Does Dietary Intake Impact Omentin Gene Expression and Plasma Concentration? A Systematic Review

Abstract

Background: Omentin is an adipokine with anti-inflammatory and insulin-sensitizing effects that can play a protective role against cardiovascular disease and diabetes. The aim was to systematically review and summarize the existing evidence on the association between overall dietary intake and omentin gene expression and circulation. Summary: A literature search was conducted in PubMed, Scopus, and Web of Science up to September 2019. Of the 1,940 retrieved articles, 20 relevant studies were included, 6 of which were observational, 11 were clinical trials in humans, and 3 were animal studies. Four randomized controlled trials (RCTs) had a high risk of bias (RoB), 1 had “some concerns”, and 2 had a low RoB. Among the nonrandomized studies with comparators, 4 had a serious RoB and 2 had a moderate RoB. In the experimental animal studies with a moderate RoB, conflicting results for omentin serum concentration were found for high-fat and low-fat diets. A high-fat diet (HFD) was shown to reduce omentin gene expression in one animal study. In the observational studies, omentin serum concentration was reduced by Ramadan fasting and saturated fatty acid (SFA) intake, and an increase in omentin gene expression was observed with monounsaturated fatty acid (MUFA) intake. There was no association of dietary inflammatory index (DII), macronutrient intake, or total calorie intake with omentin plasma concentrations. In the human interventional studies, omentin plasma concentration increased with a long-term low-calorie, low-fat diet (LFD), and no change was seen with a HFD or a short-term low-calorie diet (LCD). Key Messages: It seems that a long-term diet with a lower fat content and a balanced distribution of fatty acids, i.e., a higher MUFA and lower SFA intake, may effectively increase omentin plasma concentration, possibly via improved insulin resistance and reduced inflammation, but more research is needed to confirm or refute this.

Ramadan Fasting in Health and Disease in 2021: A Narrative Review

“…The association between overall dietary intake and omentin gene expression and circulation was investigated. 12 Twenty relevant studies were included; six were observational and eleven were human clinical trials. In the observational studies, omentin serum concentration was reduced by RF and saturated fatty acid intake.…”

Clustering and Correlations amongst NEFA, Selected Adipokines and Morphological Traits—New Insights into Equine Metabolic Syndrome

“…Human studies have demonstrated that plasma omentin concentrations are reduced in obese individuals, likely due to inflammation and apoptosis of adipose tissue [ 15 , 49 , 50 ]. Reduction of plasma omentin levels has been significantly correlated with increased waist circumference, bodyweight, dyslipidemia, high blood pressure, and glucose intolerance [ 16 , 50 , 51 ].…”

“…A systematic review of animal and clinical studies was recently conducted to assess the association between overall dietary intake and omentin expression and circulation. The results indicated that a long-term diet with reduced fat content and a balanced distribution of fatty acids, i.e., a higher monounsaturated fatty acids and lower saturated fatty acid intake, may increase insulin sensitivity, reduce inflammation, and, consequently, effectively increase the plasma concentration of omentin, but more research is needed to consolidate these assumptions [ 15 ].…”

“…Omentin is mainly expressed in stromal vascular cells and is associated with anti-inflammatory, anti-atherogenic, anti-cardiovascular, and antidiabetic properties [ 13 , 14 , 15 ]. Omentin has been positively associated with adiponectin and high-density lipoprotein levels, and negatively related to bodyweight, waist circumference, and insulin resistance [ 16 , 17 ].…”