We've already heard that eating walnuts may assist people in losing weight. Well, that's not all that they're potentially good for. A new study suggests that consuming the nuts might also help people at risk of heart disease to lower their blood pressure.
Walnuts contain a plant-based omega-3 fatty acid known as alpha-linolenic acid (ALA), which previous studies have indicated may help bring blood pressure down. Scientists at Pennsylvania State University wanted to see if eating the nuts did indeed have that effect, and if so, if it was due to more than just their ALA content.
Led by Prof. Penny Kris-Etherton, the researchers started by recruiting 45 volunteers between the ages of 30 and 65, all of whom were overweight or obese. The test subjects were all then put on a two-week "run-in" diet that replicated the typical American diet, in order to put them on a level playing field.
After that, each person was randomly assigned to follow one of three diets that reduced their saturated fat intake. One of those diets included whole walnuts as a healthier alternative to that fat, while the other two did not include walnuts, but did include the same amount of polyunsaturated fatty acids and ALA that would be supplied by the nuts.
Each person followed each diet for six weeks. During the break periods between diets, the scientists measured the volunteers' central systolic and diastolic blood pressure, brachial pressure, cholesterol, and arterial stiffness – all of which can be indicators of potential cardiovascular problems. What they found was that while all of the diets produced improvements, the walnut diet had the most pronounced effect.
"When participants ate whole walnuts, they saw greater benefits than when they consumed a diet with a similar fatty acid profile as walnuts without eating the nut itself," says Kris-Etherton. "So it seems like there's a little something extra in walnuts that is beneficial – maybe their bioactive compounds, maybe the fiber, maybe something else – that you don't get in the fatty acids alone."
It should of course be noted that the test subjects didn't simply eat walnuts along with their usual diet, as they also reduced their intake of saturated fats.
A paper on the research was recently published in the Journal of the American Heart Association.
Source: Penn State
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