Saturday, July 13, 2013

T. Colin Campbell On "Genetic Determinism"

In his new book, Whole: Rethinking The Science of Nutrition, Campbell addresses the topic of "genetic determinism" or the likelihood that disease will occur based on the existence of particular genes. Genetic determinism leans towards the "nature" end of the nature-nurture continuum. Campbell argues that focusing on genes will poorly predict disease, and that "the influence of nurture (i.e. nutrition) has far more influence on health and disease outcome than nature (i.e. genes)." He makes a good argument, especially since he's been a reductionist scientist for most of his career, someone who would by nature believe in the prescience of genes.
"A belief in genetic determinism suggests that our future health and disease events are already predestined at birth and that, as we age, we simply move from one disease benchmark to another according to the genetic blueprint we inherited at conception. This encourages the impression that there is little or nothing that we can do to prevent serious diseases like cancer. In contrast, the belief that cancer and related diseases are dependent on nutritional practices can encourage a sense of hope and lead to healthier behavior."
I visited this concept before, here, where Dr. Ornish used the phrase "genetic nihilism" instead of "genetic determinism" and argued that "genes may be our predisposition, but they are not our fate." And here where Dr. Ramachandran used the example of an inherited disorder called phenylketonuria (PKU) to illustrate the complex ("labyrinthine") interaction of genes and the environment.

Campbell offered this diagram which very simply represents the flow from our parents' genes to our own state of health or disease. Note that, in this diagram, there are two ways our body prevents disease that may be prescribed in our genes. One is by repairing those genes. The other is by diet or "nutritional interception." Campbell acknowledges that "certainly, there are nonnutrient lifestyle factors that may control gene expression," including body biochemistry, physical activity, medication, mood, and many others. But...
"However, I am suggesting that nutritional inputs are the primary factor in gene expression, and that in the vast majority of cases, the vast majority of the time, good nutrition has a much greater impact than anything else - including the most complicated and expensive genetic intervention."
Dr. Campbell advocates a whole food, plant-based diet with little or no animal products.


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