Taka
Mon, Mar-10-08, 17:16
Applied Nutrigenomics Where Genes and Food Come Together -
Part 1 by Dr. John M. Berardi, PhD, CSCS First published at
www.t-nation.com
Nutrigenomics: The study of how genes and nutrients interact.
Until recently, I knew this field of science was an exciting
area that would someday change the future of nutrition,
medicine, and more.
However, in my mind all this crazy gene-nutrient stuff was
still wrapped up in mystery. It was the stuff futurists
hypothesized about rather than the stuff physicians,
nutritionists, and health experts could use every day.
Six months ago I was fortunate to sit in on a small-group
lecture led by one of the world's top nutrigenomics
researchers, Dr. Ahmed El- Sohemy.
When I heard Dr. El-Sohemy speak, I realized that I was wrong.
With the completion of the human genome project and the latest
nutritional science, it's clear that nutrigenomics is no
longer the future of medicine. It's here today. And it's being
applied by cutting- edge health experts everyday.
As I sat in the audience, my neurons were firing like a fourth
of July light show. There was so much info flying around that
my pen couldn't move fast enough to keep up. I knew I had to
sit down to pick Dr El- Sohemy's brain.
Here's what came out of our latest conversation.
John Berardi: Dr. El-Sohemy, thanks for agreeing to do this
interview. It's much appreciated and I know everyone reading
will be fascinated by your work.
A few months back, you presented some very interesting
data looking at how genomic information can impact our
understanding of nutrition and nutrient science. In
other words, you talked about how our genes can
determine our responses to the food we eat, the
supplements we take, and more.
For those readers unfamiliar with this area of research, can
you briefly describe the field of nutrigenomics?
Dr. Ahmed El-Sohemy: Nutrigenomics, sometimes called
nutritional genomics, investigates how the foods we eat
interact with our genes to affect our health. The
questions we typically ask are, "How much of each nutrient
should a particular person consume?" and, "What are the
biological effects of a specific supplement?"
There are basically two approaches that we use to investigate
such questions.
First, we look at how common variations found throughout the
human genome explain individual differences in response to
dietary intake. For example, this area of research explains
why some people can eat a high fat diet and have no problem
with their cholesterol levels while others experience the
exact opposite response.
This line of research, sometimes referred to as nutrigenetics,
enables us to understand why some individuals respond
differently than others to the exact same nutrients.
The second approach that nutrigenomics researchers use is to
investigate how nutrients and bioactive components in food
turn on or off certain genes -- these genes impacting
important metabolic and physiologic processes in the body.
For example, researchers have identified compounds found in
broccoli that switch on a specific gene that helps the body
detoxify some of the harmful chemicals we're sometimes
exposed to.
Of course, this line of research helps us understand the
mechanisms behind how food, and specific compounds within
food, can impact our health. Berardi: This is really cool
stuff, especially since people have long proclaimed that when
it comes to nutrition, "you gotta find what works for you."
Often times this means lots of trial and error.
In essence, the field of nutrigenomics is helping to explain
why you gotta find what works for you, as well as helping to
determine whatwill work for your genetic type.
Before getting deeper into your research, I'm curious. How
does someone like you get involved in the field of
nutrigenomics? What's your background?
Ds. El-Sohemy: I first became interested in this field about
10 years ago, which is before the term "nutrigenomics" was
actually coined. At the time, I was working on my PhD in
nutritional sciences and was researching the effects of
cholesterol on cancer using rodent models.
One of my experiments gave totally unexpected results. In
fact, they were completely the opposite of those published by
other researchers. It turned out, however, that the strain of
rat that I used metabolizes cholesterol quite differently than
other strains that were used in previous experiments.
The study design was virtually identical to previous ones, but
the only real difference was the genetic background of the
animals. I realized the importance of considering genetics
when studying nutrition and it occurred to me that genetic
differences between humans could also explain why some people
respond differently than others.
So I decided to take some genetics courses and complete a
major in molecular biology. After finishing my PhD at the
University of Toronto, I went to Harvard for a fellowship to
pursue this type of research in humans.
Berardi: As such, you're definitely a pioneer in the field.
And it's awesome that we have guys like you with extensive bio
and genetics backgrounds looking into some very important
nutritional questions.
Just how can our genes impact our personal responses to the
foods we eat and the drugs we take?
Dt. El-Sohemy: Well, to start with, we've known for a long
time that individuals respond differently to certain
drugs. In fact, much of the pioneering work in
pharmacogenetics was done decades ago at the University
of Toronto.
But the concept of personalized medicine dates as far back as
480 BC when Hippocrates, the father of modern medicine, noted
that "Positive health requires a knowledge of man's primary
constitution and of the powers of various foods, both those
natural to them and those resulting from human skill."
The word "constitution" is a clear reference to our genetic
profile and the "foods resulting from human skill" can be seen
as the dietary supplements and functional foods we now have
available.
Just like with drugs, when it comes to the nutrients we take
in through our diets or the supplements we take, our genes can
cause us to respond differently from our neighbors.
Here's an example: Certain genes can affect the rate of
absorption, distribution, metabolism, or excretion of almost
everything we consume. And these differences can result in
extreme variability in how we respond. The gene that I
mentioned earlier, which can be activated by compounds found
in broccoli, is actually missing in about 20% of the
population. So some people won't benefit from the detoxifying
properties of broccoli, although they probably still benefit
from its antioxidant effects.
Understanding the basis of this variability will certainly
help us do a few things. First, it can help explain some of
the inconsistencies among previous studies that have linked
nutrients, supplements, and other bioactives to a number of
health outcomes. Second, it can help us understand how to eat
or which supplements to use based on our genetic profile.
Berardi: Indeed, I've read that based on genetic
differences, the physiological response to a certain drug or
supplement could be 70- times different at the same dose
between two individuals. While this seems shocking, it does
stand to reason.
For example, some people respond to creatine supplementation
with large performance improvements and increases in lean mass
while others have no response. From this, it's likely that one
or more of the steps -- absorption, distribution, metabolism,
or excretion -- are impacted by their different genotypes,
leading to a wide difference in response.
I know you're looking into this very thing with respect to
caffeine intake. What's your lab showing?
Du. El-Sohemy: Last year, we published a study in the Journal
of the American Medical Association to demonstrate that
in some individuals, caffeinated coffee intake lowered
the risk of heart attacks. But in other individuals the
same dose of caffeinated coffee increased the risk of
heart attacks.
Berardi: Let me guess. It had to do with the genes.
Dv. El-Sohemy: That's right. Individuals who had what we
call a 'slow' version of the gene CYP1A2 (a gene that
breaks down caffeine in the liver) have an increased
risk of a heart attack when increasing consumption of
caffeinated coffee.
However, those who have the 'fast' version of CYP1A2, have a
lower risk of heart attacks with moderate intakes of
caffeinated coffee (1-3 cups per day).
Berardi: How do people make sense of this dichotomy?
Dw. El-Sohemy: These findings suggest that caffeinated coffee
only increases heart disease in those who have a limited
capacity to break down caffeine.
The reason why those with the 'fast' version of the gene might
benefit is because they can break down caffeine very rapidly,
getting rid of the caffeine while preserving the "healthy"
antioxidants in the coffee. It's these antioxidants, not the
caffeine, which might offer protection for the heart.
So, in the end, caffeine itself probably isn't good for anyone
in terms of heart disease. But, if you can get rid of it
quickly because you're a 'fast' metabolizer of caffeine, then
you might benefit from the other compounds in either coffee or
tea, both of which are pretty good sources of antioxidants.
By the way, being a 'fast' metabolizer for caffeine doesn't
necessarily make you a 'fast' metabolizer of any other dietary
factor. The enzymes coded by each gene are quite specific to
the compounds they metabolize.
Berardi: Unfortunately for me, I don't know my CYP1A2
genotype, but I do love an occasional cup of espresso! How can
I know if I'm playing Russian roulette with my health every
time I brew up a pot of java?
Dx. El-Sohemy: Some people think they know they're 'slow'
metabolizers of caffeine because if they have a coffee in
the afternoon, it'll keep them up all night. But this just
means that caffeine binds more effectively to a specific
receptor in the nervous system, which is how caffeine acts
as a stimulant.
It doesn't tell you anything about how quickly caffeine is
broken down by the liver, which is the main organ that's
responsible for metabolizing caffeine. The only way to know
if you're a' fast' or 'slow' caffeine metabolizer is by
having a DNA test.
My lab routinely runs these genetic tests using cells that are
easily obtained by swabbing the inside of your mouth. Although
this is done primarily for research purposes and for health
care practitioners, we're also trying to develop a test that
doesn't require the use of elaborate equipment needed to
process and analyze DNA.
Berardi: Aren't some progressive health centers doing this
type of genetic testing for patients? If so, any
recommendations?
Dy. El-Sohemy: I've heard about a company that claims to offer
the CYP1A2 test based on our published study, but I can't
really comment on how reliable their test is. They haven't
done the research that we have.
SOURCE: http://www.precisionnutrition.com/members/showthread.-
php?t=10829
Part 1 by Dr. John M. Berardi, PhD, CSCS First published at
www.t-nation.com
Nutrigenomics: The study of how genes and nutrients interact.
Until recently, I knew this field of science was an exciting
area that would someday change the future of nutrition,
medicine, and more.
However, in my mind all this crazy gene-nutrient stuff was
still wrapped up in mystery. It was the stuff futurists
hypothesized about rather than the stuff physicians,
nutritionists, and health experts could use every day.
Six months ago I was fortunate to sit in on a small-group
lecture led by one of the world's top nutrigenomics
researchers, Dr. Ahmed El- Sohemy.
When I heard Dr. El-Sohemy speak, I realized that I was wrong.
With the completion of the human genome project and the latest
nutritional science, it's clear that nutrigenomics is no
longer the future of medicine. It's here today. And it's being
applied by cutting- edge health experts everyday.
As I sat in the audience, my neurons were firing like a fourth
of July light show. There was so much info flying around that
my pen couldn't move fast enough to keep up. I knew I had to
sit down to pick Dr El- Sohemy's brain.
Here's what came out of our latest conversation.
John Berardi: Dr. El-Sohemy, thanks for agreeing to do this
interview. It's much appreciated and I know everyone reading
will be fascinated by your work.
A few months back, you presented some very interesting
data looking at how genomic information can impact our
understanding of nutrition and nutrient science. In
other words, you talked about how our genes can
determine our responses to the food we eat, the
supplements we take, and more.
For those readers unfamiliar with this area of research, can
you briefly describe the field of nutrigenomics?
Dr. Ahmed El-Sohemy: Nutrigenomics, sometimes called
nutritional genomics, investigates how the foods we eat
interact with our genes to affect our health. The
questions we typically ask are, "How much of each nutrient
should a particular person consume?" and, "What are the
biological effects of a specific supplement?"
There are basically two approaches that we use to investigate
such questions.
First, we look at how common variations found throughout the
human genome explain individual differences in response to
dietary intake. For example, this area of research explains
why some people can eat a high fat diet and have no problem
with their cholesterol levels while others experience the
exact opposite response.
This line of research, sometimes referred to as nutrigenetics,
enables us to understand why some individuals respond
differently than others to the exact same nutrients.
The second approach that nutrigenomics researchers use is to
investigate how nutrients and bioactive components in food
turn on or off certain genes -- these genes impacting
important metabolic and physiologic processes in the body.
For example, researchers have identified compounds found in
broccoli that switch on a specific gene that helps the body
detoxify some of the harmful chemicals we're sometimes
exposed to.
Of course, this line of research helps us understand the
mechanisms behind how food, and specific compounds within
food, can impact our health. Berardi: This is really cool
stuff, especially since people have long proclaimed that when
it comes to nutrition, "you gotta find what works for you."
Often times this means lots of trial and error.
In essence, the field of nutrigenomics is helping to explain
why you gotta find what works for you, as well as helping to
determine whatwill work for your genetic type.
Before getting deeper into your research, I'm curious. How
does someone like you get involved in the field of
nutrigenomics? What's your background?
Ds. El-Sohemy: I first became interested in this field about
10 years ago, which is before the term "nutrigenomics" was
actually coined. At the time, I was working on my PhD in
nutritional sciences and was researching the effects of
cholesterol on cancer using rodent models.
One of my experiments gave totally unexpected results. In
fact, they were completely the opposite of those published by
other researchers. It turned out, however, that the strain of
rat that I used metabolizes cholesterol quite differently than
other strains that were used in previous experiments.
The study design was virtually identical to previous ones, but
the only real difference was the genetic background of the
animals. I realized the importance of considering genetics
when studying nutrition and it occurred to me that genetic
differences between humans could also explain why some people
respond differently than others.
So I decided to take some genetics courses and complete a
major in molecular biology. After finishing my PhD at the
University of Toronto, I went to Harvard for a fellowship to
pursue this type of research in humans.
Berardi: As such, you're definitely a pioneer in the field.
And it's awesome that we have guys like you with extensive bio
and genetics backgrounds looking into some very important
nutritional questions.
Just how can our genes impact our personal responses to the
foods we eat and the drugs we take?
Dt. El-Sohemy: Well, to start with, we've known for a long
time that individuals respond differently to certain
drugs. In fact, much of the pioneering work in
pharmacogenetics was done decades ago at the University
of Toronto.
But the concept of personalized medicine dates as far back as
480 BC when Hippocrates, the father of modern medicine, noted
that "Positive health requires a knowledge of man's primary
constitution and of the powers of various foods, both those
natural to them and those resulting from human skill."
The word "constitution" is a clear reference to our genetic
profile and the "foods resulting from human skill" can be seen
as the dietary supplements and functional foods we now have
available.
Just like with drugs, when it comes to the nutrients we take
in through our diets or the supplements we take, our genes can
cause us to respond differently from our neighbors.
Here's an example: Certain genes can affect the rate of
absorption, distribution, metabolism, or excretion of almost
everything we consume. And these differences can result in
extreme variability in how we respond. The gene that I
mentioned earlier, which can be activated by compounds found
in broccoli, is actually missing in about 20% of the
population. So some people won't benefit from the detoxifying
properties of broccoli, although they probably still benefit
from its antioxidant effects.
Understanding the basis of this variability will certainly
help us do a few things. First, it can help explain some of
the inconsistencies among previous studies that have linked
nutrients, supplements, and other bioactives to a number of
health outcomes. Second, it can help us understand how to eat
or which supplements to use based on our genetic profile.
Berardi: Indeed, I've read that based on genetic
differences, the physiological response to a certain drug or
supplement could be 70- times different at the same dose
between two individuals. While this seems shocking, it does
stand to reason.
For example, some people respond to creatine supplementation
with large performance improvements and increases in lean mass
while others have no response. From this, it's likely that one
or more of the steps -- absorption, distribution, metabolism,
or excretion -- are impacted by their different genotypes,
leading to a wide difference in response.
I know you're looking into this very thing with respect to
caffeine intake. What's your lab showing?
Du. El-Sohemy: Last year, we published a study in the Journal
of the American Medical Association to demonstrate that
in some individuals, caffeinated coffee intake lowered
the risk of heart attacks. But in other individuals the
same dose of caffeinated coffee increased the risk of
heart attacks.
Berardi: Let me guess. It had to do with the genes.
Dv. El-Sohemy: That's right. Individuals who had what we
call a 'slow' version of the gene CYP1A2 (a gene that
breaks down caffeine in the liver) have an increased
risk of a heart attack when increasing consumption of
caffeinated coffee.
However, those who have the 'fast' version of CYP1A2, have a
lower risk of heart attacks with moderate intakes of
caffeinated coffee (1-3 cups per day).
Berardi: How do people make sense of this dichotomy?
Dw. El-Sohemy: These findings suggest that caffeinated coffee
only increases heart disease in those who have a limited
capacity to break down caffeine.
The reason why those with the 'fast' version of the gene might
benefit is because they can break down caffeine very rapidly,
getting rid of the caffeine while preserving the "healthy"
antioxidants in the coffee. It's these antioxidants, not the
caffeine, which might offer protection for the heart.
So, in the end, caffeine itself probably isn't good for anyone
in terms of heart disease. But, if you can get rid of it
quickly because you're a 'fast' metabolizer of caffeine, then
you might benefit from the other compounds in either coffee or
tea, both of which are pretty good sources of antioxidants.
By the way, being a 'fast' metabolizer for caffeine doesn't
necessarily make you a 'fast' metabolizer of any other dietary
factor. The enzymes coded by each gene are quite specific to
the compounds they metabolize.
Berardi: Unfortunately for me, I don't know my CYP1A2
genotype, but I do love an occasional cup of espresso! How can
I know if I'm playing Russian roulette with my health every
time I brew up a pot of java?
Dx. El-Sohemy: Some people think they know they're 'slow'
metabolizers of caffeine because if they have a coffee in
the afternoon, it'll keep them up all night. But this just
means that caffeine binds more effectively to a specific
receptor in the nervous system, which is how caffeine acts
as a stimulant.
It doesn't tell you anything about how quickly caffeine is
broken down by the liver, which is the main organ that's
responsible for metabolizing caffeine. The only way to know
if you're a' fast' or 'slow' caffeine metabolizer is by
having a DNA test.
My lab routinely runs these genetic tests using cells that are
easily obtained by swabbing the inside of your mouth. Although
this is done primarily for research purposes and for health
care practitioners, we're also trying to develop a test that
doesn't require the use of elaborate equipment needed to
process and analyze DNA.
Berardi: Aren't some progressive health centers doing this
type of genetic testing for patients? If so, any
recommendations?
Dy. El-Sohemy: I've heard about a company that claims to offer
the CYP1A2 test based on our published study, but I can't
really comment on how reliable their test is. They haven't
done the research that we have.
SOURCE: http://www.precisionnutrition.com/members/showthread.-
php?t=10829