Pistachenoten
tegen diabetes en voor beter cholesterol.*
Uit twee verschillende studies blijken de voordelen nog eens van pistachenoten. In de ene, Canadese studie werd gekeken naar de effecten van pistachenoten op bloedsuikerwaarden al dan niet in combinatie met een koolhydraatrijk dieet. Een koolhydraatrijk dieet alleen doet bloedsuikerwaarden snel stijgen. Door toevoeging van een handvol pistachenoten stegen de bloedsuikerwaarden duidelijk minder, door meer pistachenoten toe te voegen stegen de bloedwaarden nog veel minder. Het eten van alleen pistachenoten geeft nauwelijks een verhoging van de bloedsuikerwaarden. Het stabiliseren van bloedsuikerwaarden is goed tegen het ontstaan van diabetes en de behandeling ervan. Een handje pistachenoten bij een suikerrijke maaltijd is dus verstandig. In een andere studie bleek dat cholesterolwaarden duidelijk verminderden met een dagelijkse inname van pistachenoten. Twee handjes pistachenoten per dag doen het totaal cholesterol met ruim 8% verminderen en de LDL met ruim 11%.
Eating
Pistachios May Reduce The Impact Of Carbohydrates On Blood Sugar Levels
"Heart disease remains the leading
cause of death among both men and women and another 20 million people are living
with diabetes each year so these findings are very exciting and relevant,"
said Dr. Cyril Kendall, lead researcher of the study and a professor in the
University of Toronto's Department of Nutritional Sciences. "We know that
controlling blood glucose levels is important for preventing and controlling
diabetes and recent data indicate that it is also important in preventing heart
disease. Controlling postmeal fluctuations in glucose appears to be particularly
important. Pistachios have been shown to decrease risk factors for heart disease,
however little has been known about the specific effects of pistachios on blood
glucose until now. Our preliminary findings demonstrate that suppressing the
glycemic (blood sugar) response of high carbohydrate foods may be part of the
mechanism by which pistachios contribute to cardiovascular health and to the
prevention and control of diabetes. More research is definitely warranted."
"Glycemic Response of Pistachios A Dose Response Study and Effect of
Pistachios Consumed with Different Common Carbohydrate Foods on Postprandial
Glycemia was presented today to more than 10,000 scientists at the Experimental
Biology Conference in Washington, DC. The study is the first of its kind to
examine the effects of pistachios and glucose levels in combination with
carbohydrates. The research was led by University of Toronto's Dr. Cyril Kendall
and Dr. David Jenkins - researchers well known for their studies of the glycemic
index which measures how rapidly sugars from foods are absorbed into the blood
stream. Certain carbohydrates elevate blood sugar levels more quickly than other
foods like pistachios that contain higher levels of protein, fiber and
monounsaturated fat. In general, foods that do not quickly raise blood sugar are
often considered healthier than their more processed counterparts.
Drs. Jenkins and Kendall and their research colleagues studied 10 healthy
individuals who participated in a number of acute dietary studies over the
course of two months. After an overnight fast, participants were given a one-,
two- or three-ounce serving of pistachios alone or served with a slice of white
bread and blood sugar levels were measured over a two-hour period. The findings
suggest that consumption of pistachios with a carbohydrate-rich meal
significantly lowered the d blood glucose response. As consumption of pistachios
increased, the blood sugar lowering response was enhanced. In addition, when
pistachios were consumed alone, the rise in blood glucose was minimal.
The researchers also monitored the effect of pistachios consumed with different
common carbohydrate foods on postprandial glycemia, or blood sugar levels after
eating. The addition of pistachios to a number of other commonly consumed
carbohydrate-rich foods such as mashed potatoes, pasta and rice also resulted in
significant reductions in the blood sugar response, compared to when these foods
were eaten alone.
In July 2003, the U.S. Food and Drug Administration (FDA) approved a
much-awaited qualified health claim for nuts and heart disease prevention. The
claim states, "Scientific evidence suggests but does not prove that eating
1.5 ounces per day of most nuts, such as pistachios, as part of a diet low in
saturated fat and cholesterol may reduce the risk of heart disease."
According to the California Pistachio Commission, the University of Toronto's
research findings are important for individuals who are living a heart-healthy
lifestyle and those that monitor their blood sugar levels.
"Most people with diabetes have other risk factors such as high blood
pressure and cholesterol that increase one's risk for heart disease and stroke.
When combined with diabetes, these risk factors can add up to serious health
problems," explains Constance Geiger, PhD, RD, and consultant to the
California Pistachio Commission. "Recent research has suggested that
pistachios are a heart-healthy, high-protein snack. Now people have yet another
reason to grab a handful they may blunt the blood sugar response of meals and
may be beneficial for assisting with long-term blood glucose control."
Pistachios
Lower Cholesterol, Provide Antioxidants
A
handful of pistachios may lower cholesterol and provide the antioxidants usually
found in leafy green vegetables and brightly colored fruit, according to a team
of researchers.
"Pistachio amounts of 1.5 ounces and 3 ounces - one to two handfuls -
reduced risk for cardiovascular disease by significantly reducing LDL
cholesterol levels and the higher dose significantly reduced lipoprotein ratios,"
says Sarah K. Gebauer, graduate student in integrative biosciences, Penn State,
to attendees at the Experimental Biology meeting in Washington, D.C.
The researchers conducted a randomized, crossover design, controlled feeding
experiment to test the effects of pistachios added to a heart healthy
moderate-fat diet on cardiovascular disease risk factors. Controlled feeding
experiments provide all the food eaten by study subjects for the duration of the
study segment.
Participants began the study by eating an Average American Diet consisting of 35
percent total fat and 11 percent saturated fat for two weeks. They then tested
three diets for four weeks each with a two-week break between each diet.
All three diets were variations on the Step I Diet, a cholesterol-lowering diet
in general use. The diets included a Step I Diet without pistachios which had 25
percent total fat and 8 percent saturated fat; a Step I Diet including 1.5
ounces of pistachios per day which had 30 percent total fat and 8 percent
saturated fat, and a Step I Diet including three ounces of pistachios per day
which had 34 percent total fat and 8 percent saturated fat. The researchers
added pistachios into the diets by including about half the amount of pistachios
as a snack and by incorporating the rest into such foods as pistachio muffins,
granola and pistachio pesto.
"We had really good compliance and participants were generally pleased with
the diets," says Gebauer.
Standard blood tests determined the various cholesterol levels in the
participant's blood after each diet. Researchers found that 3 ounces of
pistachios reduced the amounts of total cholesterol in the blood by 8.4 percent
and low-density lipoprotein (LDL), the so-called bad cholesterol, by 11.6
percent. The study also found that non-high density lipoproteins (non-HDL)
decreased by 11.2 percent. Non-HDL levels are considered reliable predictors of
cardiovascular disease risk.
The three-ounce pistachio diet also decreased the ratios of total cholesterol to
HDL, LDL to HDL and non-HDL to HDL and apolipoprotein B, which are all measures
of cardiovascular disease risk. "We were pleased to see a difference
between the two doses of pistachios for the lipoprotein ratios because it would
appear that pistachios are causing the effect and that they act in a dose
dependent way," says Gebauer.
In addition, during this study researchers, researchers looked at the effects of
these diets on oxidized LDL and on antioxidants in the blood.
"We were trying to see if the increased levels of antioxidants provided by
pistachios could reduce inflammation and oxidation," says Gebauer.
Pistachios contain more lutein, - normally found in dark leafy vegetables --
beta carotene - a precursor to vitamin A - and gamma tocopherol - the major form
of vitamin E - than other nuts. It is oxidized LDL and other lipproteins that
contribute to plaque formation in arteries.
The researchers reported that both the 1.5 and 3 ounce pistachio diets reduced
oxidized LDL compared with the baseline diet. Pistachio-enriched diets also
resulted in significantly higher levels of lutein in the blood. The increased
lutein from the 3-ounce pistachio diet correlated with a reduction in oxidized
LDL which may indicate that the lutein in pistachio nuts improves the risk of
cardiovascular disease by reducing serum oxidized LDL.
"Our study has shown that pistachios, eaten with a heart healthy diet, may
decrease a person's CVD risk profile," says Dr. Penny Kris-Etherton,
distinguished professor of nutrition and primary investigator of the study.
###
Researchers conducting the cholesterol study included Gebauer; Kris-Etherton;
Colin D. Kay, former Penn State post-doctoral associate now at the University of
East Anglia; UK; Sheila G. West, associate professor of biobehavioral health,
all at Penn State, and P. Alaupovic, Oklahoma Medical Research Foundation,
Oklahoma City. Researchers conducting the oxidation study included Kay, Gebauer,
West and Kris-Etherton. The California Pistachio Commission supported this study.
Partial support also came from the NIH-supported GCRC at Penn State.
(Juni 2007)