The benefits of vitamin E mainly relate to its antioxidant action in fatty (lipid) parts of the body such as cell membranes, circulating cholesterol molecules and artery walls.
Vitamin E is the collective term for two groups of naturally occurring, fat-soluble compounds: the tocopherols and tocotrienols. Nine fat-soluble substances are known to have vitamin E activity: four tocopherols (alpha, beta, gamma, delta), four tocotrienols (alpha, beta, gamma, delta) plus a ninth substance, delta-tocomonoenol, which was identified in kiwifruit skin in 2009.
Alpha-tocopherol is the most active form of vitamin E, followed by beta-tocopherol, gamma-tocopherol and delta-tocopherol, with their relative potencies approximately 100:50:25:1. The combined action of all vitamin E activity in food and supplements is usually expressed as alpha-tocopherol equivalents.
Within Europe, alpha-tocopherol is the main source of vitamin E in the diet, while in the American diet, gamma-tocopherol is the most frequent form.
Vitamin E benefits
Vitamin E is a powerful antioxidant which protects fats in the body (especially polyunsaturated fats) from the damaging effects of oxidation. Vitamin E plays an important role in maintaining healthy cell membranes and nerve sheaths, and helps to prevent circulating cholesterol molecules from the oxidation reactions which would hasten hardening of the arteries.
Vitamin E is also important for immunity and works together with selenium to increase antibody production. Vitamin E also has a strengthening effect on muscle fibres and is traditionally used to relieve muscle cramps.
Food sources of vitamin E
The main food sources of vitamin E are:
- vegetable oils (especially wheatgerm oil)
- unprocessed wholegrain cereals
- nuts and seeds.
Some vitamin E is also obtained from the fatty parts of meat.
Vitamin E is relatively unstable and breaks down when food is processed, however, so that heating destroys around 30% of the vitamin E present. Freezing foods destroys up to 80% – fresh raw foods, fortified products and supplements are therefore the best sources.
Vitamin E deficiency
Lack of vitamin E affects the nervous system and muscles (including heart muscle) and is associated with symptoms such as:
- lack of energy
- poor concentration
- muscle weakness
- poor co-ordination.
Severe, long-term deficiency due to malabsorption can lead to serious effects such as:
- abnormal heart rhythms
- scarring (necrosis and fibrosis) within heart muscle, blood vessel walls and nervous tissue.
Severe deficiency of vitamin E is rare, however.
Vitamin E and glucose control
Good intakes of vitamin E are associated with improved glucose control in type 2 diabetes. Results from 14 studies, involving 714 people did not show any benefit from vitamin E supplements in those whose vitamin E intakes were already OK, but in those with low vitamin E levels, supplements significantly reduced HbA1c and fasting insulin levels compared with controls. Vitamin E may also improve endothelial function (the ability of blood vessels to dilate) and may help to delay the onset of diabetes-related complications.
Vitamin E and heart disease
Vitamin E has a number of protective effects on the circulation, from reducing oxidation of cholesterol and preventing platelet clumping to an anti-inflammatory action that may slow the progression of atherosclerosis.
Vitamin E caused widespread excitement following the Cambridge Heart Antioxidant Study (CHAOS) in 1996. This study, published in The Lancet, divided 2002 patients with coronary heart disease into two groups: half were prescribed vitamin E and half took inactive placebo for 18 months. Taking high dose vitamin E (at least 400 i.u. daily) was found to reduce the risk of a heart attack by 77% compared with placebo.
Since then, other trials have produced less dramatic results. However, a large analysis of data from 16 trials using doses of 33 IU to 800IU, with follow-ups ranging from 6 months to over 9 years, confirmed that, compared to controls, taking vitamin E on its own significantly reduced the relative risk of a heart attack by 18% and the relative risk of a fatal heart attack by 16%. Oddly, however, it appeared to be ineffective when taking with other antioxidants. This seems strange given that vitamin C is needed to regenerate vitamin E after it has acted as an antioxidant.
Vitamin E is included in many supplements that are designed to help support a healthy heart.
Vitamin E and statins
Taking a statin drug to lower cholesterol can also lower blood levels of fat-soluble vitamin E by as much as 17%. Statins also lower co-enzyme Q10 levels, and the combined reduction of those two circulating antioxidants may mean that LDL-cholesterol is less able to withstand oxidative stress.
Analysis of data from 8 trials, involving 504 people, showed statin treatment lowered blood vitamin E concentrations by 16.30%. However, the authors adjusted the readings to account for the lower cholesterol level, and suggested that the vitamin E:total cholesterol ratio was actually improved by statin therapy. Even so, if you are on a statin, you may want to ask your doctor about taking a vitamin E supplement.
Vitamin E and fatty liver disease
Vitamin E and cataracts
People with the highest dietary intake of vitamin E have a lower risk of developing cataracts severe enough to need extraction compared to those with the lowest vitamin E intakes. Dietary surveys suggest that good intakes of antioxidants and taking supplements of vitamin E and vitamin C may reduce the risk of cataracts by as much as 50%
Vitamin E and cancer
Vitamin E and male health
Vitamin E is an important antioxidant to help maintain healthy sperm. Vitamin E is also used to treat a condition called Peyronie’s disease which causes the penis to bend during erection. Peyronie’s disease occurs when scar tissue develops in the shaft of the penis to form a lump. This makes erections painful and can make sex impossible. The cause remains unknown.
Treatment of Peyronie’s disease with vitamin E tablets (at least 200mg daily) is sometimes recommended as vitamin E helps to maintain tissue elasticity. A recent study involving 70 men with Peyronie’s disease compared several different treatments and concluded that in the group who received vitamin E there was a 50.2% reduction in plaque size which was significantly greater than in the control group. They stated that vitamin E can help to prevent the progression of Peyronie’s disease.
Vitamin E dose
Vitamin E activity is often expressed in International Units (IU) rather than milligrams.
- 1 IU = 0.67 mg alpha-tocopherol equivalents.
- Conversely: 1mg vitamin E = 1.5 IU
In general, the more polyunsaturated fatty acids you eat, the more vitamin E you need.
Average intakes of vitamin E are around 11 mg per day, with at least 90% of the population obtaining less than the recommended daily amount. Low level deficiency is therefore believed to be wide-spread.
Best vitamin E supplements
Different vitamin E molecules have different symmetry, rather like a left and right hand glove. Natural source vitamin E is the most active as it only contains molecules of one symmetry and is known as d-alpha tocopherol. Synthetic alpha-tocopherol has less biological activity as it contains both left and right hand symmetry molecules, and is known as dl-alpha tocopherol.
I advise selecting a supplement that contains natural source vitamin E (d-alpha tocopherol).
High dose vitamin E is often combined with other antioxidants, such as vitamin C, mixed carotenoids and selenium. Good dietary intakes of vitamin C in particular are important as it helps to regenerate vitamin E after it has acted as an antioxidant.
Vitamin E absorption
Because it’s fat soluble, the absorption of vitamin E depends on the presence of dietary fats and oils. It also requires a good level of pancreatic enzymes and bile, as these aid the absorption of vitamin E by digestion down fat to form small, easily absorbed globules (micelles). These fat globules are able to pass across the small intestinal wall into the lymphatic system before finally reaching the circulation.
The passive absorption of vitamin E is not that efficient, and varies between 20-80% of the amount of vitamin E you consume. When taking high, pharmacological doses of 200 mg vitamin E or more, absorption may be less than 10% over all.
Vitamin E safety
Despite being a fat-soluble vitamin that is stored in the body, vitamin E is relatively non-toxic.
High doses can cause headache, muscle weakness, double vision, tiredness and bowel looseness, and there is a theoretical risk of over-thinning the blood which could increase the risk for haemorrhagic stroke.
The tolerable upper intake level at which no adverse effects are observed during long-term use from supplements is 540mg (around 800 IU). However, in the EU, a safety factor was used to establish an upper safe level of 300mg (450 IU) per day from supplements.
In the US, the upper intake level for adults is suggested as 1000mg (1 gram or 1,500 IU) per day for supplements made from natural forms of vitamin E, but is lower at 737mg (1,100 IU) per day for supplements containing synthetic vitamin E.
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