Phenotype- It’s all important

April 19, 2008

We need to jump away from the common mind set that confuses PHENOTYPE with GENOTYPE. Phenotype is what “we get” and what actually matters. The phenotype is the “final product” that we get to see, whether it be height, weight, strength, blood pressure, cholesterol, heart disease, cancer, depression or any other feature of the organism. Genotype is the architect’s plans which usually have some differences from the building itself.

The phenotype is like the final building, the genotype like the architect’s plans, the diet like the building materials and exercise like the workmanship. Anyone who has built or renovated a house knows that mistakes in the plans (genes) are fairly uncommon compared to cheap substitute materials (poor diet) and poor workmanship (lack of exercise). We have a few genetic diseases, then a lot of gene nutrient/diet interaction diseases, then a great mass of straight out dietary diseases.

I say this because as a doctor, I think most doctors behaviour indicates that they confuse phenotype with genotype. This mindset causes a fatalism that thinks that no treatment is worthwhile other than a drug. Personally I think that variations in diet and exercise have a greater influence on variations in phenotype than do variations in genotype. Which is why I am interested in nutrition- if the previous sentence were not true, then there would be no point in studying nutrition or exercise. There would be no point in the 18,000 diet books on Amazon. But I think people’s instincts are correct, that diet does have a profound influence on health. And we can change our diet but not our genes. And we have to eat, so why not improve our health as we do it?

Even though the sentence in bold is somewhat philosophical, I hope it is not too confusing. Jerome Groopman wrote a nice book “How Doctors Think” or don’t think, or have a herd mentality like everyone else might be better titles. How we model health is profoundly important, the better our model, the better we perform. Imagine treating pneumonia before we knew about bacteria- this is a good illustration of how the correct model transforms everything.

This is Simopoulos’ Hippocratic model This expands the bio-psycho-social model to add spiritual.

I use a slightly more detailed model… You can pop in sunlight, gravity and any other attribute you wish under environmental or social. Spiritual should be a separate category but I didn’t put it in then. I’d probably also add education, government and a couple of others, Any suggestions?
Phenotype Interactions

Ben Balzer