Integrative Health Blog

The Nurture Assumption and Genomics

Posted by admin on Wed, Sep 07, 2011

by Chas Gant MD, PhD

Having certain genes which guarantee me lifetime struggles with insomnia and restlessness, I am a voracious, nocturnal bibliophile.  And as I travel frequently, books will somehow come my way which I use to bore me into a good snooze. While visiting relatives recently, I happened upon a Pulitzer Prize finalist copy of The Nuture Assumption, why children turn out the way they do, by Judith Rich Harris.  Sometimes well-written, provocative books have the opposite effect and keep me awake into the wee hours. Such was the case here. The Nuture Assumption  makes a compelling case, based on sound research on identical twins and other data, that within reasonable efforts to provide our kids with a nurturing, non-abusive, “normal” environment, parenting does not matter much in how our children turn out!

I know this sounds counter-intuitive, but after reading The Nuture Assumption , you will be armed and ready to point out to those obnoxiously, proud parents who raised exceptionally talented and gifted children, that they are full of braggadocio hot air.  And other parents, who despite their best efforts, nurtured kids who somehow became dropouts, addicts and flunkies, can now get off their guilt trips.  Peer pressure matters more than parental influences, so you parents or parents-to-be may want to take that into consideration.  However, what matters the most is genes pure and simple. Identical twins, separated at birth and brought up in utterly different circumstances, turn out pretty much the same.   In fact their quirky traits, talents, preferences and behaviors often have astonishing similarities. 

This is not to say that as parents, we should not do our best at raising our kids in loving, nurturing environments, with as many educational, athletic, spiritual, cultural and growth opportunities as possible. Obviously, abused and neglected children carry post-traumatic scars into adulthood which can make them very dysfunctional.  However, scientific evidence strongly suggests, given a relatively normal upbringing, our children’s genes matter much more in how they turn out than in how they were parented. 

Breaking through this assumption, that psychological nurturing matters, along with a little more knowledge about genetics, could radically change your whole perspective on parenting.  We now know that genetic expression can be altered with lifestyle, diet, toxin exposures and nutrition.  How genes express themselves (called “epigenetic expression”), is not caste in stone, and the genetic expression of our children, especially if we know what genes we are dealing with, can be altered extensively.  The scientific name for this emerging medical field is “predictive genomics[1].”  Since genes matter the most in how kids turn out, being able to switch some genes on and others off can put parents back in the driver’s seat.

Almost all human beings have many common genetic quirks or mutations, called polymorphisms.  A classic example is PKU or phenylketonuria, a relatively genetic disease, which you may have heard about.  PKU is common enough and potentially so devastating, that all babies in the USA are tested at birth, because if it is not addressed right away, severe mental retardation can result.

PKU is caused by quirky genes which encode for an enzyme called phenylalanine hydroxylase, which converts the amino acid phenylalanine into tyrosine (another amino acid).  Like letters in the alphabet which are strung together into words, these are two of the few dozen amino acids which are assembled into protein, the building blocks of our entire body.  PKU polymorphisms produce impotent enzymes, so phenylalanine is not as easily converted into tyrosine, and phenylalanine builds up to very high levels, causing this devastating disease. However, PKU is totally benign if a diet mostly free from phenylalanine is immediately instituted at birth and maintained for life.  Thus, even some severe genetic polymorphisms, if diagnosed, can be rendered relatively harmless, through targeted changes in diet and nutrition.

I have used functional medicine and genomics to treat many middle-aged, male patients in my 35 years of practicing medicine, whose male relatives, even non-smokers with normal blood pressure and cholesterol, all died by age 50 with heart attacks.  In their 40s, they know their number is up, and they sought out my care to determine if anything can be done about their quirky, early-heart-attack-causing genes.  After assessing their testing, the dangerous polymorphisms and about 30 biochemical risk factors for heart disease are identified, targeted interventions in diet, lifestyle, nutrition and stress levels are instituted, and like a PKU patient, laboratory retesting later shows that the risk factors which were tearing up their arteries, has been modified.  What’s also nice about predictive genomics and functional medicine is that, once this information is known, their male relatives can also benefit from switching off the early-heart-attack-causing genes.

So how does genomics change the whole perspective of parenting?  If most of the available evidence suggests that parental psychological nurturing does not matter much and that genetics is the main determinant in how kids turn out, and genes can be tested and some switched on and others switched off with lifestyle, dietary, toxicity and environmental changes, parents can now empower themselves with interventions that can make a difference. 

For instance, let’s suppose that many of your close relatives became addicted to drugs, alcohol, tobacco or psych meds by the time they reached adulthood. Or perhaps bipolar disorder is rampant in your family.  Wouldn’t you want to know which of these familial, quirky genes are putting your child at risk for these problems, and switch them off before they become dysfunctional.  Predictive genomics changes the whole parenting perspective, because it promises to give parents more control of their children’s destinies. And in a stressed-out, high-demand, toxin and junk-food-infested world which renders those with common polymorphisms increasingly vulnerable to harmful outcomes, predictive genomics is an idea whose time has come.



[1] Try googling this term, and peruse some of the 1,700,000 websites!

Topics: functional medicine, nature v. nurture, genetics