Vitamin E (α-tocopherol) !

Vitamin E is the membrane antioxidant: it slows the oxidation of cell fats, especially in nerves and red blood cells.

Updated 2026-11-01

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Key facts

A fat-soluble antioxidant that breaks the chain of lipid peroxidation in membranes.
Vitamin C regenerates it; selenium (glutathione peroxidase) works in the same defence.
Deficiency: haemolytic anaemia, peripheral neuropathy, spinocerebellar ataxia and retinopathy.
The liver's α-tocopherol transfer protein (TTPA gene) selects the α form; its failure causes ataxia with vitamin E deficiency.

Sources: vegetable oils, nuts, seeds, avocado, leafy greens.
Mechanism: the hydroxyl of the chromanol ring donates a hydrogen to a lipid peroxyl radical; the tocopheroxyl radical left behind is stable and vitamin C returns it to the active form.
Transport: absorbed with fat, it reaches the liver in chylomicrons, and α-TTP loads it into VLDL for delivery.
Deficiency (rare, nearly always from fat malabsorption or in premature babies): fragile red cells (haemolysis), degeneration of the dorsal columns and peripheral axons.
Excess (supplements): it can antagonise vitamin K and raise bleeding risk, especially with anticoagulants.
Lab: serum α-tocopherol, best expressed relative to total lipids (cholesterol and triglycerides).

A chromanol ring (carrying the antioxidant OH) joined to a saturated 16-carbon phytyl tail that sits in the lipid bilayer.
There are eight natural forms (α, β, γ, δ tocopherols and tocotrienols); the liver keeps the α form.

Its neurological picture (ataxia, loss of proprioception, areflexia) resembles Friedreich ataxia and vitamin B12 deficiency.
Premature babies are born with low stores and may develop haemolytic anaemia.
Large trials did not show that vitamin E supplements prevent cardiovascular disease or cancer.

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How does vitamin E protect membranes?

It donates a hydrogen to lipid peroxyl radicals and stops the chain reaction that oxidises unsaturated fatty acids.

Which vitamin regenerates oxidised vitamin E?

Vitamin C (ascorbate) reduces the tocopheroxyl radical and makes it active again.

Which findings suggest vitamin E deficiency?

Haemolytic anaemia, ataxia, loss of deep sensation and peripheral neuropathy in someone with fat malabsorption.

Which gene fails in ataxia with vitamin E deficiency?

TTPA, which encodes the liver protein that loads α-tocopherol into VLDL; without it the vitamin is lost in bile.

Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.

Educational information, not medical advice. For any symptom, see a health professional.

Sources: alpha-Tocopherol (CID 14985) (PubChem, NCBI, 2026) · Public domain; Vitamin E: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Ataxia with vitamin E deficiency: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); TTPA gene: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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