vitE

• vit E = tocopherol
• tocopherols + tocotrienols = vitE activity in humans + animals

  synthesised by higher plants + cyanobacteria
• main source of tocopherols = veg oil, unprocessed cereal grains, nuts

  
  

  little = f + v
• antioxidant activity: stabilise cell membrane, protect against oxidative damage, ^ PUFA intake = ^vitE requirement (0.5mg vitE per g PUFA)
• modulation of signal transduction pathways - reduce cell proliferation + platelet aggregation - atherosclerosis, adhesion, inflammation, neuroprotective effect
• tocopherol uptake - bioavailability = 50-80 %, absorbed in absence of lipids but presence helps, absorption doesn't discriminate between isoforms, liver preferentially incorporates alpha-toc -> lipoproteins
• involved in lipid peroxidation (eg in oil or body) - lipid peroxyl radical + tocopherol -> lipid peroxidase
• tocopherols considered most important lipid-soluble antioidant - high bioavailability even after ingestion - H atom to neutralise free radical (O-H bond = weaker than most phenols = H easily donated)
• ^ supplementation in animal feed = vit E accumulation in tissue
• burger with vitE rich meat = ^ a-tocopherol + storage
• deficiency v rare - neurological abnormalities, mostly with fat malabsorption, 5-10 y for symptoms to emerge
• presence of other antioxidants may contribute to vitE loss