The NUTRAOLEOUM Study, a randomized controlled trial, for achieving nutritional added value for olive oils

The Metabolic and Analytical Changes of Healthy Volunteers upon Intake of Portuguese Extra Virgin Olive Oil: A Comparison Study between Pre- and Post-Intervention

(1) Background: Extra virgin olive oil (EVOO) is studied mostly for its health benefits in preventing non-communicable chronic diseases, particularly within a Mediterranean dietary pattern. However, few studies have addressed the effect of EVOO in healthy individuals, prior to an established disease. This study aims to evaluate the impact of Northern Portuguese polyphenol-rich EVOO (NPPR-EVOO) consumption on various important clinical parameters in healthy adult volunteers. (2) Methods: This quasi-experimental intervention study assessed the impact of NPPR-EVOO for a period of 100 days. Serum total cholesterol, HbA1c, HDL-c, LDL-c, and CRP, and anthropometric measures-waist and hip perimeters, hand grip strength, and body fat-were assessed and food logs were analyzed. (3) Results: Serum HbA1c (5.12 ± 0.32%; 4.93 ± 0.24, p = 0.000) and LDL-c (96.50 ± 28.57 mg/dL; 87.41 ± 31.38 mg/dL, p = 0.017) significantly decreased following NPPR-EVOO. Also, daily energy significantly increased, but no changes in other dietary parameters, or anthropometry, were seen. Adherence to the Mediterranean diet did not explain the differences found in individuals regarding serum lipid profile and HbA1c, reinforcing the role of EVOO's effect. (4) Conclusions: NPPR-EVOO lowered the serum levels of LDL cholesterol and HbA1c, providing clues on the effect of EVOO-putative health benefits. These results pave the way for a deeper exploration of EVOO as a functional food.

Enrichment of Refined Olive Oils with Phenolic Extracts of Olive Leaf and Exhausted Olive Pomace

Refined olive oils (ROOs) are commonly enriched with synthetic antioxidants. Antioxidant extracts obtained from natural products can be used to improve the stability of these oils. In this study, ROOs were enriched through the addition of phenolic extracts from olive leaves (OLs) and exhausted olive pomace (EOP). In addition to replacing synthetic antioxidants with natural ones, this results in the valorization of these olive-derived biomasses. The most suitable method for mixing and enriching refined oils was probe-type ultrasonication using lecithin as the emulsifier. Thereafter, the change in the content of antioxidant compounds and the antioxidant capacity of the oils at 25, 35, and 45 °C were studied over 28 and 50 days of storage. The experimental results were fitted using a pseudo-first-order kinetic model. The oxidative stability index of the ROO enriched with a 2 g/L OL extract (70 h) was higher than that of a commercial ROO (46.8 h). Moreover, the oxidative stability index of the refined olive pomace oil (ROPO) enriched with a 2 g/L EOP extract (44.1 h) was higher than that of a commercial ROPO (38.9 h). In addition, the oxidative stabilities and antioxidant capacities of the oils were significantly correlated.

Wide Biological Role of Hydroxytyrosol: Possible Therapeutic and Preventive Properties in Cardiovascular Diseases

The growing incidence of cardiovascular disease (CVD) has promoted investigations of natural molecules that could prevent and treat CVD. Among these, hydroxytyrosol, a polyphenolic compound of olive oil, is well known for its antioxidant, anti-inflammatory, and anti-atherogenic effects. Its strong antioxidant properties are due to the scavenging of radicals and the stimulation of synthesis and activity of antioxidant enzymes (SOD, CAT, HO-1, NOS, COX-2, GSH), which also limit the lipid peroxidation of low-density lipoprotein (LDL) cholesterol, a hallmark of atherosclerosis. Lowered inflammation and oxidative stress and an improved lipid profile were also demonstrated in healthy subjects as well as in metabolic syndrome patients after hydroxytyrosol (HT) supplementation. These results might open a new therapeutic scenario through personalized supplementation of HT in CVDs. This review is the first attempt to collect together scientific literature on HT in both in vitro and in vivo models, as well as in human clinical studies, describing its potential biological effects for cardiovascular health.

Pharmacokinetics of maslinic and oleanolic acids from olive oil - Effects on endothelial function in healthy adults. A randomized, controlled, dose-response study

To date, pharmacokinetics of maslinic (MA) and oleanolic (OA) acids, at normal dietary intakes in humans, have not been evaluated, and data concerning their bioactive effects are scarce. We assessed MA and OA pharmacokinetics after ingestion of olive oils (OOs) with high and low triterpenic acid contents, and specifically the effect of triterpenes on endothelial function. We performed a double-blind, dose-response, randomized, cross-over nutritional intervention in healthy adults, and observed that MA and OA increased in biological fluids in a dose-dependent manner. MA bioavailability was greater than that of OA, and consumption of pentacyclic triterpenes was associated with improved endothelial function. To the best of our knowledge, this is the first time MA pharmacokinetics, and effects on endothelial function in vivo, have been reported in humans.

Effects of Virgin Olive Oils Differing in Their Bioactive Compound Contents on Biomarkers of Oxidative Stress and Inflammation in Healthy Adults: A Randomized Double-Blind Controlled Trial

A regular consumption of virgin olive oil (VOO) is associated with a reduced risk of cardiovascular disease. We aimed to assess whether the raw intake of an optimized VOO (OVOO, 490 ppm of phenolic compounds and 86 ppm of triterpenes), and a functional olive oil (FOO, 487 ppm of phenolic compounds and enriched with 389 ppm of triterpenes) supplementation (30 mL per day) during three weeks would provide additional health benefits to those produced by a standard VOO (124 ppm of phenolic compounds and 86 ppm of triterpenes) on oxidative and inflammatory biomarkers. Fifty-one healthy adults participated in a randomized, crossover, and controlled study. Urinary 8-hidroxy-2′-deoxyguanosine, plasma interleukin-8 (IL-8), and tumor necrosis factor α (TNF- α) concentrations were lower after the intervention with the FOO than after the OVOO (p = 0.033, p = 0.011 and p = 0.020, respectively). In addition, IL-8 was lower after the intervention with FOO than after VOO intervention (p = 0.002). This study provides a first level of evidence on the in vivo health benefits of olive oil triterpenes (oleanolic and maslinic acids) in healthy humans, decreasing DNA oxidation and plasma inflammatory biomarkers. The trial was registered in ClinicalTrials.gov ID: NCT02520739.

Relevance of functional foods in the Mediterranean diet: the role of olive oil, berries and honey in the prevention of cancer and cardiovascular diseases

The traditional Mediterranean diet (MedDiet) is a well-known dietary pattern associated with longevity and improvement of life quality as it reduces the risk of the most common chronic pathologies, such as cancer and cardiovascular diseases (CVDs), that represent the principal cause of death worldwide. One of the most characteristic foods of MedDiet is olive oil, a very complex matrix, which constitutes the main source of fats and is used in the preparation of foods, both raw as an ingredient in recipes, and in cooking. Similarly, strawberries and raspberries are tasty and powerful foods which are commonly consumed in the Mediterranean area in fresh and processed forms and have attracted the scientific and consumer attention worldwide for their beneficial properties for human health. Besides olive oil and berries, honey has lately been introduced in the MedDiet thanks to its relevant nutritional, phytochemical and antioxidant profile. It is a sweet substance that has recently been classified as a functional food. The aim of this review is to present and discuss the recent evidence, obtained from in vitro, in vivo and epidemiological studies, on the potential roles exerted by these foods in the prevention and progression of different types of cancer and CVDs.

Effects of Virgin Olive Oils Differing in Their Bioactive Compound Contents on Metabolic Syndrome and Endothelial Functional Risk Biomarkers in Healthy Adults: A Randomized Double-Blind Controlled Trial

The aim of this study was to evaluate the effect of virgin olive oils (VOOs) enriched with phenolic compounds and triterpenes on metabolic syndrome and endothelial function biomarkers in healthy adults. The trial was a three-week randomized, crossover, controlled, double-blind, intervention study involving 58 subjects supplemented with a daily dose (30 mL) of three oils: (1) a VOO (124 ppm of phenolic compounds and 86 ppm of triterpenes); (2) an optimized VOO (OVOO) (490 ppm of phenolic compounds and 86 ppm of triterpenes); and (3) a functional olive oil (FOO) high in phenolic compounds (487 ppm) and enriched with triterpenes (389 ppm). Metabolic syndrome and endothelial function biomarkers were determined in vivo and ex vivo. Plasma high density lipoprotein cholesterol (HDLc) increased after the OVOO intake. Plasma endothelin-1 levels decreased after the intake of the three olive oils, and in blood cell cultures challenged. Daily intake of VOO enriched in phenolic compounds improved plasma HDLc, although no differences were found at the end of the three interventions, while VOO with at least 124 ppm of phenolic compounds, regardless of the triterpenes content improved the systemic endothelin-1 levels in vivo and ex vivo. No effect of triterpenes was observed after three weeks of interventions. Results need to be confirmed in subjects with metabolic syndrome and impaired endothelial function (Clinical Trials number NCT02520739).

Oleuropein Decreases Cyclooxygenase-2 and Interleukin-17 Expression and Attenuates Inflammatory Damage in Colonic Samples from Ulcerative Colitis Patients

Oleuropein (OLE) is the major phenolic secoiridoid of olive tree leaves, and its antioxidant and anti-inflammatory activities have been demonstrated in in vitro and in vivo animal models. The aim of this study was to investigate the activity of OLE in the colonic mucosa from patients with ulcerative colitis (UC). Biopsies obtained during colonoscopy from 14 patients with active UC were immediately placed in an organ culture chamber and challenged with lipopolysaccharide from Escherichia coli (EC-LPS) at 1 μg/mL in the presence or absence of 3 mM OLE. The expression of cyclooxygenase (COX)-2 and interleukin (IL)-17 was assessed in total protein extracts from treated colonic biopsies by Western blotting. Levels of IL-17 were also measured in culture supernatant by ELISA. A microscopic evaluation of the cultured biopsies was performed by conventional histology and immunohistochemistry. The expression of COX-2 and IL-17 were significantly lower in samples treated with OLE + EC-LPS compared with those treated with EC-LPS alone (0.80 ± 0.15 arbitrary units (a.u.) vs. 1.06 ± 0.19 a.u., p = 0.003, and 0.71 ± 0.08 a.u. vs. 1.26 ± 0.42 a.u., p = 0.03, respectively) as were the levels of IL-17 in culture supernatants of OLE + EC-LPS treated colonic samples (21.16 ± 8.64 pg/mL vs. 40.67 ± 9.24 pg/mL, p = 0.01). Histologically, OLE-treated colonic samples showed an amelioration of inflammatory damage with reduced infiltration of CD3, CD4, and CD20 cells, while CD68 numbers increased. The anti-inflammatory activity of OLE was demonstrated in colonic biopsies from UC patients. These new data support a potential role of OLE in the treatment of UC.