Facts and Food Sources of Linoleic acid (LA)

Linoleic acid is called an omega-6 fatty acid because its double bonds appear after the sixth carbon in the chain. The major omega-6 fatty acid in the diet is linoleic acid. This acid is found in vegetable and nut oils, such as safflower, sunflower, soy, corn,  and peanut oil. In scientific terms, linoleic acid is a nutrient from the carbonyl functional group which comprises of two double bonds at the 9^th and 12^th carbons. As humans are not able to incorporate a double bond beyond the 9^th carbon of the fatty acid, so it could not be synthesized naturally and must be obtained through consumption.

The n-6 fatty acids are essential for infants, and in extreme long-term deficiency skin lesions and delayed growth may develop. Linoleic acid serves as a precursor of arachidonic acid (AA), which is required for synthesis of prostaglandins and other eicosanoids. Linoleic acid is metabolized in the body to arachidonic acid, which is a precursor to a number of eicosanoids. Linoleic acid is also needed for cell membrane structure and is required for the lipoproteins that transport fats in our blood.

Linoleic acid is a substrate for the synthesis of physiological regulators that are known as eicosanoids which includes prostacyclins, prostaglandins, leukotrienes and thromboxanes. These local hormones act as mediators of various biochemical processes such as regulating blood pressure, blood lipid levels, blood clotting, immune function, reproduction and inflammation. It is a crucial structural component of cell membranes and affects cell membrane properties such as flexibility, fluidity and permeability.

Dietary Sources

Dietary Reference Intake

The Adequate Intake (AI) for linoleic acid (an omega-6 FA) is 14 to 17 g per day for adult men and 11 to 12 g per day for women 19 years and older. Using the typical energy intakes for adult men and women, this translates into an AMDR of 5 10% of total energy intake.

Health Benefits of Linoleic acid

1. Heart health

When saturated fat is replaced in the diet with polyunsaturated fat, total and LDL-cholesterol levels are reduced, particularly in people with elevated levels. In fact, linoleic acid, an omega-6 fatty acid, is likely to be the most potent fatty acid when it comes to lowering blood cholesterol levels in this manner. By lowering total and LDL cholesterol, heart disease risk is lowered. Linoleic acid can be found in safflower, sunflower, corn, soybean, and canola oils. So replacing animal fat with plant fat (oil) could be helpful in preventing heart disease.

2. Brain function

Linoleic acid has a crucial role in cell membranes that impacts healthy brain function. Researcher shows that brain unesterified linoleic acid concentration promotes brain injury which suggest that linoleic acid or its metabolites which involve in natural response to injuries involving brain. Animal studies indicate that acid could be involved in neurotransmission and participates in response to ischemic brain injury such as stroke.

Study shows that mood disorders are correlated with very low concentrations of linoleic acid. Study shows that slight decrease of linoleic acid in decision making area of brain in depressed or bipolar suicidal subjects and low concentrations of this acid is present in platelets of subjects with suicidal attempts.

3. Hair and skin health

Linoleic acid deficiency results in scaly and itchy skin which is shown in animal studies. Linoleic acid has direct role to maintain water permeability barrier of skin by promoting skin hydration. It adjusts closure of skin wounds and lower acne and skin inflammation. In addition, major metabolites of linoleic acid acquire anti-proliferative properties which mean that it could prevent dispersion of malignant cells into surrounding tissues.

Research have shown that use of oils rich in linoleic acid such as argan and safflower oil on hair promotes growth of hair and acts as a natural remedy for thinning hair. It is a precursor of archidonoic acid, an omega-6 fatty acid enhance expression of various factors which are responsible for growth of hair.

4. Reproductive health

Deficiency of linoleic acid causes impaired reproductive health. As linoleic acids possess essential components of all cell membranes, it could influence reproductive processes and change production of prostaglandins. Moreover, reproductive system needs high polyunsaturated fatty acid in order to provide plasma membranes with fluidity which is required for fertilization.

Animal study shows that supplementation of linoleic acid promotes estrogenic activity and enhance reproductive performance of female rats with their ovaries removed. Results shows the potential beneficial role in treating postmenopausal and menopause symptoms such as vaginal atrophy, hot flashes, development of osteoporosis and lower cardiovascular health.

5. Enhance immunity

Polyunsaturated fats in both form omega-3 and omega-6 are useful for human autoimmune inflammatory disorders. Research shows that omega-6 fatty acids prevent and lower severity of autoimmune diseases by promoting immune function and regulates cellular immune reactions. Yet, it is true when balanced omega-6s and omega-3s. In excessive amounts of omega-6 foods such as products made from vegetable oils, it provides pro-inflammatory response.

6. Protects density of bones

Study shows that higher intake of polyunsaturated fatty acids which includes omega-6 and omega-3 fatty acids for higher density of bone minerals and lower chances of fragility fracture. These fatty acids effect bone cell metabolism, lowers the chances of fractures and osteoporosis and preserve skeletal formation.

Precautions

The deficiency of Linoleic acid could result hair loss, dry hair and poor healing of wounds.

References:

https://en.wikipedia.org/wiki/Linoleic_acid

https://draxe.com/linoleic-acid/