How healthy is olive oil and what is it good for?

Olive oil is one of the most extensively studied dietary fats. In addition to healthy monounsaturated fatty acids, it contains polyphenols: plant compounds that slow down harmful processes in the body. They act as antioxidants, reduce inflammation, and protect your cells. A review of 39 plant-based oils positions olive oil as one of the most nutrient-rich choices, though varying your intake remains sensible¹.

The strongest evidence concerns cardiovascular disease. Extra virgin olive oil is a key element of the Mediterranean diet, and that diet is associated with a clearly lower risk of heart disease, stroke, and total cardiovascular disease in both 4 randomised trials and 32 large cohort studies^2,3. On that basis, olive oil is explicitly recommended as a heart-friendly alternative to saturated fats⁴. Extra virgin olive oil also lowers total cholesterol and LDL, although that evidence is still moderate to very weak⁵.

An American cohort study with more than 221,000 participants and up to 33 years of follow-up shows that every additional 5 grams of olive oil per day is associated with 8% lower total mortality. People who replace 10 grams of butter per day with olive oil have an estimated 17% lower risk of total mortality and of dying from cancer. Higher butter consumption, on the other hand, was associated with 15% higher mortality⁶. These are associations, not proven causes, but the direction is consistent across decades.

For cancer, the picture is more nuanced. An overview of multiple meta-analyses shows that olive oil may lower the risk of breast and gastrointestinal cancer, partly thanks to the polyphenols. However, the evidence has low to very low certainty, so future research could still change this picture^5,6,7.

For gut health and blood sugar, the research is still in its early stages. There are initial indications that extra virgin olive oil favourably influences the composition of gut bacteria and gut immunity, which could also support cognitive and metabolic health via the gut-brain connection. Hard numbers are still lacking⁸. For blood sugar regulation the evidence is even weaker; no conclusions can yet be drawn from it⁵.