Walnuts: the Health-Nuts
Photo ©M-J de Mesterton 2011
The following information was captured from California Walnut Growers, circa 2007
Walnuts and other tree nuts and peanuts were recently ranked using the Index of Nutritional Quality (INQ) nutrient testing system at the Food Consulting Company of Del Mar, California [i]. According to Karen Duester, MS, RD who conducted the test, “Not surprisingly, walnuts ranked highest among the nuts in INQ. Because INQ relates to nutrient density, we looked at specific nutrients known to be abundant in nuts and peanuts: protein, fiber, omega-3, omega-6, vitamin E, potassium, magnesium, and zinc.”
On another independent scale, the Overall Nutritional Quality Index (ONQI)[ii] ranking system to be used by the Raley's grocery chain, walnuts received 82 points on a 100 point scale, an excellent score among foods and nuts [iii]. According to David Katz, MD, MPH a nationally renowned authority on nutrition and the principal inventor for the ONQI system, "When overall nutritional quality is assessed, the verdict is clear: walnuts are a great food -- they pack a lot of nutrient benefits in a nutshell!”
Jeffrey Blumberg, PhD, professor of nutrition science and policy at Tufts University and a member of the Hannaford Scientific Advisory Panel explains, “Walnuts are a whole food rich in antioxidants, alpha-linolenic acid (ALA), an essential omega-3 fatty acid, protein, fiber, and more. Whole walnuts receive the ‘best nutritional value’ three star ranking (the highest) due to their nutrient profile.”
Walnuts have nutritional qualities that are very important. One of the richest sources of alpha linolenic acid (ALA), the plant form of Omega-3, walnuts are unique among nuts and popular whole foods [v]. A one ounce serving of walnuts provides 2.57 grams of ALA, the plant form omega-3s, which is above the dietary reference intake (DRI) set by the National Academies’ Institute of Medicine. Walnuts are also one of the highest natural sources of antioxidants, according to Halvorsen’s study from American Journal of Clinical Nutrition in 2006 [vi].
15 years of clinical research on walnuts have shown benefits for the heart, and we’re not just talking about cholesterol reduction -- improved vascular function and a reduction in inflammation have also been documented [vii-xii]. Looking to the future and expanding on this base of knowledge, research is underway at a variety of prestigious universities looking into cancer, diabetes and issues of ageing.
[vi] Am J Clin Nutr. 2006 Jul;84(1):95-135
“Supportive but not conclusive research shows that eating 1.5 ounces of walnuts per day, as part of a low saturated fat and low cholesterol diet, and not resulting in increased caloric intake may reduce the risk of coronary heart disease.”
[viii] Circulation. 2002 Nov 19;106(21):2747-57
[ix] Hypertension. 2007 Aug;50(2):313-9
[x] J Am Coll Cardiol. 2006 Oct 17;48(8):1666-71
[xi] Arch Intern Med. 2007 Jun 11;167(11):1195-203.
[xii] Ann Intern Med. 2006 Jul 4;145(1):1-11
Omega-3 Fatty Acids in Walnuts
How do Omega-3s work?
Inside your favorite kinds of nuts — walnuts, almonds, pecans and others — you’ll find many vitamins, minerals and other compounds your body needs for good health. There are the antioxidants found in vitamin E; several essential minerals such as magnesium, selenium, copper and manganese; and even fiber for more effective digestion. Thiamin, niacin, folate, phosphorus and zinc are all found in nuts.
Researchers believe that omega-3 fatty acids may help reduce the risk of heart disease by making the blood less sticky and less likely to form dangerous intravenous or arterial clots. Studies have also shown that omega-3s may lower the risk of stroke and prevent arthritis. In addition, there’s good evidence that omega-3s can increase HDL (good cholesterol), further reducing the risk of stroke and heart disease.
The omega-3s found in fish oil are thought to be responsible for the significantly lower incidence of breast cancer in Japanese women as compared to women in the United States. This may be because omega-3 fatty acids inhibit the tumor growth that is promoted by the acids found in other fats, such as corn and safflower oils.
Finally, the brain itself is composed of a whopping 60 percent fat. It too needs omega-3s to help build and maintain tissue. Brain function itself may be at stake: in treating major depression, for example, omega-3s seem to work by making it easier for brain cell receptors to process mood-related signals from neighboring neurons.
What are good sources of omega-3s?
Omega-3 fatty acids are plentiful in cold-water fish such as mackerel and salmon. They’re also found in walnuts, canola oil, soybean oil, tofu and leafy green vegetables. Which would you rather sprinkle on your morning cereal or grab for a nutritious snack?
Walnuts are a delectable, convenient alternative to fish, tofu and leafy greens. In fact, just a handful of walnuts provides as much omega-3s as a comparable serving of salmon.