functional medicine and nutritional genomics - American Association ...

AAPI’S NUTRITION GUIDE TO OPTIMAL HEALTH: USING PRINCIPLES OF FUNCTIONAL MEDICINE AND NUTRITIONAL GENOMICS
and Roger Williams Ph.D. Dr. Pauling, Nobel Prize
winner for Chemistry in 1954 and Peace in 1962,
was already teaching about the importance of nutrients
in modulating physiological processes at the
biomolecular level. Roger Williams, Ph.D is credited
with developing the concept of biochemical individuality
and has been described as having ‚contributed to the
evolution of the understanding of the molecular origin
of disease‛ (1).
The catalyst for the development of present-day
nutritional genomics has been the Human Genome
Project, a multinational undertaking that began in
1990. While there were a number of goals, the
primary goal was to identify the nucleotide sequence of
the human DNA. However, the specific goals have
changed over time since the Human Genome Project
was completed in 2003, earlier than expected. Current
research is focused on identifying the total number of
genes, their chromosomal location, and their function
(2).
Why is this important to the dietitian? One reason
may be because the impact of the Human Genome
Project has created new information that is expected to
alter the approach to risk assessment of nutritional
issues. However, the dietitian’s evolving role in the
application of nutritional genomics to clinical practice
will require a deepened understanding of genomics,
gene-diet interactions and its applications to clinical
nutrition practice to occur effectively (3).
Fogg-Johnson and Kaput explain that some of the
new information of the Human Genome Project is
surfacing in areas that are not totally predictable.
Through the Human Genome Project, it has been
discovered that individual gene variations exist and are
referred to as single nucleotide polymorphisms (SNPs,
pronounced ‚snips‛). These SNPs result in differential
response to environmental factors, such as diet. The
science of how naturally occurring chemicals in foods
alter expression of genetic information at the molecular
level and how this effects the individual phenotype is
the essence of what nutritional genomics scientists
seek to uncover (4).
As investigators learn how different individuals
metabolize substances based on genetic uniqueness,
there is an increasing awareness of the important roles
specific nutrients can play in modifying the expression
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of metabolic patterns in the individual. Diet, lifestyle,
and environment have significant influence on the way
an individual can metabolize specific substances based
upon his or her genetic uniqueness. These discoveries
have opened the door for the future of molecular
medicine and the development of a personalized
medicine that recognizes aspects of diet, lifestyle, and
environment and their roles in individual disease
causation and the design of specific intervention
programs.
The takeaway from these concepts is that one size
does not fit all. Diet and nutritional intervention must
be personalized to the genetic characteristics of the
individual. Gastrointestinal health is particularly
important to achieving optimal nutrition and affords
several examples of how diet and genes interface and
how the field of nutritional genomics can assist the
registered dietitian (R.D.) in maximizing nutrition care
interventions for the individual.
The Healthy Gut
The gastrointestinal (GI) tract is the second largest
body surface area. The condition of this organ and the
maintenance of its uniquely balanced microflora is
essential to optimal health (5). The healthy intestinal
wall is coated with hundreds of different species of
microorganisms, both beneficial and pathogenic bacteria
numbering in the trillions (5). This rich protective
coating of microorganisms acts in concert with the
physical barrier provided by the cells lining the
intestinal tract and other factors to provide the body
with important filter-like protection. So, in addition to
digesting, absorbing and eliminating food substances
and nutrients, the normal GI tract functions as a
critical semi-permeable (selective) barrier between the
internal and external environment. This prevents toxic,
antigenic or pathogenic molecules or microorganisms
from entering the bloodstream (6). Ultimately, the
importance of the intestinal microflora and, more
specifically, its composition, in physiological and
pathophysiological processes in the human GI is
becoming more evident (6).
Inflammatory Bowel Disease
Inflammatory bowel disease (IBD) is a critical and
chronic disorder of the intestines. Generally, its
complications can be severe, widespread and very