Non-alcoholic fatty liver disease (NAFLD) is a relatively new disease. Largely lifestyle related, NAFLD is not linked to excess alcohol consumption – which is often perceived to be the cause of most liver problems. NAFLD represents a spectrum of liver conditions, ranging from fatty liver through to cirrhosis and liver cancer. It has been estimated that NAFLD affects up to one in three adults in the UK, and research has shown that it is closely linked to obesity and type 2 diabetes. The rising prevalence of these conditions, particularly in younger people, will mean that NAFLD remains a growing clinical concern for the future.
To understand what happens to patients with NAFLD, we first need to understand how our bodies manage fat. Normally your fat is stored under the skin, but if this fat store becomes full then fat can start to build up in and around your organs – such as the liver. An accumulation of excess liver fat is the first stage in the development of NAFLD. Currently there are no drugs approved for the treatment of NAFLD, and so the best route to slowing the disease’s progression is reducing the amount of fat through weight loss. This can be achieved through changes in diet and increasing levels of physical activity and exercise.
At Newcastle University we’ve been looking at the effects of different types of exercise on NAFLD. Our studies were the first to demonstrate that both resistance training and modified high-intensity interval training can reduce the amount of fat in the liver (regardless of weight loss) in people with NAFLD. We have also shown that people with NAFLD undertake less physical activity and are more sedentary on a day-to-day basis than their healthier counterparts. The challenge now is to translate these research findings into clinical practice.
The NIHR has funded a research programme in Newcastle upon Tyne that aims to investigate and optimise the current care pathway for people with NAFLD, with a focus on lifestyle interventions and exploring questions such as: When and how are people being diagnosed? What information and advice are they being given? And what happens to them next? This programme‘s ultimate outcome will be a range of new tools to support patients in making long-term lifestyle changes: to lose weight, keep the weight off and move more.
NAFLD is a condition researched as part of the NIHR Newcastle Biomedical Research Centre (BRC). The NIHR BRC, a partnership between Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University, aims to improve lives through world-class research in ageing and long-term conditions. NAFLD is a key part of the liver disease research theme within the NIHR Newcastle BRC.
How changes to diet can improve NAFLD?
The jury is still out on what type of diet is most effective in managing NAFLD – but the key seems to be reducing calorie intake. This can be achieved through reducing portion sizes, and cutting the amounts of fat and sugar in your diet – as both of these are high in calories. Scientific evidence suggests that limiting the consumption of fizzy drinks and processed-food may help to slow disease progression.
Clinicians often agree on 10% reduction in body weight as the best approach to managing NAFLD – but the more weight you can lose the better. Losing even a relatively small amount of body weight can have important health benefits. To start, recording what you eat and drink (including the quantities) in a food diary can highlight the areas where change could be possible.When trying to lose weight, it is important to set yourself realistic goals and then keep checking back over time to see if you have achieved them. For example: you could try reducing the amount of sugar that you add to your hot drinks by half a spoon a week, or you could make the switch from full-fat to semi-skimmed milk. Often making lots of small changes can actually result in long-term, sustainable weight loss.
Physical activity and exercise – what should you be doing and how much?
Exercise has been shown to reduce the amount of fat stored in the liver .However, it is more effective to exercise at the same time as changing your diet. Different types of exercise such as cardio (e.g. cycling or jogging), resistance (strength training) and high-intensity interval training have all proven effective in reducing liver fat. The most important thing is finding the type of exercise and diet approaches you enjoy the most – and which you will be able to continue in the long-term.
Increasing your day-to-day physical activity levels is also beneficial in the treatment of NAFLD. Simple changes – such as standing rather than sitting, walking to work, and taking the stairs instead of the lift – can be easy ways of getting more physical activity into your day without having to join a gym or run a marathon. Physical activity trackers can be useful in helping you to monitor the changes you make to your activity levels. Pedometers are a cheap way to capture step count, while some of the more sophisticated monitors on the market can also tell you about the intensity of your physical activity, its duration and even how many calories you’ve burned.
Changes like these can not only boost your metabolism, but will also increase the amount of calories you use up – which is vital if you’re trying to lose weight.
Dr Kate Hallsworth, Senior Research Physiotherapist and NIHR Clinical Lecturer.