It's no secret that people need ample calcium
and vitamin D to maintain strong bones, even in their twilight years. Now, a
study suggests that protein may be important in reducing bone loss in elders.
The 70- to 90-year-old men and women with the highest protein intakes lost
significantly less bone over a four-year period than those who consumed half as
muchor less. Animal protein, as well as overall protein intake, was
associated with preserving bone.
The findings run counter to studies of
younger people that found diets high in protein, especially animal protein,
caused the body to excrete more calcium. However, they confirm several large
population studies showing protein to have a positive overall effect on bone.
The study was conducted by researchers with
the Hebrew Rehabilitation Center for Aged, Research and Training Institute;
Boston University; and the Jean Mayer USDA Human Nutrition Research Center on
Agingall in Boston, Mass. Their findings are reported in the Journal
of Bone and Mineral Research, 2000 (vol. 15, pp. 2504-2512).
Using data from 615 participants in the
Framingham (Mass.) Osteoporosis Study, the researchers examined the
relationship between the participants' protein intakes in 1988-89 and changes
in their bone mineral density four years later. They accounted for all factors
known to increase risk of bone loss, including weight change, calcium and total
energy intakes, smoking, alcohol and caffeine intakes, physical activity and,
for the women, estrogen use.
Participants who reported the lowest daily
protein intakesroughly equivalent to half a chicken breasthad lost
significantly more bone in the hip and spine four years later than those with
the highest intakesequivalent to about 9 oz. of steak and a cup of tuna
salad. The group with the next lowest intakeequivalent to about two cups
of cottage cheese dailyalso lost more bone than the highest-intake group,
though the loss was significant only at the hip.
People can search the USDA food composition
tables for the protein content of more than 6,000 foods at:
http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl
For more information, contact
Katherine L. Tucker, (617) 556-3351,
Jean Mayer USDA Human Nutrition Research
Center on Aging, Boston, MA
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Planning a cookout? To be on the safe side,
you'd be wise to check the internal temperature of those ground beef burgers
with a meat thermometer instead of relying on color. ARS researchers found that
the way in which the meat is handled before cooking can make it look like it's
been adequately cookedto a temperature of at least 160 degrees
Fwhen it really hasn't been.
The researchers cooked ground beef patties on
a gas grill and used a thermometer to determine when the burgers reached 135,
151 and 160 degrees Fthe temperature at which Eschericia coli is
killed. They also cooked burgers until the meat color turned brown without
using a thermometer. Purchased at the local supermarket, some of the ground
beef was shaped into patties and cooked immediately; some was shaped into
patties and frozen; and some was frozen in its bulk form.
They found that a burger with a brown center
is not necessarily safe to eat. Premature browning was not evident in frozen
patties that were thawed and then cooked. But beef that was frozen in bulk,
thawed, formed into patties, and immediately cooked appeared brown in the
center at unsafe temperatures. Also, burgers removed from the grill with pink
centers continued to brown for several minutes. Patties cooked to 135 degrees F
and allowed to sit for about four minutes looked the same as those cooked to
160 degrees F.
The research, published in the Journal of
Muscle Foods, 2000 (vol.11, pages 213-226), reinforces the current advice
to use a meat thermometer when cooking burgers. USDA's Food Safety and
Inspection Service uses these findings to suggest guidelines for safe food
temperatures.
For more information, contact
Bradford W. Berry, (301)
504-8994, Food Technology
and Safety Laboratory, Beltsville, MD
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Cayenne peppera popular spice for
flavoring foodis known for its heat-producing properties due to the
substance capsaicin. ARS scientists have found that the peppers contain another
potent substance in the saponin chemical family that kills several noxious
fungi and yeasts, including Candida albicans. And because this
saponincalled CAY-1is not toxic to human cells at microbe-killing
doses, a Denver, Colo., firm has begun testing its potential as a candidate
drug for treating patients with fungal infections. MycoLogics, Inc., has a
cooperative agreement with ARS, which has filed for a patent on the
compound.
The ARS researchers discovered CAY-1 while
looking for plant compounds that could be used as crop protectants against
spoilage microorganisms such as Aspergillus fungi, which produce
aflatoxins. Cayenne peppers topped an unusual list of organismsincluding
Cecropia moths, tree frogs and bacteriathat produce other novel
antifungal compounds.
The researchers speculated that CAY-1's
properties might also interest medical researchers seeking candidate compounds
to fight emerging fungal threats to human health. That curiosity led to
collaborative studies with researchers at the National Institutes of Health,
the University of Cincinnati and MycoLogics, Inc.
Different CAY-1 concentrations were tested
against germinating and non-germinating cultures of four bacterial, six fungal
and one yeast species. In one test against C. albicans, which causes
thrush in babies and vaginal infections in women, a solution of 2.6 parts per
million curbed the microbe's growth by 93 percent. And none of the CAY-1
concentrations tested caused harm to human cervix cell cultures. CAY-1 also
wasn't toxic to cells from lung tissue, where Aspergillus and
Pneumocystis carinii fungi can cause serious infections in
immuno-compromised patients.
For more information, contact
Tony J. De Lucca, (504)
286-4253, Southern Regional Research
Center, New Orleans, LA
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Now there's a practical approach to reducing
two major foodborne pathogens in pigs and cows. ARS researchers found that
sodium chlorateoxidized table saltfed in low doses before
slaughter, selectively kills the pathogens Salmonella typhimurium and
E. coli O157:H7. They fed 45 weaned pigs as much as 0.04 grams of sodium
chlorate per kilogram of body weight after being inoculated with S.
typhimurium. Within 16 hours, the number of pathogenic cells in the
intestines dropped from 1,000 per milliliter to less than 10.
The treatment is effective because
Salmonella and E. coli O157:H7 have an enzymerespiratory
nitrate reductasethat beneficial intestinal bacteria lack. This enzyme
converts the sodium chlorate to chlorite, which kills the harmful bacteria. The
beneficial bacteria lack the enzyme, so they are unharmed by the added
chlorate.
Gut and lymph tissue in meat animals are
major reservoirs for Salmonella or E. coli O157:H7. The U.S.
Centers for Disease Control and Prevention estimate that about 1.4 million
cases of human salmonellosis and 73,000 cases of diarrheal illness caused by
O157:H7 occur in the United States each year.
USDA applied for a patent on behalf of the
ARS inventors, who are seeking a cooperative research partner to further
develop the work for commercial meat processing. The researchers suggest an
alternative to adding sodium chlorate to the feed: add it to the animals'
drinking water upon arrival at the processing facility. However, the U.S. Food
and Drug Administration would need to approve any wide-scale use of this
technique.
For more information, contact
David J. Nisbet, (979) 260-9368, or
Robin C. Anderson, (979) 260-9317,
Food and Feed Safety Research Unit,
College Station, TX
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Take some oysters, liver, nuts and seeds,
wash them down with a little cocoa, and top them off with a chocolate bar for
dessert. While this combination may not appeal to your taste buds, including
these foods in a well-balanced diet may reduce your risk of colon cancer,
according to recent animal studies by ARS scientists. These foods are all high
in copperan essential trace element that is below the new recommended
intake (0.9 milligram per day) in about one-quarter of U.S. diets.
New studies of mice and rats add to evidence
that a low-copper diet significantly increases risk of colon cancerthe
second leading cause of cancer mortality in the United States and the fourth
worldwide. Diet is thought to be the single greatest contributor to colon
cancer in humans, possibly accounting for 35-45 percent of the disease risk.
Now, copper joins selenium, calcium, carotenoids and fiber as being important
for a healthy colon.
The researchers will soon report in
Biofactors that rats raised on only one-fifth of their copper
requirement had significantly more precancerous lesions in their colons than
the animals that got adequate copper after both groups were given a
cancer-causing chemical. And copper-deficient colon cells showed enzyme
abnormalities that have been reported in precancerous lesions in both humans
and rats.
The researchers also looked for a copper
connection in mice with a genetic predisposition to develop intestinal tumors.
Since the mouse mutation is similar to one found in some human families, these
animals make a good model for testing the effects of dietary changes. Not
surprisingly, the mice fed the copper-deficient diet had significantly more and
bigger tumors than the animals fed adequate copper. These findings were
reported in Cancer Letters, 2000 (vol. 159, pp. 57-62).
For more information, contact
Cindy D. Davis, (701) 795-8380,
Grand Forks Human Nutrition Research Center, Grand Forks, ND
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Mothers who want their growing daughters to
get ample calciumso necessary for building bonestake heed: Actions
really do speak louder than words. A new study found that mothers who routinely
drank milk and consumed few soft drinks had daughters who did the same.
Likewise, mothers who routinely drank soft drinks and avoided milk had
soft-drink-loving daughters who drank little milk. The study involved nearly
200 pairs of 5-year-old European-American girls and their mothers.
Reporting in the Journal of Nutrition,
2001 (vol. 131, pp. 246-250), the researchers found that mother-daughter pairs
who drank more soft drinks also consumed less calcium. Girls who consumed more
than one serving of non-juice or soft drink beverage daily consumed an average
150 milligrams less calcium per day than their soft-drink-limiting peers.
Although other foods can provide adequate calcium in the diet, dairy foods
remain the primary source for most children.
According to national dietary surveys, while
calcium intake among 2- to 5-year-olds is usually adequate, the average 9- to
18-year-old consumes just over half of the 1,300 mg of calcium daily
recommended for this age group. One in five consumes a mere 500 mg each
dayor less.
The findings suggest that by simply being a
good role model and making milk and other low-fat dairy products more available
in the home, mothers can increase how much calcium their daughters consume. And
this could yield personal benefits. Currently, less than one in 10 women meets
the daily calcium recommendation for adults. For those who can't consume milk,
other good sources of calcium include calcium-fortified soy beverages, tofu and
breakfast cereals; canned fish with soft bones, such as sardines and salmon;
and dark-green leafy vegetables.
For more information, contact
Jennifer Fisher, (713) 798-7000,
Children's Nutrition Research Center at
Baylor College of Medicine, Houston, TX;
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Our bodies can't make enough of the B vitamin
choline if we are low in it and a second B vitaminfolate. That's
according to a study by ARS and university researchers. The findings agree with
some animal studies conducted earlier at the ARS center in Boston and by other
nutrition researchers elsewhere. In all, these investigations helped pave the
way to the current recommended choline intake of 425 milligrams a day for women
and 550 mg for men.
The study with male and female volunteers
included low-folate, low-choline regimens that provided as little as 13 percent
of today's recommended daily allowance of folate. No severe choline or folate
deficiencies occurred during the study. But blood levels of choline decreased
an average of 25 to 28 percent in men and women during the low-folate,
low-choline stints, the researchers reported in the Journal of
Nutrition, 1999 (vol. 129, pp. 712-717). Those levels returned to at least
normal when researchers provided more folate.
Meats, dairy products and soy foods are rich
in choline. Folate is highest in orange juice, green leafy vegetables like
spinach, and bread flour or other grain products fortified with this vitamin.
Nuts and liver contain both nutrients.
Choline helps us absorb and use fats. It s
required for making acetylcholine, a neurotransmitter needed for muscle
control, memory storage and other functions. Both nutrients contain what's
known as a methyl group, which the body uses to form genetic material, or DNA.
For more information, contact
Robert A. Jacob through
June 6, 2001 at (701) 795-8456, Grand
Forks Human Nutrition Research Center, Grand Forks, ND; thereafter, at
(530) 752-4726, Western Human Nutrition Research Center, Davis, CA;
rjacob@whnrc.usda.gov
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Fresh red raspberries will be available
through July thanks to Coho, a new variety released by ARS and the agricultural
experiment stations of Oregon, Washington and Idaho. Coho will extend the
availability of fresh berries by 7 to 10 days compared to Tulameen, the current
late-season standard throughout much of the world. Raspberries are low in fat
and a good source of dietary fiber. Along with blueberries and blackberries,
they are also a rich source of anthocyanins, which are potent
antioxidants.
Coho gives high yields of bright-red, very
firm berries. It should grow well in the Pacific Northwest and California, or
in other raspberry-growing areas where winter temperatures don't fall below
zero degrees F. The Pacific Northwestincluding Oregon, where Coho was
most extensively testedand California produce 95 percent of the nation's
fresh red raspberries. Growers can obtain plants through several nurseries in
the Northwest, and consumers may be able to find Coho berries this
summer.
For more information, contact
Chad E. Finn, (541) 750-8759,
Northwest Center for
Small Fruit Research, Corvallis, OR
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Starch, water and oil
can mix to become a material with an unusual variety of forms. Called Fantesk
by its ARS developers, the material has led to partnerships with industry to
develop a wide array of new products. Under one of the latest agreements with
ARS, Azure Waves Seafood, Inc., of Cincinnati, Ohio, is developing seafoods
seasoned with herbs and spices in breading made from Fantesk. Other food
applications on the horizon include cheeses, soft-serve ice cream, cookies and
muffins.
Fantesk is formed first as a gel when starch,
such as cornstarch, and an oil, such as soy oil, are processed in pressurized
steam. Tiny droplets of oil remain well distributed in the starch without a
greasy feel. The tiny oil droplets, 0.1 to 10 microns in diameter, are ideal
places to encapsulate certain fat-soluble compounds that contribute flavor to
foods.
For more information, contact
Craig J. Carriere, (309)
681-6551, National Center for
Agricultural Utilization Research, Peoria, IL
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When the nationwide food survey begins
in 2002, interviewers will be armed with new tools to ensure that their
data collection accurately reflects what people eat in America. In addition
to the traditional measuring cups, spoons and rulers, interviewers will
have a new Food Model Booklet full of scientifically designed, life-size
pictures. These will help respondents better estimate the size of that
slice of pizza, serving of french fries or glass of cola they consumed
during the previous 24 hours. It's one result of three years of work by
ARS scientists.
To put the servings in perspective, the
researchers had a grid, wedges, circles and several amorphous mounds printed
on transparent pages that overlie an image of a full-size dinner plate
straddled by a full-size knife. The different-sized moundsfor estimating
foods ranging from a dollop of whipped cream to a heap of spaghettiappear
to have depth.
Grid overlay in Food Model Booklet.
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One of two mound overlays in Food Model Booklet.
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The researchers also expanded and improved
the method of questioning respondents to help them remember forgotten
foodsnonalcoholic and alcoholic beverages, sweets, snacks, breads and
other easily overlooked foods. This new Multiple Pass Method has a number of
built-in cues to help jog the memory. In two pilot studies, respondents
recalled eating more foods than were reported by their counterparts in the last
survey. In one study, they reported 300 more calories, on average.
To further ensure accuracy, the survey
research group automated the whole interview, computerizing questions, prompts,
and details about the food and how it was prepared. The program contains 2,400
questions about foods with 21,000 possible answers.
The USDA nationwide food survey is being
integrated with the National Health and Nutrition Examination
Surveybetter known as NHANESwhich is directed by the U.S.
Department of Health and Human Services' National Center for Health Statistics
in Hyattsville, Md. That means respondents will report their food intakes and
also receive a comprehensive physical exam in NHANES' mobile exam centers.
For more information, contact
Alanna Moshfegh, (301) 504-0170,
Food Surveys
Research Group, Beltsville, MD
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