If you really like bananas, carefully choose the healthiest fruits. It is pretty hard to resist this sweet and delicious tropical fruit, but there is one special thing you should be aware of when buying bananas.

Fully ripe bananas contain a substance known as TNF, or Tumor Necrosis Factor, which has the power to fight abnormal cells. Ripe bananas develop dark spots on their skin.

The more spots it has, the higher immunity enhancing effect it has. Bananas are quite popular in Japan.

A Japanese scientific research showed that ripe bananas contain TNF which provides strong anticancer properties. TNF increases the power of your immune system. Researchers concluded that consuming ripe bananas is a great way to prevent life-threatening diseases and cancer.

The strength of TNF depends on the ripeness of your fruits, so you may want to look for a fully ripe fruits.

Fruit’s nutrient content changes as it ripens. As bananas ripen, their antioxidant level increases gradually. In fully ripe bananas with dark spots on their skin starch turns into simple sugar, which are a lot easier to digest.

Japanese scientists did a research based on the health benefits of different ripe fruits, including banana, grape, apple, watermelon, pineapple, pear and persimmon.

The research showed that only ripe bananas provide maximum benefits. They stimulate the production of white blood cells, boost immunity and produce TNF. Experts recommend eating a banana or 2 a day to boost your immunity and fight cold, flu and the like.

Bananas with a lot of dark spots contain a considerable amount of TNF-alpha and they are 8 times healthier than green or fresh bananas without any spots, i.e. 8 times more effective in improving the function of white blood cells.

TNF is a cytokine, or a substance that is secreted by certain cells in the immune system and has the ability to affect other cells. This works amazing when it comes to fighting abnormal cells.

Many studies have shown that the level of TNF induction increases markedly with the number of dark spots on the skin right before the peel turns brown.

Bananas are often compared to Lentinan, a chemical immunostimulant that is administered intravenously and acts as an anti-cancer agent. This means that ripe bananas act as anti-cancer agents and stimulate the production of white blood cells, which prevent cell mutation.

Note: Store fully ripe bananas in your fridge to stop any further loss of nutrients. Fresh bananas with brown spots on their skin are ripe enough and you can eat them immediately. Avoid over-ripe bananas with completely brown or split open skin.