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Independent effects of diet and exercise training on fat oxidation in non-alcoholic fatty liver disease

View Article: PubMed Central - PubMed

ABSTRACT

Aim: To investigate the independent effects of 6-mo of dietary energy restriction or exercise training on whole-body and hepatic fat oxidation of patients with non-alcoholic fatty liver disease (NAFLD).

Methods: Participants were randomised into either circuit exercise training (EX; n = 13; 3 h/wk without changes in dietary habits), or dietary energy restriction (ER) without changes in structured physical activity (ER; n = 8). Respiratory quotient (RQ) and whole-body fat oxidation rates (Fatox) were determined by indirect calorimetry under basal, insulin-stimulated and exercise conditions. Severity of disease and steatosis was determined by liver histology; hepatic Fatox was estimated from plasma β-hydroxybutyrate concentrations; cardiorespiratory fitness was expressed as VO2peak. Complete-case analysis was performed (EX: n = 10; ER: n = 6).

Results: Hepatic steatosis and NAFLD activity score decreased with ER but not with EX. β-hydroxybutyrate concentrations increased significantly in response to ER (0.08 ± 0.02 mmol/L vs 0.12 ± 0.04 mmol/L, P = 0.03) but remained unchanged in response to EX (0.10 ± 0.03 mmol/L vs 0.11 ± 0.07 mmol/L, P = 0.39). Basal RQ decreased (P = 0.05) in response to EX, while this change was not significant after ER (P = 0.38). VO2peak (P < 0.001) and maximal Fatox during aerobic exercise (P = 0.03) improved with EX but not with ER (P > 0.05). The increase in β-hydroxybutyrate concentrations was correlated with the reduction in hepatic steatosis (r = -0.56, P = 0.04).

Conclusion: ER and EX lead to specific benefits on fat metabolism of patients with NAFLD. Increased hepatic Fatox in response to ER could be one mechanism through which the ER group achieved reduction in steatosis.

No MeSH data available.


Basal β-hydroxybutyrate concentrations before and after 6 mo of energy restriction (n = 6) or exercise training (n = 10). A: Average responses; B: Individual responses. aP < 0.05 between pre and post treatment.
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Figure 2: Basal β-hydroxybutyrate concentrations before and after 6 mo of energy restriction (n = 6) or exercise training (n = 10). A: Average responses; B: Individual responses. aP < 0.05 between pre and post treatment.

Mentions: As shown in Figure 2, basal plasma β-hydroxybutyrate concentrations, increased significantly in response to ER (0.08 ± 0.02 mmol/L vs 0.12 ± 0.04 mmol/L, P = 0.03) but remained unchanged in response to EX (0.10 ± 0.03 mmol/L vs 0.11 ± 0.07 mmol/L, P = 0.39). This result (unchanged β-hydroxybutyrate concentrations in response to EX) was confirmed also when the analysis was performed excluding the outlier (0.09 ± 0.03 mmol/L vs 0.09 ± 0.03 mmol/L, P = 0.87) (Figure 2). In the combined cohort including participants from both groups, there was a negative association between pre-post intervention changes in β-hydroxybutyrate and in hepatic steatosis (r = -0.56, P = 0.04) (Figure 3). This relationship persisted after controlling for changes in body weight (r = -0.67, P = 0.02) and percentage body weight (r = -0.56, P = 0.05).


Independent effects of diet and exercise training on fat oxidation in non-alcoholic fatty liver disease
Basal β-hydroxybutyrate concentrations before and after 6 mo of energy restriction (n = 6) or exercise training (n = 10). A: Average responses; B: Individual responses. aP < 0.05 between pre and post treatment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037327&req=5

Figure 2: Basal β-hydroxybutyrate concentrations before and after 6 mo of energy restriction (n = 6) or exercise training (n = 10). A: Average responses; B: Individual responses. aP < 0.05 between pre and post treatment.
Mentions: As shown in Figure 2, basal plasma β-hydroxybutyrate concentrations, increased significantly in response to ER (0.08 ± 0.02 mmol/L vs 0.12 ± 0.04 mmol/L, P = 0.03) but remained unchanged in response to EX (0.10 ± 0.03 mmol/L vs 0.11 ± 0.07 mmol/L, P = 0.39). This result (unchanged β-hydroxybutyrate concentrations in response to EX) was confirmed also when the analysis was performed excluding the outlier (0.09 ± 0.03 mmol/L vs 0.09 ± 0.03 mmol/L, P = 0.87) (Figure 2). In the combined cohort including participants from both groups, there was a negative association between pre-post intervention changes in β-hydroxybutyrate and in hepatic steatosis (r = -0.56, P = 0.04) (Figure 3). This relationship persisted after controlling for changes in body weight (r = -0.67, P = 0.02) and percentage body weight (r = -0.56, P = 0.05).

View Article: PubMed Central - PubMed

ABSTRACT

Aim: To investigate the independent effects of 6-mo of dietary energy restriction or exercise training on whole-body and hepatic fat oxidation of patients with non-alcoholic fatty liver disease (NAFLD).

Methods: Participants were randomised into either circuit exercise training (EX; n = 13; 3 h/wk without changes in dietary habits), or dietary energy restriction (ER) without changes in structured physical activity (ER; n = 8). Respiratory quotient (RQ) and whole-body fat oxidation rates (Fatox) were determined by indirect calorimetry under basal, insulin-stimulated and exercise conditions. Severity of disease and steatosis was determined by liver histology; hepatic Fatox was estimated from plasma &beta;-hydroxybutyrate concentrations; cardiorespiratory fitness was expressed as VO2peak. Complete-case analysis was performed (EX: n = 10; ER: n = 6).

Results: Hepatic steatosis and NAFLD activity score decreased with ER but not with EX. &beta;-hydroxybutyrate concentrations increased significantly in response to ER (0.08 &plusmn; 0.02 mmol/L vs 0.12 &plusmn; 0.04 mmol/L, P = 0.03) but remained unchanged in response to EX (0.10 &plusmn; 0.03 mmol/L vs 0.11 &plusmn; 0.07 mmol/L, P = 0.39). Basal RQ decreased (P = 0.05) in response to EX, while this change was not significant after ER (P = 0.38). VO2peak (P &lt; 0.001) and maximal Fatox during aerobic exercise (P = 0.03) improved with EX but not with ER (P &gt; 0.05). The increase in &beta;-hydroxybutyrate concentrations was correlated with the reduction in hepatic steatosis (r = -0.56, P = 0.04).

Conclusion: ER and EX lead to specific benefits on fat metabolism of patients with NAFLD. Increased hepatic Fatox in response to ER could be one mechanism through which the ER group achieved reduction in steatosis.

No MeSH data available.