Effect of the ingestion of vegetable oils associated with energy-restricted normofat diet on intestinal microbiota and permeability in overweight women.

Previous studies suggest that the type of dietary fatty acid may modulate the intestinal bacterial ecosystem. However, this effect is still inconclusive. Thus, the aim of this study was to investigate the effect of the intake of vegetable oils rich in different types of fatty acids, associated with energy-restricted normofat diets, on the composition of intestinal microbiota and permeability, on LPS concentrations, and fecal short chain fatty acids and pH. This was a 9 consecutive weeks (±5 days), randomized, parallel, double-blind clinical trial. Overweight women received daily breakfast containing 25 mL of one of the test oils: soybean oil (n = 17), extra virgin olive oil (n = 19) or coconut oil (n = 16). Blood, fecal and urine samples were collected on the first and last day of the experiment for the analysis of the variables of interest. The consumption of the three oils did not affect the diversity and relative abundance of intestinal bacteria. We observed an increase in bacterial richness estimated by the Chao 1 index, and a reduction in the concentration of isovaleric fatty acid in the group that ingested soybean oil. Paracellular and transcellular permeability increased after the ingestion of extra virgin olive oil and coconut oil. However, LPS concentrations remained unchanged. The intake of different types of fatty acids associated with the energy-restricted normofat diet modestly affected the intestinal microbiota and permeability, without resulting in metabolic endotoxemia in overweight women.

Effects of dietary fat quality on metabolic endotoxaemia: a systematic review.

In this systematic review, we critically evaluated human clinical trials that assessed the effects of dietary fat quality on metabolic endotoxaemia. The studies were selected from three databases (PubMed, Scopus and Cochrane Library), and the keywords were defined according to the Medical Subject Headings indexing terminology. Two authors searched independently, according to the pre-defined selection criteria. Quality and risk assessment of bias for each selected study were also evaluated. The results of the included studies demonstrated associations between higher SFA intake and increased postprandial lipopolysaccharide (LPS) concentrations. On the other hand, after the consumption of PUFA, bloodstream LPS concentrations were lower. However, in none of the long-term studies, the consumption of dietary fats did not seem to exert effects on LPS concentration. Hence, SFA seem to act as a risk factor for transient increase in endotoxaemia, while PUFA demonstrated exerting a protective effect. Taken together, the evidence suggests that the dietary fatty acid profile may influence bloodstream endotoxin concentrations through modulation of factors such LPS clearance, alkaline phosphatase activity, bile acid metabolism, intestinal permeability and intestinal microbiota composition.

Consumption of extra virgin olive oil improves body composition and blood pressure in women with excess body fat: a randomized, double-blinded, placebo-controlled clinical trial.

PURPOSE: Despite the fact that extra virgin olive oil (EVOO) is widely used in obese individuals to treat cardiovascular diseases, the role of EVOO on weight/fat reduction remains unclear. We investigated the effects of energy-restricted diet containing EVOO on body composition and metabolic disruptions related to obesity. METHODS: This is a randomized, double-blinded, placebo-controlled clinical trial in which 41 adult women with excess body fat (mean ± SD 27.0 ± 0.9 year old, 46.8 ± 0.6% of total body fat) received daily high-fat breakfasts containing 25 mL of soybean oil (control group, n = 20) or EVOO (EVOO group, n = 21) during nine consecutive weeks. Breakfasts were part of an energy-restricted normal-fat diets (-2090 kJ, ~32%E from fat). Anthropometric and dual-energy X-ray absorptiometry were assessed, and fasting blood was collected on the first and last day of the experiment. RESULTS: Fat loss was ~80% higher on EVOO compared to the control group (mean ± SE: -2.4 ± 0.3 kg vs. -1.3 ± 0.4 kg, P = 0.037). EVOO also reduced diastolic blood pressure when compared to control (-5.1 ± 1.6 mmHg vs. +0.3 ± 1.2 mmHg, P = 0.011). Within-group differences (P < 0.050) were observed for HDL-c (-2.9 ± 1.2 mmol/L) and IL-10 (+0.9 ± 0.1 pg/mL) in control group, and for serum creatinine (+0.04 ± 0.01 µmol/L) and alkaline phosphatase (-3.3 ± 1.8 IU/L) in the EVOO group. There was also a trend for IL-1ß EVOO reduction (-0.3 ± 0.1 pg/mL, P = 0.060). CONCLUSION: EVOO consumption reduced body fat and improved blood pressure. Our results indicate that EVOO should be included into energy-restricted programs for obesity treatment.