Physiologically, blood and bile intimately tie liver and heart health together:
· Blood – The liver receives 25 percent of the blood pumped by the heart and filters over two quarts of blood a minute. To ensure optimal circulation and filtration, the heart pumps blood while the liver cleans it.
· Bile – To dissolve fat in the blood vessels, the liver produces up to two cups of bile a day. Without bile, our arteries would be as hard as rocks without any hope of circulating blood throughout the heart, liver or remainder of the body.
Atherosclerosis comes from the Greek words athero (meaning gruel or paste) and sclerosis (hardness). It describes the process in which deposits of fatty substances, cholesterol, cellular waste products, calcium and other substances build up in the inner lining of an artery. Called plaque, this buildup can grow large enough to significantly reduce the blood’s flow through an artery. In addition to the danger of breaking off and throwing a blood clot into circulation, this restriction of blood flow can cause high blood pressure, heart disease and can even contribute to some liver diseases.
Study Confirming the Link
Although the heart and liver share in the responsibility of keeping us healthy, scientists are now discovering similarities in these organs during illness. In the June 2007 Journal of Hepatology, Italian researchers reported on their trial indicating early signs of atherosclerosis are linked with several types of chronic liver disease. By studying the thickness of the carotid arteries in the necks of over 200 patients with one of three forms of chronic liver disease – chronic Hepatitis B, chronic Hepatitis C and non-alcoholic steatohepatitis (a kind of fatty liver disease) – a relationship between the two was discovered.
An increase in the thickness of carotid neck arteries is considered by experts to be an indicator of early atherosclerosis. Found to be independent of other factors contributing to atherosclerosis, the researchers realized the following about carotid artery thickness:
· It was lowest in healthy controls with an average value of 0.84.
· It was elevated in people with Hepatitis B with an average value of 0.97.
· It was elevated in people with Hepatitis C with an average of 1.09.
· It was highest in people with non-alcoholic steatohepatitis with an average value of 1.23.
The authors concluded that Hepatitis B, Hepatitis C and non-alcoholic steatohepatitis are strongly associated with early atherosclerosis. This study clearly demonstrates the interconnectivity between heart and liver health. Based on the Italian research results, we can predict that lowering the amount of plaque accumulation in the arteries may lower susceptibility to several liver diseases.
There are many approaches to keeping your body healthy and resistant to the increasingly common occurrences of heart and liver disease. By understanding that the health of our arteries impacts more than just blood pressure, we realize how important it is to keep our blood circulation system at an optimal level of operation.
Researchers have identified molecular changes that occur in the liver that may explain why people with liver disease have abnormal cholesterol levels. In conjunction with liver panel tests, these changes may predict the severity of a patient’s condition.
In the study, researchers from Virginia Commonwealth University showed that more seriously diseased livers produce more cholesterol than healthy organs, and also lack a receptor that instructs cells to remove cholesterol from the blood. These findings explain why people with liver disease frequently have unhealthy cholesterol levels.
This link to high cholesterol levels helps explain why people with liver disease often experience cardiovascular complications.
Additionally, the research showed that the presence of these abnormalities predicted the progression of patients’ conditions. Individuals were more likely to have severe cases when these abnormalities were present than when they weren’t.
This new understanding of factors that influence the development of serious liver problems could help doctors more effectively diagnose and treatment the condition.Given the skyrocketing rates of non-alcoholic fatty liver disease, which are largely a result of the obesity epidemic, this could come as a major benefit to the healthcare system.
People with non-alcoholic fatty liver disease have an accumulation of fat in the liver that is not caused by drinking alcohol. The fat can cause inflammation and scarring in the liver and progress to life-threatening illness.
The new findings “suggest that patients with coronary artery disease should be screened for liver disease, and likewise [patients with non-alcoholic fatty liver disease] should be evaluated for coronary artery disease,” said Dr. Rajiv Chhabra, a gastroenterologist at Saint Luke’s Health System’s Liver Disease Management Center in Kansas City, Mo.
Researchers looked at upper-abdominal CT scans of nearly 400 patients and found that those with non-alcoholic fatty liver disease were more likely to have coronary artery disease. The effect of non-alcoholic fatty liver disease was stronger than other more traditional risk factors for heart disease, such as smoking, high blood pressure, diabetes, high cholesterol, metabolic syndrome and being male.
Chhabra conducted the study with a colleague, Dr. John Helzberg. Their findings were presented at the American Gastroenterological Association’s recent annual meeting.
Current treatments for non-alcoholic fatty liver disease include diet changes, exercise and increased monitoring.
Non-alcoholic fatty liver disease is the most common liver disorder in Western countries, and is of growing concern among doctors due to rising rates of obesity and diabetes.
“If current trends continue, the prevalence of [non-alcoholic fatty liver disease] is expected to increase to 40 percent of the population by 2020,” Helzberg said in a Saint Luke’s Health System news release.
Data and conclusions presented at meetings should be considered preliminary until published in a peer-reviewed medical journal.
— Robert Preidt
Fatty liver disease and your heart
About one in three adults has nonalcoholic fatty liver disease, an often-silent condition closely linked to heart disease.
Image: decade3d/ iStock
The largest organ inside your body, your liver performs hundreds of vital functions. It converts food into fuel, processes cholesterol, clears harmful toxins from the blood, and makes proteins that help your blood clot, to name a few. But an alarming number of Americans have a potentially dangerous accumulation of fat inside their livers. Known as nonalcoholic fatty liver disease (NAFLD), this condition is a leading cause of chronic liver disease in the United States—and an increasingly recognized contributor to heart disease.
“NAFLD increases the risk of heart disease independent of other traditional risk factors such as high blood pressure and cholesterol,” says Dr. Kathleen Corey, director of the Fatty Liver Disease Clinic at Massachusetts General Hospital. Among people with NAFLD, heart disease is the top killer, accounting for more than 25% of deaths.
The obesity connection
Prior to 1980, fatty liver disease was rarely diagnosed except in people who drank large amounts of alcohol. However, scientists discovered that excess body fat and diabetes can also cause fatty liver disease, even in people who drink very little. As Americans have gotten fatter, so have their livers. Up to one-third of American adults have NAFLD, and nearly all (90%) people with severe obesity who are candidates for weight-loss surgery have the disease. Half of people with diabetes have NAFLD.
Under the microscope, the fat buildup inside the liver looks just like alcohol-induced fatty liver disease. But NAFLD affects people who consume little or no alcohol. They also often have high cholesterol and triglyceride levels. But not everyone with obesity, diabetes, and abnormal lipids has the problem. And some people with fatty livers have none of these risk factors, suggesting that genes and other factors play a role.
Diagnosing the problem
The early stage of NAFLD is an accumulation of fat in liver cells called steatosis (steato means fat). It has no symptoms; it’s usually discovered when a blood test reveals slightly elevated liver enzymes or by chance during an imaging test done for another reason. A doctor may then order additional tests to rule out other possible liver problems, such as hepatitis C, which is caused by a virus. An ultrasound of the liver can reveal signs of steatosis and a change in the texture of the liver. But a definitive diagnosis requires a liver biopsy, which involves inserting a needle into the right side of the abdomen and extracting a small piece of liver tissue that can be examined under a microscope. Liver biopsies are an invasive procedure, so they aren’t entirely free of risk or complications. But they’re also fairly routine these days and can be done on an outpatient basis. Whether a doctor will order a biopsy to nail down a diagnosis depends on many factors, including whether the person is obese or has diabetes or shows other signs of liver trouble.
Over time, as many as 40% of people with NAFLD will develop a more serious form of the condition, called nonalcoholic steatohepatitis (NASH). In this condition, the fat within the liver causes the liver to become inflamed. Most patients with NASH have no symptoms, although some report fatigue and discomfort in the upper right of the abdomen. In a subset of those with NASH, fibrosis or scarring of the liver will develop. Severe scarring, known as cirrhosis, increases the risk of liver cancer and end-stage liver disease. Currently, along with hepatitis C and alcohol-related liver damage, cirrhosis due to NASH is one of the leading reasons for a liver transplant in the United States. With the sharp rise in NAFLD cases, experts expect that fatty liver complications will be the leading cause within a decade.
The heart disease link
Growing evidence suggests there’s a strong link between NAFLD and dangerous plaque inside the heart’s arteries. The inflammatory compounds and other substances pumped out by a fat-afflicted liver might promote the atherosclerotic process that damages the insides of arteries and makes blood more likely to clot. This combination may lead to a heart attack or a stroke.
Most people who’ve had a heart attack or face a high risk of one take cholesterol-lowering statins. Liver damage is a very uncommon side effect with statins. But these drugs are still safe for people with NASH and, according to some research, may even help improve the condition.
Weight loss and other treatments
Treating NAFLD focuses on reducing or preventing further fatty buildup in the liver, mainly by addressing the underlying causes: obesity, diabetes, and elevated blood lipids.
Even losing just a little weight can make a difference. A recent study in JAMA Internal Medicine found that people who participated in a moderate to vigorous exercise program and lost just 3% to 6% of their body weight reduced their relative liver fat levels by 35% to 40%. “Even if you don’t lose weight, exercise can reduce fat in the liver,” says Dr. Corey. “I advise my patients to do at least 90 minutes of aerobic exercise weekly.”
As for diet, the recommendation is similar to what doctors advise for preventing heart disease: Eat plenty of vegetables, fruits, and whole grains, and modest amounts of lean protein, like fish and chicken. Limit saturated fats (found in meat, dairy, and eggs), refined carbohydrates (anything made with white flour), and added sugar, especially from sodas and other sweetened beverages. People with NAFLD should limit the amount of alcohol they drink, and those with NASH should avoid it completely. Treating conditions such as diabetes and high blood pressure also helps.