Walnuts are a delicious way to add extra nutrition, flavor and crunch to a meal. While walnuts are harvested in December, they are available year round and a great source of those all-important omega-3 fatty acids.
It is no surprise that the regal and delicious walnut comes from an ornamental tree that is highly prized for its beauty. The walnut kernel consists of two bumpy lobes that look like abstract butterflies. The lobes are off white in color and covered by a thin, light brown skin. They are partially attached to each other. The kernels are enclosed in round or oblong shells that are brown in color and very hard.
While there are numerous species of walnut trees, three of the main types of walnuts consumed 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 type in the United States and features a thinner shell that is easily broken with a nutcracker. The black walnut has thicker shells that are harder to crack and a much more pungent distinctive flavor. The white walnut features a sweeter and oilier taste than the other two types, although it is not as widely available and therefore may be more difficult to find in the marketplace. Within these basic types of walnuts, there are dozens of different varieties (also called cultivars). It's not uncommon to see research studies that evaluate several dozen different cultivars of English or black walnuts. All types and varieties of walnuts can have unique nutrient composition. Sometimes within a particular type of walnut—for example, English walnut—there is a surprising amount of nutritional variety. The bottom line here is to not to get caught up in thinking that one main type of walnut (for example, English versus black) is best, but to take advantage of the nutritional variety offered by walnuts overall.
Health Benefits of Walnuts
With a handful of 4 or 5 nut vapors in a day, keeping your heart healthy, it helps to reduce cholesterol levels. Walnut starts showing its effect within 4 hours of eating.
Walnuts have higher antioxidant activity than any other common nut
This activity comes from vitamin E, melatonin and plant compounds called polyphenols, which are particularly high in the papery skin of walnuts
A preliminary, small study in healthy adults showed that eating a walnut-rich meal prevented oxidative damage of “bad” LDL cholesterol after eating, whereas a refined-fat meal didn’t
That’s beneficial because oxidized LDL is prone to build up in your arteries, causing atherosclerosis
Walnuts are significantly higher in omega-3 fat than any other nut, providing 2.5 grams per 1-ounce (28-gram) serving
Omega-3 fat from plants, including walnuts, is called alpha-linolenic acid (ALA). It’s an essential fat, meaning you have to get it from your diet.
According to the Institute of Medicine, adequate intake of ALA is 1.6 and 1.1. grams per day for men and women respectively. A single serving of walnuts meets that guideline
Observational studies have shown that each gram of ALA you eat per day lowers your risk of dying from heart disease by 10%