At 70, actor Billy Bob Thornton, star of Landman, has revealed that his health and diet are closely tied to his rare AB negative blood type. In a recent interview on the Howie Mandel Does Stuff podcast, Thornton explained that his unusual blood type — found in less than 1% of the population — has contributed to a series of food sensitivities and allergies, prompting him to adopt a highly restricted diet.

Thornton told Mandel, “I’m allergic to wheat, dairy… I can’t eat meat, like pork or beef or any of that stuff.” He explained that AB negative blood is associated with fewer digestive enzymes, which can make processing certain foods more difficult. “I just assumed everybody felt like sh‑it after they ate. I didn’t know, but anyway… I can’t have dairy, wheat… can’t eat meat, like pork or beef or any of that stuff,” he said.

Because of these restrictions, Thornton’s meals are extremely limited. He shared some of his typical foods, which include gluten-free chips paired with dairy-free cream cheese. In a humorous anecdote, he described eating a grape with spicy Dijon mustard at a green room event, which unexpectedly became one of his favorite snack combinations.

“This is one of the best things I’ve ever had in my lifetime,” he said, noting how he improvises when the available food is incompatible with his restrictions.

AB negative blood is the rarest of the eight major blood types, found in fewer than 1% of Americans. According to Dr. Michael DeShields, clinical advisor at the Discovery Institute in New Jersey, the “A” and “B” refer to antigen markers on red blood cells, while “negative” indicates the absence of the Rh factor protein.

Despite its rarity, AB negative blood has no inherent medical symptoms or daily health effects. People with AB negative are highly valued as universal plasma donors, and the type occurs only when one parent contributes A, B, or O and the other provides an Rh factor that results in a negative blood type.

For anyone curious about whether they have AB negative blood, Dr. DeShields recommends routine blood testing, which can be done through donation centers, medical procedures, or routine lab work. There are also home blood typing kits available for those who want to find out privately.

While AB negative blood itself does not create medical problems, there are situations where it matters. Blood transfusions, for instance, can be more complicated due to the rarity of compatible donors. Similarly, pregnancy can require monitoring if the mother has an Rh-negative blood type, though modern medicine can prevent complications with a specialized injection.

Dr. DeShields also noted that ongoing research is exploring whether blood type may influence risks for certain conditions, such as clotting disorders, infections, or heart disease, though any connections are generally weak and not a cause for concern in daily life.

Thornton’s diet reflects both the physical realities of his rare blood type and a careful approach to maintaining health as he ages. By adhering to restrictions that accommodate his digestive sensitivities, he continues to perform at a high level in demanding roles like Landman.

While some might view his diet as extreme, it underscores a principle that Thornton embraces: listening to your body and adapting your lifestyle accordingly. Even small improvisations, like a grape with mustard, become meaningful ways to navigate everyday eating without compromising health.

Billy Bob Thornton’s candid discussion of his AB negative blood type and the diet it necessitates gives fans a rare glimpse into the personal side of a Hollywood veteran. While AB negative blood is exceptionally rare, it carries no daily health limitations beyond considerations for blood donation and pregnancy. Thornton’s story shows how awareness of one’s unique physiology can influence lifestyle choices, allowing him to continue a successful acting career while maintaining his well-being.

His combination of humor, adaptability, and health-conscious decisions reflects a practical approach to aging gracefully in the public eye — one that many fans find both surprising and inspiring.