Heck of an author/authority! I have an article from a Phoenix, Arizona paper where he did a lecture when he was 63:

Paavo Airola, Ph.D., is an internationally recognized nutritionist, bestselling author and contributing editor for Let's Live Magazine. He is president of the International Academy of Biological Medicine, Inc. and a world leading authority on natural healing. His classic masterpiece, How to Get Well, is acknowledged by doctors and critics to be "the best book on nutrition and biological medicine ever published". It is an international #1 bestseller and is used as a textbook in many universities. Dr. Airola is a frequent featured speaker at health and professional symposia worldwide; he recently completed a lecture tour of Japan and has been a visiting lecturer at Stanford University Medical School.