Among people with high cholesterol (that’s nearly one-third of American adults, for those keeping score at home), foods rich in omega-3 fatty acids may help reduce levels of LDL, or “bad,” cholesterol. Now a new study finds that some types of these polyunsaturated fats — namely the alpha linolenic acid found in walnuts and flax seeds — can also improve people’s response to stress.
For the study published in the Journal of the American College of Nutrition, 22 adults with high LDL levels were put on one of three calorie-matched diets with identical amounts of fat and protein: a standard American diet without nuts; a similar diet, with 1.3 ounces of walnuts and a tablespoon of walnut oil replacing some of the fat and protein; and a third diet including walnuts, walnut oil and 1.5 tablespoons of flax seed oil. (More on Time.com: The ‘Other’ Salt: 5 Foods Rich in Potassium)
Study participants who consumed walnuts and walnut oil not only reduced their LDL levels, but they also showed significant drops in resting blood pressure and, most surprisingly, in their blood pressure response to stress. Participants’ blood pressure was measured as they either delivered a speech or put one foot in a bucket of cold water, both considered low-grade stressors in most people.
The study’s author told the Los Angeles Times:
“This is the first study to show that walnuts and walnut oil reduce blood pressure during stress,” said Sheila G. West, associate professor of biobehavioral health. “This is important because we can’t avoid all of the stressors in our daily lives. This study shows that a dietary change could help our bodies better respond to stress.”
Volunteers who consumed flax seed oil in addition to the walnuts did not further reduce their stress responses, but they did show improvement on a separate measure of vascular health. They also showed decreases in levels of C-reactive protein, a blood marker of inflammation that has been associated with an increased risk of heart disease.
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