"In the latter nineteenth century, a Russian doctor of immunology, Elie Metchnikoff, was intrigued by the healthy life spans of people who lived in the tribes of the northern Caucasus Mountains. What contributed to their long lifespan and their resistance to life-threatening diseases? A possible factor lay wrapped up in a leather satchel used to hold fermented milk. Observing the connection between the beverage and longevity, Dr. Elie Metchnikoff began his research on beneficial bacteria and the longevity of life that led to his book, The Prolongation of Life. He studied the biological effects and chemical properties of the kefir elixir whose name came from the Turkish word “kef” or “pleasure.” To this day, kefir is one of the most widely enjoyed beverages in Russia. Kefir has since found its way into America, where it is marketed in several flavors and can be found at your local grocery store. It is one product of the billion-dollar functional food industry marketed with all sorts of health claims from improving digestion to preventing cancer. What is the scientific evidence that kefir is a functional food? Expert nutritionists agree that probiotics, such as kefir, reduce the symptoms of lactose intolerance and can ward off virally caused diarrhea. While some health claims remain unsubstantiated, scientific studies are ongoing to determine the validity of other health benefits of probiotics. The Native Hawaiians also consumed a daily probiotic in their diet commonly known as poi (pounded taro). In precolonial Hawai‘i, poi was used for a wide variety of dietary and medicinal purposes. Aside from poi’s nutrient-dense composition, fermented poi has numerous compounds created in the fermentation process that are very beneficial to the health of the human body. As a probiotic, evidence suggests that poi can be useful in helping diseases such as diarrhea, gastroenteritis, irritable bowel syndrome, inflammatory bowel disease, and cancer. Another well-known probiotic to the local people of Hawai‘i is kimchi. Kimchi is a traditional Korean food that is manufactured by fermenting vegetables, usually cabbage. Similar to kefir and poi, kimchi has also shown similar health benefits as a probiotic food. The Japanese also have traditional fermented foods such as natto. Natto is made from fermented soybeans and has many health benefits as a probiotic. Along with the beneficial components, natto is very nutrient-dense, containing carbohydrates, fats, protein, fiber, vitamins, and minerals. Other common foods we ferment in our diet include miso, sauerkraut, kombucha, and tempeh."