Dha

Docosahexaenoic acid (DHA) is a long‑chain omega‑3 polyunsaturated fatty acid (C22:6n‑3) that constitutes ~40 % of the polyunsaturated fatty acids in the human brain and retina.

• It is an essential structural component of neuronal membranes, where it modulates fluidity, signaling, and neuro‑development.
• Humans synthesize DHA only in limited amounts from α‑linolenic acid, making dietary or supplemental DHA the primary means of maintaining optimal tissue levels.

• Cognitive function: Randomized controlled trials (RCTs) show DHA supplementation improves episodic memory and processing speed in older adults (e.g., 800 mg/day for 12 months).
• Neuro‑development: Prenatal and early‑life DHA (200–300 mg/day) supports visual acuity and cognitive outcomes in infants.
• Cardiovascular health: Meta‑analyses link 1 g/day DHA (often combined with EPA) to modest reductions in triglycerides (≈15 %) and blood pressure (≈2 mm Hg systolic).
• Inflammation & joint health: DHA-derived resolvins and protectins attenuate inflammatory cytokines (IL‑6, TNF‑α) in arthritis and metabolic syndrome models.
• Metabolic support: DHA enhances insulin sensitivity via membrane phospholipid remodeling, improving glucose uptake in skeletal muscle in several human trials.

• DHA incorporates into phospholipid bilayers of cell membranes, especially phosphatidyl‑cholines and phosphatidyl‑ethanolamines.
  • Its high degree of unsaturation increases membrane fluidity, facilitating receptor function and ion channel activity.
• DHA serves as a substrate for cyclooxygenase, lipoxygenase, and cytochrome‑P450 enzymes, producing specialized pro-resolving mediators (e.g., resolvin D1, protectin D1) that dampen NF‑κB signaling and promote resolution of inflammation.
• In neuronal cells, DHA enhances synaptic plasticity by modulating BDN‑TrkB signaling, promoting dendritic spine growth, and supporting neurotransmitter release.
• In the vasculature, DHA activates peroxisome proliferator‑activated receptor‑α (PPAR‑α) and G‑protein‑coupled receptor 120 (GPR120), leading to lipid oxidation and reduced endothelial adhesion molecule expression.

• IUPAC name: (4Z,7Z,10Z,13Z,16Z,19Z)-Docosahexaenoic acid.
• Molecular formula: C₂₂H₃₂O₂; molecular weight 328.49 g/mol.
• Structure: A 22‑carbon chain with six cis‑double bonds at positions 4, 7, 10, 13, 16, and 19, giving a highly unsaturated, amphiphilic molecule.
  • The terminal carboxyl group confers acidic character (pKa ≈ 4.8), while the long hydrocarbon chain provides lipophilicity.
  • DHA is a constituent of phospholipid membranes, mainly as sn‑2 acyl chain of phosphatidyl‑cholines.
  • Its high degree of unsaturation makes it prone to oxidation; thus, antioxidant‑stabilized formulations (e.g., vitamin E‑coated capsules) are common to prevent peroxidation.

• Natural DHA is predominantly derived from marine sources: wild‑caught fatty fish (salmon, mackerel, sardines) and micro‑algae (Schizochytrium, Crypthecodinium).
  • Algal DHA is the preferred source for vegetarian/vegan supplements and offers a controlled, contaminant‑free product.
• Extraction typically uses supercritical CO₂ or solvent-based methods, followed by molecular distillation to concentrate DHA and remove EPA, heavy metals, and oxidized lipids.
• High‑purity DHA (>95 % total omega‑3) is verified by gas‑chromatography or LC‑MS.
• Quality‑focused manufacturers employ nitrogen‑flushed, opaque packaging with added antioxidants (e.g., tocopherols) to maintain stability.
• Third‑party certifications (e.g., IFOS, USP) assure potency, purity, and absence of environmental contaminants.