Extra-virgin olive oil and the gut-brain axis: influence on gut microbiota, mucosal immunity, and cardiometabolic and cognitive health

Abstract

Extra-virgin olive oil (EVOO), a popular functional food and major source of fat in the Mediterranean diet, possesses a variety of healthful components, including monounsaturated fatty acids and bioactive phenolic compounds that, individually and collectively, exert beneficial effects on cardiometabolic markers of health and act as neuroprotective agents through their anti-inflammatory and antioxidant activities. The gut microbiota and health of the intestinal environment are now considered important factors in the development of obesity, metabolic disease, and even certain neurodegenerative conditions via the gut-brain axis. Recently, data are emerging which demonstrate that the health-promoting benefits of EVOO may also extend to the gut microbiota. In this review, we aimed to examine findings from recent studies regarding the impact of EVOO on gut microbiota and intestinal health and explore how modulations in composition of gut microbiota, production of microbially produced products, and activity and functioning of the mucosal immune system may lead to favorable outcomes in cardiovascular, metabolic, and cognitive health.

Keywords: Alzheimer disease; extra-virgin olive oil; gut microbiota; metabolic health; mucosal immunity.

Figure 1

Schematic overview of the numerous health benefits of extra-virgin olive oil.

Figure 2

Potential therapeutic effects of extra-virgin olive oil (EVOO) on Alzheimer disease. Extra-virgin olive oil may help prevent and even halt the progression of Alzheimer disease by reducing β-amyloid (Aβ) deposits and tau neuropathologies by enhancing autophagy and clearance mechanisms across the blood-brain barrier. Extra-virgin olive oil reduces astrocyte and microglial cell activation by reducing inflammatory cytokine production. Extra-virgin olive oil’s widespread antioxidant effects may also lead to enhancement of brain antioxidant enzymes and a reduction in reactive oxygen species (ROS).

Figure 3

Impact of extra-virgin olive oil (EVOO) on gut microbiota and mucosal immunity. Extra-virgin olive oil modulates the gut microbiota by acting as both a prebiotic (encouraging the growth of beneficial bacteria) and antibacterial (reducing the growth of pathogenic bacteria). Extra-virgin olive oil promotes the growth of certain bacteria that are capable of producing microbial metabolites such as short-chain fatty acids (SCFAs). Short-chain fatty acids and other gut microbiota-generated metabolites can positively influence the mucosal immune system by increasing T-regulatory (Treg) cells as well as the production of anti-inflammatory cytokines such as IL-10 and TGF-β, which assist in reducing local inflammation and promoting immune tolerance to commensals and other harmless dietary antigens. Extra-virgin olive oil may also promote an increase in intestinal IgA, providing further protection against pathogenic bacteria and promoting homeostasis of the gut microbiota.