True Hannah, you should not stay under the sun for too long. To get your daily vit D you only need about 10 minutes a day. Then you do not need to supplement vit D. POM
http://health.usnews.com/health-news/family-health/heart/articles/2008/06/23/time-in-the-sun-how-much-is-needed-for-vitamin-d
http://health.usnews.com/health-news/family-health/heart/articles/2008/06/23/time-in-the-sun-how-much-is-needed-for-vitamin-d