18:1 n-9, 9-Octadecenoic Acid, Cis-9-Octadecenoic Acid, (9Z)-Octadec-9-Enoic Acid, Octadec-9-Enoic Acid, Octadecenoic Acid.


Overview Information

Oleic acid is an omega-9 fatty acid. It can be made by the body. It is also found in foods. Highest levels are found in olive oil and other edible oils.

Oleic acid is most commonly used for preventing heart disease and reducing cholesterol. It is also used for preventing cancer and other conditions, but there is no good scientific evidence to support these other uses.

Don't confuse oleic acid with diets and oils containing oleic acid, such as the Mediterranean diet, olive oil, and canola oil or sunflower oil made to have higher levels of oleic acid. See separate listings for these topics.

How does it work?

Oleic acid is a type of fatty acid. Oils with oleic acid are used to replace saturated fats in the diet. Oleic acid might improve heart conditions by lowering cholesterol and reducing inflammation.

Uses & Effectiveness?

Possibly Effective for

  • Heart disease. Using cooking oils that provide about 20 grams (1.5 tablespoons) of oleic acid in place of dietary fats with higher amounts of saturated fat might reduce the risk of heart disease. But research is limited.
  • High cholesterol. Using cooking oils rich in oleic acid might help lower cholesterol. These oils include olive oil, some sunflower oils, and canola oil.

Insufficient Evidence for

  • Bladder cancer. People with higher blood levels of oleic acid seem to have a lower risk of bladder cancer. But the amount of oleic acid in the blood can be affected by more than just intake from foods. So, it's still unclear if increasing intake of oleic acid from food reduces bladder cancer risk. It's also unknown if oleic acid supplements can help prevent bladder cancer.
  • Breast cancer. Eating more foods that contain oleic acid doesn't seem to prevent breast cancer. It's unknown if oleic acid supplements can help prevent bladder cancer.
  • Diabetes. Following a low-fat diet that includes food with oleic acid doesn't seem to lower cholesterol in people with diabetes.
  • Diarrhea. Taking oleic acid might reduce the number of bowel movements in some people with diarrhea. But more research is needed.
  • High blood pressure. Eating oil high in oleic acid might not help to lower high blood pressure. But more research is needed.
  • Obesity. Some early research shows that using cooking oil containing oleic acid reduces fat around the abdomen by a small amount in people who are obese. It also seems to help to lower cholesterol in some people who are obese and at risk for heart disease. But using similar cooking oils without oleic acid also seem to have benefit. So, it's unclear if the oleic acid causes these improvements.
  • Pancreatic cancer. People who get more oleic acid from their diet may have a lower risk of pancreatic cancer. But not all research agrees.
  • Poor nutrient absorption that occurs when part of the small intestine is missing or removed (short bowel syndrome). Early research shows that taking oleic acid doesn't reduce diarrhea or help with nutrient absorption in people with short bowel syndrome.
  • Stroke. People with higher blood levels of oleic acid seem to have a lower risk of stroke. But the amount of oleic acid in the blood can be affected by more than just intake from foods. So, it's still unclear if increasing intake of oleic acid from food reduces stroke risk. It's also unknown if oleic acid supplements can help prevent bladder cancer.
  • A type of inflammatory bowel disease (ulcerative colitis). People who get more oleic acid from their diet might have a lower risk of ulcerative colitis. But not all research agrees.
  • Rapid gastric emptying (dumping syndrome).
  • Build up of fat in the liver in people who drink little or no alcohol (nonalcoholic fatty liver disease or NAFLD).
More evidence is needed to rate the effectiveness of oleic acid for these uses.
Side Effects

Side Effects & Safety

When taken by mouth: Oleic acid is LIKELY SAFE when used in food amounts. There isn't enough reliable information to know if oleic acid is safe when taken by mouth as a medicine.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if oleic acid is safe to use as a medicine when pregnant or breast-feeding. Stay on the safe side and stick to food amounts.



We currently have no information for OLEIC ACID Interactions.



The following doses have been studied in scientific research:



  • For heart disease: Using cooking oils that provide 20 grams (1.5 tablespoons) of oleic acid per day in place of other saturated fats and oils has been used.
  • For high cholesterol: Cooking oils that contain high amounts of oleic acid in place of other saturated fats and oils has been used.

View References


  • Cater, N. B., Heller, H. J., and Denke, M. A. Comparison of the effects of medium-chain triacylglycerols, palm oil, and high oleic acid sunflower oil on plasma triacylglycerol fatty acids and lipid and lipoprotein concentrations in humans. Am.J Clin.Nutr. 1997;65(1):41-45. View abstract.
  • Banim PJ, Luben R, Khaw KT, Hart AR. Dietary oleic acid is inversely associated with pancreatic cancer - Data from food diaries in a cohort study. Pancreatology. 2018;18(6):655-660. View abstract.
  • Barbour JA, Howe PR, Buckley JD, Bryan J, Coates AM. Effect of 12 weeks high oleic peanut consumption on cardio-metabolic risk factors and body composition. Nutrients. 2015;7(9):7381-98. View abstract.
  • Ben Fradj MK, Ouanes Y, Hadj-Taieb S, et al. Decreased oleic acid and marine n?-?3 polyunsaturated fatty acids in Tunisian patients with urothelial bladder cancer. Nutr Cancer. 2018;70(7):1043-1050. View abstract.
  • Bowen KJ, Kris-Etherton PM, West SG, et al. Diets enriched with conventional or high-oleic acid canola oils lower atherogenic lipids and lipoproteins compared to a diet with a western fatty acid profile in adults with central adiposity. J Nutr. 2019;149(3):471-478. View abstract.
  • Cao Y, Hou L, Wang W. Dietary total fat and fatty acids intake, serum fatty acids and risk of breast cancer: A meta-analysis of prospective cohort studies. Int J Cancer. 2016;138(8):1894-904. doi: 10.1002/ijc.29938. View abstract.
  • Carrillo C, Cavia Mdel M, Alonso-Torre S. Role of oleic acid in immune system; mechanism of action; a review. Nutr Hosp. 2012;27(4):978-90. View abstract.
  • Carrillo C, Cavia Mdel M, Alonso-Torre SR. Antitumor effect of oleic acid; mechanisms of action: a review. Nutr Hosp. 2012;27(6):1860-5. View abstract.
  • Chen X, Li L, Liu X, et al. Oleic acid protects saturated fatty acid mediated lipotoxicity in hepatocytes and rat of non-alcoholic steatohepatitis. Life Sci. 2018;203:291-304. View abstract.
  • Compher CW, Kinosian BP, Rubesin SE, Ratcliffe SJ, Metz DC. Energy absorption is reduced with oleic acid supplements in human short bowel syndrome. JPEN J Parenter Enteral Nutr. 2009;33(1):102-8. View abstract.
  • de Silva PS, Luben R, Shrestha SS, Khaw KT, Hart AR. Dietary arachidonic and oleic acid intake in ulcerative colitis etiology: a prospective cohort study using 7-day food diaries. Eur J Gastroenterol Hepatol. 2014;26(1):11-8. View abstract.
  • Duarte Moreira Alves R, Boroni Moreira AP, Silva Macedo V, Brunoro Costa NM, Gonçalves Alfenas Rde C, Bressan J. High-oleic peanuts increase diet-induced thermogenesis in overweight and obese men. Nutr Hosp. 2014;29(5):1024-32. View abstract.
  • Dumas JA, Bunn JY, Nickerson J, et al. Dietary saturated fat and monounsaturated fat have reversible effects on brain function and the secretion of pro-inflammatory cytokines in young women. Metabolism. 2016;65(10):1582-8. View abstract.
  • FDA completes review of qualified health claim petition for oleic acid and the risk of coronary heart disease. November 2018. Available at: www.fda.gov/Food/NewsEvents/ConstituentUpdates/ucm624758.htm. Accessed January 25, 2019.
  • Gillingham LG, Robinson KS, Jones PJ. Effect of high-oleic canola and flaxseed oils on energy expenditure and body composition in hypercholesterolemic subjects. Metabolism. 2012;61(11):1598-605. View abstract.
  • Gillingham, L. G., Gustafson, J. A., Han, S. Y., Jassal, D. S., and Jones, P. J. High-oleic rapeseed (canola) and flaxseed oils modulate serum lipids and inflammatory biomarkers in hypercholesterolaemic subjects. Br J Nutr 2011;105(3):417-427. View abstract.
  • Gilmore LA, Walzem RL, Crouse SF, et al. Consumption of high-oleic acid ground beef increases HDL-cholesterol concentration but both high- and low-oleic acid ground beef decrease HDL particle diameter in normocholesterolemic men. J Nutr. 2011;141(6):1188-94. View abstract.
  • Harden CJ, Dible VA, Russell JM, Garaiova I, Plummer SF, Barker ME, Corfe BM. Long-chain polyunsaturated fatty acid supplementation had no effect on body weight but reduced energy intake in overweight and obese women. Nutr Res. 2014 Jan;34(1):17-24. View abstract.
  • Higashi K, Shige H, Ito T, et al. Effect of a low-fat diet enriched with oleic acid on postprandial lipemia in patients with type 2 diabetes mellitus. Lipids. 2001;36(1):1-6. View abstract.
  • Hlais S, El-Bistami D, El Rahi B, Mattar MA, Obeid OA. Combined fish oil and high oleic sunflower oil supplements neutralize their individual effects on the lipid profile of healthy men. Lipids. 2013;48(9):853-61. View abstract.
  • Jones PJ, Jew S, AbuMweis S. The effect of dietary oleic, linoleic, and linolenic acids on fat oxidation and energy expenditure in healthy men. Metabolism. 2008;57(9):1198-203. View abstract.
  • Jones PJ, MacKay DS, Senanayake VK, et al. High-oleic canola oil consumption enriches LDL particle cholesteryl oleate content and reduces LDL proteoglycan binding in humans. Atherosclerosis. 2015;238(2):231-8. View abstract.
  • Jones PJ, Senanayake VK, Pu S, Jenkins DJ, Connelly PW, Lamarche B, Couture P, Charest A, Baril-Gravel L, West SG, Liu X, Fleming JA, McCrea CE, Kris-Etherton PM. DHA-enriched high-oleic acid canola oil improves lipid profile and lowers predicted cardiovascular disease risk in the canola oil multicenter randomized controlled trial. Am J Clin Nutr. 2014 Jul;100(1):88-97. View abstract.
  • Kien CL, Bunn JY, Stevens R, et al. Dietary intake of palmitate and oleate has broad impact on systemic and tissue lipid profiles in humans. Am J Clin Nutr. 2014;99(3):436-45. View abstract.
  • Lin HC, van Citters GW, Heimer F, Bonorris G. Slowing of gastrointestinal transit by oleic acid: a preliminary report of a novel, nutrient-based treatment in humans. Dig Dis Sci. 2001;46(2):223-9. View abstract.
  • Liu X, Kris-Etherton PM, West SG, et al. Effects of canola and high-oleic-acid canola oils on abdominal fat mass in individuals with central obesity. Obesity. 2016;24(11):2261-2268. View abstract.
  • Madigan C, Ryan M, Owens D, et al. Dietary unsaturated fatty acids in type 2 diabetes: higher levels of postprandial lipoprotein on a linoleic acid-rich sunflower oil diet compared with an oleic acid-rich olive oil diet. Diabetes Care 2000;23:1472-7. View abstract.
  • Mennella I, Savarese M, Ferracane R, Sacchi R, Vitaglione P. Oleic acid content of a meal promotes oleoylethanolamide response and reduces subsequent energy intake in humans. Food Funct. 2015;6(1):204-10. View abstract.
  • Morin SJ, Gaziano JM, Djoussé L. Relation between plasma phospholipid oleic acid and risk of heart failure. Eur J Nutr. 2018;57(8):2937-2942. View abstract.
  • Mozaffarian D, Clarke R. Quantitative effects on cardiovascular risk factors and coronary heart disease risk of replacing partially hydrogenated vegetable oils with other fats and oils. Eur J Clin Nutr. 2009;63(Suppl 2):S22-33. View abstract.
  • Samieri C, Féart C, Proust-Lima C, et al. Olive oil consumption, plasma oleic acid, and stroke incidence: the Three-City Study. Neurology. 2011;77(5):418-25. View abstract.
  • Steffen BT, Duprez D, Szklo M, Guan W, Tsai MY. Circulating oleic acid levels are related to greater risks of cardiovascular events and all-cause mortality: The Multi-Ethnic Study of Atherosclerosis. J Clin Lipidol. 2018;12(6):1404-1412. View abstract.
  • Tsuchiya A, Nagaya H, Kanno T, Nishizaki T. Oleic acid stimulates glucose uptake into adipocytes by enhancing insulin receptor signaling. J Pharmacol Sci. 2014;126(4):337-43. View abstract.
  • Voon PT, Ng TK, Lee VK, Nesaretnam K. Diets high in palmitic acid (16:0), lauric and myristic acids (12:0 + 14:0), or oleic acid (18:1) do not alter postprandial or fasting plasma homocysteine and inflammatory markers in healthy Malaysian adults. Am J Clin Nutr 2011;94:1451-7. View abstract.

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