Fava beans, also known as broad beans, can cause some people to experience a sudden, rapid breakdown of their red blood cells — a condition known as hemolytic anemia.
Back in the 1950s, researchers found that some patients who received primaquine — an anti-malarial drug — developed hemolytic anemia and had lower levels of G6PD in their blood.
So there are even more of these threatening molecules in your body, and without their bodyguard enzyme to protect them, your red blood cells end up sustaining a lot of damage — and prompting hemolytic anemia.