Identical twins have always been the subject of much study. Since they are genetically identical, much has been made of their proving or disproving the nature versus nurture argument. If you missed that one, it goes like this: Are your genes (nature) the most powerful determinants of your future, or is your environment (nurture) the most important thing.
The emerging science of epigenetics has shown us that, for the average person, with average genes, at least 70% and perhaps as much as 80% of what happens in terms of health span and life span is epigenetic and thus, in most cases, subject to environmental causes. Complicating matters somewhat is the fact that epigenetics are also ‘heritable’, meaning you get much of your epigenome from your parents as well. The good or bad news with that is that you can influence even inherited epigenetics, to a large degree.
I’ll get back to identical twins in a second, but I want you to understand a few things.
First, you are not beholden to your parents’ fate. A good friend of mine and a doctor and I had a friendly argument the other day. Jack, I will call him, lost his dad to a massive heart attack at age 46, from a specific lesion of the coronary arteries, known as left main disease. Jack himself started with chest pain in his early 40’s and was diagnosed with, you guessed it: left main disease. His cardiologist told him this was very likely heritable, e.g. a genetic trait. No attention was paid to the fact that Jack lived under his father’s roof for 25 years, ate the same things and had exposure to the same stresses and more, since he became a doctor. Undoubtedly he was sleep deprived and still has no idea what his Omega 6 to Omega 3 “fish oil” levels are.
While it is true that Jack may have a genetic predisposition and a specific “allele” (a form of a gene that can exist in several different forms and confer several different risks or lower risks) for left main lesions, it is also likely that, that allele is expressing itself in spades because of the environmental factors and epigenetics results of those factors.
Which brings me back to identical twins. Recent studies in brain development of identical twins, with regards to both autism and schizophrenia, suggest that there are major differences in brain development that depend on the environment in the womb and the placental development and flow to each twin. In other words, the healthier twin usually correlates directly with more, or more balanced nutrients and more normal birth weight. Now understand, I am taking a very complex topic and simplifying it greatly for you, but a couple of key concepts come out here.
First, identical twins do not always have an identical intrauterine environment. They may get different nutrients, different amounts of calories, different maternal hormones or growth factors, different temperatures and toxins, etc., etc. If you are saying “Duh” right now, then please remember that placental/intrauterine medicine is still in its infancy – no pun intended. These studies alone should stimulate much more interest and hopefully research dollars, to investigate the effects of the intrauterine environment.
Second, these effects during the pre-natal period have far reaching effects that may not show up for years, or even decades. Hence, the explanation why kids of moms who took Omega 3’s and who had higher Omega 3 intake during their own first five years of development turned out to have better hand-eye coordination and scholastic performance in their adolescent years! There are probably many more examples of nutrient-based advantages kids have when their moms eat healthy, but you can understand why that one is among my favorites.
Third, this kind of epigenetic “manipulation” may not be fixable in the adult stage, as it may permanently alter gene expression. In other words, autistic and schizophrenic children are not likely to become fully functioning adults, at least in the more severe cases. The good news is that in milder cases, huge amounts of progress can be made.
So too, it is with my friend Jack and his heart disease. So too, it is with you and whatever maladies or ghosts of your parental genetic past you may be facing.
For the majority of us, epigentics means we are responsible. So remember that the next time you reach for a donut!
Doc