An energy-restricted high-protein diet supplemented with β-cryptoxanthin alleviated oxidative stress and inflammation in nonalcoholic fatty liver disease: a randomized controlled trial.

The efficacy of β-cryptoxanthin (BCX), a high-protein diet (HPD), or both in reducing oxidative stress and inflammation in nonalcoholic fatty liver disease (NAFLD) has never been examined within a randomized controlled trial (RCT). Thus, we aimed to assess the efficacy of an energy-restricted HPD supplemented with BCX in alleviating these conditions in NAFLD in an RCT design. We hypothesized that this combination may improve oxidative stress and inflammation in NAFLD as compared to a standard energy-restricted diet. Ninety-two ultrasonographically confirmed overweight/obese adult NAFLD patients attending an outpatient clinic in Ahvaz, Iran, were recruited for this 12-week, single-center, parallel-group, double-blind RCT from 2017 to 2018. Subjects were randomized into 4 equal groups (n = 23): HPD-BCX (energy-restricted HPD + BCX), HPD (energy-restricted HPD + placebo), BCX (standard energy-restricted diet + BCX), and control (standard energy-restricted diet + placebo). Serum levels of oxidative stress- and inflammation-related markers, as primary outcome measures, were determined at baseline and at the study end point. The 1-way analysis of covariance models in the intention-to-treat population (N = 92) showed that the HPD-BCX group achieved greater 12-week reductions in malondialdehyde, high-sensitivity C-reactive protein, interleukin-6, and total cytokeratin-18 (CK18-M65) but higher increases in total antioxidant capacity and adiponectin compared to the control group (mean differences for malondialdehyde, high-sensitivity C-reactive protein, interleukin-6, total cytokeratin-18, total antioxidant capacity, and adiponectin were -1.9 nmol/mL, -1.0 mg/L, -2.0 ng/L, -270.9 ng/L, 2.5 U/mL, and 1.9 mg/L, respectively; all P < .001). These results show that an energy-restricted HPD supplemented with BCX more efficaciously alleviates oxidative stress and inflammation in NAFLD as compared to a standard energy-restricted diet.