With the increase in cases of obesity and diabetes globally, we are also seeing a rise in rates of liver disease. This worrying trend is more prominent in Singapore, with 40% of adults experiencing non-alcoholic fatty liver disease as compared to 27% globally.
Not only does fatty liver disease affect liver functions, but it could also develop into more sinister conditions including cancer. But how does fatty liver occur, and how is it associated with cancer? Read on to learn more about the causes of fatty liver, and how you can lower the risk of getting this condition.
Understanding Fatty Liver Disease
The liver carries out many functions, one of which is to break down and synthesise fats. When the liver fails to metabolise fats fast enough, it can result in fatty liver disease (FLD), which is a condition when excess fats build up in the liver cells.
Fatty liver disease is broadly categorised into 2 types: Non-alcoholic and alcoholic. Non-alcoholic fatty liver disease (NAFLD) happens to those who do not drink, or drink minimally. Commonly seen in people with insulin resistance or obesity, NAFLD can develop into a serious form of fatty liver disease called non–alcoholic steatohepatitis, or NASH, which causes the liver to swell. Overtime, NASH could lead to liver scarring (cirrhosis) or liver cancer.
On the other hand, alcoholic fatty liver disease is caused by excessive drinking. One of the liver’s functions is to break down alcohol. When you drink too much, the liver has to invest more energy towards alcohol metabolism, meaning that not enough is spent on digesting fats, leading to fat buildup in the liver. Excessive alcohol consumption has also been associated with decreased very low-density lipoproteins (VLDL), which transport cholesterol and other fats from the liver to tissues for energy. Fats cannot be released from the liver without a balanced amount of VLDL.. Beyond that, alcohol metabolism also releases toxic byproducts, which increases the risk of liver damage over time.
Several causes and risk factors are contributing to fatty liver disease:
- Obesity
- Alcohol
- Unhealthy diet and lack of exercise
- Family history of fatty liver disease
Fatty acid disease typically does not present any symptoms. However, depending on the severity of the disease and one’s body constitution, symptoms can include:
- Fatigue
- Weakness
- Weight loss
- Abdominal pain
- Jaundice (yellowing of the skin)
- Swelling in the abdomen and limbs
Can Fatty Liver Cause Cancer?
Fatty liver disease can develop into cancer, especially if left untreated. A study found that patients with NAFLD have a higher incidence rate of gastrointestinal-related cancer than those without NAFLD. The most common cancer associated with fatty liver disease is liver cancer (hepatocellular carcinoma). The risk increases as NAFLD progresses to liver cirrhosis, with 85% of cirrhosis patients developing hepatocellular carcinoma within the next few years. In cirrhosis, new liver cells are continuously regenerated to replace damaged cells, likely caused by inflammation. This can increase the risk of genetic mutations, a key cause of cancer cell growth.
NAFLD is also associated with a higher risk of other gastrointestinal cancers such as colorectal, kidney, and stomach cancer. This is not all that surprising as our gastrointestinal organs work together and share the same environment. Inflammation or changes in the gut bacteria can promote the growth of cancer cells in the surrounding organs. Some studies have also found an association between fatty liver and cardiovascular and breast cancer as well.
There are many underlying mechanisms to explain the association between fatty liver disease and cancer. The liver receives fats from our diet and metabolises them in the mitochondria, an organelle that produces energy. Too many fats can cause oxidative stress, destroying the mitochondria. This inhibits lipid metabolism and creates a negative loop of further accumulating more fats. Over time, the fats chemically suppress the expression of proteins required to stop tumour growth, and instead upregulate those that induce cell proliferation. When cells grow uncontrollably, a tumour is formed. As these effects are not specific to one organ, they can cause a myriad of cancers in various parts of the body.
The danger is high especially since oxidative stress reduces immune signalling, an important defence mechanism against tumour growth. Hence, timely diagnosis and treatment is crucial to curb cancer growth while it is still in its early stages.
Risk Factors and Contributing Factors
Obesity
Excess fat tissue disrupts how the body uses insulin, leading to insulin resistance. This can cause the liver to become overloaded with fat, promoting the development of NAFLD. Furthermore, obesity fuels chronic inflammation throughout the body, damaging cells and creating an environment susceptible to cancer development. This inflammation, along with hormonal changes associated with obesity, can increase the risk of various cancers.
Insulin resistance
Insulin does not just control blood sugar levels – it also helps to store fats in adipose tissues. Insulin resistance means more fatty acids are in the bloodstream and transported to the liver to be metabolised instead of being stored. However, the amount of fatty acids is more than what the liver can handle. As the rate of fat accumulation is faster than fat metabolism, this eventually causes fats to build up in the liver, causing fatty liver disease.
Excessive alcohol consumption
As alcohol is digested in the liver, too much alcohol means that the liver has to work in overdrive to metabolise alcohol, leaving less energy to metabolise other products such as fats.
Family history of fatty liver disease
Studies have shown that NAFLD can run in families with mutated genes related to fat metabolism. Genetic conditions like lipoprotein lipase deficiency affect the body’s ability to break down fats, leaving patients predisposed to obesity and fatty liver.
The Importance of Early Detection and Prevention
Early detection facilitates early treatment. However, as fatty liver disease and cancer are asymptomatic in their early stages, sometimes we are unaware that we could have the disease until they become severe. Hence, regular screening is important to detect the presence of fatty liver or tumour growths while they are still easily manageable.
At Centre of Screening & Surgery, we provide various liver screening tests to detect any abnormalities in the liver, such as excess fats, scarring, infection, and tumours. The screening includes a thorough medical history and physical examination, followed by some of the following tests:
- Blood tests: Detects if enzymes and protein levels are normal. A high white blood cell count could be indicative of an infection.
- Imaging tests e.g. ultrasound, CT scan, and MRI. It allows doctors to visualise the shape, size, and texture of the liver. Any masses, tumours, scarring, or inflammation can be detected as well.
- Liver biopsy: Involves the extraction of a small sample of liver tissue to be examined under a microscope. This helps doctors obtain an accurate diagnosis of any anomalies.
Currently, there are no medications approved for NAFLD. However, some may be prescribed to lower the risk factors that caused FLD:
- Insulin: For patients with insulin resistance
- Antioxidants: For FLD caused by oxidative stress
- Lipid synthesis inhibitors: Inhibitors like statins can block our body’s synthesis of fatty acids, which helps to lower the amount of fats in the liver
- Vitamin E: Improves liver health and reduces inflammation
Of course, prevention is better than cure. Maintaining a healthy weight through lifestyle modifications can drastically reduce the risk of fatty liver disease and other health problems. Be conscious of what you eat; minimise saturated or high-sugar foods and incorporate more fruits and vegetables into your diet. 2 drinks per day for men, and 1 for women.
Aim for 150 minutes of moderate to vigorous exercise every week. From walking, jogging, pilates, badminton – the list of activities you can do are endless!
Conclusion
Fatty liver disease can progress into cancer if left untreated. Inflammation, scarring, and excess fats common in fatty liver can trigger uncontrolled cell division.
However, with the right treatment, fatty liver disease is manageable. Regular liver screening can check for anomalies that could have gone unnoticed since most patients do not experience any symptoms. Of course, the best treatment is prevention. Adopt a healthy lifestyle of a well-balanced meal and regular exercise to keep those fats away!
Protect Your Health Today
If you suspect that you may have fatty liver disease or experience gastrointestinal pain, feel free to visit us at the Centre for Screening and Surgery. Our clinic specializes in cancer screening and treatment of cancers at an early stage with minimally invasive procedures. Call us to book an appointment today!
