For future reference, you're not going to get a significant amount of TNF by eating one banana, and the digestive tract would break it down too much. You would have to consume a lot of bananas to get an amount of TNF worth mentioning. Not to mention, TNF is inflammatory -- explaining why it promotes immune cells to fight invaders -- but inflammatory proteins can also be found in the background of various diseases, such as Inflammatory Bowel Disease, Crohn's disease, and Alzheimer's, and the list goes on.
In an animal experiment carried out by a professor in Tokyo U comparing the various health benefits of different fruits, using banana, grape, apple, water melon, pineapple, pear and persimmon, it was found that banana gave the best results. It increased the number of white blood cells, enhanced the immunity of the body and produced anti-cancer substance TNF. The recommendation is to eat 1 to 2 banana a day to increase your body immunity to diseases like cold, flu and others.
According to the Japanese professor, yellow skin bananas with dark spots on it are 8 times more effective in enhancing the property of white blood cells than the green skin version.
Tumor necrosis factor: One of multiple proteins capable of inducing necrosis (death) of tumor cells that possess a wide range of proinflammatory actions.