When I read that our sewers were the main beneficiary of vitamin supplements (to put it as delicately as possible 😉 I decided to only take a one a day (but I’m pretty bad about taking even that). It seems like I made the right choice:

Taking high doses of vitamin E supplements can increase the risk of lung cancer, research suggests.
The US study of 77,000 people found taking 400 milligrams per day long-term increased cancer risk by 28% – with smokers at particular risk.

It follows warnings about similar risks of excessive beta-carotene use.
[…]
The researchers followed people aged between 50 and 76 for four years and looked at their average daily use of vitamin C and folic acid, and vitamin E supplements.
Over the course of the study, 521 people developed lung cancer.
Smoking, family history and age all had unsurprisingly strong links to cancer risk.
And while neither vitamin C or folic acid use had any effect on lung cancer risk, vitamin E use did.