Docosahexanoic Acid (DHA)
Omega fatty acids are essential unsaturated fatty acids with a double bond (C=C) starting after the third carbon atom from the end of the carbon chain.
Prominent & useful omega 3 fatty acids are EPA & DHA.
Source:
Fish oil.
Dosage:
There is no Dietary Reference Intake (DRI) established. 2 to 4 grams (2000 to 4000 mg) of EPA and DHA daily.
Structure of DHA:
Mechanism of action:
- DHA inhibit the synthesis of inflammatory cytokines TNF α & IL 1beta. It competitively inhibits conversion of Arachidonic acid to the Pro-inflammatory ecosanide prostaglandins E2 & LT leukotin B4 thus reducing their synthesis.
- DHA inhibits 5- LOX (lipoxygenase) pathways responsible for conversion of arachidonic acid to inflammatory leukotrienes in nutrophiles & monocytes & can suppress phospholipids C-mediated signal transduction & also involved in inflammatory events.
Incorporation of EPA & DHA into articular cartilage chondrocyte membrane results in dose dependant reduction in the expression & activity of proteoglycon degrading enzyme.
DHA is generally associated with EPA & they are intercovertable.
Metabolism:
EPA & DHA triacyl glycerol, after ingestion, undergo hydrolysis via lipase to form monoglycerol & free fatty acids.
Then EPA & DHA are transported by circulation to various tissues on the body where they are mainly used for the synthesis of phospholipids.
Phospholipids further incorporated in the cell membrane of RBC, platelets & CNS. DHA is taken up by brain in preference to other fatty acid.
Role:
- Clinical evidence is strongest for heart disease and problems that contribute to heart disease, but omega-3 fatty acids may also be used for:
- Reducing triglyceride levels.
- Reducing blood pressure in people with untreated hypertension.
- It reduces the risk of heart diseases.
- Helps to control diabetes.
- Fish oil helps reduce symptoms of Rheumatic Arthritis, including joint pain and morning stiffness.
- Omega-3 fatty acids may help increase levels of calcium in the body and improve bone strength.
- Help to treat depression symptoms.
