Tänään julkaistiin toinenkin tutkimus hiilihydraattien vähentämisen
terveyttä edistävistä vaikutuksista. Tutkimuksessa
Effects of Protein, Monounsaturated Fat, and Carbohydrate Intake on Blood
Pressure and Serum Lipids: Results of the OmniHeart Randomized Trial
Lawrence J. Appel; Frank M. Sacks; Vincent J. Carey; Eva Obarzanek; Janis F.
Swain; Edgar R. Miller III; Paul R. Conlin; Thomas P. Erlinger; Bernard A.
Rosner; Nancy M. Laranjo; Jeanne Charleston; Phyllis McCarron; Louise M.
Bishop; for the OmniHeart Collaborative Research Group
JAMA. 2005;294:2455-2464.
<http://jama.ama-assn.org/cgi/content/abstract/294/19/2455>
todettiin, että hiilihydraattien osittainen korvaaminen ruokavaliossa
tyydyttämättömillä (pääasiassa kertatyydyttämättömillä) rasvahapoilla tai
proteiinilla (joista puolet kasvislähteistä) alensi verenpainetta, paransi
lipidiprofiilia ja pienensi sydän- ja verisuonitautiriskiä. Alla tutkimuksen
abstrakti:
"Context Reduced intake of saturated fat is widely
recommended for prevention of cardiovascular disease. The
type of macronutrient that should replace saturated fat
remains uncertain.
Objective To compare the effects of 3 healthful diets,
each with reduced saturated fat intake, on blood pressure
and serum lipids.
Design, Setting, and Participants Randomized, 3-period,
crossover feeding study (April 2003 to June 2005)
conducted in Baltimore, Md, and Boston, Mass.
Participants were 164 adults with prehypertension or
stage 1 hypertension. Each feeding period lasted 6 weeks
and body weight was kept constant.
Interventions A diet rich in carbohydrates; a diet rich
in protein, about half from plant sources; and a diet
rich in unsaturated fat, predominantly monounsaturated
fat.
Main Outcome Measures Systolic blood pressure and low-
density lipoprotein cholesterol.
Results Blood pressure, low-density lipoprotein
cholesterol, and estimated coronary heart disease risk
were lower on each diet compared with baseline. Compared
with the carbohydrate diet, the protein diet further
decreased mean systolic blood pressure by 1.4 mm Hg (P =
.002) and by 3.5 mm Hg (P = .006) among those with
hypertension and decreased low-density lipoprotein
cholesterol by 3.3 mg/dL (0.09 mmol/L; P = .01), high-
density lipoprotein cholesterol by 1.3 mg/dL (0.03
mmol/L; P = .02), and triglycerides by 15.7 mg/dL (0.18
mmol/L; P<.001). Compared with the carbohydrate diet, the
unsaturated fat diet decreased systolic blood pressure by
1.3 mm Hg (P = .005) and by 2.9 mm Hg among those with
hypertension (P = .02), had no significant effect on low-
density lipoprotein cholesterol, increased high-density
lipoprotein cholesterol by 1.1 mg/dL (0.03 mmol/L; P =
.03), and lowered triglycerides by 9.6 mg/dL (0.11
mmol/L; P = .02). Compared with the carbohydrate diet,
estimated 10-year coronary heart disease risk was lower
and similar on the protein and unsaturated fat diets.
Conclusion In the setting of a healthful diet, partial
substitution of carbohydrate with either protein or
monounsaturated fat can further lower blood pressure,
improve lipid levels, and reduce estimated cardiovascular
risk."
Kommentti:
Fewer Carbs Boost DASH Diet's Heart Benefits
<http://news.yahoo.com/s/hsn/20051115/hl_hsn/fewercarbsboostdashdietsheartbenefits>
"TUESDAY, Nov. 15 (HealthDay News) -- Two carbohydrate-
reduced versions of the government's Dietary Approaches
to Stop Hypertension (DASH) diet have a beneficial effect
on blood pressure, cholesterol levels and long-term
cardiovascular risk, researchers report.
The new diet shifts about 10 percent of calories from
carbohydrates to either protein-rich foods or to
monounsaturated fats such as olive or canola oil.
"This diet should be a frontrunner," said Dr. Frank
Sacks, one of the authors of the study and a professor of
medicine and nutrition at Brigham and Women's Hospital
and Harvard in Boston. "It improved the whole
cardiovascular risk spectrum. A lot of patients are tough
to control with the medications we have. Patients might
not even need drugs if they go on the diet."
"This is a modified version of the old diet," Sacks
explained. "The DASH diet was a real breakthrough for
lowering blood pressure and we changed it. We reduced the
carbohydrate content and replaced it with unsaturated fat
or protein, and it lowered blood pressure more and
improved lipids, and overall cardiovascular risk goes
down."
He called the new regimens "an improvement over something
that's already good."
Another expert agreed that the two new versions of the
DASH diet, as well as the original DASH, which was
developed by the National Heart, Lung and Blood
Institute, should work.
"These are just alternative versions," said Dr. Jay
Skyler, a professor of medicine and associate director of
the diabetes research institute at the University of
Miami School of Medicine. "To me, whether you get a
little bit more lowering with one or another diet than
the other matters less than the fact that you ought to
stick to any one of these three. They're all better than
the conventional diet that these people were on."
The findings were presented Tuesday at the American Heart
Association's annual meeting in Dallas, and also appear
in the Nov. 16 issue of the Journal of the American
Medical Association.
The DASH diet has been considered the gold standard of
heart-healthy nutrition since it was pioneered in the
mid-1990s. The original diet was carbohydrate-rich,
emphasizing fruits, vegetables and low-fat dairy
products. Unfortunately, in addition to lowering "bad" or
LDL cholesterol, the regimen also reduced "good" or HDL
cholesterol, and had no effect on blood fats called
triglycerides.
To help make the regimen even healthier, the same
researchers updated the diet and compared the two new
versions with the old one.
For this study, 164 adults aged 30 and older with
elevated blood pressure were assigned to one of three
diets: one in which carbohydrates represented 55 percent
of calories (close to the original DASH diet); one that
shifted 10 percent of carbohydrate calories to protein
(about two-thirds from plant sources and the rest from
chicken and egg whites); and one that shifted 10 percent
of calories to unsaturated fat, mostly olive or canola
oils. About half of the participants were black, a group
at especially high risk of developing hypertension.
All of the diets lowered participants' blood pressure,
LDL cholesterol and estimated coronary heart disease
risk, the researchers report, and the protein and
unsaturated fat diets showed even better improvements.
Compared to the old diet, the enhanced-protein version
decreased blood pressure by an extra 1.4 mm Hg overall
and by an extra 3.5 mm Hg among those with hypertension;
it decreased LDL cholesterol by an additional 3.3 mg/dL
and triglycerides by 15.7 mg/dL.
Compared to the original DASH diet, the unsaturated fat-
rich version decreased systolic blood pressure by an
additional 1.3 mm Hg overall and by 2.9 mm Hg among those
with hypertension; it increased HDL cholesterol by an
extra 1.1 mg/dL and lowered triglycerides by 9.6 mg/dL.
Both the protein and unsaturated fat diets reduced heart
disease risk more than the DASH diet.
Breakfast was similar in all three diets and included
fresh fruit, fruit juice, whole grain cereal and skim
milk. Lunches and dinners were varied. A typical protein-
diet dinner might include one ounce of raisins and
cherries, where the carbohydrate dinner included a
peppermint patty.
How practical are the improvements? All the study
participants were given their meals. In the real world,
people will have to prepare these meals themselves.
"Would people be able to stick to any of these as
effectively when they're doing it at home? That's the
unknown thing here," Skyler said. "I think whatever
people will stick to and are happy with will work. I
would be happy with the results of any of these three."
Sacks said his team was working on making the diet easy
to use. "Our next project is to work on foods and menus
and things that people can use, to give people more
specific guidance," he said. "Hopefully that'll be out in
a couple or three months. We feel a sense of urgency to
get some real practical stuff out like we did with the
DASH diet."
An accompanying editorial also emphasized the need for
lifestyle changes such as more exercise, in addition to
diet, to keep blood pressure low.
A second study, also presented Tuesday at the American
Heart Association meeting, found that men and women who
reduced their sodium intake lowered their risk of
cardiovascular disease or death by 26 percent.
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