Brian Clement on raw goat's milk, yoghurt, kefir, casein and the China study Question: Is it healthy to eat raw goat's milk or cow's milk, fermented with kefir? Brian Clements answer: The number one cause of cancer is casein from cow’s milk. Read the China study by doctor Campbell (and watch the other video that I will post on the blog today). Fermented fat is even worse, it is a carcinogen. It oxidizes and is no longer able to communicate with other cells. The only time when we ever suggest to use goat's milk is in the desperate situation, when a mother can’t give breast milk to her child and only up to the age of two years old.