A YouTube star who credited her vegan lifestyle for "curing" her of breast cancer has died from the disease, her niece and channel co-host confirmed.

Mari Lopez, who vlogged alongside her niece Liz Johnson on their Mari & Liz channel, succumbed to breast cancer in December, after it spread to her blood, liver and lungs. Lopez had told her followers that taking on a vegan lifestyle cured her breast cancer in just three months.

In a video called "Cancer Transformation FAQ," Lopez claimed: "The lemon-ginger blast helped me remove inflammation from my body," but acknowledged to experiencing "food withdrawals" during her 90-day juice cleanse.

Lopez also claimed on her YouTube channel, which had 11,761 subscribers, that becoming a vegan and her faith stopped her from being a lesbian. She told viewers: "I was healed by God and faith and used to live a gay lifestyle."

She also revealed that she opted to skip cancer treatments, saying she preferred to continue "on this path of going natural".

Lopez said at the time: "It's over, it is done with, I am healed. I feel it in my spirit and in my body."

Johnson confirmed that her aunt had died from the disease, but claimed veganism could have saved her aunt, despite it spreading, if her carer had not fed her meat. In a video posted earlier this week, Johnson said that Lopez passed away because she did not continue with her "juicing/raw vegan diet".

"My aunt passed away in December because her cancer came back... [She] was inconsistent in her diet and spiritual life," Johnson said. "My aunt didn't continue juicing [or her] raw vegan diet when she got diagnosed again - she chose to do radiation and chemo."

Johnson told viewers that as her aunt became increasingly ill, she asked to have her videos removed from YouTube. Johnson said she refused.

"My mom would buy her burgers and things like that, and she didn't want to eat that but after a while she was just OK with it," she said. "When you give in too many times, you end up saying whatever...I feel like that's what causes the issues."

She continued: "People have sent me many emails about positive changes after juicing, and some have told me that they chose to do chemo.

"Some are still alive, and unfortunately, some are not. We never claimed that this would 100% work for everyone."

Johnson said she plans to continue posting videos of the "benefits" of juicing and noted that she would be adding disclaimers to her aunt's old videos informing viewers of her death.