Fatty liver disease

"As the nation gets heavier, our livers will get fatter."
---Chin Hee Kim, MD

Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease AND it affects 20-30% of the US population per Drs. Kim and Younossi writing in the Cleveland Clinic Journal of Medicine(1). NAFLD can range from no big deal fat in liver through inflammation and liver cell damage (nonalcoholic steatohepatosis or NASH) to cirrhosis, liver cancer, or liver failure.

The standard, automated laboratory blood profile includes a panel of liver enzymes. These transaminases(2) which are involved in the production of amino acids are part of the biochemical equipment within liver cells. They are normally present in the bloodstream in small amounts, but disruption of liver cells causes their blood levels to rise. A case of hepatitis skyrockets transaminase levels into the 1,000s and beyond, but even very low level elevations found on lab screening are worthy of follow-up because they may indicate an ongoing, asymptomatic inflammatory liver process that can ultimately lead to cirrhosis and liver failure.

Often, elevated liver enzymes or liver function tests (LFTs) in overweight persons demonstrating signs of metabolic troubles (fat concentrated around the waistline, elevated blood pressure, elevated triglycerides, low HDL, or high blood sugar) are the first sign of NAFLD. This fatty liver business is usually asymptomatic and only noted on lab testing. In order to chase down the cause of abnormal LFTs, we next order tests to check for chronic hepatitis B or C infections, auto-immune liver disease, or metabolic diseases such as abnormally stored copper or iron in the liver. An ultrasound of the liver is fairly accurate in assessing the presence of fat in the liver.

Liver biopsy is the best way to determine if the fatty liver troubles are benign or carry a risk of progression from nonalcoholic steatohepatosis to scarring and permanent liver damage or failure. Once diagnosed, the best approach to treating fatty livers is the same strategy that improves overall health in overweight persons on the road to diabetes or heart disease. These include weight loss (including use of bariatric or gastric bypass procedures), trials of various drugs that promote insulin sensitivity such as metformin, Actos, or Avandia or drugs that lower triglycerides and raise HDL levels such as statins and gemfibrozil. Fatty livers are more sensitive to damage from regular alcohol intake.

If you tend to pack the pounds around your waistline, be sure to ask your doctor to test your liver enzymes.
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1) Kim, HK and Younossi, ZM. Nonalcoholic fatty liver disease: A manifestation of the metabolic syndrome. Cleveland Clinic Journal of Medicine. October, 2008, Vol 75, pp 721-728.
2) Aspartate transaminase (AST) and alanine transaminase (ALT) levels generally range up to 40 or so. In mild NAFLD, AST <> ALT.

Fidgeting and weight loss

I got a pedometer that actually works this holiday season. I discovered not only do I get well over half of my recommended 10,000 steps in a 90 minute Jazzercise workout (did that yesterday), but also that I don't sit still very long. This reminded me of a study I wrote about some time ago, so I thought I'd share it with you that you might consider the health benefits of racing around looking for your keys etc. as you consider your New Year's Resolution List (1. Fidget more, 2. Run upstairs to answer the phone instead of putting the handset on the table next to your recliner, etc.).

Consider inclinometers and triaxial accelerometers. Gizmos found in the instrument panel of a fighter jet that were sewn for this study into the high-tech underwear encasing the more or less active behinds of twenty Minnesotans. While all of the subjects were self-proclaimed 'couch potatoes,' half were lean and half were mildly obese. Dr. James Levine and colleagues then recorded 25 million underwear-generated data points on posture and movement from each subject over ten days. The Mayo Clinic investigators believe the results may explain why some persons tend to put on the pounds more easily than others.

Healthy adults gain weight when energy in (food) exceeds energy out (daily activity). While energy expenditure occurs during exercise, a large part of our daily calorie output is Non-Exercise Activity Thermogenesis or NEAT. Dr. Levine defines NEAT as "physical activities other than volitional exercise, such as the activities of daily living, fidgeting, spontaneous muscle contraction, and maintaining posture when not recumbent." The more you twitch, squirm, and generally fussbudget through your daily activities, the more calories you burn in this unexpected way. The researchers discovered that their obese volunteers were seated daily for 164 minutes more than were lean participants. In fact, if the heavier group had demonstrated the same NEAT behavior as their skinnier colleagues, they would've burned off an extra 350 calories per day or the equivalent of 7 pounds per year.

The Mayo endocrinologists had previously conducted research on the effects of overeating on NEAT. They stuffed an extra 1000 calories/day over 8 weeks into sixteen normal weight volunteers. During the two month feeding extravaganza, the subjects increased their energy output in subtle but significant ways, burning the majority of the extra calories as NEAT. Based on these studies, the researchers theorize that while obese individuals may "have a biologically determined posture allocation" (genetically inclined to hit the recliner), perhaps they can be taught to consciously overcome their torpid destiny with increased body busyness as part of a weight loss program.

It may take a village to make you overweight. New evidence suggests that those bacterial hangers-on living in your gastrointestinal tract may be partly to blame for the state of your waist.

Microbiologists at Washington University in St. Louis checked out the gut bugs in mice of various sizes. The docs found that the resident GI fauna differed predictably based on the size of the host.

Furthermore, when the researchers analyzed the intestinal microbes of obese people, they found the population skewed heavily towards Firmicutes and short on Bacteroidetes compared with normal weight controls. After weight loss, the little Firmicutes lost ground to a growing group of Bacteroidetes, assuming a pattern more consistent with that of their leaner colleagues.

If mousy microbes are at all indicative of those that we carry through life, here's what your little gut friends may be doing to you:

Microbes from the obese mice had more genes for processing starches and complex sugars and produced more simple sugars and fatty acids--that is, calories--for the gut to absorb.

You snooze, you lose?

I've always wondered at my patients who get up early--really early--to go exercise. Losing sleep to lose weight may be a losing proposition. Multiple studies suggest that short sleep duration is associated with obesity. So sleep in and skip the pumpkin latte--that's a better strategy for health.

"Snickers Bar Theory"

Dr. William Blank of New York's Lutheran Medical Center has written an excellent explanation as to why a little extra food each day goes a long way towards adding on the pounds:

"Let's assume that a person is of normal weight and that his weight has remained perfectly stable for 2 years. That means that, through activity and exercise, the person burns the same number of calories that he consumes each day.

Now, let's add to that equation one Snickers bar eaten every day (or for that matter any other candy bar or small bag of chips), but the person does no additional exercise to burn off those extra calories.

In 1 week, he will have gained about half a pound. Now, multiply that by 52 weeks, and in 1 year he could gain 26 pounds. In 5 years, the amount gained would have reached 130 pounds--all from an addtional, unburned daily candy bar."