"We investigated mechanisms of action to explain the cholesterol-lowering effects of the pistachio diets," says Sarah K. Gebauer, recent Penn State Ph.D. recipient, currently a post-doctoral research associate, USDA Beltsville Human Nutrition Research Center.
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.
The participants began the study by eating a typical 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 about 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, as a control, a Step I Diet with no pistachios and about 25 percent total fat and 8 percent saturated fat. The pistachio enhanced diets were Step I Diets with 10 and 20 percent of the energy supplied by pistachio nuts, respectively. The 10 percent pistachio diet had 30 percent total fat and 8 percent saturated fat and the 20 percent pistachio diet had 34 percent total fat and 8 percent saturated fat.
The participants ate half their pistachios as a snack and the rest incorporated into meals.
The researchers report in the most recent issue of the American Journal of Clinical Nutrition that "Inclusion of pistachios in a healthy diet beneficially affects cardiovascular disease risk factors in a dose-dependent manner, which may reflect effects on Stearoyl CoA Desaturase (SCD). " The researchers used the ratio of two fatty acids, 16:1 and 16:0 in plasma as a marker for SCD, an enzyme that is involved in the body's synthesis of fatty acids.
"SCD is an important enzyme involved in cholesterol metabolism," says Gebauer.
They found the ratio of 16:1/16:0 was significantly lower, suggesting a decrease in SCD activity, after eating the 20 percent energy pistachio diet compared to the control diet which had no pistachios. Also, the change in the 16:1/16:0 ratio was correlated with the change in cholesterol, suggesting that SCD activity may contribute to the lipid-lowering effects of pistachios. That, accompanied by the dose-dependent effects of the pistachios, begins to unravel the way in which pistachios improve cardiovascular health.
Compared to the control diet, the 20 percent pistachio diet lowered LDL cholesterol -- bad cholesterol -- about 12 percent and the 10 percent energy pistachio diet lowered LDL cholesterol by 9 percent that suggests a 9 to 12 percent decrease in coronary heart disease risk. The relationships of total cholesterol to HDL cholesterol and LDL cholesterol to HDL cholesterol may be more powerful predictors of cardiovascular risk. The effects of the 10 and 20 percent energy diets showed a dose dependent effect on these ratios.
However, the researchers note that the reduction in LDL cholesterol observed was seven times greater than would be expected from only the fatty acid profile of pistachios. They suggest that the lipid lowering effects not only reflect the fatty acid profile of the diet, but also are the result of other bioactive substances in pistachios, perhaps phytosterols and fiber.
"Our study has shown that pistachios, eaten with a heart healthy diet, may decrease a person's CVD risk profile, says Penny Kris-Etherton, distinguished professor of nutrition and primary investigator of the study."
A'ndrea Elyse Messer | EurekAlert!
Infants later diagnosed with autism follow adults’ gaze, but seldom initiate joint attention
24.05.2019 | Schwedischer Forschungsrat - The Swedish Research Council
When wheels and heads are spinning - DFG research project on motion sickness in automated driving
22.05.2019 | Technische Universität Berlin
A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.
The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
24.05.2019 | Physics and Astronomy
24.05.2019 | Medical Engineering
24.05.2019 | Life Sciences