Understanding the Nutrition: What effect does olive oil have on your body?

October 21, 2025 •

4 min read

A 28-year study involving over 90,000 U.S. adults found that consuming more than half a tablespoon of olive oil daily was linked to a 28% lower risk of dying from dementia. This powerful evidence, among other studies, shows how significant the answer to the question, 'what effect does olive oil have on your body?', can be for your long-term health..

Quick Summary

Olive oil, particularly extra virgin, provides the body with healthy monounsaturated fats, antioxidants, and anti-inflammatory compounds. These elements combine to offer significant cardiovascular benefits, support brain health, enhance gut microbiota, and help reduce chronic inflammation. Proper consumption and choosing the right quality are essential for maximizing its positive effects.

Key Points

Rich in Healthy Fats: Olive oil is predominantly composed of heart-healthy monounsaturated fats, which help lower cholesterol and reduce inflammation.
Powerful Anti-inflammatory Effects: The polyphenol oleocanthal in extra virgin olive oil has been shown to have anti-inflammatory effects comparable to ibuprofen.
Supports Heart and Brain Health: Regular consumption is strongly linked to a lower risk of heart disease, stroke, and neurodegenerative conditions like Alzheimer's disease.
Enhances Gut Health: The polyphenols in EVOO act as a prebiotic, fostering a balanced and healthy gut microbiota and strengthening the gut barrier.
Weight Management Aid: When used to replace unhealthy fats, olive oil can support long-term weight management by promoting satiety and a healthy metabolism.
Not All Olive Oils Are Equal: For maximum health benefits, choose cold-pressed extra virgin olive oil over refined varieties, which are stripped of most beneficial compounds.
Moderation is Key: Despite its benefits, olive oil is calorie-dense, so it should be consumed in moderation and used as a substitute for other fats to prevent weight gain.

The Core Components: Fats and Antioxidants

Olive oil is a liquid fat made from pressing olives, but not all varieties offer the same health benefits. Extra virgin olive oil (EVOO) is the highest-quality grade, produced via cold-pressing without chemicals or heat, which preserves its beneficial compounds. Refined olive oil, however, undergoes processing that strips away many of these healthy components. The primary health-promoting components in high-quality olive oil are:

Monounsaturated Fats (MUFAs): Oleic acid is the predominant MUFA in olive oil, comprising over 70% of its content. These fats are resistant to high heat and have been shown to reduce inflammation and support cardiovascular health.
Antioxidants and Polyphenols: EVOO is rich in powerful antioxidants like vitamins E and K, as well as polyphenols such as oleocanthal and hydroxytyrosol. These compounds combat oxidative stress, which is a major driver of chronic diseases like heart disease and cancer.
Oleocanthal: A potent anti-inflammatory agent found in EVOO, this polyphenol acts similarly to ibuprofen by inhibiting enzymes involved in inflammatory pathways.

Impact on Cardiovascular Health

Cardiovascular disease is the leading cause of death worldwide, and extensive research has consistently shown that incorporating high-quality olive oil into the diet can significantly reduce risk factors and improve outcomes.

Improves Cholesterol Levels: Replacing unhealthy saturated fats with the MUFAs found in olive oil can help lower 'bad' low-density lipoprotein (LDL) cholesterol. Furthermore, the antioxidants in EVOO protect LDL particles from oxidation, a crucial step in the development of heart disease.
Lowers Blood Pressure: Studies have shown that regular consumption of olive oil, particularly EVOO, can help reduce blood pressure, a primary risk factor for heart disease. This effect is attributed to both its fatty acid profile and polyphenols.
Enhances Blood Vessel Function: Olive oil can improve the function of the endothelium, which is the inner lining of blood vessels. This leads to better blood vessel health and reduces the risk of clotting.

Benefits for Brain Function and Cognitive Health

Emerging research suggests that olive oil's benefits extend beyond the heart, with strong evidence supporting its role in supporting brain health and combating neurodegenerative diseases.

Combats Oxidative Stress: The potent antioxidants in EVOO, like oleocanthal, help reduce oxidative stress in the brain, a factor implicated in the progression of neurodegenerative diseases such as Alzheimer's.
Improves Cognitive Performance: Several studies have linked olive oil consumption with improved memory and cognitive function. In individuals with mild cognitive impairment, EVOO consumption has been shown to enhance brain connectivity and blood-brain barrier function.

Promoting Gut Health and Digestion

Modern research is increasingly highlighting the interconnectedness of gut health with overall wellness. Olive oil plays a beneficial role by positively influencing the gut microbiome.

Modulates Microbiota: The polyphenols in EVOO have been shown to act as prebiotics, promoting the growth of beneficial gut bacteria, such as Bifidobacteria and Lactobacilli. At the same time, it can help reduce populations of harmful bacteria.
Reduces Inflammation in the Gut: The anti-inflammatory properties of oleocanthal and other compounds help to reduce inflammation within the gastrointestinal tract. This can help lower the risk of conditions like inflammatory bowel disease.
Aids Digestion: Olive oil can act as a natural laxative, helping to soften stools and alleviate constipation when consumed in moderation.

Grades of Olive Oil and Their Effects

Choosing the right type of olive oil is crucial for reaping the maximum health benefits. The grade is determined by the production process and directly impacts the oil's composition and effects on your body.


Feature	Extra Virgin Olive Oil (EVOO)	Refined Olive Oil	Standard Olive Oil	Olive-Pomace Oil
Processing	Cold-pressed, no heat or chemicals	Treated with heat and chemicals to remove defects	Blend of refined and virgin olive oils	Extracted from pomace with solvents and heat
Antioxidants	Highest levels of polyphenols and antioxidants	Very low, as removed during processing	Lower due to high refined oil content	Minimal due to extensive processing
Flavor/Aroma	Rich, fruity, and robust flavor	Mild or neutral flavor	Milder than EVOO	Mild, but lower quality
Health Benefits	Maximum potential benefits for heart, brain, etc.	Minimal; mainly provides monounsaturated fats	Moderate benefits	Minimal nutritional value
Best Use	Dressings, finishing, light sautéing	High-heat cooking, baking	General cooking	Often used commercially or in soap

Potential Side Effects and Considerations

While olive oil is generally safe and beneficial, excessive consumption can lead to negative side effects.

Weight Gain: As a calorie-dense fat (approximately 120 calories per tablespoon), overconsumption can lead to weight gain, undermining other health benefits. Moderation is key, with guidelines often suggesting 1–4 tablespoons per day.
Digestive Issues: For some, an overly high intake can cause digestive discomfort or diarrhea.
Interactions with Medication: Olive oil's ability to lower blood pressure and blood sugar means individuals on related medications, such as insulin or antihypertensive drugs, should monitor their levels to avoid them dropping too low. It is important to consult a healthcare professional in such cases.

Conclusion

The evidence is clear: olive oil, especially high-quality extra virgin olive oil, offers a range of profound health benefits for the body. Its rich concentration of monounsaturated fats and antioxidants provides significant support for cardiovascular health, cognitive function, and the gut microbiome, while also acting as a powerful anti-inflammatory agent. For optimal effects, it is crucial to prioritize high-quality EVOO and consume it in moderation as a replacement for less healthy saturated fats. By incorporating this golden elixir into a balanced diet, individuals can leverage its medicinal properties to support long-term health and wellness. For more details on the extensive scientific evidence, explore the studies cited at the National Institutes of Health.

Frequently Asked Questions

While consuming extra virgin olive oil (EVOO) raw, like in salad dressings or for drizzling, preserves its full flavor and antioxidant profile, it is also highly stable for cooking. Heating EVOO at moderate temperatures, like for sautéing, does not degrade its health benefits. For high-heat cooking, some prefer refined olive oil due to its neutral flavor and higher smoke point, though it offers fewer nutritional benefits.

Most research suggests that daily consumption of at least half a tablespoon, and often up to 1-4 tablespoons, is associated with a reduced risk of chronic diseases. For optimal results, use it to replace less healthy saturated fats in your diet.

Olive oil can act as a natural moisturizer due to its antioxidant and vitamin content. However, direct application may clog pores or irritate sensitive skin, especially for those prone to acne. Using skincare products that are properly formulated with olive oil is often a safer alternative.

Extra virgin olive oil is the least processed, cold-pressed variety with the highest concentration of polyphenols and antioxidants. Refined olive oil undergoes chemical and heat treatments that strip away most of these beneficial compounds, resulting in a milder flavor but minimal health benefits.

Olive oil is calorie-dense, so consuming it in excessive quantities without adjusting total calorie intake can lead to weight gain. However, when used as a substitute for less healthy fats and in moderation, it has been associated with less weight gain over the long term.

Excessive consumption can contribute to weight gain and potentially cause digestive issues like diarrhea. Individuals on medication for blood pressure or diabetes should be cautious, as olive oil can lower both, and should consult a doctor.

Store olive oil in a cool, dark place away from heat and light, ideally in a dark glass bottle. Exposure to oxygen, heat, and light can cause it to degrade and lose its beneficial properties over time.