Oleic acid: benefits, dosage, contraindications

Anti-inflammatory

Increasing dietary intake of oleic acid may be beneficial for patients with diseases involving inflammatory processes, including cardiovascular disease and ulcerative colitis. It appears that oleic acid inhibits leukocyte adhesion to endothelial cells in vitro, likely by impeding the expression of molecules involved in this process. In addition, it seems to counter inflammatory processes in aortic endothelial cells. In men, a diet high in oleic acid lowers levels of C-reactive protein (CRP), an inflammatory marker, compared with a diet high in palmitic acid. A recent meta-analysis of 31 trials found that adding extra oleic acid to the diet for at least 4 weeks reduces CRP levels, but did not affect other inflammatory markers such as tumor necrosis factor, interleukin-6 (IL-6), fibrinogen, plasminogen activator inhibitor type 1, soluble intracellular adhesion molecule, or soluble vascular cell adhesion molecule 1.

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Cardiovascular

The benefits of oleic acid for cardiovascular health may be attributed to its effects on blood lipids. Human research indicates that consumption of canola oil rich in oleic acid prevents LDL (low-density lipoprotein) particles from binding to the arterial wall. This phenomenon may contribute to reducing the risk of atherosclerosis, a condition characterized by the accumulation of lipid plaques in the arteries, which is a major risk factor for cardiovascular diseases such as heart attacks and strokes. One proposed mechanism for the reduction in LDL cholesterol levels observed with oleic acid is increased expression of the hepatic LDL receptor, as shown in animal studies. This receptor plays a key role in cholesterol metabolism by facilitating the removal of LDL particles from the blood, which helps lower LDL cholesterol levels. Furthermore, oleic acid may also decrease fatty acid oxidation, a process that can lead to the formation of oxidized LDL, a particularly atherogenic form of cholesterol because it is readily incorporated into arterial plaques. Additionally, the increase in HDL cholesterol (high-density lipoproteins) often observed with an oleic acid-rich diet is another protective factor against cardiovascular disease. HDL cholesterol is known to exert several beneficial effects, including the transport of cholesterol from peripheral tissues to the liver for excretion, which is often called the "reverse cholesterol transport". In addition, HDL has anti-inflammatory and antioxidant properties that may help reduce the risk of developing atherosclerosis.

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Anticancer

Oleic acid plays a promising role in the prevention of various types of cancer, including pancreatic cancer. In vitro studies have shown that oleic acid can inhibit the proliferation, progression, and metastasis of several examined cell lines. Possible mechanisms include inhibition of breast cancer–associated genes such as HER-2 and interference with other intracellular signaling pathways. Furthermore, oleic acid is capable of inducing apoptosis in cancer cell lines in vitro, potentially by increasing intracellular reactive oxygen species and interfering with other cellular cascades. A cohort study found an inverse association between dietary oleic acid intake and the risk of developing pancreatic ductal adenocarcinoma (pancreatic tumor). This study involved 23,658 participants, aged 40 to 74, of whom 88 developed pancreatic cancer after a mean follow-up of 8.4 years. Increased oleic acid consumption was associated with a reduced risk of pancreatic ductal adenocarcinoma, particularly significant among individuals with a body mass index (BMI) greater than 25, suggesting a potential protective role of oleic acid against the development of this type of cancer, possibly by influencing hyperinsulinemia.