Hormesis - Controversy

Controversy

Whether hormesis is common or important is controversial. At least one peer-reviewed article accepts the idea, claiming that over 600 substances show a U-shaped dose-response relationship. Calaberese and Baldwin wrote:

One percent (195 out of 20,285) of the published articles contained 668 dose-response relationships that met the entry criteria.

The idea that low dose effects may be (sometimes strikingly) different is accepted, but that the low dose effect is positive is questionable.

The hypothesis of hormesis has generated the most controversy when applied to ionizing radiation. This theory is called radiation hormesis. For policy making purposes, the commonly accepted model of dose response in radiobiology is the linear no-threshold model (LNT), which assumes a strictly linear dependence between the risk of radiation-induced adverse health effects and radiation dose.

The United States National Research Council (part of the National Academy of Sciences), the National Council on Radiation Protection and Measurements (a body commissioned by the United States Congress) and the United Nations Scientific Committee on the Effects of Ionizing Radiation (UNSCEAR) all agree that radiation hormesis is not clearly shown, nor clearly the rule for radiation doses.

A report commissioned by the French National Academy concluded that there is sufficient evidence for hormesis occurring at low doses and that LNT should be reconsidered as the methodology used to estimate risks from low level sources of radiation, like deep geological repositories for nuclear waste. On the other hand, the United States-based National Council on Radiation Protection and Measurements states that there is insufficient evidence for radiation hormesis and that radiation protection authorities should continue to apply the LNT model for purposes of risk estimation.