Radiation Hormesis

How about Radiation Hormesis?  If people living in Denver have less cancer (except for skin
cancer) than people living at sea level and if a person in a brick home in Denver receives three
times the radiation of someone living in a wood-frame home in Palo Alto, then perhaps we
need some radiation just like we need some parasites for our immune system to fight lest we
get IBS, Crohn’s or asthma.


Bernard Cohen at University of Pittsburgh
In the 4th edition of Intermediate Physics for Medicine and Biology, Russ Hobbie and I
discuss the work of physicist Bernard Cohen (1924-2012). In Chapter 16 (Medical Use of X
Rays), we describe the dangers of radon gas, and show a picture from a 1995 study by Cohen
studying lung cancer mortality as a function of radon gas level (our Fig. 16.57). Interestingly,
the mortality rate goes down as radon exposure increases: exactly the opposite of what you
would expect if you believed radiation exposure from radon caused lung cancer. In this blog
entry, I consider two questions: who is this Bernard Cohen, and how is his work perceived



This paper examines the underlying factors that contributed to the marginalization of
radiation hormesis in the early and middle decades of the 20th century. The most critical
factor affecting the demise of radiation hormesis was a lack of agreement over how to define
the concept of hormesis and quantitatively describe its dose-response features. If radiation
hormesis had been defined as a modest overcompensation to a disruption in homeostasis as
would have been consistent with the prevailing notion in the area of chemical hormesis, this
would have provided the theoretical and practical means to blunt subsequent legitimate
criticism of this hypothesis. A second critical factor undermining the radiation hormesis
hypothesis was the generally total lack of recognition by radiation scientists of the concept of
chemical hormesis which was markedly more advanced, substantiated and generalized than
in the radiation domain. The third factor was that major scientific criticism of low dose
stimulatory responses was galvanized at the time that the National Research Council (NRC)
was organizing a national research agenda on radiation and the hormetic hypothesis was
generally excluded from the future planned research opportunities. Furthermore, the
criticisms of the leading scientists of the 1930s which undermined the concept of radiation
hormesis were limited in scope and highly flawed and then perpetuated over the decades by
other ‘prestigious’ experts who appeared to simply accept the earlier reports. This setting was
then linked to a growing fear of radiation as a cause of birth defects, mutation and cancer,
factors all reinforced by later concerns over the atomic bomb. Strongly supportive findings on
hormetic effects in the 1940s by Soviet scientists were either generally not available to US
scientists or disregarded as part of the Cold War mindset without adequate analysis. Finally, a
massive, but poorly designed, US Department of Agriculture experiment in the late 1940s to
assess the capacity for low dose plant stimulation by radionuclides failed to support the
hormetic hypothesis thereby markedly lessening enthusiasm for research and funding in this
area. Thus, the combination of a failed understanding of the hormetic hypothesis and its
linkage with a strong chemical hormesis database, flawed analyses by prestigious scientists at
the critical stage of scientific research development, reinforced by a Cold War mentality led to
marginalization of an hypothesis (i.e., radiation hormesis) that had substantial scientific
foundations and generalizability.


Limited Human Brain