Vitamin E

Don't take vitamin E supplements above about 30 IU a day. Nuts, seeds and olive oil supply enough.

What it is, and why the pill isn't the food

Vitamin E is a family of related compounds, mainly tocopherols. The diet supplies a mix of them, from nuts, seeds and olive oil. Supplements deliver one form in isolation, alpha-tocopherol.

That difference matters. High doses of alpha-tocopherol lower the body's levels of gamma-tocopherol, the form in food that does most of the anti-inflammatory work, so a megadose can leave you worse off than the food it was meant to concentrate.^[1]

It is also part of a wider pattern. Pooling 78 randomised trials in almost 300,000 people, antioxidant supplements did not prevent death, and in the trials at low risk of bias, vitamin E was among those linked to slightly higher mortality.^[2]

The harm record at 400 IU a day or more

The same finding has turned up across several trials:

• More deaths. A 2005 meta-analysis of high-dose trials found about 39 extra deaths per 10,000 people.^[3]
• More heart failure. In a long-term trial in people with vascular disease or diabetes, hospital admissions for heart failure went up on vitamin E.^[4]
• More prostate cancer in men. In a large cancer-prevention trial in men, those taking vitamin E had about 17% more prostate cancer than those on placebo.^[5]

The US Preventive Services Task Force recommends against taking vitamin E, or beta-carotene, to prevent heart disease or cancer. That is a Grade D recommendation, its firmest "don't".^[6]

Stroke: a trade-off, not a straight harm

Across nine randomised trials in 118,765 people, vitamin E did not change total stroke (in the seven trials that reported it), but it shifted the type. The five trials that reported bleeding (haemorrhagic) strokes found about 22% more of them, an estimate that only just cleared statistical significance. The five that reported clot (ischaemic) strokes found about 10% fewer.

In the authors' own absolute terms, that is one extra bleeding stroke for every 1,250 people taking vitamin E, against one clot stroke prevented for every 476. They still advise against indiscriminate use, because bleeding strokes are the more damaging kind.^[7]

Around exercise

Vitamin E also turns up in the case against antioxidant pills taken around training. In a four-week trial in 39 healthy young men, 1,000 mg of vitamin C plus 400 IU of vitamin E a day abolished the training-induced gain in insulin sensitivity.^[8] A later 12-week trial of 21 men on the same vitamin E dose, with half the vitamin C, did not replicate it.^[9] The signal is unsettled; the practical advice in Supplements to avoid is simply not to take high-dose antioxidants in the hours around training.

What to do

1. Skip vitamin E supplements above about 30 IU a day, and above all the 400 IU-plus doses where the harms were found.
2. Get it from food. Nuts, seeds and olive oil supply enough, along with the gamma-tocopherol that high-dose pills deplete.
3. Don't take high-dose vitamin E in the hours around training.

Further reading

• Miller ER 3rd et al. Meta-analysis: high-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med 2005.^[10]
• Lonn E et al. Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial. JAMA 2005.^[11]
• Klein EA et al. Vitamin E and the risk of prostate cancer: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA 2011.^[12]
• Schürks M et al. Effects of vitamin E on stroke subtypes: meta-analysis of randomised controlled trials. BMJ 2010.^[13]
• Jiang Q. Gamma-tocopherol, a major form of vitamin E in diets: Insights into antioxidant and anti-inflammatory effects, mechanisms, and roles in disease management. Free Radic Biol Med 2022.^[14]