Nutrigenomics
Kofi
myself.
http://www.nytimes.com/aponline/national/AP-FIT-Genetic-Diet.html
Scientists Look to DNA for Nutrition Ideas
By THE ASSOCIATED PRESS
Published: October 13, 2005
Filed at 8:17 p.m. ET
NEW YORK (AP) -- As a registered dietitian, Ruth DeBusk has eaten a
healthy diet for a long time. As a geneticist, she wondered if she could
do better.
So earlier this year, she had her DNA tested by a company that gives
personalized nutrition advice based on genetics. The results indicated
she needed more folate.
So DeBusk doubled her minimum amount of folate, a B vitamin found in
leafy greens and citrus.
''I'm more diligent about being sure that I get it every day if
possible, because it really matters,'' said DeBusk, who has a private
practice in Tallahassee, Fla., and has written a book on nutrition and
genetics.
''I'll actually make an effort to drink a glass of orange juice or eat
an extra big salad in the evening, being aware it hasn't been one of my
better folate days.''
That's the way it's supposed to work in a field called nutritional
genomics or nutrigenomics. The basic idea is this: There are genes that
affect the risk of getting illnesses like heart disease, cancer,
osteoporosis and diabetes, and the impact of those genes can be modified
by what you eat. Everybody carries one version or another of each of
those genes. So why not find out what gene versions you have and base
dietary advice on that?
''Every time we go to the supermarket we're using educated guesses about
what we should eat and what we shouldn't eat,'' says Raymond Rodriguez,
director of the National Center of Excellence for Nutritional Genomics
at the University of California, Davis.
In the future, more of that guesswork may be replaced with accurate,
personal DNA-based dietary advice, which Rodriguez says is ''rapidly
emerging on the horizon.''
But that time isn't here yet, most experts say. Nutrigenomics is still
in its infancy, with plenty to be learned, and it's not yet clear what
role it may play in standard medical practice.
Most of the research targets heart disease and cancer, and scientists
may be ready to deliver personalized diet recommendations in those areas
within five years, said Jose Ordovas, director of the nutrition and
genomics laboratory at the U.S. Department of Agriculture Nutrition
Research Center at Tufts University in Boston.
''We have scientific evidence that the concept is right, that we can
provide something along those lines in the future,'' Ordovas said. ''We
are not there yet.''
No? You can walk into some pharmacies or grocery stores right now and
pay $99 for a DNA test kit that will get you personalized diet advice
for heart health, bone health, or any of three other areas. It's from
Sciona Inc., a small company based in Boulder, Colo., that started
offering DNA-based diet advice in 2001. Such tests are also available by
mail order and on the Internet.
Sciona customers collect their own DNA with a cheek swab, complete a
diet and lifestyle questionnaire and send it all in for analysis. Sciona
encourages customers to review its advice with a doctor.
The company acknowledges that some scientists say it's too soon to offer
such a service, but says its testing is based on solid research. Current
testing focuses on 19 genes and the company is studying others, said
Rosalynn Gill-Garrison, chief scientific officer and a company founder.
Sciona's approach basically starts with standard healthy-eating
recommendations and modifies them when genetic analysis indicates a need
for something more, Gill-Garrison said.
After a DNA test, Sciona may recommend steps like eating more broccoli
or omega-3 fatty acids, she said, or limiting caffeine to protect
against bone loss.
Gill-Garrison said studies show that people with a certain version of a
gene called MTHFR tend to have high blood levels of a substance called
homocysteine, which has been linked to a higher risk of heart disease
and stroke. Studies also show that people with this gene version can
reduce their homocysteine levels by taking in more folate, she said. So
that's the advice Sciona customers with that gene version get.
High levels of homocysteine also can be spotted with a standard blood
test at a doctor's office.
Ordovas said the trouble with anybody providing gene-based dietary
advice now is that scientists don't yet have the whole picture of what
genes should be considered. With current tests, it's like trying to size
up a landscape by looking through a keyhole, he said. You can't tell
what you're not seeing.
''At least in that very narrow region of our genome that they are
looking, they have potential that they may provide some valuable
information, and it could benefit some people,'' he said. But advice
based on current tests ''can also be misleading because you are ignoring
pieces that are very important,'' he said.
Rodriguez said he doubts anybody will be harmed by the current tests,
and that they're beneficial because they get people to think about diet
and lifestyle. But he said they remind him of the first VCRs or CD
players to hit the market.
''It is an expensive new technology ... and it will probably, in my
estimation, become more efficient, more accurate and more affordable
with time.''
DeBusk, who said she has no financial ties to any of the companies,
figures the time for DNA-based diet advice has come.
''The scientist in me says we shouldn't do this now, we need to wait
another 20 years until many studies have been done,'' she said. But her
clients want to know what the best science is right now, and ''it's
difficult to say, 'Come back in 20 years.' You can't do that.
''Do we know everything we'd like to know? No... Do we know enough to
start introducing this type of technology and start the long process of
educating people? I would say yes.''
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On the Net:
Sciona, Inc.: http://sciona.com
UC Davis nutrigenomics center: http://nutrigenomics.ucdavis.edu
Tufts lab: http://hnrc.tufts.edu/departments/labs/genomics.shtml
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