If a human were to consume the golden apples of Idunn would that allow them to live significantly longer than a normal human lifespan?
Follow-up question to How long do Asgardians live for?
Some of these comics came up as a mention of the Apples of Idunn:
Journey into Mystery Vol 1, #100
In this story Thor wishes Janes to become immortal so he may marry her, implicating the apples will make her immortal.
Fear Itself: The Fearless Vol 1 #3
Another mention of the golden apple, this time to be used on a SHIELD agent.
With Sharon on the verge of becoming a vampire, Valkyrie surrenders a golden apple to save her life. Black Widow reminds her that this doesn't change anything, as she has to face the consequences of her actions. But with no time to explain herself, Valkyrie summons her winged horse and flees.
Looking at Sharon's Page on the marvel wikia, it appears that this appple was never administered.
Fear Itself: The Fearless Vol 1 #7
Flashback to Asgard, long ago: The newly-chosen shieldmaiden, Valkyrie, is hailed by the Warriors Three, who give her one of the Golden Apples of Idunn.
From the wording of the summary there is no indication that she is made a Shieldmaiden by virtue of the apple. She latter gives six apples to a doctor. She advises him to give a slice to poorly people to make them all-better. I don't know if she'd just hand out an armful of apples to mortals if it would make them immortal...
So we have 2 cases of the apples being offered to immortalize someone, and 1 case of them just being handed out like medpacs from an FPS. I'd wager that they can make someone immortal, but that it probably takes more than just an apple to do so. Once you do, or you are an Asgardian they would then extend your life span.
Source: Marvel Wikia page on the Golden Apples of Idunn