By Gary L. Wenk, Ohio State University

Articles are intended for educational purposes only, and are no substitute for professional treatment. Please consult with a certified professional for patient treatment.

If you are on a DASH diet or the Mediterranean diet you are probably eating fruits, vegetables, and low-fat dairy foods, as well as whole-grain foods, fish, poultry, and nuts. You are also probably consuming olive oil as a substitute for unhealthy vegetable or coconut oils. Olive oil, particularly the extra virgin (EVOO) preparation, contains lots of antioxidants—just look at that rich color; it screams anti-oxidants—and also has significant anti-Inflammatory properties. Everyone knows that these are the two most important properties of healthy foods.

Your body clearly benefits from eating olive oil. Does your brain care?

Answering this question is not easy. First of all, olive oil is a complex blend of various chemicals. It would be nice to know which are most advantageous and whether they influence brain health directly or indirectly. A recent study attempted to find answers using an animal model that mimics conditions of multiple sclerosis (MS) in the human brain.

MS is characterized by brain inflammation leading to numerous degenerative changes. The brain inflammation present in MS patients is thought to be driven by changes in the gut microbiome. Scientists now understand that the gut microbiome plays a significant role in both the progression and severity of MS. This is the likely scenario: An imbalance in the gut bacteria leads to inflammation, chemical debris released from the bacteria migrate out of the gut into the blood and then into the brain. The most harmful of these bacterial debris is called lipopolysaccharide (LPS) and it can induce a powerful inflammatory response inside the brain. Humans with MS have elevated LPS in their brain, spinal cord, and blood. 

Olive oil modifies how your gut microbiome communicates with your brain. Olive oil’s beneficial effects on the human brain and body are likely related to the presence of the polyphenols hydroxytyrosol (HT) and Oleic acid (OA). HT protects cells that are under oxidative stress. OA is a monounsaturated omega-9 fatty acid that is generally higher in olive oil than vegetable fats. It has beneficial effects on blood cholesterol levels. 

In the current study of an animal model of MS, EVOO, as well as OA or HT alone, demonstrated potent anti-inflammatory and antioxidant effects. Administration of EVOO, OA, and HT reduced the degree of lipid and protein oxidation. This is important because lipid and protein oxidation is caused by oxidative stress and produces toxic levels of free radicals that harm neurons. EVOO, OA, and HT administration also increased levels of the neuroprotective enzyme glutathione. Glutathione provides protection against oxidative damage in the brain and also reduces the negative actions of LPS. The level of various pro-inflammatory proteins in the brain were also significantly reduced by EVOO, OA, and HT. 

So, yes, your brain benefits a lot from adding olive oil to your diet and these benefits originate in response to the changes that olive oil makes to your gut microbiome. Olive oil should become a big part of the diet for anyone with an aging brain.

Gary L. Wenk is Professor of Psychology & Neuroscience & Molecular Virology, Immunology and Medical Genetics at the Ohio State University and Medical Center. He is the author of “Your Brain on Food” (3rd Edition, 2019, Oxford University Press)