Researchers are convinced—more than ever before—about the nutritional benefits of walnuts when consumed in whole form, including the skin. We now know that approximately 90% of the phenols in walnuts are found in the skin, including key phenolic acids, tannins, and flavonoids.
The form of vitamin E found in walnuts is somewhat unusual, and particularly beneficial. Instead of having most of its vitamin E present in the alpha-tocopherol form, walnuts provide an unusually high level of vitamin E in the form of gamma-tocopherol to provide significant protection from heart problems.
Walnuts not only taste great but are a rich source of heart-healthy monounsaturated fats and an excellent source of those hard to find omega-3 fatty acids. Like most nuts, they can easily be added to your Healthiest Way of Eating. Just chop and add to your favorite salad, vegetable dish, fruit, or dessert.
No aspect of walnuts has been better evaluated in the research than their benefits for the heart and circulatory system. Some review studies have emphasized the very favorable impact of walnuts on "vascular reactivity," namely, the ability of our blood vessels to respond to various stimuli in a healthy manner. In order to respond to different stimuli in a healthy way, many aspects of our cardiovascular system must be functioning optimally. These aspects include: ample presence of antioxidant and anti-inflammatory nutrients, proper blood composition, correct balance in inflammation-regulating molecules, and proper composition and flexibility in our blood vessel walls. Researchers have determined the ability of walnuts to have a favorable impact on all of these aspects. The chart below summarizes some key research findings about walnuts and heart health:
Research on the blood pressure benefits of walnuts has been mixed. We suspect that these mixed results are related to the surprising differences in mineral composition amongst different varieties of walnuts. Researchers have long been aware of the relationship between healthy blood pressure and intake of specific minerals, including potassium, calcium, and magnesium. In multiple studies, these minerals have a much greater impact on blood pressure than the mineral sodium (familiar to most people in its sodium chloride form, i.e., everyday table salt). We've seen studies showing the following ranges for key blood pressure-regulating minerals in walnuts:
Even though there are valuable amounts of these blood pressure-regulating minerals in virtually all varieties of walnuts, the ranges above may help explain why some studies have shown statistically significant benefits from walnuts on blood pressure while others have not.
In addition, addition of walnuts to participant diets has also been shown to decrease "abdominal adiposity"—the technical term for the depositing of fat around the mid-section. Importantly, the benefits of added walnuts have been achieved without causing weight gain in any the studies we've seen to date.
Walnuts have also produced a good track record in the research as a desirable food for support of weight loss and for prevention of obesity. That finding often surprises people because they think of high-fat, high-calorie foods as a primary contributing factor to obesity and to weight gain. In general, overconsumption of high-fat, high-calorie foods is a primary contributing factor to obesity and weight gain.
While walnut trees have been cultivated for thousands of years, the different types have varying origins. The English walnut originated in India and the regions surrounding the Caspian Sea, hence it is known as the Persian walnut. In the 4th century AD, the ancient Romans introduced the walnut into many European countries where it has been grown since. Throughout its history, the walnut tree has been highly revered; not only does it have a life span that is several times that of humans, but its uses include food, medicine, shelter, dye and lamp oil.
How to Enjoy
Mix crushed walnuts into plain yogurt and top with maple syrup.
Add walnuts to salads or healthy sautéed vegetables.
Purée walnuts, cooked lentils and your favorite herbs and spices in a food processor. Add enough olive or flax oil so that it achieves a dip-like consistency.
Add walnuts to your favorite poultry stuffing recipe.
To roast walnuts at home, do so gently— (about 75°C) oven for 15-20 minutes—to preserve the healthy oils. For more on the effect of high heat roasting on nuts, please see the following article.
Make homemade walnut granola: Mix together approximately 1/2 cup of honey, 3 to 4 tablespoons of blackstrap molasses, a tablespoon of vanilla, a dash of salt, and a teaspoon each of your favorite spices, such as cinnamon, ginger and/or nutmeg. Place 6-8 cups of rolled oats in a large bowl and toss to coat with the honey-blackstrap mixture. Then spread on a cookie sheet and bake at (135°C) for 45 minutes. Cool and mix in 1/2 to 1 cup of walnuts.