A walnut is a drupe. A drupe is a type of fruit in which an outer fleshy part surrounds a shell (what we sometimes call a pit) with a seed inside. Some examples of drupes are peaches, plums, and cherries—but walnuts, almonds, and pecans are also drupes.
Walnuts are the super nut for heart-healthy antioxidants. Scientific study positions walnuts in the No. 1 slot within the family of foods that lay claim to being among Mother Nature’s most “nearly perfect” packaged foods.
A 2015 study piloted by researchers at the David Geffen School of Medicine at UCLA found a positive relationship between walnut consumption and cognitive functioning in adults. This also included the ability to concentrate. According to the findings published in the Journal of Nutrition, Health and Aging, consuming a handful of walnuts per day can lead to cognitive benefits, regardless of age.
Walnuts and antioxidants
Walnuts, in comparison to other nuts, contain the highest-level of antioxidants, which help to promote brain function. Joe Vinson, Ph.D., who did the analysis, said, “walnuts rank above peanuts, almonds, pecans, pistachios and other nuts”. A handful of walnuts contains almost twice as much antioxidants as an equivalent amount of any other commonly consumed nut.
They also contain alpha-linolenic acid, a plant-based omega-3 fatty acid that is important for brain health and development. But because walnuts are relatively high in fat and calories, no more than an ounce or a small handful per day is recommended.
Walnut health benefits
Cardiovascular Benefits: No aspect of walnuts has been better evaluated in the research than their benefits for the heart and circulatory system. Some studies have stressed the positive impact of walnuts on “vascular reactivity” which is the ability of our blood vessels to respond to various stimuli in a healthy manner. In order to respond to diverse stimuli in a healthy way, many aspects of our cardiovascular system must be working 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.
Metabolic Syndrome: In the United States, as many as 1 in 4 adults may be qualified for diagnosis with Metabolic Syndrome (MetS). MetS is a constellation of problematic and overlapping metabolic complications including excessive blood fats (triglycerides), high blood pressure, inadequate HDL cholesterol, and obesity (as measured by waist circumference, and/or body mass index). Latest studies have shown that around one ounce of walnuts daily over a period of 2-3 months can help reduce several of these MetS-related problems. Also, the addition of walnuts to participants diet has also been shown to decrease “abdominal adiposity” — the technical term for the depositing of fat around the mid-section. Importantly, the MetS benefits of added walnuts have been realized without causing weight gain in any of the studies we’ve seen to date.
Anti-Cancer Benefits: Given the broad diversity, antioxidant and anti-inflammatory nutrients found in walnuts, it’s not unexpected to see research on this tree nut presenting measurable anti-cancer benefits. The antioxidant properties of walnuts help lower risk of chronic oxidative stress, and the anti-inflammatory properties help lower risk of chronic inflammation. Prostate cancer and breast cancer are the best-studied types of cancer with respect to walnut intake, and their risk has been found to be reduced by fairly large amounts of walnut consumption (approximately 3 ounces per day). For prostate cancer, the evidence is slightly stronger, as more studies have involved human subjects. For breast cancer, most of the evidence has been based on studies of rats and mice.
Though walnut trees have been grown for thousands of years, the different types have varying origins. The English walnut originated in India; it is known as the Persian walnut. In the 4th century AD, the ancient Romans introduced this nut into many European regions. Throughout its history, the walnut tree has been highly revered; not only does it have a very long life span (several times that of humans), but its uses include food, medicine, shelter, dye and oil.
Black walnuts and white walnuts are native to North America, specifically the Central Mississippi Valley and Appalachian area. They played a significant role in the diets and lifestyles of Native Americans.
China is presently the largest commercial producer of walnuts in the world, with about 360,000 metric tons produced each year. The United States is second, with about 294,000 metric tons of production, and a large majority of this is grown in California, particularly within the San Joaquin and Sacramento Valleys. The combined walnut production of Iran and Turkey is approximately the same as the United States, and the Ukraine and Romania are next in terms of total walnut production.
Photo credit User Böhringer