Oleic acid is the most common unsaturated fatty acid in human cells. Our body can make oleic acid from triglycerides or other fatty acids. It is an omega-9 fatty acid with a vital and under appreciated role in cell membrane function. As part the phospholipids in cell membranes, it is thought to be important for cell membrane fluidity. Perhaps due to the importance of cell membrane fluidity, and by other mechanisms, oleic acid is important for:
- Hormone responsiveness.
- Mineral transport.
- Proper immune function.
- Anti tumor effects by altering cell proliferation and apoptosis (cell death).
- Membrane-protein interactions and signal transduction.
- Improves oxidative stress, lipid peroxidation, ROS (reactive oxygen species).
- Reduces pro inflammatory arachidonic-derived eicosanoids.
- Modulates intracellular pathways important in cell activation.
- Modulates gene expression in cytokine production.
Oleic acid, like all fats, is also a major energy source for our cells, being broken down to acetyl groups used for energy (ATP).
SYMPTOMS OF DEFICIENCY
Since we can make oleic acid from other fats, and this is not considered an essential nutrient, there are no specific deficiency symptoms listed for oleic acid. Given all the important membrane fluidity functions that are affected by oleic acid, I suspect a deficiency of this important nutrient will show up in chronic disease like cancer and heart disease, hormone related disorders such as thyroid and type 2 diabetes, and perhaps others. Disorders related to increased toxins, may also, in part, be made worse by a deficiency of oleic acid.
This monounsaturated fat is found in vegetable oils, nuts and seeds, and in animal fats. Because animal fats also pack a huge burden of less healthy saturated fats and cholesterol, you are wise to get most of your fats from plant sources. The institute of medicine recommends your fat intake represent 20-35% of your daily caloric intake. Most Americans far exceed this and unfortunately most of our fats come from the less healthy saturated animal fat source. The National Health and Nutrition Examination Survey 2005-2005 in the USA found that almost 40% of our oleic acid (MFA18:1) came from grain based deserts, chicken, sausage, franks, bacon, ribs, pizza, and mixed mexican food dishes.
Healthier sources of oleic acid are avocados and avocado oil, olive oil, nuts and nut oils, and other vegetable oils. These sources provide 36-73 grams of oleic acid per 100 grams of intake.
SAFETY AND TOXICITY
There is no known direct toxicity from the intake of too much fat. At intakes exceeding 50-100 grams, you may experience some diarrhea. Obviously, one would gain weight if you continue to eat too much of any fat.
TOLERABLE UPPER LIMITS
Since there is no toxicity and no RDA (Recommended Daily Allowance), I would recommend you limit intake to a maximum of about 30% of your caloric intake (as fats). Remember that omega-3 fatty acids are essential fatty acids (linoleic acid and linolenic acid, EPA ,and DHA) and vital for proper brain function, heart health, and more. Thus while making sure you get your avocado, nuts, or a tablespoon of oleic rich oils, I would recommend at least a tablespoon of ground flax seed or flax seed oil. Fatty fish, like salmon, are also great sources of omega-3 oils, however in most cases they pack a huge dose of toxins like aluminum and pesticides, so use caution, especially for pregnant women and young children.
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