Researchers found that a pistachio-enriched diet resulted in increases in serum antioxidants and decreases in oxidized low-density lipoproteins (LDL), or so-called ‘bad’ cholesterol, when compared to a diet without pistachios.
The study, conducted by researchers at The Pennsylvania State University, is published in the June 2010 issue of The Journal of Nutrition.
It adds to a growing body of science supporting the health benefits, and the heart benefits in particular, of increased consumption of nuts, such as almonds, macadamia, and walnuts.
However, pistachios have one of the highest antioxidant capacities of all nuts and contain more b-carotene, g-tocopherol and lutein - an antioxidant also found in dark green leafy vegetables.
This latest study was completed by 10 males and 18 females who were healthy and non-smoking, aged 35–61 and with moderately elevated LDL-cholesterol.
Participants consumed a typical Western diet for two weeks as a baseline diet. They were then randomized to each of the three experimental diets for four weeks - a lower-fat control diet without pistachios, a diet with one serving of pistachios (ie 32–63 g/d) and a diet with two servings of pistachios (63–126g/d).
The results suggest that consumption of pistachios in the context of a heart-healthy diet confers cardioprotective benefits “beyond established lipid-lowering effects, including a decrease in oxidized-LDL”. This, the researchers believe, is the result of both a decrease in LDL cholesterol concentrations and an increase in serum antioxidants, such as lutein and g-tocopherol.
The authors concluded: “The consumption of the pistachio-enriched diets resulted in increases in serum antioxidants and decreases in oxidized-LDL relative to the control diet.
“These data suggest that a heart-healthy diet rich in pistachios has a beneficial effect on serum antioxidants, as well as oxidized-LDL. Beneficial effects on multiple CVD risk factors would be expected to reduce overall CVD risk beyond that achieved by decreases in LDL-cholesterol alone through lowering cholesterol and the benefits of the antioxidants in the nuts.”
The market potential of heart health benefits has been highlighted by America’s Western Pistachio Association (WPA), which has worked with Penn State University regarding the potential health benefits of the nuts.
In 2008 research carried out at the university and funded by the WPA found that pistachios significantly reduced inflammation at a cellular level – a recognised risk factor for heart disease – as well as reducing cholesterol and blood pressure.
WPA executive director, Richard Matoian, told this publication at the time that such studies “give manufacturers a good reason to think about including pistachios in their products, to give their products a nutritional profile that they might not find anywhere else”.
The authors of the latest research said that previous studies were conducted in free-living individuals and none controlled for SFA or antioxidant content of the background diets.
They added that their study of the antioxidant effects of pistachios was “unique” because it “utilized a controlled-feeding crossover design and two doses of pistachios and controlled for saturated fat intake”.
Source: The Journal of Nutrition
Pistachios Increase Serum Antioxidants and Lower Serum Oxidized-LDL in Hypercholesterolemic Adults