the exposure of the esophagus to the upward rushing acid is short-lived.

Reflux is backwards, upward flow of stomach contents to the esophagus

Reflux is a more leisurely affair. The muscular valve at the junction of the esophagus and the stomach is not a tight one, and it is subject to the effects of foods and drugs, and diseases that limit its responsiveness (see sidebar). Reflux is more common in people with hiatal hernias – upward slippage of the stomach top into the chest through a weak spot in the diaphragm (muscle between the abdomen and chest). With a stomach full of actively digesting food, reflux can occur simply with lying down or bending over, positions that limit gravity’s help in holding stomach contents down. And held down they must be, for at least awhile, because the stomach is a reservoir where the initial breakdown of food occurs.

The abdomen is a crowded space

The reservoir sits like a pool behind a dam, awaiting opening of the pyloric valve between the stomach and small intestine. The stomach shares close quarters with the liver, spleen, pancreas, small intestine and colon – and with fat tucked around all these organs. The more fat -and the tighter belts and pants are – the less the space available. The upper valve, between the esophagus and the stomach, is the weak link when pressure rises; it gives way while the pyloric valve holds fast, and stomach contents flow into the esophagus. The upper valve also yields in pure overeating (e.g. hot-dog eating contests), when the stomach fills faster than digestion can proceed.

Acid in the wrong location causes trouble

Chronic exposure to stomach acid inflames the lining of the esophagus, and then diseases appear – shallow erosions, deeper ulcers, and scars that interfere with swallowing. Risk of esophageal cancer rises. Acid reflux can go as high as the mouth and erode the enamel of the teeth, add to gum disease, and produce mysterious sore throats and hoarseness. Lung problems and asthma are more frequent in people with chronic reflux.

Reducing stomach acid works, but may cause other problems

Heartburn sometimes requires medical evaluation (see sidebar), but is often responsive to simple antacids like Maalox that temporarily lower stomach acidity. Powerful, safe and effective drugs called proton-pump inhibitors (Prilosec, Nexium, etc.) block the last step of acid production in the stomach. Reflux goes on, but stomach contents are no longer corrosive. But no drugs are free of unintended consequences. Without acid, food digestion is slower. Risks of pneumonia and gastrointestinal infections in long-term users rise, suggesting that in an acid-free environment, bacteria survive in the gut and spill upward into the respiratory tract. Some researchers believe that proton-pump inhibitors also turn acid production off in osteoclasts, cells that build bone, resulting in an increased rate of hip fractures in long-term users. One very worrisome statistic in the age of altering stomach acidity is a rise in rates of esophageal cancer, though the cause of the rise is not fully understood. Lack of stomach acid, however, has long been known to be a risk factor for the development of stomach cancer.

New generations have replaced my grandparents and TV and social media outdraw after-dinner talk, but heartburn, though renamed, is still just a symptom of a mechanical problem – acid reflux. Blunting the effects of acid with over-the-counter or prescription drugs is a temporary solution that does nothing for the inciting problem – the reflux. Weight loss, smoking cessation, elevation of the head of the bed (on 6-9” blocks), avoidance of large meals and offending foods and drugs, and allowing several hours to elapse between meals and bedtime are the keys to taming reflux and keeping GER from becoming GERD.
______________________________________________________________________________

Common Factors in Patients with Heartburn:
• Obesity, the most common factor.
• Diabetes (delays stomach emptying)
• Pregnancy (space shortage + hormone effects)
• Medications: antihistamines, antidepressants, narcotics, calcium channel blockers for high blood pressure and heart disease, progesterone, anticholinergics (bladder control drugs), some sedatives and tranquilizers
• Foods: fried foods, chocolate, alcohol, caffeine and others.
• Smoking(stimulates stomach acid)
• Asthma and anti-asthmatic medications
• Hiatal hernia
• Stomach outlet obstruction by ulcer or tumor

Seek a Medical Evaluation for Heartburn that:
• Wakes you up at night
• Happens regularly, more than once a week
• Is unresponsive to simple antacids like Maalox or Rolaids
• Recurs promptly after antacids or drugs wear off
• Has associated symptoms: nausea, vomiting, abdominal pain, difficulty swallowing, increasing abdominal girth, or blood in the stool

Posted by medical plaintalk

Physician turned medical writer.

Human Foie Gras: The New Plague of Fatty Livers

“M. Apicius [Marcus Gavius Apicius, a first century AD Roman gourmet] made the discovery, that we may employ the same artificial method of increasing the size of the liver of the sow, as of that of the goose; it consists in cramming them with dried figs, and when they are fat enough, they are drenched with wine mixed with honey, and immediately killed.”

— Pliny the Elder, The Natural History, Book VIII, Chapter 77

For thousands of years, humans have created a tasty delicacy called foie gras from the livers of certain animals. Foie gras, which means “fatty liver” in French, is made by force-feeding animals, usually geese or ducks, a mash consisting of fat-soaked grain. Fatty livers are most easily induced in animals that regularly store extra fat for energy before migration. Humans also store energy easily, and modern lifestyles, including diets heavy in fat-soaked carbohydrates, have inadvertently created an epidemic of fatty livers in people. Some researchers estimate that the problem now affects one-third of the US population.

Alcoholism was the main cause of fatty livers in the past

Doctors have long been familiar with fatty livers in alcoholics, in whom a combination of the toxicity of alcohol and dietary deficiencies converts liver cells into fat-laden bubbles. This condition is known as alcoholic steatosis and is the first step along a road that can lead to cirrhosis and liver failure. Alcoholic steatosis can be reversed if the patient stops drinking. If not, it can become progressively worse, leading to inflammation of the liver called alcoholic steatohepatitis. Ultimately this inflammatory degeneration can lead to a scarred and shrunken liver (cirrhosis) and to liver failure.

Non-alcoholic fatty liver becomes a new diagnosis

By 1980, the appearance of fatty livers and the kinds of problems that are associated with them in nondrinkers forced doctors to devise a new diagnosis—nonalcoholic fatty liver disease (NAFLD). As in alcohol fueled liver disease, NAFLD can also lead to inflammation, a condition called nonalcoholic steatohepatitis (NASH), and to cirrhosis and liver failure in some patients. Progression from NAFLD to NASH seems to require the additional effects of viral hepatitis or of toxic substances, like certain medications, both of which also play a role in some alcoholic liver disease progression.
…..and becomes a serious problem

Since the 1980s, the prevalence of NAFLD has been climbing in parallel with the numbers of people affected by the metabolic problems of obesity, insulin resistance, and type 2 diabetes. Like these problems, NAFLD is now affecting younger people, even children. By 2006, NAFLD and NASH were the leading reasons patients were referred to liver specialists. They were also the leading cause behind diagnoses that led to 4 to 10 percent of liver transplants. While it is very difficult to make accurate estimates about the overall prevalence of NAFLD, by now it is clear that it is very common in people who have abdominal obesity, insulin resistance, and type 2 diabetes—perhaps affecting as many as 75 percent of such individuals.
Why fat in the liver is bad for you

In a state of good health, the liver functions silently. Tucked up under the ribs on the right side of the abdomen, it is the size and shape of a deflated football and is the second largest organ in the body (the skin is the largest). The liver coordinates energy storage and regulation and makes proteins and cholesterol necessary to the health of all cells in the body. It also makes and secretes bile to absorb fats from the intestine and filters toxins from the blood to destroy them or ship them out with bile. The liver also stores vitamins and regulates the blood’s ability to clot in a fine-tuned range.
If necessary, the liver stores fat in its cells. Generally, this is a temporary state, and the fats are transported back to the body for use as an energy source or for storage in fat tissue. Obesity, insulin resistance, and diabetes, however, work together to keep fat in liver cells. Despite the stored fat the liver can continue to function well, producing no symptoms, unless other factors produce inflammation and scarring. NALFD is often discovered incidentally, because of abnormal liver function blood tests from inflammation, or a scan of the abdomen for other problems.

Fat plus inflammation can trigger liver failure

When fat accumulation in the liver is accompanied by inflammation or occurs in someone who already has a scarred liver from other problems, like heavy alcohol use or hepatitis, liver failure and cirrhosis ( shrinkage from scarring) may follow. It is estimated that 20 percent of those with NAFLD have inflammatory changes in their livers, moving them from a diagnosis of NAFLD to a diagnosis of steatohepatitis, or NASH, which increases their risk of developing liver failure and cirrhosis. Unfortunately, there are no easy tests to determine the presence or absence of inflammation in the liver, and patients may have no symptoms. Liver function tests may remain normal, and although liver biopsy provides a definite diagnosis, it carries some risks and thus is not a suitable screening test for patients who have no symptoms or findings.
Symptoms of liver disease

Symptoms of liver disease can be very vague until liver scarring and failure are well advanced. Fatigue, vague abdominal pain, and digestive complaints, as well as enlargement of the liver are early indicators. Jaundice (yellowing of the skin and eyes), fluid in the abdomen, poor clotting, and bleeding from the intestinal tract are late symptoms. Most people who have fatty livers will not go on to this degree of failure, just as most alcoholics do not, but there is no easy way to know who will and who won’t.

What can be done?

In the presence of NAFLD it is important to avoid liver toxins such as alcohol and many drugs. With gradual weight loss, it is possible to reverse the accumulation of fat in the liver and to reduce liver inflammation, particularly if the weight loss program includes significant exercise to improve insulin sensitivity. Even in transplanted livers, NAFLD can recur as long as obesity, diabetes, and insulin resistance remain. Obesity surgery appears to reverse some of the liver problems in affected people and may yield new insights into the mechanism of insulin resistance. While researchers are striving to develop drugs that improve insulin resistance and alter fat transport and storage mechanisms, prevention, as always, is the best advice. This will require education, patience, self-discipline, and hard work, and it is particularly important for young people. While foie gras from a goose is tasty, its development in humans is undesirable.

Posted by medical plaintalk

Physician turned medical writer.

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