Funny, I became vegan after having first experienced the great health benefits of a diary-free diet. I thought I might be able to eliminate all my health problems by getting rid one by one of all other animal products (and processed sugar). Not eating meat did help further improve my skin and digestion, so I was very motivated to try a 100% vegan diet. Bad Idea.
I had eliminated all diary at the advice of a dermatologist, and along with having great skin I had the immense surprise of solving two
lifelong health problems. For the first time in my life I wasn't calcium deficient (irronically) which also helped decrease my photophobia quite a bit, because I didn't have weak eye muscles anymore due to constanty low calcium levels, and I no longer suffered from, uhm, constipation.
Oh, and before I got rid of diary, I had been having intense pain in my knees for a little under 2 years, the kind that almost made me faint a few times. No more diary, no more joint pain.
What is a poison for some, is a blessing for others it seems.