What happens when you drink olive oil

Drinking olive oil — typically a small amount, a teaspoon to a tablespoon — delivers compounds that your digestive system absorbs and your body uses in several ways. The main active ingredient is oleic acid, a monounsaturated fat that makes up about 70% of olive oil. Extra virgin olive oil also contains polyphenols, plant compounds with antioxidant and anti-inflammatory properties that are largely lost in refined versions.

The research on drinking olive oil comes mostly from observational studies of people who eat Mediterranean diets (which include olive oil as a staple) and from controlled trials where researchers give people olive oil and measure specific markers in their blood. These studies show measurable effects on cholesterol, inflammation, and blood vessel function — but the effects are modest, and they appear strongest when olive oil replaces other fats rather than being added on top of your current diet.

Key Takeaways

  • Olive oil consumed regularly may help lower LDL (bad) cholesterol and reduce markers of inflammation, based on human trials and observational data from Mediterranean diet studies.
  • The polyphenols in extra virgin olive oil appear responsible for most anti-inflammatory effects, while refined olive oil retains the fat but loses these compounds.
  • Drinking olive oil works best as a replacement for less healthy fats (butter, seed oils high in omega-6) rather than as an addition to your current diet.
  • Most benefits appear at doses of 1 to 2 tablespoons daily, and effects take weeks to months to show up in blood markers.
  • Olive oil is calorie-dense (120 calories per tablespoon), so drinking it without reducing calories elsewhere can lead to weight gain.

How olive oil affects cholesterol and blood fats

The strongest evidence for olive oil involves its effect on cholesterol. Multiple human trials show that replacing saturated fats (butter, fatty meat) or refined carbohydrates with olive oil lowers LDL cholesterol — the type that builds up in artery walls — by roughly 5 to 10%. A landmark 2013 trial published in the New England Journal of Medicine followed over 7,000 people in Spain and found that those eating a Mediterranean diet with added olive oil had fewer heart attacks and strokes than a control group over five years.

The effect appears to depend on what you replace. When olive oil substitutes for butter or coconut oil, LDL drops. When it replaces refined carbohydrates (white bread, sugar), the drop is even larger. But if you add olive oil to your diet without removing something else, the extra calories can raise triglycerides and weight, which can offset the cholesterol benefit.

Anti-inflammatory effects and polyphenols

Extra virgin olive oil contains polyphenols — compounds like oleocanthal and oleuropein that give it a peppery taste. In laboratory and animal studies, these polyphenols reduce inflammatory markers and behave similarly to some anti-inflammatory drugs at the cellular level. Human trials show that people who drink extra virgin olive oil have lower blood levels of C-reactive protein and interleukin-6, two markers of systemic inflammation.

The catch: refined olive oil, which has been heated and chemically processed, loses most of its polyphenols and retains mainly the oleic acid fat. So if you want the anti-inflammatory benefit, you need extra virgin olive oil, not light or pure olive oil. The polyphenol content varies by harvest time (early harvest has more) and storage (they degrade over months), so a bottle sitting on a shelf for a year will have fewer active compounds than a fresh one.

Blood vessel function and blood pressure

Olive oil appears to improve how blood vessels work. The oleic acid and polyphenols both help blood vessel walls relax and dilate, which lowers resistance to blood flow. In human trials, people who consume olive oil regularly show improved endothelial function — the ability of blood vessel linings to respond to changes in blood flow — measured by ultrasound or other imaging.

Blood pressure effects are smaller and less consistent. Some trials show a modest drop (2 to 5 mmHg systolic) in people with high blood pressure, while others show no change. The effect, when present, appears after 4 to 12 weeks of regular consumption and is strongest in people who also reduce sodium intake or lose weight.

Weight and calorie considerations

Olive oil is 120 calories and 14 grams of fat per tablespoon. If you drink a tablespoon daily without cutting calories elsewhere, you add 840 calories per week — enough to gain roughly 0.25 pounds per week, or 13 pounds per year. This matters because weight gain can erase the cholesterol and inflammation benefits.

The studies showing cardiovascular benefit typically involved people who replaced other fats with olive oil, not people who added it. If you want to drink olive oil for its health effects, the practical approach is to use it instead of butter on bread, instead of mayo in salads, or instead of vegetable oil in cooking — not in addition to those things. Portion control is important: most research uses 1 to 2 tablespoons daily, not larger amounts.

What the evidence does not show

Olive oil is sometimes promoted for weight loss, liver health, or cancer prevention. The weight loss claim contradicts the calorie density — olive oil has not been shown to speed metabolism or reduce appetite. For liver health, animal studies suggest polyphenols may protect liver cells, but human trials are absent. For cancer, observational data from Mediterranean populations shows lower cancer rates, but olive oil is one of many dietary differences, and no controlled trial has tested whether olive oil alone prevents cancer.

Olive oil also does not replace medication. If you have high cholesterol or high blood pressure, the blood pressure or cholesterol-lowering effect of olive oil is real but small — typically equivalent to a low dose of a statin or blood pressure drug. It can be part of a broader dietary change, but it should not replace prescribed treatment without your doctor's input.

How to use olive oil for potential health benefit

If you want to drink olive oil, extra virgin is the choice: it has the polyphenols that refined versions lack. A tablespoon in the morning, drizzled on salad, or mixed into a smoothie is a common approach. The taste is strong, so many people mix it with lemon juice or vinegar to make it more palatable.

Consistency matters more than dose. The studies showing benefit involved daily consumption over weeks to months, not occasional use. Store the bottle in a cool, dark place — polyphenols degrade in heat and light, so a bottle that has been sitting in sunlight or above the stove will have fewer active compounds. Once opened, use it within a few months.

The effect is modest. You should not expect dramatic changes in cholesterol or blood pressure from olive oil alone. It works best as part of a broader pattern: replacing saturated fats, eating more vegetables and whole grains, reducing refined carbohydrates, and maintaining a stable weight. If you have a diagnosed condition like high cholesterol or heart disease, talk to your doctor before relying on olive oil as a treatment.

Frequently Asked Questions

Is it safe to drink olive oil every day?

Yes, for most people. A tablespoon daily is safe and is the amount used in most research. The main risk is excess calories — if you do not reduce other foods, daily olive oil will lead to weight gain. People with certain digestive conditions (severe IBS, pancreatitis) may find large amounts of fat trigger symptoms, so start with a small amount.

Does olive oil help with constipation?

Yes, in some cases. The fat in olive oil can have a mild laxative effect by lubricating the digestive tract and slowing gastric emptying. A tablespoon in the morning may help, but this is not the same as the cardiovascular or anti-inflammatory benefits. If constipation is chronic, fiber and hydration are more reliable first steps.

Can I cook with olive oil or does heat destroy the benefits?

Cooking with olive oil does destroy polyphenols — heat breaks them down. Extra virgin olive oil has a smoke point around 375°F, so it is not ideal for high-heat cooking anyway. For the polyphenol benefit, use extra virgin olive oil raw: drizzle it on finished dishes, mix it into dressings, or drink it straight. For cooking, refined olive oil or another oil works fine.

How much olive oil do I need to see health benefits?

Most studies use 1 to 2 tablespoons daily. Effects on cholesterol and inflammation markers typically appear after 4 to 12 weeks of consistent use. More is not better — drinking 3 or 4 tablespoons daily adds calories without adding proportional benefit and increases the risk of weight gain.

Is extra virgin olive oil worth the higher price?

If you are drinking it or using it raw, yes. Extra virgin has the polyphenols that deliver the anti-inflammatory effect. If you are cooking with it, no — heat destroys those compounds anyway, so a cheaper refined olive oil works just as well. Check the label: "extra virgin" means it was cold-pressed and not chemically refined.