I got this from a quick google. It looks pretty good but there are lots of other sites if you want more info...
http://www.healthyfellow.com/163/natural-skin-care/
Here's the most relevant excerpt:
This final experiment supports the earlier findings I shared about flaxseed oil. In this trial, a purified fish oil supplement was tested to see if it could help improve skin elasticity in women.
24 healthy, middle-aged women participated in this study. For 3 months they were asked to take fish oil on a daily basis, after which a special dermatological assessment was made using a device called an “optical cutometer”. It was found that there was a 10% increase in skin elasticity by the end of the trial.
ETA: BTW, I don't think I had seen this research before! I had incorporated healthy fats in my diet for health reasons (and to improve memory) and noticed the improvement in my own skin! Anyway, if I did see this research beforehand, I guess it hasn't improved my memory all that much, lol!