That’s my primary assessment of an article I read in Current Opinion on Clinical Nutrition and Metabolic Care. The title is “Low-carbohydrate ketogenic diets, glucose homeostasis, and nonalcoholic fatty liver disease.”
Don’t assume mouse physiology is the same as human’s
The article’s more about mice than my patients.
The authors share some stats about nonalcoholic fatty liver disease (NAFLD):
- the earliest stage is fat build-up in the liver
- 15% of the nonobese population has NAFLD
- 65% of the obese have NAFLD
- it can progress to an inflammatory disorder (nonalcoholic steatohepatitis (NASH)
- about two out of 10 NASH patients progress to cirrhosis within 10 years
- NAFLD is an independent predictor of heart and vascular disease, an even stronger predictor than overall body fat mass (even visceral fat)
- insulin resistance is strongly linked to NAFLD
The Washington University School of Medicine authors say good things about low-carbohydrate ketogenic diets for weight loss and seizure control. They spend the rest of the article talking about rodent physiology and lab chows—right up Carbsane Evelyn‘s alley. But not mine. Bores me to tears.
They do mention the small Browning study that showed a very-low-carb ketogenic diet superior to a calorie-restricted diet for reducing liver fat in humans. Weight loss by various methods is a standard recommendation for humans with NAFLD; I wouldn’t be surprised multiple different diets worked. It may be the weight loss, not the diet, that does the trick. We have just one human study thus far indicating a ketogenic diet is more effective short-term.
Here’s the full Browning study if you care to read it yourself.
If I were obese and had NAFLD, I’d go on a very-low-carb ketogenic diet (like this one).
Steve Parker, M.D.
Reference: Schugar, Rebecca, and Crawford, Peter. Low-carbohydrate ketogenic diets, glucose homeostasis, and nonalcoholic fatty liver disease. Curr Opin Clin Nutr Metab Care, 2012, vol. 15. doi: 10.1097/MCO.0b013e3283547157
Loss of excess weight is a mainstay of therapy for nonalcoholic fatty liver disease. A very-low-carb diet works better than a reduced-calorie diet, according to a study in the American Journal of Clinical Nutrition.
Nonalcoholic fatty liver disease (NAFLD) occurs in 20 to 40% of the general population, with most cases occuring between the ages of 40 and 60. It’s an accumulation of triglycerides in the liver. For every week I work in the hospital, I see five or 10 scans (either CT scans or sonograms) that incidentally show fat build-up in the liver.
Nonalcoholic steatohepatitis (NASH) is a subset of NAFLD, perhaps 30% of those with NAFLD. Steatohepatitis involves an inflammatory component, progressing to cirrhosis in 3 to 26% of cases.
Researchers at the University of Texas Southwestern Medical Center assigned 18 obese subjects (average BMI 35) to either a very-low-carb diet (under 20 grams a day) or a low-calorie diet (1200 to 1500 calories a day) for two weeks. Liver fat was measured by magnetic resonance technology. The low-carb groups’ liver fat decreased by 55% compared to 28% in the other group. Weight loss was about the same for both groups (4.6 vs 4 kg).
This small study needs to be replicated, ideally with a larger group of subjects studied over a longer period. Nevertheless, it appears that a very-low-carb diet may be one of the best dietary approaches to nonalcoholic fatty liver disease. And I bet it’s more sustainable than severe calorie restriction. The Ketogenic Mediterranean Diet, by the way, provides 20-30 grams of carb daily.
Steve Parker, M.D.
Reference: Browning, Jeffrey, et al. Short-term weight loss and hepatic triglyceride reduction: evidence of a metabolic advantage with dietary carbohydrate restriction. Am J Clin Nutr, May 2011 vol. 93 no. 5 1048-1052. doi: 10.3945/ajcn.110.007674