Vitamin		Study	Dosage	Outcome
Vitamin E
	Primary prevention	ATBC24	50 mg per day	−
	Secondary prevention	ATBC subset25	50 mg per day	+ (alone)
				− (with β-carotene)
		CHAOS26	400 or 800 IU per day	+
		CLAS22 *	>100 IU per day	+ (dose dependent)
Vitamin C
	Primary prevention	Chinese Cancer Prevention Trial23	125 mg per day	0
	Secondary prevention	CLAS22		0
β-Carotene
	Primary prevention	ATBC24	20 mg per day	−
		Chinese Cancer Prevention Trial23	15 mg per day	+ (combined with vitamin E and selenium)
		CARET27		−
		Physicians' Health Study28		0
	Secondary prevention	ATBC subset25	20 mg per day	− (alone and combined with vitamin E)