A diet rich in walnuts and walnut oil is associated with preparing the body to deal better with stress, according to a team of researchers who looked at how these foods, which contain beneficial fats, influence blood pressure at rest and under stress.
Walnuts are a rich source of fiber, antioxidants, and unsaturated fatty acids, particularly alpha linolenic acid, an omega-3 fatty acid, and these compounds are thought to be responsible for the beneficial effects on blood pressure.
One of the researchers explained:
"People who show an exaggerated biological response to stress are at higher risk of heart disease,"
"We wanted to find out if omega 3-fatty acids from plant sources would blunt cardiovascular responses to stress."
They found that including walnuts and walnut oil in the diet lowered both resting blood pressure and blood pressure responses to stress in the laboratory, in 22 healthy adults.
They report their findings in the current issue of the Journal of the American College of Nutrition.
"This is the first study to show that walnuts and walnut oil reduce blood pressure during stress,"
"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."
The researchers used a randomized, crossover study design. Tests were conducted at the end of each six-week diet, and every participant consumed each of the three diets in random order, with a one-week break between.
Diets included an "average" American diet - a diet without nuts that reflects what the typical person in the U.S. eats each day.
The second diet included 1.3 ounces of walnuts and a tablespoon of walnut oil substituted for some of the fat and protein in the average American diet.
The third diet included walnuts, walnut oil and 1.5 tablespoons of flaxseed oil. The three diets were matched for calories and were specifically designed for each participant so that no weight loss or gain occurred. The walnuts, walnut oil, and flax oil were either mixed into the food in such offerings as muffins or salad dressing or eaten as a snack. About 18 walnut halves or 9 walnuts make up the average serving used by the researchers.
After each diet, the participants underwent two stress tests. In the first test, they received a topic; and they were given two minutes to prepare a three-minute speech, which they presented while being videotaped. The second stressor was a standard physical test of stress consisting of submerging one foot in ice-cold water. Throughout these tests, the researchers took blood pressure readings from the participants.
Results showed that average diastolic blood pressure - the "bottom number" or the pressure in the arteries when the heart is resting - was significantly reduced during the diets containing walnuts and walnut oil.
Walnuts Fight Disease
Walnuts are a wonderful health-giving and nutritious snack food. They have the highest level of omega-3 fats compared to any other nut and are one of the richest sources of antioxidants. They are also a good source of B vitamins like folic acid and minerals such as magnesium and copper. They are an excellent source of a type of Vitamin E called gamma-tocopherol, which is associated with fighting cancer.
Another valuable effect of walnuts is fighting inflammation. Inflammation plays a role in many of the debilitating conditions of age and the damage caused by chronic inflammation has been linked with the development of cancers and other degenerative diseases of the brain and body. Research has found that eating just half a dozen walnuts a day is enough to reduce your risk of inflammation.