Despite ample evidence gathered over centuries in Europe & US in favor of a dietary cause, Pellagra was believed by many to be an infectious disease until the mid 1900s.
Vitamin D going through a similar revolution right now. Quote from my doc: "if they had discovered it today, they would have called it a hormone [not a vitamin] due to all the things it does in the body." Unless you have an outdoors job, you probably don't have enough, and guess which newsworthy illness it's a major risk factor for?
Lessons from History | 3. Pellagra & Misinformation
Vitamin D going through a similar revolution right now. Quote from my doc: "if they had discovered it today, they would have called it a hormone [not a vitamin] due to all the things it does in the body." Unless you have an outdoors job, you probably don't have enough, and guess which newsworthy illness it's a major risk factor for?