The self-help guru has had a long and interesting career. One reporter notes:

His first tome, “The Complete Guide to Health and Nutrition,” [published in 1986] led to a decades long column in Penthouse magazine, where Null railed on topics like the ineffectiveness of mainstream cancer treatment and the deadly health risks of vaccinations.

In the last decade, Null’s brand of quackery has given some fans pause with his trafficking in outright denialism. From Wikipedia:

In addition to his promotion of alternative cancer treatments, Null has argued that HIV is harmless and does not cause AIDS. In his  [2002] book AIDS: A Second Opinion, Null questioned the role of antiretroviral medication and instead advocated a range of dietary supplements for HIV-positive individuals.

Null, as you might expect, is fiercely opposed to genetically modified foods. Indeed, “natural health” proponents are among the most fanatical opponentsof GMOs.