Fatty liver is also called Non-alcoholic Fatty liver Disease (NAFLD). It has become the most common chronic disease in the USA, affecting one in three people (in the UK the figure is 20-30% of adults and worryingly 20% of all children). It is closely linked with obesity and also with metabolic syndrome (see separate leaflet).
It is normally diagnosed with a liver scan. Blood tests typically show raised liver enzymes. It is generally benign but in one in six cases can go on to a more serious condition called non-alcoholic steatohepatitis (NASH) where inflammation, scarring and fibrosis are found in the liver. About 5-10% of patient with NASH develop cirrhosis.
Two studies shed an interesting light on this. In a Swedish study, a group of volunteers deliberately ate two fast food meals daily and had their liver enzymes monitored. At the onset their blood tests were normal. After one week 75% had abnormal liver enzymes suggesting they were developing liver damage after one week.
In a second study, the SUCRE controlled trial, a group aged between 9 and 19 years old were investigated. They found 25 out of the 42 already had signs of fatty liver. They were put on two diets of equal calories, one with sugar and one without. Those on the sugar-free diet reduced their liver fat by 29% over the 10 days, their fasting insulin went down 10% and triglycerides were halved whereas those taking sugar did not.
This result was ground-breaking. It demonstrated conclusively that it was not calories but sugar that was responsible for fatty liver (and diabetes).
What strikes me about these studies is how quickly the liver can be harmed by junk food and how quickly in can reverse when on a healthy diet.
However, here is another crucial study which helps us understand fatty liver. In this ground-breaking study mice were fed them either chow, (a rodent feed made from ground wheat with fish and animal products), 4% soybean oil or 19% soybean oil. Those fed chow had no problems. Those fed 4% soybean oil developed fatty liver at 36 weeks. Those 19% soybean oil developed fatty liver at 19 weeks and severe liver damage at 36 weeks. What does this mean? It means that soybean oils (and other processed oils) are a major cause of fatty liver.
Vegetable oils are everywhere; they make up 32% of the calories in the standard western diet (sugar 22%). Soybean oils were responsible for 0.02% of calories in 1909 but 20% by 2000. They cause 9% more weight gain than fructose. They have no nutritional value and a worrying number of harmful effects (weight gain, diabetes, heart disease, increased mortality). They are among the most damaging foods we can eat. One of the best things you could do for your health is avoiding processed foods (which virtually all contain these oils) and avoid highly-processed cooking oils like sunflower, soybean, safflower, rapeseed (also called canola) and corn oils. Cook in butter, lard or (good quality) olive oil instead.
The best diet for NAFDL is one with little or none of the foods which convert into sugar, such as refined carbohydrates (white flour, most bread, white rice, cooked potatoes and processed foods) but even more important a diet with no sugar (or to be more specific no fructose – 50% of sugar is fructose). High-fructose corn syrup, which is present in almost all processed food, contains more fructose than sugar (55%). Sugar, high-fructose corn syrup and industrial oils are the major drivers for this disease. One study found 80% of people with NAFL were taking high fructose corn syrup and 30% were taking it daily.
Unlike other sugars, such as glucose, fructose can only be broken down in the liver, and once the liver is overloaded with fructose it starts to malfunction.
A more detailed version of the dietary changes for fatty liver can be found on the leaflet for metabolic syndrome leaflet. The first and essential step is stopping sugar and high-fructose corn syrup. The second step is removing vegetable oils. The third step is reducing refined carbohydrates and diet drinks. Eating plenty of fruit and vegetables whilst reducing meat and dairy, avoiding snacking, having a long gap between the last food in the day and first in the morning (ideally over 12 hours) and exercising more can also help.
Toxicity may be a further factor in fatty liver. On study showed that rats exposed to the weed killer, glyphosphate (Roundup), at a dose which was a staggering 5000 times below than safety limit developed fatty liver. Many of our crops, especially wheat are contaminated with traces of glyphosphate.
Drugs, too, can be a cause of fatty liver. These include steroids, diltiazem, amiodarone, tamoxifen and AIDs drugs.