Olive oil is one of the most well-supported healthy foods in nutrition science. Its benefits center on heart health, where replacing saturated fats like butter with olive oil has been linked to a 19% lower risk of dying from cardiovascular disease. The FDA recognizes this, noting that about 1½ tablespoons (20 grams) per day of high-oleic-acid oils like olive oil, used in place of saturated fats, may reduce the risk of coronary heart disease.
What’s in a Tablespoon
A single tablespoon of olive oil contains about 119 calories, nearly all from fat. But the type of fat matters. Of the roughly 14 grams of total fat, about 10 grams are monounsaturated, the kind consistently associated with better cholesterol levels and lower heart disease risk. Only about 1.4 grams are polyunsaturated, and saturated fat makes up a small fraction. You also get nearly 2 milligrams of vitamin E (about 13% of the daily value) and 8 micrograms of vitamin K.
The calorie density is worth noting. Olive oil is still a fat, and adding it on top of an already calorie-heavy diet won’t help. The benefits come from using it instead of butter, margarine, or other saturated fats, not in addition to them.
Heart Disease and Stroke Protection
The strongest evidence for olive oil sits squarely in cardiovascular health. The PREDIMED trial, one of the largest and most influential nutrition studies ever conducted, found that people assigned to a Mediterranean diet supplemented with extra virgin olive oil reduced their risk of major cardiovascular events by 31% compared to a control diet. A separate large U.S. study tracking over 90,000 adults found that higher olive oil intake was associated with a 19% lower risk of dying from cardiovascular disease specifically.
These aren’t small, short-term studies. The U.S. cohort was followed for decades, and the results held up after adjusting for other dietary and lifestyle factors. The mechanism is straightforward: monounsaturated fat helps lower LDL (“bad”) cholesterol while preserving or raising HDL (“good”) cholesterol, and the plant compounds in olive oil reduce inflammation in blood vessel walls.
A Natural Anti-Inflammatory
Extra virgin olive oil contains a compound called oleocanthal that works similarly to ibuprofen. It blocks the same inflammation-producing enzymes (COX-1 and COX-2) that over-the-counter pain relievers target. In lab studies, oleocanthal actually inhibited these enzymes more effectively than ibuprofen at equivalent concentrations, blocking 41% to 57% of enzyme activity compared to ibuprofen’s 13% to 18%.
That doesn’t mean a drizzle of olive oil replaces a pain reliever for a headache. The amounts you consume through diet are far lower than what’s used in lab experiments. But chronic, low-grade inflammation drives many diseases, from heart disease to cancer to arthritis, and the daily anti-inflammatory effect of olive oil compounds adds up over years. If you’ve ever noticed a peppery, slightly throat-burning sensation from good olive oil, that’s the oleocanthal. The stronger the burn, the higher the concentration.
Brain Health and Dementia Risk
A Harvard-led study of over 92,000 adults followed for 28 years found that people who consumed more than 7 grams of olive oil per day (roughly half a tablespoon) had a 28% lower risk of dying from dementia compared to those who rarely or never consumed it. That’s a meaningful reduction for such a simple dietary habit. The results held even after accounting for genetic risk factors for Alzheimer’s disease, suggesting the benefit isn’t limited to people with favorable genetics.
The protective effect likely comes from multiple pathways: reduced inflammation in brain tissue, better blood flow through healthier arteries, and the antioxidant activity of olive oil’s plant compounds protecting neurons from damage over time.
Blood Sugar: Modest but Real Effects
The relationship between olive oil and blood sugar control is more nuanced than the heart and brain data. A comprehensive meta-analysis of 51 clinical trials involving over 4,300 participants found that olive oil consumption didn’t significantly change fasting blood sugar, insulin levels, or HbA1c (a marker of long-term blood sugar control) in a straightforward, linear way.
However, the picture isn’t that simple. When researchers looked more closely at dosing, a daily intake of 25 to 50 grams (roughly 2 to 3½ tablespoons) did improve insulin resistance specifically. And the duration of use mattered: longer periods of olive oil consumption showed nonlinear improvements in insulin, insulin resistance, and HbA1c. In other words, olive oil probably won’t dramatically change your blood sugar overnight, but consistent use over months may help your body respond to insulin more efficiently.
Extra Virgin vs. Other Grades
Not all olive oil delivers the same benefits. Extra virgin olive oil is mechanically pressed from olives without heat or chemical solvents, preserving the plant compounds responsible for most of the health effects. To earn the “extra virgin” label under international standards, the oil must have a free acidity of no more than 0.8% and meet strict limits on oxidation, meaning it hasn’t degraded or gone rancid.
“Regular” or “light” olive oil has been refined, a process that strips out most of the polyphenols, oleocanthal, and other bioactive compounds. You still get the monounsaturated fat, which is good for cholesterol, but you lose the anti-inflammatory and antioxidant benefits that make extra virgin olive oil stand out from other cooking oils. Refined olive oil is essentially a neutral fat with a better fatty acid profile than butter, while extra virgin is that plus a package of protective plant compounds.
How Much to Use and How to Use It
The FDA’s qualified health claim is based on about 1½ tablespoons (20 grams) per day. The dementia study saw benefits at just over half a tablespoon daily. The blood sugar data suggests 2 to 3½ tablespoons for insulin resistance improvements. A reasonable target for most people is 1 to 2 tablespoons per day, which aligns with typical Mediterranean diet patterns.
Practical ways to hit that range: use olive oil as your default cooking fat for sautéing vegetables, drizzle it over salads instead of creamy dressings, add it to grain bowls, or dip bread in it instead of spreading butter. Extra virgin olive oil has a smoke point around 375 to 410°F, which is high enough for most home cooking. The old advice that you shouldn’t cook with extra virgin olive oil is largely a myth; it’s stable enough for sautéing and roasting, though deep-frying at very high temperatures is better suited to other oils.
Store olive oil in a cool, dark place and use it within a few months of opening. Light and heat degrade the beneficial compounds over time. A dark glass bottle in a cabinet is ideal. If your olive oil tastes flat or waxy rather than grassy, fruity, or peppery, it’s either old, low quality, or both.