Impact of Hypocaloric Hyperproteic Diet on Gut Microbiota in Overweight or Obese Patients with Nonalcoholic Fatty Liver Disease: A Pilot Study.

BACKGROUND

NAFLD is likely to become the most common cause of chronic liver disease. The first-line treatment includes weight loss.

AIMS

To analyze the impact of a hypocaloric hyperproteic diet (HHD) on gut microbiota in NAFLD patients.

METHODS

Fifteen overweight/obese patients with NAFLD were included. At baseline and after a 3-week HHD (Eurodiets(®), ~1000 kcal/day, ~125 g protein/day), we measured gut microbiota composition and function by shotgun metagenomics; body weight; body composition by bioelectrical impedance analysis; liver and visceral fat by magnetic resonance imaging; plasma C-reactive protein (CRP); and liver tests. Results between both time points, expressed as median (first and third quartile), were compared by Wilcoxon signed-rank tests.

RESULTS

At baseline, age was 50 (47-55) years and body mass index 34.6 (32.4, 36.7) kg/m(2). HDD decreased body weight by 3.6 % (p < 0.001), percent liver fat by 65 % (p < 0.001), and CRP by 19 % (p = 0.014). HDD was associated with a decrease in Lachnospira (p = 0.019), an increase in Blautia (p = 0.026), Butyricicoccus (p = 0.024), and changes in several operational taxonomic units (OTUs) of Bacteroidales and Clostridiales. The reduced liver fat was negatively correlated with bacteria belonging to the Firmicutes and Bacteroidetes phyla (a Ruminococcaceae OTU, r = -0.83; Bacteroides, r = -0.73). The associated metabolic changes concerned mostly enzymes involved in amino acid and carbohydrate metabolism.

CONCLUSIONS

In this pilot study, HHD changes gut microbiota composition and function in overweight/obese NAFLD patients, in parallel with decreased body weight, liver fat, and systemic inflammation. Future studies should aim to confirm these bacterial changes and understand their mode of action.

TRAIL REGISTRATION

Under clinicaltrials.gov: NCT01477307.