https://www.nature.com/articles/s41598-020-72699-9
"higher ornithine levels were associated with lower breast cancer risk in females."
Foods that Increase Ornithine
Ornithine is considered non-essential; we don’t need to eat it because our bodies can make it. However, some foods measurably increase ornithine in the blood. Surprisingly, the foods that appear to increase blood ornithine the most are grain proteins and watermelon [40, 15].
People who ate a diet high in grain proteins had significantly higher ornithine levels than those who ate mostly meat or dairy proteins. Meanwhile, people who drank large quantities of watermelon juice (more than a kilogram per day) experienced an 18% increase in blood ornithine [40, 15].
To increase your grain protein intake, choose whole grains with high protein content like quinoa and amaranth [41].