Fatty Liver And Diabetes
Diabetes mellitus, or type 2 diabetes, usually develops in men or women over 40 years of age although it is now being seen in overweight children.It is a condition that occurs when your body cannot regulate the amount of glucose in your blood. Glucose is a sugar produced when you digest your food. It is also produced and stored by your liver.
Blood glucose levels are regulated by insulin, a hormone produced by your pancreas. Problems start when your body either does not produce enough insulin (as in type I diabetes) or if the muscle, liver and fat cells do not respond normally to insulin. This latter situation is called insulin resistance and leads to a high level of glucose in the blood (hyperglycemia), which is harmful. Insulin also helps your liver to metabolise (process) fats and to release them into the blood. While fats are a necessary source of energy, too much fat in the blood is bad for you. It is now thought that insulin resistance interferes with this process and causes an accumulation of triglyceride fats in the liver cells.
Having too much triglyceride and another lipid that may be better known, cholesterol, in the bloodstream is known as hyperlipidaemia. Cholesterol is also taken in from our diet and produced by the liver. High levels of a so-called ‘bad’ cholesterol known as LDL cholesterol (low density lipoprotein cholesterol) can lead to heart disease. Counter to this, there is a ‘good’ cholesterol (HDL, high density lipoprotein cholesterol) that removes the LDL cholesterol and gets rid of it through the liver. Thus, having a ratio of high LDL to low HDL in the blood is not desirable.
Fatty Liver And Obesity
Not everyone who is overweight or obese will develop a fatty liver and not everyone who has a fatty liver is overweight. However, the majority of people with non alcoholic fatty liver disease are overweight.The terms ‘overweight’ and ‘obese’ describe two different categories above what is considered a healthy body size.
As tall people are generally heavier than short people, a person’s weight is not particularly useful in assessing their risk of fatty liver disease or metabolic syndrome. The ratio between height and weight, known as the body mass index (BMI), is a more useful measurement. Calculating body mass index (BMI) is now the accepted method for working out whether you are normal, overweight or obese.
A healthy BMI is regarded as being between 18.5 and 25kg/m². A BMI between 25 and 30kg/m² is defined as overweight. If your BMI is over 30kg/m² then you qualify as obese.Obesity can also be defined according to the distribution of fat on your body. Fat that gathers on your hips can make you look pear-shaped (known as ‘gynoid’) while having fat around your abdomen will give you an apple-shaped appearance (‘android’). It is known, for example, that obese people with insulin resistance most commonly have abdominal fat.
In men, abdominal obesity is defined in a waist circumference greater than 40 inches or 102 cm. In women, this is a waist circumference greater than 35 inches or 88 cm. However, the normal range for BMI and waist circumference is not based on how people look. It is based on their likely risk of developing health problems according to how much they are overweight or obese (BMI-related morbidity).
There are more overweight and obese people in the UK than any other country in Europe but not as many as there are in the US. For the majority, the root causes of becoming overweight or obese are down to:
*eating too much (and too much fatty food in particular)
* drinking too much alcohol
* not doing enough exercise.
In England alone, more than one in five people (20%) are now defined as obese. A similar ratio is now emerging among boys and girls aged between 2 and 15 years. As more and more people lead inactive lives and carry extra weight around with them, so the number of cases of fatty liver, in particular NASH, is rising.
Fatty Liver–NAFLD and NASH
Non alcoholic fatty liver disease (NAFLD)
NAFLD is actually a term for a wide range of conditions characterised by the build-up of fat in the liver cells of people who do not drink alcohol excessively.At one end of this range is simple fatty liver, or steatosis. This is the stage where fat is first detected in the liver cells and is generally regarded as benign (harmless).Non alcoholic steatohepatitis (NASH) is a significant development in NAFLD. This is a more aggressive condition that may cause scarring to the liver and can progress to cirrhosis. Cirrhosis causes irreversible damage to the liver and is the most severe stage in NAFLD.
In simple terms it may be easiest to think of NAFLD as having the following stages:
1. fatty liver
2. a form of hepatitis known as non alcoholicsteatohepatitis (NASH)
3. fibrosis
4. cirrhosis
NAFLD can affect a wide range of people. In general, the older you are the more chance there is that you may have the condition. NAFLD is typically seen in people aged around 50 and more commonly in men than women. It is hard to be precise about how many people have some form of NAFLD but it is estimated that one in five people (20%) in the UK have the earliest stages of NALFD, or steatosis.
People most at risk of NAFLD are those who:
*are obese
* have insulin resistance, associated with diabetes
* have hypertension (high blood pressure)
* have hyperlipidaemia (too much cholesterol and triglyceride in their blood)
* are taking certain drugs prescribed for other conditions.
* have been malnourished, starved or given food intravenously.
Non alcoholic steatohepatitis (NASH)
Non alcoholic steatohepatitis (NASH) is a more advanced form of NAFLD in which there is inflammation in and around the fatty liver cells. This may cause swelling of your liver and discomfort or pain around it. If you place your right hand over the lower right hand side of your ribs it will cover the area of your liver.With intense, on-going inflammation a build up of scar tissue may form in your liver. This process is known as fibrosis, and can lead to cirrhosis. NASH is now considered to be one of the main causes of cirrhosis.
Cirrhosis is usually the result of long-term,continuous damage to the liver. This is where irregular bumps, known as nodules, replace the smooth liver tissue and the liver becomes harder.The effect of this, together with continued scarring from fibrosis, means that the liver will run out of healthy cells to support normal functions. This can lead to complete liver failure.
NASH should be distinguished from acute fatty liver disease, which may occur during pregnancy or with certain drugs or toxins (poisons). This condition is very rare and may lead rapidly to liver failure.
What Is Fatty Liver Disease?
There should be little or no fat in a healthy liver. For most people, carrying a little fat in the liver causes no problems. Fatty liver is the name given to a condition in which you have too much fat in your liver. This is caused by the build-up of fats called triglycerides. These are the most common fats in our bodies. They belong to a group of fatty, waxy substances called lipids that your body needs for energy and cell growth.We get triglycerides from our diet and they are also made in the liver. The liver processes triglycerides and controls their release. It combines them with special proteins to form tiny spheres called lipoproteins which it sends into the bloodstream to circulate among the cells of your body. When this process is interrupted and the flow of triglycerides to the liver is increased, their release, or ‘secretion’, from the liver is slowed down. This is what leads to the build-up of fat in your liver cells.
Until recently fatty liver was considered rare and relatively harmless. It was not thought to progress to chronic (long-term) or serious liver disease.Today it is one of the most common forms of liver disease and is known to lead to advanced conditions. In the majority of cases fatty liver does not cause any harm but for an increasing number of people the effects of having fat in their liver over a long period may lead to inflammation causing swelling and tenderness (hepatitis) and then to scarring (fibrosis).
In some people, this can progress to a condition known as cirrhosis, which can be life-threatening. Clinical knowledge about fatty liver is still coming together but common risk factors are obesity, diabetes and drinking too much alcohol. While the relationship between these factors is not fully known, they can be considered triggers for progression to other types of liver disease. If alcohol is the cause of fatty liver it is called alcoholic liver disease (ALD). This leaflet is for people worried about fatty liver that is not caused by alcohol. This is known as non alcoholic fatty liver disease (NAFLD).
How Liver Disease Develops
Liver damage develops over time. Any inflammation of the liver is known as hepatitis, whether its cause is viral or not. A sudden inflammation of the liver is known as acute hepatitis. Where inflammation of the liver lasts longer than six months the condition is known as chronic hepatitis.Fibrosis is where scar tissue is formed in the inflamed liver. Fibrosis can take a variable time to develop.
Although scar tissue is present the liver keeps on functioning quite well. Treating the cause of the inflammation may prevent the formation of further liver damage and may reverse some or all of the scarring. Cirrhosis is where inflammation and fibrosis has spread throughout the liver and disrupts the shape and function of the liver. With cirrhosis, the scarring is more widespread and can show up on an ultrasound scan. Even at this stage, people can have no signs or symptoms of liver disease. Where the working capacity of liver cells has been badly impaired and they are unable to repair or renew the liver, permanent damage occurs.
This permanent cell damage can lead to liver failure or liver cancer. All the chemicals and waste products that the liver has to deal with build up in the body. The liver is now so damaged that the whole body becomes poisoned by the waste products and this stage is known as end stage liver disease. In the final stages of liver disease the building up of waste products affects many organs. This is known as multiple organ failure. Where many organs are affected, death is likely to follow.
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