Which force has a larger influence on our health? Our environment, or our DNA? Learn more about these two competing forces here.

1. Environment or Genetics?
Which Influences our Health the Most?
The Debate:

2. Nature vs. Nurture: An Ongoing
Conversation
Which is more influential to our health? The world around us
(how we’re “nurtured”), or the DNA we’re born with (our
nature)? Scientists have been exploring environmental and
genetic causes of health conditions for decades to determine if
and how these two forces shape our health.
While we know that our genes determine our chemical makeup,
we also know that our physiological processes have the ability
to be shaped by our environment; were our body solely
programmed by genetics, things like vaccines and antibiotics
wouldn’t work.

3. The Immune System
A recent study published by Stanford
University researcher Mark Davis
found that when it comes to our
immune system, environment
unquestionably has more influence
than genetics.
Davis’s research using identical twins
found that:
Of the 200 components of each twin’s
immune system tested, there was found
to be too much variation between each
twin to determine that immune systems
were shaped by genetics.
Researchers have long been
interested in the body’s immune
system. Through research,
they’ve discovered that every
immune system is unique, as we
each have different numbers of
proteins and cells that influence
our body’s ability to fight
disease .
So what accounts for this
distinct composition? Is it our
DNA, or what we’re exposed to
in our environment?

4. In fact, environment played a larger role than genetics in more than
3/4ths of the parameters evaluated.
Researchers also tested variations in responses to flu vaccines and
found that twins had very different antibody production levels;
were environment not at play, these levels would have been
identical.
The study further looked at sets of twins in which one twin was
infected with cytomeglovirus (which typically lays dormant in the
body) and one twin was not. It found that these sets of twins have
greater variation in their overall immune system performance than
those that are both uninfected. This virus in particular influenced
60% of the immune system parameters evaluated.
More Results

5. Genetics and Dementia
Sometimes genetics is the only or predominant factor at play in our
health. For example, a new study from the University of Edinburgh
finds specific genetic signals that indicate an individual will develop
dementia.
Four different regions associated with strong thinking skills were
evaluated and found to contain genetic signals that determine the
performance of these regions.
This is the first study that demonstrates that genetics influence
mental deficiencies in old age.

6. Dual Influence
So we know that some physiological functions
are predominantly influenced by our
environment, while others are predominantly
influenced by genetics. But what about
conditions in which both environment and
genetics are equally at play, or conditions in
which the cause is too ambiguous to identify?

7. Obesity, Genetics and Environment
Scientists have discovered an “obesity gene” called FTO that
increases an individual’s risk of becoming obese. 16 percent of
people with two copies of the FTO gene were significantly more
likely to become obese.
However, scientists are challenged to determine when and how
environmental factors like eating habits and exercise influence
these genes.
Regardless of the extent of environmental influence, we now know
for certain that even just one gene can influence our chances for
becoming obese.

8. Searching for Causes of Autism
Autism is a neurodevelopmental disorder that affects millions of individuals in
the United States and around the world, and is increasing in prevalence each
year.
Researchers have long been attempting to identify the cause of autism, and have
conducted studies to either pinpoint environmental triggers or identify genetic
mutations.
Researchers like David and Mark Geier have conducted studies that
demonstrate that vaccines that contain certain harmful elements like the
compound Thimerosal increase a child’s risk of developing autism.
Other research, such as that recently published in Nature, identifies over 60
different genes that maintain a 90 percent or higher chance of increasing a
child’s risk for autism.

9. Equal Influence?
The exact cause or causes of autism are generally still
considered to be unknown. Researchers of
environmental and genetic causes have both presented
extensive findings, but others believe that
environmental factors and genes could be equally at
play.
A recent study published in The Journal of American
Medicine Association found that half of the cases of
autism result from genetic mutations, and half result
from environmental factors, which were not specified.

10. Case-Specific Causes
Ultimately, the debate between environment and
genetic influence is case specific. In some
instances, our health is affected by our exposure to
certain elements of the world around us, and in
some instances, our health is primarily shaped by
our genetic makeup. Or, as seems to be most often
the case, these two factors are both influential to
our health.
Sources : http://sfari.org/news-and-opinion/news/2014/environment-genetics-may-contribute-equally-to-
autism-risk, http://www.psmag.com/nature-and-technology/genetics-lifestyle-matter-obesity-epidemic-
97848, http://news.sciencemag.org/biology/2015/01/environment-more-genetics-shapes-immune-system