A person's entire immune system can be rejuvenated by fasting for as little as three days as it triggers the body to start producing new white blood cells, a study suggests. But it is a question of wonder that what researchers are revealing today is already revealed hundred of years ago by ayurvedic physician. Fasting is one of the main kinds of Ayurvedic treatment and is mentioned as " Langhana" or " Aptarpana" in ayurvedic texts. Langhana therapy imparts lightens to the body. It makes the body thin and light. It is of two types i.e. Shodhana and Shamana. Shodhana type of langhana treatment is that treatment which expert imbalanced doshas out of body forcibly by decoction, vomiting, Purgation etc. while shaman type of Langhana is that palliative type of treatment in which nor the body expels the increased doshas out of the body neither it increases the normal, but makes the abnormal doshas normal. It can be done by with standing hunger (fasting) digestive, physical activity etc. Now modern research has also reached to the same conclusion what ayurvedic physicians has revealed hundred of years ago Fasting for as little as three days can regenerate the entire immune system, even in the elderly, scientists have found in a breakthrough described as "remarkable". Although fasting diets have been criticised by nutritionists for being unhealthy, new research suggests starving the body for as little3 days kick-starts stem cells into producing new white blood cells, which fight off infection.

Scientists at the University of Southern California say the discovery could be particularly beneficial for people suffering from damaged immune systems, such as cancer patients on chemotherapy. It could also help the elderly whose immune system becomes less effective as they age, making it harder for them to fight off even common diseases. The researchers say fasting "flips a regenerative switch" which prompts stem cells to create brand new white blood cells, essentially regenerating the entire immune system.

"When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged," Dr Longo said.