CONDITIONS & DISORDERS
NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD): NUTRITION AND LIFESTYLE ADVICE Dr Laura Wyness Registered Nutritionist Laura is a Nutrition Consultant providing research and communication services to a variety of sectors, including charities, commercial companies and local authorities. www. laurawyness.com
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Until recently, NAFLD was considered to be quite rare and harmless. For most people, a fatty liver can remain free of inflammation and asymptomatic. However, there seems to be an increasing number of people with NAFLD due to the rising obesity figures. Individuals who have had a fatty liver for some time are more likely to develop inflammation causing scarring (or fibrosis). In these people, this can progress to potentially life-threatening liver cirrhosis. So, how prevalent is NAFLD? Who is at risk? What diet and lifestyle advice is appropriate? WHAT DOES THE LIVER DO?
The liver is involved in around 500 different reactions in the body. These include filtering and cleaning the blood; fighting infections; producing bile which helps digest fats; storing glycogen and some vitamins and minerals; producing and maintaining the balance of hormones, enzymes and proteins; and getting rid of waste substances from the body. It has the unique ability to repair itself, although it can sometimes be damaged beyond repair. WHAT IS FATTY LIVER?
Fatty liver occurs when too much fat builds up in liver cells. Although it is normal for liver cells to contain a small amount of fat, more than about 5% fat is considered too much. Liver disease is often associated with drinking too much alcohol. Excessive alcohol can result in a build-up of fat in the liver. However, fatty liver in people who drink within the alcohol guidelines is known as nonalcoholic fatty liver disease (NAFLD). This is a disease that is quietly becoming more prevalent and poses an increasing threat to public health. It is estimated that NAFLD affects 25% of people globally.1 The UK NICE
guidelines state that about two to three people in every 10 have NAFLD.2 Prevalence has doubled over the past 20 years due to the rise in obesity levels, mainly as a result of sedentary lifestyle and poor diet.3,4 NAFLD is now the commonest cause of abnormal liver function test results in the UK and the commonest cause of liver disease in western countries.3 NAFLD develops in four stages (see Table 1) with the first being simple fatty liver or steatosis. Too much fat in lever cells is caused by an accumulation of triglycerides. There are few, if any, symptoms in the early stages of NAFLD, so it often goes unnoticed. For many people, fatty liver does not develop further and can be reversed with a healthy diet and lifestyle. However, for some, fatty liver develops into nonalcoholic steatohepatitis (NASH) or fibrosis. The cause of progression from NAFLD to NASH remains unclear and researchers have estimated that approximately 20% of those with prolonged simple fatty liver will go on to develop NASH and fibrosis.5 NASH, which is thought to affect up to 5% of the UK population,6 occurs when the build-up of fat in the liver cells is accompanied with inflammation. Inflammation occurs as part of the process of repairing damaged tissue. If left unchecked, the liver may eventually not be able to regenerate fast enough and the inflammation tissue can remain as a scar. This is known as fibrosis and can take a variable amount of time, sometimes several years, to develop. www.NHDmag.com October 2017 - Issue 128
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