Oleic Acid
Also known as Omega-9, 18:1, cis-9-octadecenoic acid
Oleic acid is the most common monounsaturated fatty acid in the diet and an omega-9 fat. It is the main fatty acid in olive oil and is found in many nuts and seeds.
Why it matters
What it does in your body
- Main energy-providing fat in olive oil and many nuts
- Helps shift cholesterol balance favorably when it replaces saturated fat
- A component of cell membranes throughout the body
Intake guidance
How much you need
There is no separate daily target for oleic acid. It is part of your total dietary fat, and the body can make monounsaturated fatty acids like oleic acid on its own, so it is not considered essential. The practical goal is to use oleic-rich fats such as olive oil in place of saturated fats.
What affects it
What affects your intake
Oil choice
Olive oil, high-oleic sunflower oil, and canola oil are especially rich in oleic acid.
Replacement effect
The heart benefit comes mainly from using oleic-rich oils instead of butter or other saturated fats.
In practice
Good to know
Good to know: oleic acid is the fat that makes olive oil heart-healthy. Studies link it to lower LDL (harmful) cholesterol while preserving HDL (helpful) cholesterol, and it is a central part of the Mediterranean diet. The body can also make oleic acid, including by converting stearic acid, so you do not need to seek it out, but choosing oleic-rich oils over saturated fats is a smart swap.
Where to get it
Best food sources
The bottom line
Oleic acid is the good fat in olive oil, avocados, and nuts. Use these in place of saturated fats rather than trying to hit a specific intake number.
Track oleic acid automatically
Oleic Acid is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.
Sources and method
The classification, roles, and guidance on this page come from the references below, drawing on the Institute of Medicine (now the National Academies) Dietary Reference Intakes and reputable nutrition science.
- Dietary Guidelines for Americans, 2020-2025
- Harvard T.H. Chan School of Public Health, The Nutrition Source
This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.