Happy St. Paddy’s Day, everyone. The Ides of March have passed, and spring is around the corner. On March 17th, everyone is Irish, and wisdom and wit are in the air:
May the roof above us never fall in, and may we friends beneath it never fall out.
You’ll never plough a field by turning it over in your mind.
A good laugh and a long sleep are the two best cures.
Here, here! I’ll drink to that. . . . But only in moderation.
I’ve been reading a lot these days about liver disease, but not of the alcoholic variety. It seems nonalcoholic fatty liver disease, abbreviated NAFLD, is on the rise in the United States, especially among children.
According to the Mayo Clinic, NAFLD is the most common form of chronic liver disease in this country, affecting between 80 and 100 million people, 7 million of whom are children. In the past 20 to 30 years, the rate of NAFLD among U.S. children has reportedly tripled, so that about 10 percent now have it.
NAFLD goes hand-in-hand with the U.S. obesity crisis. The human liver is supposed to contain some fat; but if more than five to 10 percent of your liver’s weight consists of fat (lipids), you likely have NAFLD. The Mayo Clinic says NAFLD “is an umbrella term for a range of liver conditions affecting people who drink little to no alcohol.” The medical term for a fatty liver is steatosis. See http://www.mayoclinic.org/diseases-conditions/nonalcoholic-fatty-liver-disease/home/ovc-20211638.
Most children and adults with NAFLD are asymptomatic, in which case the condition is only detected when tests done for other reasons indicate a liver problem. This typically happens when blood tests reveal elevated liver enzymes, and physicians explore the cause. When symptoms do present, they are usually persistent fatigue and pain in the upper right abdomen, below the diaphragm, where the liver is located. Because the liver takes up some space in the left upper abdomen, too, pain may occur there as well. The fatty liver is enlarged.
NAFLD can be reversed if it hasn’t reached an advanced stage. Lifestyle changes—better nutrition, increased exercise—can mitigate and reverse its effects. Gradual weight loss—not rapid weight loss—is crucial. (See my last blog about a heart-healthy diet.)
In a severe, advanced stage, NAFLD is known as nonalcoholic steatohepatitis, which is characterized by liver inflammation that can progress to scarring (cirrhosis) and irreversible damage, just like the damage caused by heavy alcohol use. Nonalcoholic steatohepatitis, abbreviated as NASH, can cause liver failure.
The symptoms of advanced NAFLD include abdominal swelling (known as ascites); enlarged blood vessels just beneath the skin’s surface; enlarged spleen; enlarged breasts in men; red palms; and jaundice (yellowed skin and eyes), in addition to fatigue and abdominal pain.
According to the Mayo Clinic, it is not known why some people store more fat in their livers than other people do, or why some fatty livers develop inflammation that progresses to cirrhosis and others do not. There definitely are links, however, between NAFLD and NASH and:
2) insulin resistance (when body cells don’t take up glucose in response to insulin)
3) high blood sugar (or actual type 2 diabetes)
4) high levels of fats in the blood, especially triglycerides
These conditions appear to promote fat deposits. They are known risk factors for NAFLD and NASH, along with sleep apnea, high LDL cholesterol, hypothyroidism, metabolic syndrome (which is a cluster of abnormalities that are linked to heart disease), and others listed by the Mayo Clinic on its website: See http://www.mayoclinic.org/diseases-conditions/nonalcoholic-fatty-liver-disease/symptoms-causes/dxc-20211639.
While NAFLD occurs in every age group, it is found predominantly in people in their 40s and 50s. Prevalence also appears to vary according to ethnicity, with higher rates in those of Asian and Latin descent and lower rates in those of African descent. The explanation for these differences is not clear. See “Ethnicity and Nonalcoholic Fatty Liver Disease,” at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278533/.
In the United States, Hispanics, predominantly of Mexican descent, are at particular risk for NAFLD and tend to have a more aggressive disease course. Men also have much higher rates of NAFLD and NASH than women do, perhaps because of their increased tendency to store fat in their abdomens. See “Gender and Racial Differences in Nonalcoholic Fatty Liver Disease” at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033285/.
Mayo says 20 percent of people with NASH will progress to cirrhosis (late-stage scarring), which is the liver’s response to inflammation-induced injury. If the liver cannot halt the inflammation and the cirrhosis continues, it can lead to liver cancer and end-stage failure that would necessitate a liver transplant. The idea of children with fatty livers having transplants is a sad one, indeed.
THE LIVER: GRAND CENTRAL STATION
I have long been impressed by the liver, a 3-pound organ that acts as a metabolic factory, performing hundreds of essential functions. It’s a marvel, and, yet, I think it’s not well understood by most people outside of medicine, who tend to associate it with alcohol, cirrhosis, and, perhaps, hepatitis. In other words, we only think about our livers when they’re diseased.
What does the liver do? According to an overview by the National Library of Medicine, it converts the nutrients in our diets into substances that our bodies can use, stores these substances, and supplies our cells with these substances when they’re needed. It also takes up toxic substances and either converts them into harmless substances or makes sure that these substances are released from our bodies. See https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072577/.
A physician on everydayhealth.com refers to the liver as Grand Central Station, a metaphor that I find most apt. http://www.everydayhealth.com/news/facts-about-your-liver/ The following information about this station is excerpted principally from the NLM’s overview:
The liver has two lobes, which are separated by a band of connective tissue that anchors it to the abdominal cavity. The gallbladder, which stores the bile that the liver produces for digestion, is located in a small hollow on the underside of the larger right-side lobe. Many canals carrying blood and bile run between the cells of the liver’s tissue.
The liver has its own circulatory system, separate from the rest of the body. It receives oxygenated blood from the hepatic arteries—as part of the body’s systemic circulation— but it gets 75 percent of its blood from veins in its own system. This is so it can function as a filtration center.
Deoxygenated blood coming from the digestive organs flows through the portal vein to the liver, carrying nutrients, medication, and toxic substances. The liver processes, stores, alters, detoxifies, and passes these substances back into the blood through hepatic veins that drain into the inferior vena cava (which heads to the heart), or releases them in the bowel to be eliminated. This is how the liver can remove alcohol from the blood and get rid of the byproducts of medications that it breaks down.
With the help of vitamin K, the liver also produces proteins that are important in the formation of blood clots. It further helps to break down old or damaged blood cells.
In fat metabolism, the liver cells break down fats and produce energy. These cells also produce 800 to 1000 ml of bile each day, which they collect in small ducts and then pass on to ducts that carry the bile to the duodenum of the small intestine, where it breaks down and absorbs fats.
The liver plays an important role in the metabolism of carbohydrates and proteins, as well. With carbohydrates, it helps to ensure that the level of sugar (glucose) in your blood stays constant. It removes excess sugar from blood supplied by the portal vein and stores it as glycogen. If your blood-sugar level is too low, the liver will break down glycogen and release sugar into the blood. The liver also stores vitamins and minerals and releases them into the blood when they are needed.
Bottom line: If you take care of your liver, it will take care of you.
Happy St. Patrick’s Day, all! Go easy on the green beer, Guinness cake, and soda bread, but help yourself to the cabbage. And . . .
May your thoughts be as glad as the shamrocks. May your heart be as light as a song. May each day bring you bright, happy hours that stay with you all the year long.