"Your body doesn't have the energy it needs to filter toxins, causing it to believe that it has an infection, so it's always inflamed," she told the mag. "You create antibodies that attack your glands, so you have to eat clean."
The "Avatar" actress, married to Marco (Perego) Saldana with twin boys Cy and Bowie, also shared that her mother and sister suffer from the disease.
In order to get a better handle on the issue and her health, she now keeps a gluten and dairy free diet with her husband. But, she wasn't always so on top of her eating game.
"I had a great time in my twenties," she admitted. "Then your doctor says you're losing calcium in your bones. What the f--- is that?! I would hear those conversations with my mom and grandma, thinking I'd never get there. I'm going to live forever! But all of a sudden it hits you. I s--- you not, it's from night to day."
Opening up about her health issues isn't the only big news in Zoe's life as of late. She also just revealed that her Italian-born hubby Marco became a U.S. citizen on July 20.
Zoe shared an Instagram post with Marco and her own mother, who moved here many years ago from the Dominican Republic.
"My mom has been a citizen since she was a young girl. Her mother arrived in NYC in 1961 and brought my mother from Dominican Republic when she was 10," Zoe explained on Instagram. "My sisters and I are indebted to them both. Because of them we are American women. So proud she is here supporting Marco!"
She also noted that another famous star was getting his citizenship the same day. "Oh check out who is getting their naturalization today too... David Oyelowo and his Wife!!!!! Congrats! #newuscitizen," she added.
Zoe, 38, posted one more pic with her man and their cute kiddos in front of an American flag.
"God Bless The United States Of America. #fatherandsons #newuscitizen #newcitizen," she wrote.