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COVER STORY

LIVER DISEASE AND DIET This article provides an overview of the functions and diseases of the liver.

Rebecca Gasche Registered Dietitian, Countess of Chester Hospital NHS Trust

The liver is the largest solid organ and has over 500 functions. Located under the ribs on the right-hand side of the body, it sits within the biliary system, which includes the gallbladder and bile ducts. Around 60% of the liver is made up of hepatocytes (liver cells), which help to absorb nutrients and detoxify harmful substances from the blood. Other functions of the liver include:1 • processing digested food from the intestine to turn into energy; • regulating levels of amino acids, fats and glucose in the blood; • combatting infection; • neutralising and destroying drugs and toxins; • manufacturing bile; • storing iron and other vitamins; • manufacturing, breaking down and regulating hormones; • making enzymes and proteins. To name but a few!

Liver disease may occur at varying severities. It may start as steatosis (fatty liver), but if left unmanaged, it can lead to fibrosis, which is the excessive build-up of scar tissue, and lastly cirrhosis (permanent scarring) of the liver.2 Liver cirrhosis may be compensated or decompensated. Compensated liver cirrhosis is where there is irreversible scarring of the liver, but the liver is able to function as normal and carries no additional symptoms. Decompensated cirrhosis can be classed as end-stage liver disease and carries additional symptoms, for example, ascites, jaundice and encephalopathy. Dietary advice is particularly needed in alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD)

DISEASES OF THE LIVER

ALCOHOLIC LIVER DISEASE (ALD)

When our liver becomes damaged, this can affect a number of its functions. Damage to the liver may occur due to injury, infections, effects on the biliary system, alcohol intake, or an autoimmune condition (see Table 1). It may affect the hepatocytes directly, or the surrounding biliary system.2

Rebecca has a keen interest and specialises in gastroenterology dietetics. She currently works in the community setting in the Chester area, running clinics and group sessions, to manage a wide range of gastroenterology conditions.

REFERENCES Please visit the Subscriber zone at NHDmag.com

ALD covers a range of liver conditions from steatosis to cirrhosis, as a result of damage caused by alcohol. Protein energy malnutrition (PEM) is common in people with ALD, effecting around 80% of patients3 and, more specifically, it is thought that 80100% of patients with decompensated

Table 1: Examples of liver disease1 Alcoholic liver disease (ALD)/hepatitis

Primary sclerosing cholangitis (inflammation/scarring of the bile ducts)

Non-alcoholic fatty liver disease (NAFLD)

Wilson’s disease (a build-up of copper in the body)

Autoimmune hepatitis (inflammation caused by the body’s immune system attacking the liver)

Haemochromatosis (iron overload)

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CONDITIONS & DISORDERS Table 2: Examples of a 50g carbohydrate snack4 • • • •

300ml milk and 3 plain or chocolate biscuits 1½ slices plain or fruit cake 5 plain or chocolate biscuits 1 bottle juice-based 1.5 kcal/ml supplement

cirrhosis will have PEM.4 This explains why nutrition support is vital in this patient group, but why is it occurring? The addition of symptoms in decompensated ALD can contribute to PEM. Ascites, which is the accumulation of fluid in the abdomen, can result in patients having increased protein requirements, early satiety, nausea, vomiting and increased energy requirements.2 Encephalopathy occurs as a result of the liver being unable to play its role in detoxifying the blood, which can lead to changes in the brain. This is not necessarily long term, but can cause patients to become confused or suffer from reduced consciousness. They may forget to eat, or think that they have already eaten, as well as have a suppressed appetite.1 Social isolation, poor cooking skills and financial aspects may also impact on a patient’s nutritional status.4 If a patient has been consuming high amounts of alcohol over a long period of time, it is likely that they have not been having sufficient nutrition, and that their main source of energy was coming from alcohol.2 In addition to this, patients with liver cirrhosis have higher energy and protein requirements. It is suggested that compensated liver disease patients aim for 25-35kcal/kg/day and 1.2-1.5g/kg/day of protein. In decompensated liver disease patients, these requirements are higher still at 35-40kcal/ kg/day and 1.2-1.5g/kg/day.4 DIETARY ADVICE FOR ALD

Dietary advice aims to prevent PEM, reduce symptoms of ascites or encephalopathy and ensure that the body has a sufficient supply of carbohydrate and protein. Patients with decompensated liver disease are advised the following:2,5-7 • Eat small, regular meals and aim to eat some carbohydrate every two to three hours. • Have a high-calorie high-protein diet. • Have a snack before bed which contains 50g of carbohydrate. 12

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• 2 thick slices of toast and jam • 1½ bottle milk-based 1.5 kcal/ml supplement • Breakfast cereal with milk and banana

• Follow a low-salt diet (no-added-salt diet). • Abstain from alcohol. Carbohydrate supply is important, as carbohydrates are broken down into glucose and stored in the liver as glycogen, to be used as the body’s main energy source. This is released between meals, or when fasting overnight, to supply the body with energy. However, the liver's ability to store glycogen is reduced in decompensated liver disease, resulting in the body looking to source energy from protein stores instead, in a process called gluconeogenesis.5,6,7 Having a regular intake of carbohydrate helps to prevent this from happening. Due to the body ‘fasting’ overnight, it is especially important that a 50g carbohydrate snack (see Table 2) is eaten before bed to keep stores supplied and prevent gluconeogenesis. A low-salt diet is particularly recommended for the management of ascites, as excess salt in the diet may worsen the amount of fluid stored. Studies have shown that a no-added-salt diet (120mmol/day sodium) is as beneficial as a low-sodium diet (40mmol/day sodium), and one small study actually found that patients adhering to a low-sodium diet compared to a no-added-salt diet, showed lower energy and protein intakes. As a result, patients with ascites should be encouraged to follow a no-addedsalt diet – reducing foods high in salt due to processing, such as, tinned products, processed meats and, obviously, salty snacks, such as salted nuts and crisps. OTHER CONSIDERATIONS

Anthropometry – assessing if a patient is at risk of malnutrition – is important in this patient group and, therefore, calculating BMI and percentage weight loss is a priority. However, for those patients with ascites, or oedema, a dry weight should be estimated first.2 Table 3 shows estimations for dry weight. In addition to BMI and percentage weight loss, alternative measurements should also be considered, such as hand grip strength and upper


CONDITIONS & DISORDERS Table 3: Estimations for dry weight Guide for assessing weight of:

Ascites

Peripheral oedema

Minimal

2.2kg

1.0kg

Moderate

6.0kg

5.0kg

Severe

14.0kg

10.0kg

Adapted from reference 4

arm anthropometry. These help to assess muscle function, and the results can be compared to an expected population.2 Hand grip measurements can be particularly useful in demonstrating rapid changes in a patient’s nutritional status.8 Encephalopathy Dietary treatment for encephalopathy aims to ensure that the patient is meeting their energy and protein requirements. It was once thought that low-protein diets were needed, however, this is no longer advised, as there is a lack of evidence that low-protein diets worsen encephalopathy and can actually worsen nutritional status.9,10 Meeting protein requirements helps to ensure that the body is not utilising amino acids from muscle stores, which produce ammonia and can worsen symptoms. Patients are often prescribed lactulose and aim to have their bowels opening two to three times per day, to eliminate any excess ammonia from the body.4 Vitamins Considerations for B vitamins, fat soluble vitamins (A, D, E and K) and calcium should be considered in patients with liver disease.4 Patients with ALD are often prescribed thiamine, as alcohol metabolism is dependent on thiamine as a co-factor.4 Calcium and vitamin D requirements are increased in cirrhotic liver patients due to the increased risk of osteoporosis and osteomalacia. Therefore, it is advised that patients aim for 1000mg calcium and 800IU of vitamin D per day.11 NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD)

NAFLD can be described as the liver manifestation of metabolic syndrome, and it is estimated that one in three people in UK have the early stages.12 It is often diagnosed as a coincidental finding from abnormal liver tests, as

it can be asymptomatic in the earlier stages. Risk factors for NAFLD include being overweight, Type 2 diabetes, high blood pressure, high cholesterol, age over 50 years, smoking, poor diet and a sedentary lifestyle.13-14 NAFLD can occur at varying severities:15 1 Steatosis – a build-up of fat in the hepatocytes. This may often go undetected and is usually discovered following tests for another reason. 2 Non-alcoholic steatohepatitis (NASH) – the liver starts to become inflamed, estimated to affect 5% of the population. 3 Fibrosis – persistent inflammation of the liver causing scar tissue to occur, but the liver is still able to function as normal. 4 Cirrhosis – irreversible scarring of the liver, which can lead to liver failure. Nutritional assessment As well as weight and BMI, it is important to monitor HDL, LDL, triglycerides, waist circumference and HbA1c if diabetic.16 Dietary advice Lifestyle advice is crucial for patients with NAFLD, due to the strong link between NAFLD and insulin resistance. Weight loss strategies can help to reduce the risk of developing Type 2 diabetes and can also improve liver histology.17,18 There are a number of studies supporting weight loss to reduce fat in the liver, and it is thought that a weight loss of 3-5% is necessary to reduce steatosis; however, a greater loss of 10% may be needed for more advanced inflammation.19 NASH can be reversed by reducing weight and increasing physical activity. Suggested physical activity recommendations are 150 minutes of moderate-intensity and 75 minutes of vigorous activity per week, in addition to muscle strengthening activity twice a week – the same advice provided for diabetes prevention trials.20 www.NHDmag.com April 2019 - Issue 143

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Issue 143 Liver disease and diet  

Issue 143 Liver disease and diet