Extra virgin olive oil (EVOO) consumption and antioxidant status in healthy institutionalized elderly humans

Role of dietary pro-oxidants in the maintenance of health and resilience to oxidative stress

The average length of human life is increasing, but so does the incidence of age- and lifestyle-related diseases. Improving diet and lifestyle is a key strategy for lifelong health and underlying mechanisms may well include increasing resilience pathways. The purpose of this review is to highlight and evaluate novel mechanisms by which dietary pro-oxidants, including bioactive phytochemicals and fatty acids, increase reactive oxygen species (ROS) concentrations just enough to activate transcription factor activation of nuclear factor erythroid 2 related factor 2 (Nrf-2) and heat shock factor (HSF), leading to an increase in levels of antioxidant enzymes and heat shock proteins that protect against the damaging effects of ROS. An increasing number of in vivo studies have now shown that dietary pro-oxidant compounds can increase the production of such resilience products. In most studies, dietary pro-oxidants normalized levels of antioxidant enzymes that were decreased by a range of different challenges, rather than raising levels of resilience products per se. Also, it is important to consider that the antioxidant response can be different for different organs. For future studies, however, the measurement of resilience markers may significantly improve our ability to prove the efficacy by which dietary bioactives with pro-oxidant capacities improve lifelong health.

Extravirgin Olive Oil Consumption Reduces Risk of Atrial Fibrillation

Background—

The PREDIMED (Prevención con Dieta Mediterránea) primary prevention trial showed that a Mediterranean diet enriched with either extravirgin olive oil or mixed nuts reduces the incidence of stroke, myocardial infarction, and cardiovascular mortality. We assessed the effect of these diets on the incidence of atrial fibrillation in the PREDIMED trial.

Methods and Results—

Participants were randomly assigned to 1 of 3 diets: Mediterranean diet supplemented with extravirgin olive oil, Mediterranean diet supplemented with mixed nuts, or advice to follow a low-fat diet (control group). Some departures from individual randomization occurred in a subset of the trial because members of the same household and small clinics in one of the 11 recruiting centers were allocated by clusters instead of individually. Incident atrial fibrillation was adjudicated during follow-up by an events committee blinded to dietary group allocation. Among 6705 participants without prevalent atrial fibrillation at randomization, we observed 72 new cases of atrial fibrillation in the Mediterranean diet with extravirgin olive oil group, 92 in the Mediterranean diet with mixed nuts group, and 89 in the control group after median follow-up of 4.7 years. The Mediterranean diet with extravirgin olive oil significantly reduced the risk of atrial fibrillation (hazard ratio, 0.62; 95% confidence interval, 0.45–0.86 compared with the control group) after adjusting for propensity scores and using robust variance estimators to account for the intra-cluster correlations. No effect was found for the Mediterranean diet with nuts (hazard ratio, 0.86; 95% confidence interval, 0.63–1.16). In secondary analyses done after excluding all participants randomized in clusters, the results did not materially change.

Conclusions—

In the absence of proven interventions for the primary prevention of atrial fibrillation, this post hoc analysis of the PREDIMED trial suggests that a lower incidence of atrial fibrillation was found after an intervention with extravirgin olive oil in the context of a Mediterranean dietary pattern.

Clinical Trial Registration—

URL: http://www.controlled-trials.com . Unique identifier: ISRCTN35739639.

The effect of olive oil on osteoporosis prevention

The incidence of osteoporosis and associated fractures is found to be lower in countries where the Mediterranean diet is predominant. These observations might be mediated by the active constituents of olive oil and especially phenolic compounds.

OBJECTIVE

To review current knowledge by searching for all relevant publications since 2001 in the MEDLINE, EMBASE and Cochrane Library databases, using the descriptors: Mediterranean diet, virgin olive oil, phenols, bone, osteoblast and osteoporosis.

RESULTS AND CONCLUSIONS

Published evidence suggests that olive oil phenols can be beneficial by preventing the loss of bone mass. It has been demonstrated that they can modulate the proliferative capacity and cell maturation of osteoblasts by increasing alkaline phosphatase activity and depositing calcium ions in the extracellular matrix. Further research on this issue is warranted, given the prevalence of osteoporosis and the few data available on the action of olive oil on bone.

Membrane composition and dynamics: a target of bioactive virgin olive oil constituents

The endogenous synthesis of lipids, which requires suitable dietary raw materials, is critical for the formation of membrane bilayers. In eukaryotic cells, phospholipids are the predominant membrane lipids and consist of hydrophobic acyl chains attached to a hydrophilic head group. The relative balance between saturated, monounsaturated, and polyunsaturated acyl chains is required for the organization and normal function of membranes. Virgin olive oil is the richest natural dietary source of the monounsaturated lipid oleic acid and is one of the key components of the healthy Mediterranean diet. Virgin olive oil also contains a unique constellation of many other lipophilic and amphipathic constituents whose health benefits are still being discovered. The focus of this review is the latest evidence regarding the impact of oleic acid and the minor constituents of virgin olive oil on the arrangement and behavior of lipid bilayers. We highlight the relevance of these interactions to the potential use of virgin olive oil in preserving the functional properties of membranes to maintain health and in modulating membrane functions that can be altered in several pathologies. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.

Biological Activities of Phenolic Compounds of Extra Virgin Olive Oil

Over the last few decades, multiple biological properties, providing antioxidant, anti-inflammatory, chemopreventive and anti-cancer benefits, as well as the characteristic pungent and bitter taste, have been attributed to Extra Virgin Olive Oil (EVOO) phenols. In particular, growing efforts have been devoted to the study of the antioxidants of EVOO, due to their importance from health, biological and sensory points of view. Hydrophilic and lipophilic phenols represent the main antioxidants of EVOO, and they include a large variety of compounds. Among them, the most concentrated phenols are lignans and secoiridoids, with the latter found exclusively in the Oleaceae family, of which the drupe is the only edible fruit. In recent years, therefore, we have tackled the study of the main properties of phenols, including the relationships between their biological activity and the related chemical structure. This review, in fact, focuses on the phenolic compounds of EVOO, and, in particular, on their biological properties, sensory aspects and antioxidant capacity, with a particular emphasis on the extension of the product shelf-life.

Effect of bioactive substances found in rapeseed, raspberry and strawberry seed oils on blood lipid profile and selected parameters of oxidative status in rats

Rapeseed, strawberry and raspberry seed oils are a rich source of polyunsaturated fatty acids and antioxidants such as tocols, bioflavonoids and phytosterols. The aim of the study was to determine changes in the blood lipid profile of rats fed with rapeseed, strawberry and raspberry seed oils and their effects on selected parameters of oxidative status. The experiment was carried out on male Wistar rats. The oils were administered by oral gavage for 5 weeks once daily at the dose of about 0.8 ml per rat. Blood samples were taken before and after supplementation period. The activity of superoxide dismutase (SOD) and glutathione peroxidase (cGPx) was assessed in erythrocytes and contents of triglycerides (TG), total cholesterol, low-density fraction of cholesterol (LDL) and high-density fraction of cholesterol (HDL) were assessed in plasma. The experiment shows that oils supplemented in the diet for 5 weeks had no significant effect on the level of triglyceride (TG), total cholesterol as well as HDL and LDL fractions. Reduced activity of cGPX and SOD in the group of rats receiving raspberry and strawberry seed oils suggests that these native oils may contribute to oxidative stability (improves antioxidant status). Thus, strawberry and raspberry seed oils can be considered as special biological oils, which constitute potential nutraceuticals reducing oxidative stress.