Black walnuts, also known as American walnuts, are from the tree botanically known as Juglans nigra, which grows throughout the eastern and central part of the United States, particularly in the Midwest and the Appalachian mountains. Black walnuts have a thicker shell and a stronger flavor than the other two varieties popular in America: the English---or Persian---walnut, and the white walnut, sometimes called the butternut. Black walnuts, which offer many nutritional benefits, are a healthy dietary choice.
Nutritional Basics
Just 1/4 cup of walnuts, about 25 g---or .88 oz.---contains 163 calories, a relatively modest caloric investment for all the benefits contained in the nuts. According to The World's Healthiest Foods, the same 1/4 cup yields 3.81 g of protein, 3.43 g of carbohydrates, 1.68 g of dietary fiber and 16.3 g of fat. The website points out that the fat in walnuts contains high levels of healthy monounsaturated fat. Walnuts.org breaks it down this way: 1 oz. of walnuts---just a bit over 1/4 cup---contains 18 g of total fat, 2.5 g of monounsaturated fat, and 13 g of polyunsaturated fat, which includes 2.5 g of of alpha-linolenic acid, a beneficial plant-based fatty acid.
Omega-3 Fatty Acids
Black walnuts are particularly rich in omega-3 essential fatty acids; The World's Healthiest Foods states that 1/4 cup of shelled walnuts contains 90.8 percent of the daily recommended value of these protective fats. The website adds that omega-3s offer cardiovascular protection by helping to prevent erratic heart function, making blood less likely to clot in arteries, and improving the ratio of healthful HDL cholesterol to detrimental LDL cholesterol. University of Maryland Medical Center concurs that omega-3 fatty acids found in walnuts---particularly alpha-linolenic acid---can help prevent heart disease, lower blood pressure and reduce levels of trigylcerides, or fats, in the blood.
Vitamins and Minerals
According to the United States Department of Agriculture, 1/4 cup of black walnuts contains gamma-tocopherol---a form of vitamin E---in the amount of 8.9 mg. The World's Healthiest Foods notes that 1/4 cup of black walnuts contains 6.13 percent of the daily value of folate, or vitamin B-9. According to the Office of Dietary Supplements, folate is needed to produce and maintain red blood cells, as well as to produce DNA and RNA. Walnuts are also a very good source of the mineral manganese, offering up 42.50 percent of the DV in 1/4 cup. The University of Maryland Medical Center states that managanese is needed to form bones and connective tissues.
Amino Acids
A quarter cup of black walnuts contains 12.2 percent of the daily value of cystine, a sulfur-containing amino acid that helps to form healthy hair, skin and bones. It also contains the amino acids phenylalanine, leucine, arginine, lysine, and 15.63 percent of the DV of tryptophan, an essential amino acid important for restful sleep and stable mood.
Beta-sitosterol
The United States Department of Agriculture lists 1/4 cup of walnuts as containing 32 mg of the phytosterol beta-sitosterol. According to the University of Maryland Medical Center, this plant sterol can stop cholesterol from being absorbed by the intestines, lowering levels of harmful LDL cholesterol.
Member Comments