Improving non-alcoholic fatty liver disease with a plant-based diet

Non-alcoholic fatty liver disease (NAFLD) is a condition where too much fat is accumulated in the liver cells (steatosis) due to poor lifestyle choices.

The early stage of NAFLD, also known as ‘fatty liver’, is estimated to affect one in five people in the UK, according to The British Liver Trust.

It is closely linked with poor metabolic health and most commonly seen in people who have obesity, type 2 diabetes and increased cardiovascular risk factors. Fatty liver on its own is not known to cause harm, but can lead to serious liver damage, including cirrhosis (permanent scarring and damage to the liver) if it gets worse.

NAFLD is diagnosed by assessing risk factors and investigations that include blood tests (which may not always reflect abnormality early on) and ultrasound scans. Some people may require examination of a sample of liver tissue (biopsy) to know the exact staging of the disease.

As a GP, I myself have noticed a growing number of incidental findings of fatty liver of ultrasound scans. This is not surprising given the rise in obesity, type 2 diabetes, heart attacks and strokes amongst the UK population.

Research shows that lifestyle and dietary changes play a key role in the management of NAFLD¹. It is important to start making these changes in the early stages while scarring has not started.

Common causes of fatty liver disease

Smoking, being overweight, high blood pressure, high cholesterol or diabetes and consuming ultra-processed food increase the risk of fatty liver². Sadly, it is a condition that is affecting children too; which was not heard of a few decades ago.

Dietary recommendations for fatty liver disease

Changing dietary composition with the aim to lose 5-10 percent of the body weight has been proven to be beneficial for fatty liver³.

Current evidence supports improvement in fatty liver when calorie restriction is combined with a Mediterranean diet (MD)⁴, which includes antioxidant rich whole plant-based foods and is limited in red meat, poultry, dairy and eggs. The abundance of polyphenols, increased fibre with reduced saturated fats in the MD helps to reduce intracellular fat.

A recent randomised controlled trial (which you can read more about at bmcmedicine.biomedcentral.com) compared the MD to green-MD, where green tea and mankai (a kind of duckweed) shake were included along with physical exercise.

After 18 months both intrahepatic fat and body weight were reduced more in the green-MD as compared to the MD. It was interesting, though not surprising, that both MD and green-MD proved to be better than following standard healthy diets.

What are the macros for fatty liver disease?

Looking at the macronutrients, studies show that saturated fats, present in red meat, dairy, poultry and most animal-based food, can negatively impact fatty liver⁵.

Trans fats, abundant in ultra-processed food, are also included in this category. Including polyunsaturated fats, in the form of olive oil, avocados, nuts and seeds, which are mostly sourced from plants, promote reduction in steatosis.

NAFLD is common among people consuming higher amounts of protein in the form of red and processed meat⁶. Increased intake of animal protein is linked with the high levels of carnitine and choline, which are converted trimethylamine (TMO) by the gut bacteria and subsequently to trimethylamine-N-oxide (TMAO) in the liver.

Increased levels of TMAO has been associated with mortality in people with NAFLD⁷. Protein sources from a whole food plant-based diet (WFPBD), on the other hand, can be supportive to liver health, being low in saturated fat, carnitine as well as choline⁸.

WFPB sources of protein include tofu, tempeh, legumes, edamame beans, lentils, quinoa and a variety of nuts and seeds.

Refined carbohydrates, such as white pasta, bread, cereals, sugar-laden baked goods and soft drinks have been proven to cause more fat deposition in the liver, resulting in NAFLD⁹.

Having complex carbs in the diet in the form of whole grains, brown rice, lentils, chia seeds and various fruits can be immensely beneficial, as they are high in fibre, nutrient dense and support healthy gut bacteria.

Gut microbiome importance

Recent breakthroughs in understanding the development of NAFLD are showing that a disrupted gut microbiome could be one of the leading causes of inflammation and fat deposition within the liver¹⁰.

Not surprisingly, here again a balanced WFPBD can play a vital role, as the fibre in complex carbohydrates, vegetables and fruits provides beneficial substrate for a healthy gut microbiome to thrive, reducing overall inflammation¹¹.

Sadly, sugary beverages and processed food are becoming the driving causes of NAFLD in not just adults, but also in children as young as nine years old. Ultra-processed food is not only poor in nutrients, but the chemical additives are a disruptor of healthy gut microbiome.

Support the liver with lifestyle changes

Regular exercise, specifically combining aerobic or high intensity interval training along with resistance training can support weight loss and improve health in NAFLD. The current guidelines advise 150 minutes of exercise per week.

Maintaining healthy weight and aiming to reduce 5-10 percent of weight, if overweight, can reduce steatosis (deposition of fat in liver cells) and improve NASH (nonalcoholic steatohepatitis) .

Improving hydration, keeping water as the main beverage, is also something I constantly talk about when advising my own patients, as it is an easy way to support pathways that remove toxins from the body. Aiming for 1.5 litres of water a day would be a good start.

Of course, talking about liver health can’t be complete without touching on the subject of toxins! Organic, unprocessed foods are best to reduce the toxin load¹², but also being mindful of chemicals we are exposed to through plastic use, personal products, as well as those used to clean our surroundings. Reducing alcohol intake and quitting smoking is, of course, helpful too.

A balanced whole food, plant-based diet can be very effective when combined with calorie restriction and exercise for improving fatty liver.

Below Improving hydration by drinking 1.5 litres of water every day is an easy way to help our bodies remove toxins effectively.

Got the seasonal sniffles? Find out how to manage and treat the symptoms of hayfever.

Featured image © eddows via Adobe Stock

References

1. Nseir W, Hellou E, Assy N. (2014) Role of diet and lifestyle changes in nonalcoholic fatty liver disease. World J Gastroenterol. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4110565/
2. Huh Y, Cho YJ, Nam GE. (2022) Recent Epidemiology and Risk Factors of Nonalcoholic Fatty Liver Disease. J Obes Metab Syndr. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8987457/
3. Perdomo CM, Frühbeck G, Escalada J. (2019) Impact of Nutritional Changes on Nonalcoholic Fatty Liver Disease. Nutrients. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470750/
4. Anania C, Perla FM, Olivero F, Pacifico L, Chiesa C. (2018) Mediterranean diet and nonalcoholic fatty liver disease. World J Gastroenterol. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5960814/
5. Parks E, Yki-Järvinen H, Hawkins M. (2017) Out of the frying pan: dietary saturated fat influences nonalcoholic fatty liver disease. J Clin Invest. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5272176/
6. Rahimi-Sakak F, Maroofi M, Emamat H, Hekmatdoost A. (2022) Red and Processed Meat Intake in Relation to Non-Alcoholic Fatty Liver Disease Risk: Results from a Case-Control Study. Clin Nutr Res. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8844531/
7. Theofilis P, Vordoni A, Kalaitzidis RG. (2022) Trimethylamine N-Oxide Levels in Non-Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis. Metabolites. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9784457/
8. Li HY, Gan RY, Shang A, Mao QQ, Sun QC, Wu DT, Geng F, He XQ, Li HB. (2021) Plant-Based Foods and Their Bioactive Compounds on Fatty Liver Disease: Effects, Mechanisms, and Clinical Application. Oxid Med Cell Longev. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939748/
9. Yki-Järvinen H, Luukkonen PK, Hodson L, Moore JB. (2021) Dietary carbohydrates and fats in nonalcoholic fatty liver disease. Nat Rev Gastroenterol Hepatol. Available at: https://pubmed.ncbi.nlm.nih.gov/34257427/
10. Tokuhara D. (2021) Role of the Gut Microbiota in Regulating Non-alcoholic Fatty Liver Disease in Children and Adolescents. Front Nutr. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8267179/
11. Tomova A, Bukovsky I, Rembert E, Yonas W, Alwarith J, Barnard ND, Kahleova H. (2019) The Effects of Vegetarian and Vegan Diets on Gut Microbiota. Front Nutr. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6478664/
12. Mie A, Andersen HR, Gunnarsson S, Kahl J, Kesse-Guyot E, Rembiałkowska E, Quaglio G, Grandjean P. (2017) Human health implications of organic food and organic agriculture: a comprehensive review. Environ Health. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5658984/