Vitamin D is a hormone (incorrectly named a vitamin before realizing it was such)- so supplementing Vitamin D is a form of HRT. Best way to get it naturally is to sun your bare chest in direct sunlight for at least 15 minutes per day. Get lots of it during the spring-fall so you have enough on reserve during the winter to avoid Seasonal Affective Disorder.

Increase your fiber intake (specifically dark leafy greens) to likely improve your bowel situation.