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Gene
science sheds new light on nutrition
April 14, 05
Suzanne Havala Hobbs
The
science of nutrition has come a long way from the basic four
food groups. New information is leading to some innovative
ways of thinking about diet and health.
One result: an emerging field that combines nutrition science
and genetics. Nutritional genomics – or nutrigenomics
– is the study of how foods interact with our genes
to promote or protect against diseases such as coronary artery
disease, cancer, high blood pressure, diabetes and obesity.
These problems disproportionately affect minority populations
in the U.S. According to researchers from the Nutrigenomics
Center at the University of California-Davis, African American
men have a 60 percent greater risk of developing prostate
cancer than white men, and half of all adult Pima Indians
in the U.S. have Type 2 diabetes, as compared to only 6.5
percent of whites.
Nutrigenomics can also explain why some people can eat onions
or chile peppers and others can’t, or why some people
tolerate alcohol better than others.
Researchers hope that nutrigenomics will someday make it possible
to make dietary recommendations tailored to individuals’
health risk profiles, based on their genetic makeup and environmental
factors that may affect the expression of certain genes.
Yet another related and evolving field – nutritional
anthropology – focuses on ways that genes interact with
culture and lifestyle, sometimes permitting the body to adapt
to foods people have been dependent on over generations.
A classic example: 10,000 years ago in Northern Europe, a
genetic mutation occurred among people who kept dairy herds.
The genetic change made them lactose tolerant – able
to digest milk sugar as adults. Normally, humans don’t
drink milk after infancy, when weaning is triggered as the
body becomes lactose intolerant.
Today, people with Northern European ancestry can comfortably
digest dairy products, whereas most other adults around the
world cannot.
For example, 98 percent of southeast Asians, 90 percent of
Asian Americans, 79 percent of African American adults, and
55 percent of Mexican American men are lactose intolerant
and experience nausea, cramps, bloating, gas and diarrhea
when they drink milk, say researchers at UC-Davis.
Many immigrants and others living in the U.S. may be genetically
programmed to thrive on diets outside the American norm.
According to Gary Paul Nabhan, a natural historian and author
of “Why Some Like It Hot: Food, Genes, and Cultural
Diversity” (Island Press, 2004), “More and more
scientists now accept that ethnic cuisines have deep-seated
ecological underpinnings and evolutionary trajectories that
are of great significance to the health status of their consumers.”
“Our ancestral homelands do not lie in some remote,
nearly unreachable place, but instead are imbedded in our
genes and our cultural food preferences,” writes Nabhan.
As the science of nutrigenomics and studies of the relationships
between food, genes, and culture develop, changes in dietary
guidance policy are likely to follow. Current government dietary
recommendations are based on studies that do not reflect our
nation’s growing cultural diversity. According to Census
2000 data, today’s white majority will be the minority
by the year 2050.
Researchers at the Nutrigenomics Center at UC-Davis point
out: “Dietary guidelines such as the food guide pyramid
developed by the USDA and the recommended dietary allowances
(RDA) established by the National Research Council, assume
all Americans are the same – culturally, socio-economically,
physiologically and genetically.”
Not for long.
More information about the Nutrigenomics Center at UC-Davis
is available online at http://nutrigenomics.ucdavis.edu.
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