Walnuts are a whole healthy food. They are part of the tree nut family, which include Brazil nuts, cashews, hazelnuts (filberts), macadamia nuts, pecans, pine nuts, pistachios and walnuts.
The three main types of walnuts are the English (or Persian) walnut, Juglans regia; the black walnut, Juglans nigra; and the white (or butternut) walnut, Juglans cinerea. The English walnut is the most popular in the United States. The black walnut has a more pungent distinct flavor. The white walnut has a sweeter and oilier taste than the other two.
Walnuts are a rich source of omega-3 (anti-inflammatory), rich in antioxidants, minerals ( calcium, chromium, iron, magnesium, phosphorus, potassium, selenium, vanadium, and zinc), a more bio-available source of B6, and vitamin E (gamma-tocopherol).
Researchers have found that approximately 90% of the phenols in walnuts are found in the skin—phenolic acids, tannins, and flavonoids.
Due to its high omega-3 content, walnuts have been found to enhance cardiovascular health and reduction in abdominal fat without weight gain. Recent studies have shown that approximately one ounce of walnuts (7 whole or 14 halves) over a period of 2-3 months can help reduce Metabolic Syndrome(MetS), which include excessive blood fats (triglycerides), high blood pressure, inadequate HDL cholesterol, and obesity (as measured by waist circumference, and/or body mass index).
For a person with type 2 diabetes, 1-2 ounces of walnuts has provided benefits towards their cardiovascular system—lower the blood fat composition: less LDL cholesterol and less total cholesterol.
Scientists have found that one ounce is the minimal amount needed to provide a significant benefit—7 shelled walnuts or 14 walnut halves.
Due to its high anti-inflammatory nutrients and anti-oxidant properties, research has shown that consuming a large amount of walnuts (approximately 3 ounces per day) has reduced he risk of prostate cancer in human subjects. The increase consumption of walnut has been found to lower the risk of breast cancer in rats.
Researchers are finding that the larger intake of walnuts (67 grams of fat from walnuts or 4 ounces of walnuts on a daily bases) aids in better bone stability and less mineral lose from the bones.
Due to its high anti-inflammatory nutrients ( omega-3 fatty acids; phytonutrients including tannins, phenolic acids, and flavonoids; quinones like juglone; and other anti-inflammatory phytonutrients), researchers have found that walnuts are a desirable food for the support of weight loss and the prevention of obesity since obesity involves chronic, unwanted inflammation.
Other research studies involving rats and mice have looked into the relationship of walnuts to memory and general thought processes.
Several study authors have hypothesized about melatonin (a hormone-like substance that is critical in the regulation of sleep, daily circadian rhythms, light-dark adjustment, and other processes) found in walnuts playing an important role in anti-cancer benefits.
George Mateljan, “Walnuts: What’s New and Beneficial About Walnuts, ” n.d. < http://whfoods.org/genpage.php?tname=foodspice&dbid=99> (accessed August 14, 2011)