Pistachios lower cholesterol, provide antioxidants

Apr 30, 2007

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 today (April 30) 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.

Source: Penn State

Explore further: Oil-swishing craze: Snake oil or all-purpose remedy?

add to favorites email to friend print save as pdf

Related Stories

Pistachios offer multiple benefits

May 20, 2010

(PhysOrg.com) -- Pistachio nuts, eaten as part of a healthy diet, can increase the levels of antioxidants in the blood of adults with high cholesterol, according to an international team of nutritional scientists.

Walnuts are top nut for heart-healthy antioxidants

Mar 27, 2011

A new scientific study positions walnuts in the No. 1 slot among a family of foods that lay claim to being among Mother Nature's most nearly perfect packaged foods: Tree and ground nuts. In a report here today at the 241st ...

Pistachios may reduce lung cancer risk

Dec 08, 2009

A diet that incorporates a daily dose of pistachios may help reduce the risk of lung and other cancers, according to data presented at the American Association for Cancer Research Frontiers in Cancer Prevention Research Conference, ...

Recommended for you

Suddenly health insurance is not for sale

19 hours ago

(HealthDay)— Darlene Tucker, an independent insurance broker in Scotts Hill, Tenn., says health insurers in her area aren't selling policies year-round anymore.

Study: Half of jailed NYC youths have brain injury (Update)

19 hours ago

About half of all 16- to 18-year-olds coming into New York City's jails say they had a traumatic brain injury before being incarcerated, most caused by assaults, according to a new study that's the latest in a growing body ...

Autonomy and relationships among 'good life' goals

Apr 18, 2014

Young adults with Down syndrome have a strong desire to be self-sufficient by living independently and having a job, according to a study into the meaning of wellbeing among young people affected by the disorder.

User comments : 0

More news stories

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...