Researchers from Barcelona's Hospital Clinico conducted a study on 24 adult participants, half of whom had normal cholesterol levels, and half of whom had moderately high levels of cholesterol. Each group was fed two high-fat meals of salami and cheese, eaten one week apart. During one meal, the researchers supplemented the food with five teaspoons of olive oil. The researcher added eight shelled walnuts to the other meal, the following week.
Tests after each meal showed that both the olive oil and the walnuts helped reduce the onset of dangerous inflammation and oxidation in the arteries after the meals, which were high in saturated fat. However, unlike the olive oil, the walnuts also helped the arteries maintain their elasticity and flexibility, even in the participants with higher cholesterol.
Lead researcher Dr. Emilio Ros said walnuts' protective effects could be because the nuts are high in antioxidants and ALA, a plant-based omega-3 fatty acid. Walnuts also contain arginine, which is an amino acid that the body uses to produce nitric oxide -- necessary for keeping blood vessels flexible.
Professor Robert Vogel, of Maryland University, said, "This demonstrates that the protective fat from walnuts actually undoes some of the detrimental effects of a high-saturated-fat diet, whereas neutral fat, such as olive oil, does not have as much protective ability." Vogel also said walnuts -- not olive oil, as most people believe -- could be the reason the Mediterranean diet is so beneficial.
Natural health advocate Mike Adams, author of the Honest Food Guide -- a nutritional reference guide available for free download at www.HonestFoodGuide.org -- said raw nuts and seeds offer "astonishing health benefits" to those who consume them regularly.
"For maximum benefit, it is important that all nuts be consumed in their raw, unprocessed and unsalted form," Adams said. "Cooking or roasting nuts destroys much of their nutritional value."
Ros recommended consumers eat 1 ounce of walnuts each day, but warned against consumers believing they could eat an unhealthy diet and simply offset the consequences with walnuts.
"Instead, [consumers] should consider making walnuts part of a healthy diet that limits saturated fats," Ros said.
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