Liver Disease: Dietary Choices That Help and Hurt

Liver disease is devastating because the liver is a vital organ; it detoxifies your body and plays a pivotal role in food digestion. When the liver is unhealthy, the entire body is affected. Unfortunately, the liver is easily injured, and special care is needed to keep it healthy and functioning at its best. Symptoms of liver problems can include yellowed skin and eyes (jaundice), swelling of the lower extremities and abdomen, nausea and vomiting, stomach pain, exhaustion, anorexia, itchy skin, dark urine, and pale stools (via the Mayo Clinic). 

Liver disease can be caused by infection, transmitted via parasites or viruses. Hepatitis is the most common infection contracted via infected food, sex, and shared needles. There are hepatitis A and B vaccines but none for hepatitis C. 

Several autoimmune and genetic diseases can also cause liver damage. Sometimes, liver disease is caused by lifestyle factors, including chronic alcohol use, a poor diet, drug abuse, and even the use of certain dietary supplements. People who are obese or have type 2 diabetes are at higher risk than others. Certain chemicals, including those found in insecticide and paint aerosols, can be hazardous to the liver, as well. 

Eat plenty of fibrous foods to prevent liver disease

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with obesity, elevated blood lipids, and type 2 diabetes. Indeed, insulin resistance is thought to be the number one cause of NAFLD. Sadly, roughly 20-30% of patients with NAFLD will progress to non-alcoholic steatohepatitis, which in turn can advance to cirrhosis and liver cancer; liver transplant is sometimes necessary if this occurs. 

NAFLD has been associated with dysbiosis (an unhealthy gut microbiota). According to one study published in Nutrients in 2020, dietary fiber (especially insoluble fiber), prebiotics, and weight loss via calorie restriction can prevent disease progression if initiated in the early stages. Reducing caloric intake by at least 30% improves insulin resistance and fatty liver disease. 

By eating foods rich in prebiotics, you can feed and nourish the healthy bacteria in the gut (the probiotics) so that they thrive. Sources of prebiotics and fiber include asparagus, garlic, onions, Jerusalem artichoke, wheat, banana, peas, and beans. In this specific study, participants who consumed at least 7.5 grams of insoluble fiber each day demonstrated significantly improved liver health. Insoluble fiber is found in wheat bran, vegetables, and whole grains (MedlinePlus). 

Avoid alcohol

According to the American Liver Foundation, drinking too much alcohol is a risk factor for developing fatty liver disease, alcoholic hepatitis, and alcohol-related cirrhosis. Early on, you can reverse damage. However, once cirrhosis has developed (in 10-20% of heavy drinkers, usually after a decade of heavy drinking), the disease is irreversible and can be fatal. People who are obese, malnourished, and drink heavily are at exceptionally high risk for developing liver disease. Alcohol-related liver disease can cause internal bleeding, brain disorders,, kidney failure, and liver cancer. 

The Cleveland Clinic defines one drink as a 12-ounce bottle of beer, a 5-ounce glass of wine, or a 1.5-ounce shot of hard liquor. Each of these drinks contains 14 grams of alcohol. Drinking more than 40 grams of day appears to cause pathologic changes of alcoholic hepatitis in men (according to autopsy results). In comparison, more than 80 grams is associated with more severe alcoholic hepatitis. More than 60 grams for men, or 20 grams for women, dramatically increases the risk of cirrhosis. Daily drinking appears to be more harmful than occasional binge drinking.

Eat olive oil

According to a study published in the World Journal of Gastroenterology, people with nonalcoholic fatty liver disease have higher triglyceride levels and produce more VLDL (very low-density LDL) after eating, even if their fasting blood lipids are within normal limits. This indicates that people with this condition have difficulty appropriately metabolizing the fat they consume. By decreasing total fat intake and focusing on the monounsaturated fatty acids found in olive oil, or the polyunsaturated fatty acids found in fish oil, these changes in lipids were mitigated among study participants. 

You don’t want to start guzzling olive oil, though. Overeating of the good fats found in olive oil and avocados can still lead to the increasingly common fatty liver disease, especially when combined with a high-starch diet. 

In one study, mice were divided into groups that consumed either saturated or monounsaturated fat, paired with either sucrose or starch, in one of four different high-calorie diets. All diets were composed of approximately 40% carbohydrate, 40% fat, and 20% carbohydrate to mimic the average American diet.  The mice were allowed to eat as much as they wanted. After six months, all of the mice had grown obese and had developed fatty liver. Shockingly, the mice that ate the starch-monounsaturated fat diet had the most severe disease. They accumulated a whopping 40% more liver fat than the mice in the other three diet groups. 

The researchers believe, based on other physical findings, that the starch-monounsaturated fat diet might increase cell death and inflammation in the abdomen. This fat is quickly carried to the liver, encouraging the development of fatty liver disease.

Avoid fried food

As described in a study published in Nutrients, NAFLD is correlated with obesity and type 2 diabetes. Additionally, oxidative stress might be to blame for this increasingly common liver disease. 

Previous research, including an insightful study printed in Diabetes Care, clarifies that saturated fat increases inflammation and is a prime suspect in the development of hyperlipidemia and insulin resistance. As the authors of this study point out, a high intake of saturated fat (but not polyunsaturated) has increased the amount of triglyceride stored in the liver, even in young nonobese adults. The liver also uses the simple sugars to create lipids (hepatic de novo lipogenesis). 

In this research project, participants were divided into three groups. All groups ate a high-calorie diet for three weeks. Still, one group was assigned a high saturated fat diet (coconut oil, butter, blue cheese), one group was instructed to eat a high unsaturated fat diet (olive oil, pesto, pecans), and the third group ate a diet high in simple sugars (orange juice and sugar-sweetened beverages). Both high-fat groups ate diets composed of 60% fat, while only 24% of the calories in the high-carb group came from fat. Although only 38 participants completed the study, all were comparable in terms of demographic background, BMI, and biochemical characteristics.

All of the high-calorie diets caused an increase in triglycerides stored in the liver, although the saturated fat-rich diet increased levels more than the unsaturated fat-rich diet. Unsurprisingly, the high-carbohydrate diet increased hepatic de novo lipogenesis. Ceramides, which are an independent risk factor for heart disease, were elevated in the participants consuming the high saturated fat diet.

Drink coffee

Coffee gets a bad rap that it doesn’t necessarily deserve. In a study published in BMC Public Health, among 384,818 coffee drinkers and 109,767 non-coffee drinkers, the coffee drinkers had lower rates of chronic liver disease, steatosis, death from chronic liver disease, and liver cancer (hepatocellular carcinoma). These trends held whether the coffee was decaffeinated, instant, or ground.  

In another study published in Clinical Gastroenterology and Hepatology, Elliot Tapper, MD, an associate professor of internal medicine at Michigan Medicine, and liver specialists from Harvard Medical School worked together to analyze the results of 4,510 people who had participated in the National Health and Nutrition Examination Survey (NHANES). They used a test, called the elastography exam, to assess the elasticity of the liver. The more elastic and less stiff this organ is, the healthier it generally is. They discovered that those participants who drank more than three cups of coffee a day had less liver stiffness. The participants with more elastic livers are believed to carry a lower risk for cirrhosis and liver cancer. 

Avoid raw or undercooked shellfish

Anyone can get sick from eating raw oysters and other shellfish and might suffer from vomiting or diarrhea, but those with chronic liver disease and the resultant immune issues can die. The V. vulnificus infection progresses rapidly to septic shock and death in these individuals. As many as 20% of people who contract this infection, which besides sepsis, can cause blistering skin lesions and necessitate amputations, will die. Scariest of all — a contaminated oyster will not look, smell, or taste differently (via the CDC). 

The CDC recommends that consumers throw out any shellfish with open shells before cooking. Shellfish in the shell should be boiled until the shells open, plus an additional three to five minutes. Alternatively, the shellfish can be added to a steamer full of steaming water and cook for another four to nine minutes. If the shells do not open on their own, never try to pry them open yourself — throw these stubborn shellfish away. If you’re preparing shucked oysters, be sure to boil them for at least three minutes, fry them in hot oil for at least three minutes, or bake at 450 for 10 minutes. 

Eat green vegetables to prevent liver disease

In a study published in the Proceedings of the National Academy of Sciences, scientists at the Karolinska Institutet in Sweden found that the inorganic nitrate in green leafy vegetables reduces the accumulation of fat in the liver. One group of mice was fed a regular diet for mice, one was given a high-fat diet that mimicked a typical Western diet, and the last group received a high-fat diet supplemented with nitrate. Not surprisingly, the mice in the high-fat group put on the most weight and had high blood glucose. The mice who received the high-fat diet but were also supplemented with nitrate had significantly less weight gain, lower blood pressure, better insulin sensitivity, lower blood glucose, and a much lower proportion of fat in the liver. Celery, spinach, lettuce, and rocket are rich sources of inorganic nitrate.

Green leafy vegetables in the cruciferous family, such as Brussels sprouts, broccoli, and mustard greens, are also high in fiber. They may increase detoxification enzymes and protect the liver from insult. A separate mouse study published in 2016 in The Journal of Nutrition found that broccoli lessened the development of tumors and fatty liver disease. The authors pointed out that people living in the United States have begun to eat much more broccoli in the past two decades, which is especially good since one in two adults in the U.S. now has some degree of NAFLD, and liver cancer is the fifth most common cancer in men globally with a five-year survival rate of only 17%. The study emphasizes that broccoli has previously been found to decrease the risk of numerous types of cancer, including bladder, breast, prostate, and colon. 

Avoid salty foods

For the love of your liver, it might be time to think about how much salty processed food you’re eating. According to the FDA, the average American eats about 3,400 mg of sodium per day, even though the Dietary Guidelines for Americans recommend that we cap our intake at 2,300 mg per day. An article published in the Journal of Agricultural and Food Chemistry caught the attention of many health professionals in 2016 by revealing that when adult mice were fed a high-salt diet, or chick embryos were exposed to a sodium-rich environment, their livers were damaged. The liver cells were misshapen, died easily, and did not proliferate as usual. One positive finding: treating the damaged cells with vitamin C did somewhat improve the situation. 

Individuals who have already been diagnosed with advanced liver disease (cirrhosis) must strictly limit their salt intake to decrease the risk of complications, especially those related to fluid retention, which commonly occurs in the late stages of liver disease (via the University of Utah). 

Eat soy-based foods

Soy protein could significantly reduce fat accumulation and triglycerides in the livers of obese individuals, according to a study presented by University of Illinois researchers at the annual meeting of the American Society for Biochemistry and Molecular Biology in 2012.  According to animal research, soy protein from sources like tofu and yogurt appears to alleviate the liver damage caused by a high-fat diet.  Indeed, the obese rats fed soy in this study had a 20% decrease in triglycerides and overall fat accumulation in the liver (via EurekAlert). 

A more recent study, this one appearing in the Iranian Journal of Basic Medical Sciences, determined that soy decreased liver enzymes, body weight, and serum malondialdehyde (an essential marker of oxidative stress) in patients with nonalcoholic liver disease. The authors described soy as having antiobesity and antioxidant properties. 

Among 66 patients with NAFLD, combining a reduced-calorie diet with soy milk for eight weeks decreased serum insulin and indicators of insulin resistance compared to a reduced-calorie diet without soy milk. The soy milk group also demonstrated reduced blood pressure in this study, published in Complementary Therapies in Medicine. 

Avoid copper if you have Wilson disease

Wilson disease is a genetic disorder that causes large amounts of copper to accumulate in soft tissues, including the liver, brain, and eyes. Symptoms often don’t become evident until adolescence but can become apparent anytime between the ages of six and 45, often presenting initially with liver disease and psychiatric conditions (via MedlinePlus). 

Individuals with Wilson disease must take medications that remove excess copper from the body and also take zinc, which stops the intestines from absorbing copper (via the Cleveland Clinic). Many patients are also told to limit the amount of copper-rich foods they eat. The primary dietary sources of copper are oysters and other shellfish, whole grains, beans, nuts, potatoes, and organ meats. However, dark leafy greens, dried fruits, cocoa, black pepper, and yeast are also sources of this mineral (via MedlinePlus). 

The NIH Office of Dietary Supplements adds that wild mushrooms, sunflower seeds, tofu, salmon, avocado, and asparagus also contribute a healthy dose of copper and would need to be avoided by those with Wilson disease who are instructed to limit their consumption. 

Eat fatty fish

According to a 2015 review published in the World Journal of Gastroenterology, omega-3 polyunsaturated fatty acids in fish oil reduce fat accumulation in the liver and lessen the rise in liver enzymes, insulin resistance, and inflammation associated with fatty liver disease. On the other hand, depletion of omega-3 fatty acids spurs the development of hepatic steatosis and NAFLD. Atlantic salmon and herring are the richest sources of omega-3 fatty acids, and research has shown that fish oil supplements exhibit the same efficacy as consumption of these types of seafood. 

The authors emphasize that a few studies have even shown benefits from omega-3 supplementation among children with NAFLD. Additionally, among children with obesity or metabolic syndrome, supplementation has proven to reduce blood pressure, cholesterol and triglyceride levels, and insulin resistance. 

Avoid refined carbohydrates and high-fructose corn syrup

The authors of a fascinating study printed in Hepatobiliary Surgery and Nutrition describe why drinking beverages sweetened with high-fructose corn syrup (HCFS) contribute to NAFLD — by increasing hepatic de novo lipogenesis, as discussed above. This production of fat by the liver (de novo lipogenesis) is responsible for more than a quarter of the liver fat stored in those with NAFLD. 

Although only 15% of non-obese people have NAFLD, 65% of obese and 85% of highly obese individuals do. The consumption of HCFS has been implicated in the skyrocketing number of people coping with both obesity and NAFLD. The chronic inflammation that occurs with obesity and insulin resistance also plays a crucial role in developing NAFLD. 

Because fructose is not easily absorbed in the intestines, it is almost entirely cleared by the liver. This metabolism that occurs in the liver stimulates fat creation and increases triglycerides both in the blood and stored in the liver. 

Eat nuts

In the same review that explored the potential relationship between omega-3 fatty acids and liver disease, the researchers determined that the healthy fats and vitamin E in nuts, as well as the fiber and phytochemicals, are to thank for the positive health effects of these popular snacks foods. Studies have found that eating several handfuls of nuts each week reduces the risk of cardiac events and is linked to lower rates of high cholesterol, obesity, type 2 diabetes, and high blood pressure. 

Walnuts are particularly rich in polyunsaturated fatty acids and antioxidants. Not coincidentally, walnuts, in particular, appear to improve liver function tests in patients with NAFLD, although other tree nuts do as well. In summary, the authors noted that “nuts show much therapeutic potential in treating patients with NAFLD through improvements to lipid profile, hepatic steatosis, and inflammation.” 

In another study published by Liver International, among 23,915 participants enrolled in the Tianjin Chronic Low-Grade Systemic Inflammation and Health (TCLSIH) Cohort Study, those participants who consumed nuts at least four times a week had the lowest risk of NAFLD. 

Limit red meat to prevent liver disease

According to research published in the Journal of the National Cancer Institute, several components of red meat have been implicated in the development of chronic liver disease and liver cancer, according to research published in the Journal of the National Cancer Institute. Among 49,006 participants (median age of 62.6) in the National Institutes of Health – AARP Diet and Health Study, there was an inverse relationship between white meat consumption and risk of chronic liver disease, but a higher risk among those who ate the most red meat and saturated fat. 

Medical professionals have long understood the risk of iron overload for liver cancer, which explains why phlebotomy and low iron diets are essential for the management of hepatitis C.

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