Nonalcoholic fatty liver disease affects up to a third of Americans, taking a toll on our collective health. Nutrition and lifestyle changes can turn it around.
Our livers are in trouble. Up to one in three American adults and one in 10 American children have fatty liver disease, a condition in which fat accumulates in the liver and compromises its function. Yet, despite many doctors calling this a pandemic, it’s making few headlines.
These facts may come as a surprise, but the liver is a stealth organ. Essential to health, it performs some 500 bodily processes, playing a crucial role in detoxification, digestion, hormone balance, blood-sugar regulation, and immune-system function — mostly without ever calling attention to itself. Liver problems often remain hidden until they cause other serious health issues.
“Fatty liver disease is like hypertension,” says Robert Lustig, MD, a pediatric endocrinologist at the University of California, San Francisco. “People walk around not knowing they have a problem until it’s too late. They used to call hypertension the ‘silent killer.’ Now it’s fatty liver disease.”
Fatty liver affects 70 percent of diabetic adults and up to 45 percent of obese children in Western societies. Though the disorder is commonly associated with a high body-mass index, it is not exclusively tied to that metric: Lean people can have fatty livers, too, says Robert Rountree, MD, a Boulder, Colo.–based integrative practitioner who has diagnosed the condition in patients of all sizes.
Fatty liver is traditionally connected with alcohol abuse, but today nonalcoholic fatty liver disease
(NAFLD) is the most common form of chronic liver ailment in developed nations, and sufferers may never even imbibe, or they do so only moderately.
Adding to the sense of alarm, NAFLD is typically asymptomatic until it has advanced to more serious liver conditions, explains Lustig. Most cases are diagnosed only after running routine blood work for other health complaints.
NAFLD is dangerous because the triglyceride fats a damaged liver releases into the bloodstream are “a better predictor of heart disease than LDL cholesterol ever was,” says Lustig. NAFLD is also closely associated with metabolic syndrome, which involves high blood pressure, high blood sugar, and weight gain; it’s a precursor to diabetes, stroke, and cognitive decline.
Left untreated, NAFLD may progress to nonalcoholic steatohepatitis (NASH), an inflammatory condition of the liver. The damage from NASH can cause fibrosis in the liver, which may then lead to cirrhosis and, ultimately, liver failure.
“By 2020, NAFLD will be the No. 1 reason we’re doing liver transplants,” says Dina Halegoua-DeMarzio, MD, a gastroenterologist who specializes in liver disease at Thomas Jefferson University Hospitals in Philadelphia.
The situation is serious, but there is a bright spot: Almost all the factors that contribute to NAFLD are related to lifestyle. Changing what you eat, exercising more, and reducing toxins in your environment can significantly improve your liver’s health. With these interventions, NAFLD is largely preventable and, until its latest stages, reversible.
The Other Drinking Problem
How has a disease once associated primarily with alcoholics ensnared a third of Americans in just a few short decades?
The answer may lie, at least in part, in a beverage that’s legal at any age: soda.
According to many healthcare experts, the steep rise in NAFLD cases is likely connected to the two- to three-fold increase in the number of overweight and obese children in the United States in the last 20 years. These conditions tax the liver early in life and set the stage for a host of health problems down the road.
NAFLD itself appears to be fueled by a combination of factors, including the consumption of high-fructose corn syrup (HFCS) in soda and other processed foods, a sedentary lifestyle, and exposure to environmental toxins.
Of the three, HFCS may make the biggest impact. Many liver experts connect the preponderance of HFCS in the Western diet to the rise in fatty liver: Current estimates show the average American consumes 41 pounds of HFCS per year. (Remarkably, this is a decrease from an annual per capita consumption of 62 pounds in 2000, possibly thanks to public-health campaigns to reduce sugar and soda consumption.) Still, Rountree calls HFCS “the new tobacco.”
Unlike the fructose in fruit, honey, and cane sugar, the fructose in HFCS comes in an unbound form, thanks to the industrial process used to create it. This makes HFCS sweeter, cheaper (because it’s more concentrated than sugar), and easier to overconsume than other sources of fructose. It also damages liver and gut health.
Still, on the surface this sounds all wrong: If something we consume triggers fatty liver, wouldn’t it be dietary fat? Oddly, no. Instead, multiple studies suggest it is not dietary fat but overall caloric intake that provokes the accumulation of fat in the liver.
Rountree explains that excess fat in the liver either comes from surrounding adipose tissue (in a process sparked by elevated insulin, which triggers fat storage) or is created in the liver when we eat high concentrations of fructose. This second process is known as de novo lipogenesis, which translates as “making new fat.”
When we eat or drink something with fructose, the liver must process it. The body’s preferred fuel-storage molecule is glycogen, but the liver can’t turn fructose into glycogen efficiently. Because the fructose must be stored somewhere, the liver converts it into fat, the body’s other energy-storage molecule. “Your liver has no choice,” explains Lustig.
The body processes alcohol in a similar way. “Fructose is metabolized virtually identically to how alcohol is metabolized,” says Lustig. “That’s why sugar is considered the alcohol of a child.”
Once fat has begun to accumulate in the liver, one of two things happens: The fat can return to the circulatory system as triglycerides, which stick to arterial walls and contribute to atherosclerosis, or it can stay in the liver and wreak havoc on liver function.
“The presence of fat in the liver causes stress to the liver cells surrounded by the fat,” says Halegoua-DeMarzio. The new fat cells move in next to healthy liver cells, irritating and inflaming them. “Then those irritated liver cells lay down scar tissue, and that decreases liver function.” This is how NAFLD progresses to NASH.
Yet even before steatosis sets in, liver function erodes, causing problems throughout the body. A compromised liver reduces the body’s capacity to eliminate toxins and hormone byproducts and weakens the immune system.
It also inhibits blood-sugar regulation. Once the liver gets fatty from too much fructose, the pancreas starts to overcompensate for its sluggish teammate. It kicks out more insulin to aid the liver, which backfires by catalyzing new fat. This makes fatty liver disease both a trigger and a result of metabolic dysfunction, in which fat-burning slows and insulin becomes dysregulated, leading to a host of other health issues.
“I never think of fatty liver as separate from metabolic dysfunction,” says functional-medicine physician Frank Lipman, MD, coauthor of The New Health Rules: Simple Changes to Achieve Whole-Body Wellness. Likewise, metabolic dysfunction can’t be separated from the conditions that result from it: type 2 diabetes, cardiovascular disease, and stroke.
The nutritional triggers for the NAFLD pandemic aren’t limited to the damaging effects of the standard American diet. Choline deficiency is another key factor.
Choline is a vitamin-like essential nutrient that helps transport fat inside the body. The best dietary sources are whole eggs and liver; supplements are also useful. When a person is deficient in choline, fat gets into the liver but can’t get out.
“Without enough choline, we’re overproducing fat and under-eliminating it,” says Rountree. “The drain is clogged.”
Sedentary lifestyles are another factor in NAFLD. Exercise has myriad health benefits, and it protects the liver in a straightforward manner: Exercise burns more fat than sitting does.
Finally, the liver is the body’s main detoxification organ, and today we’re exposed to an unprecedented volume of toxins. “Humans have become rent-free storage systems for synthetic chemicals,” Rountree says, noting that some 2,000 new chemicals are registered for use in the United States each year. This burgeoning toxic load can overwhelm our already-taxed livers.
Environmental toxins are nothing new. Lead poisoning is believed to have helped bring down the Roman Empire. But today we wrestle with more chemicals as well as the interaction of those chemicals, the effects of which experts are still struggling to understand.
Meanwhile, the accumulation of multiple toxins is an exponential challenge to the liver. The toxins in plastics can disrupt our endocrine systems. Lead is a neurotoxin. If the body must tackle both at once, it must work that much harder to process them.
Yet we don’t have to escape toxins completely to be healthy. The liver is designed to help us clear them before they do damage. By limiting our exposure — as well as improving our nutrition and reducing our intake of fructose-laden food and drinks — we can make its job substantially easier.
A healthy liver means a healthy metabolism, a healthy cardiovascular system, and a healthy body overall. So it’s worth taking a few measures to optimize this organ’s function. Experts recommend these steps to prevent and reverse NAFLD, and to maintain a healthy liver.
Ditch high-fructose corn syrup.
Processed foods and soda are the top sources of HFCS in the diet, says Halegoua-DeMarzio, and she views it as a primary cause of NAFLD. Making whole foods — especially vegetables, pastured-animal proteins, nuts and seeds, and some low-glycemic fruits (think cherries, blueberries, and grapefruit) — the mainstays of your nutrition plan is a boon to liver health.
Be mindful with fruit.
Fruits contain fructose in varying amounts; they also contain fiber, pectin, and often an enormous number of phytonutrients. When fructose is part of this matrix of healthy plant compounds, its impact on the liver is less severe, says Rountree. Consuming fructose as an isolated chemical is when it starts causing health problems.
At the same time, fruit affects everyone differently.
“Theoretically, we should all be able to eat fruit, and the fiber should slow digestion,” says Lipman. “But a lot of people — I’m one of them — have problems when they eat a lot of fruit. People have different tolerances.”
If eating a certain fruit puts you on the blood-sugar roller coaster, eat it only in moderation. Stick with fruits or other foods that don’t leave you “hangry.”
Get your daily fiber.
“Fiber prevents the intestines from absorbing fructose too soon, so you don’t get that tsunami on the liver,” says Lustig. When you eat fruit, pair it with foods that are high in fiber so the liver isn’t flooded with fructose. Ideal pairings include chia- and flaxseeds, nuts and nut butters, avocados, and leafy greens.
Embrace healthy fats.
Experts generally agree that healthy fats don’t contribute to NAFLD (trans fats, on the other hand, are a problem). To support good metabolism and cognitive function, turn to the healing fats found in small, oily fish; olives and olive oil; avocados; nuts and seeds; grassfed-animal protein; and coconut oil and ghee.
Still, clinicians who treat people with metabolic syndrome and NAFLD say a small percentage of patients who reduce sugar don’t see sufficient improvements in their liver enzyme and triglyceride counts, likely due to genetic differences that affect how well someone metabolizes fat. These people might benefit from limiting the amount of saturated fat in their diet.
Skip fast food.
The trans fats and HFCS found in processed fast food damage the liver. Just drive by the drive-through.
It’s estimated that only 10 percent of Americans meet or exceed their recommended daily choline intake. Eating choline-rich foods, including eggs and liver, boosts its stores in the body. Supplemental choline (often in the form of phosphatidylcholine) can be helpful if your levels remain low due to genetic variations or an overpopulation of bad gut microbes.
Ease up on medications where possible.
Frequent use of over-the-counter medications can harm the liver. Nutritionist Ann Louise Gittleman, PhD, CNS, cites a study of 300 patients by the University of Texas Southwestern Medical Center that found that 38 percent of liver-failure cases and 37 percent of severe liver disease were associated with excessive use of acetaminophen, the active ingredient in Tylenol.
Before any medication can be effective, it must be processed by the body, and this job falls largely to the liver, explains Gittleman. The more pharmaceuticals we ingest — through prescription drugs or over-the-counter remedies — the harder the liver must work. So take prescribed medications only as recommended, and consult with your healthcare provider to make sure they’re necessary.
Meanwhile, Rountree says, no pharmaceuticals have been approved by the FDA for treating NAFLD. The blood-sugar-lowering drug Metformin can help stabilize type 2 diabetes but has a minimal effect on fat accumulation in the liver.
Minimize toxic exposure.
The list of toxins that exact a toll on the liver is long, but take special care to avoid the following: persistent organic pollutants (POPs), which include insecticides such as DDT and chemicals used in large-scale industrial and agricultural operations; common herbicides such as atrazine and glyphosate; and heavy metals like lead, mercury, and arsenic.
This is easier than it sounds. Eating organic foods, avoiding lawn chemicals, and using a high-quality water filter for your shower and drinking water can all significantly reduce exposure to these compounds.
Guar gum is a powerful soluble-fiber supplement that has been shown in animal studies to reduce fat accumulation and inflammation in the liver. In supplement form, it’s partially hydrolyzed, so its otherwise-unpleasant taste disappears. (It also doesn’t cause gas and bloating the way it can when combined with some foods.)
Another helpful supplement is nicotinamide riboside, a precursor to nicotinamide adenine dinucleotide (NAD). A coenzyme found in all living cells, NAD plays an important role in extracting energy from food and repairing DNA damage. Our bodies’ NAD level decreases as we age, says Rountree, and “when NAD gets low, you don’t burn fat as efficiently, so fat accumulates.”
Studies show that losing just 3 to 5 percent of total body weight can significantly improve fatty liver. Consider high-intensity interval training for the most substantial fat-burning benefits. (For more on interval training, see “HIIT It!”)
All this is good news. It means that even if we find out we’re further down the road to fatty liver than we suspected, we can always turn back.