Not all olive oils are healthy: Doctor reveals 4 secrets to choosing the right kind, warns wrong choice may harm brain

Choosing the right olive oil is crucial for brain health, as not all varieties offer the same benefits, warns Taiwanese neurologist and brain science doctor Cheng Chun-yu. While extra virgin olive oil can support cognitive function, refined olive oils might be associated with cognitive decline, potentially accelerating brain aging.

A study published in "Microbiome" in early 2026 tracked participants for two years. Researchers found that individuals consuming extra virgin olive oil showed better overall cognitive function, language skills, and executive function. Higher intake of this type of oil also correlated with greater gut microbiota diversity. Conversely, those consuming refined olive oil tended to experience a decline in these cognitive areas, along with lower gut microbiota diversity.

The significant difference between the two types lies in their processing. Extra virgin olive oil is extracted using physical and mechanical methods without high temperatures or chemical solvents, preserving beneficial polyphenols, antioxidants, and vitamins that offer anti-inflammatory and neuroprotective potential. Refined olive oil, however, undergoes processes like deacidification, decolorization, and high-temperature deodorization, which can strip away beneficial compounds and potentially alter the oil's quality.

Dr. Cheng advises consumers to look for labels indicating "Extra Virgin" or "Virgin," with "cold-pressed" or "cold-extracted" being preferable. She recommends avoiding oils labeled "Pure," "Light," or "Pomace," as these are typically refined. "Light" does not refer to lower calories but a milder flavor and refinement process. Packaging is also important; opt for dark glass bottles or tin cans to minimize oxidation from light. Checking harvest and production dates is also advised, as earlier harvests often mean fresher olives with richer polyphenol content. Prioritizing single-origin oils with clearly marked regions is also suggested.

Extra virgin olive oil can be used in everyday cooking, not just for cold dishes, as long as it's not heated to the point of smoking. It can be used in medium-low heat cooking, as a dip with soy sauce or balsamic vinegar, or drizzled over vegetables, meats, soups, and whole grains. For maximum benefit, Dr. Cheng emphasizes combining olive oil consumption with a diet rich in vegetables, legumes, whole grains, fish, and nuts, while reducing refined carbohydrates, processed foods, sugary drinks, and sweets that can harm gut health and negate olive oil's positive effects.