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Dietary Comparison Effects of Intrahepatic Fat and Postprandial Glycemia 

Mar 31, 2020
 
Editor: Steve Freed, R.PH., CDE

Author: Deonna Andrews, PharmD Candidate 2020 of Florida Agricultural & Mechanical University College of Pharmacy and Pharmaceutical Sciences 

Dietary habits play an essential part in our overall health, and can negatively affect metabolic health. Researchers studied the effect of two diets on intrahepatic triacylglycerol content, hepatic de novo lipogenesis, & whole-body postprandial metabolism.

Predicting the development of metabolic syndrome and type 2 diabetes, the presence of nonalcoholic fatty liver disease represents a spectrum of liver-related conditions. These conditions range from steatosis to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma, which is the most prevalent liver disease worldwide. The mere presence of nonalcoholic fatty liver disease can exacerbate the metabolic abnormalities that occur with type 2 diabetes. Obesity being the primary risk factor for nonalcoholic fatty liver disease, researchers believe that increased hepatic de novo lipogenesis is an underlying cause in the development of nonalcoholic fatty liver disease and insulin resistance.   

Observationally, previous studies have reported that diets high in fat and free sugars are indeed related to nonalcoholic fatty liver disease. Interventional studies showed consistent findings that hypercaloric foods enriched in fat or sugars increased intrahepatic triacylglycerol. A separate study reported that the consumption of 1,000 excess kcal/day as saturated fat increased intrahepatic triacylglycerol content to a greater extent of 55% than consuming excess calories as unsaturated fatty acids or free sugars. Lastly, a study reported that intrahepatic triacylglycerol increased to a higher level with overfeeding of saturated fatty acids when compared with diets eating either fructose or polyunsaturated fat.  

The objective of this study was to determine the influence of dietary fats and sugars on the risk of developing metabolic diseases. Researchers sought to probe the effect of two eucaloric diets, one consisting of saturated fats and the other with free sugars, on intrahepatic triacylglycerol content, hepatic de novo lipogenesis, and whole-body postprandial metabolism in overweight males. Every participant was metabolic disease free, had a BMI between 25 and 30 kg/m, were not taking medication known to affect lipid or glucose metabolism, were nonsmokers and consumed alcohol within recommended limits. This was a randomized crossover design in which participants completed two four-week dietary interventions separated by a 7-week wash-out period where they returned to their habitual diet.  

Comparison of pre- to post-diet were assessed using a paired t-test. Using a two-way repeated-measures ANOVA, postprandial data were compared with the time and experimental diet as within-subject effects, as well as a Bonferroni post hoc analysis where appropriate. Statistical significance was considered at a p-value < 0.05.  

Upon the conclusion of this study, researchers found that a diet consumption of saturated fats significantly increased intrahepatic triacylglycerol by ten percent. However, a diet enriched with free sugars was not significant on the intrahepatic triacylglycerol. An exaggerated postprandial glucose and insulin response was observed with the saturated fat consumption diet when compared with the free sugar consumption diet. Even when considering the similarities between the diets, whole-body fat oxidation, lipolysis, and de novo lipogenesis, the free sugar diet showed results that had a significant decrease in plasma total, HDL, and non-HDL cholesterol and fasting beta-hydroxybutyrate plasma concentrations.   

Overall, a diet prominent in saturated fats is more harmful to a person’s metabolic health than a diet prominent in free sugars. Although these findings are substantial, there are limitations that should be considered. First, food was not provided to participants as in some previous studies, which resulted in participants gaining weight in the saturated fats diet. Also, only overweight males were studied and any findings in females would differ from what was reported in this study. 

Practice Pearls: 

  • Dietary consumption has the potential to influence nonalcoholic fatty liver disease. 
  • Researchers found that a diet high in saturated fats is more harmful than a diet high in free sugars. 
  • Limitations exist which are not inclusive of both genders.  

 

Parry, Siôn A., et al. “Intrahepatic Fat and Postprandial Glycemia Increase After Consumption of a Diet Enriched in Saturated Fat Compared With Free Sugars.” Diabetes Care, American Diabetes Association, 12 Mar. 2020, care.diabetesjournals.org/content/early/2020/03/12/dc19-2331. 

 

Deonna Andrews, PharmD Candidate 2020 of Florida Agricultural & Mechanical University College of Pharmacy and Pharmaceutical Sciences 

 

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