Combine with a diet low in saturated fats, eating walnuts may help lower blood pressure in people at risk for cardiovascular disease, according to a new Penn State study. In a randomized, controlled trial, researchers examined the effects of replacing some of the saturated fats in participants’ diets with walnuts. They found that when participants ate whole walnuts daily in combination with lower overall amounts of saturated fat, they had lower central blood pressure.
According to the researchers, central pressure is the pressure that is exert on organs like the heart. This measure, like blood pressure measure in the arm the traditional way, provides information about a person’s risk of developing cardiovascular disease (CVD). Penny Kris-Etherton, Distinguish Professor of Nutrition at Penn State, said the study suggests that because walnuts lower central pressure, their risk of CVD may have also decreased.
Walnuts without eating nut
When participants ate whole walnuts, they saw greater benefits than when they consume a diet with a similar fatty acid profile as walnuts without eating the nut itself, Kris-Etherton said. So it seems like there’s a little something extra in walnuts that are beneficial maybe their bioactive compounds, maybe the fiber, maybe something else that you don’t get in the fatty acids alone.
Alyssa Tindall, recent student in Dr. Kris-Etherton’s lab and a new Ph.D. graduate in nutrition, said the study was one of the first to try to uncover which parts of the walnuts help support heart health. Walnuts contain alpha linolenic acid ALA a plant based omega-3 that may positively affect blood pressure, Tindall said. They want to see if ALA was the major contributor to these heart-healthy benefits; so if it was other bioactive component of walnuts, like polyphenols.
For the study, the researchers recruited 45 participants with overweight or obesity; so who were between the ages of 30 and 65. Before the study began, participants were place on a “run in” diet for two weeks. Putting everyone on the same diet for two weeks prior to the start of the study helped put everyone on the same starting plane,” Tindall said. “The run-in diet included 12 percent of their calories from saturated fat; which mimics an average American diet.
Participants were randomly assign
After the run-in diet, the participants were randomly assign to one of three study diets; so all of which include less saturated fat than the run-in diet. The diets included one that incorporated whole walnuts; so one that include the same amount of ALA and polyunsaturated fatty acids without walnuts; also one that partially substituted oleic acid (another fatty acid); hence for the same amount of ALA found in walnuts, without any walnuts.
All three diets substituted walnuts or vegetable oils for five percent of the saturated fat content of the run-in diet; also all participants follow each diet for six weeks; hence with a break between diet periods. Following each diet period, the researchers assessed the participants for several cardiovascular risk factors including central systolic; so diastolic blood pressure, brachial pressure, cholesterol, and arterial stiffness.
The researchers found that while all treatment diets had a positive effect on cardiovascular outcomes; hence the diet with whole walnuts provided the greatest benefits; so including lower central diastolic blood pressure. In contrast to brachial pressure which is the pressure moving away from your heart and measure with an arm cuff; so in the doctor’s office central pressure is the pressure moving toward your heart.
Instead of reaching for fatty red meat or full-fat dairy products for a snack; so consider having some skim milk and walnuts, Kris-Etherton said. They think it boils down to how we can get the most out of the food we’re eating, specifically; so how to get a little more bang out of your food buck.’ In that respect, walnuts are a good substitute for saturated fat.