I must confess, I had rarely thought too much about the ubiquitous walnut, beyond observing it in the occasional trendy salad (and wishing it were pecans instead), or enjoying it in a chunk of honey-dripping baklava. And yes, the occasional silverware box made of walnut wood has caught my eye in an antique store, but I thought no more of it. Little did I know that the uses of the walnut have been innumerable and fascinating for millennia...
Even an incomplete sampling of its uses is overwhelming. The wood has been used for fine furniture, yokes for oxen, shoes, gunstocks, and airplane propellers. The whole shells were employed as razors in Louis XI's French court; ground shells have been utilized as a filling for dental cavities, as a polish for metal, and as thermal insulation in rocket nose cones. The hulls produced hair dye and pen ink, and the ancient Egyptians used the oil in the embalming process of mummies. And of course the nut itself has appeared on gourmet menus through the ages, from Ancient Persia to Pompeii to Spago.
And the medicinal applications were nothing short of encyclopedic. The nut, leaves, bark, wood, and roots were variously used to treat any and all skin ailments -- sores, gangrene, dandruff, hives, open wounds, lice -- as well as internal problems, such as diarrhea, inflamed tonsils, and morning sickness. In Chinese medicine, the walnut is said to warm and hold Qi in the lungs and help kidneys to grasp the Qi.
I have always been fascinated by the medieval notion that the visual characteristics of a particular foodstuff are a clue to its medicinal properties. Hence the persimmon, shaped like a heart, was believed to be beneficial for that organ; and the walnut, whose wrinkled shell resembles a brain, was thought to affect mental capabilities. And indeed current research has shown that notion to be remarkably accurate -- the omega-3 fats in walnuts encourage brain-cell membranes to allow optimum absorption of necessary nutrients, thereby boosting 'brain-power.'
But that is only the beginning of the enormous benefits to be derived from this least-exotic of nuts. Omega-3 fats have been shown to provide cardiovascular protection by reducing high cholesterol levels and arterial inflammation, as well as helping to prevent and control high blood pressure; and their anti-inflammatory properties assist in treating asthma, rheumatoid arthritis, and eczema. See, those practitioners in the Middle Ages knew what they were doing!
Other available nutrients include ellagic acid, which supports the immune system and provides antioxidant activity against free radicals, and l-arginine, which may mitigate the effects of hypertension. Research has also shown that walnuts help to reduce the risk of gallstones, provide bio-available melatonin to encourage better sleep, and promote bone health by reducing bone loss.
So I think we can safely conclude that walnuts absolutely need to be a daily part of a healthy diet, and in point of fact the much-vaunted "Mediterranean Diet" traditionally includes generous helpings of this widely-available and inexpensive nut.
Getting and Using Them
If you're buying walnuts still in the shell, choose ones that feel heavy, and are not cracked, stained, or pierced. You'll probably mostly be buying them already shelled, so a few pointers: if buying from bulk containers, make sure they smell fresh not rancid, that the bins are covered, and that the store seems to have fast turnover; if buying bagged, check the date stamp if available, and make sure the nuts don't appear shriveled or rubbery.
Due to their high fat content, it's best to store the shelled nuts tightly sealed in the refrigerator, or even the freezer; that way they will last up to six months or so.
Oh, and walnut oil is an excellent way to derive the desired health benefits - drizzle a little on salad greens with a squeeze of lemon, or on some sliced melon with prosciutto. Use it sparingly -- it's intense!
Sea Scallop & Shiitake Skewers w/ Walnut-Mint pesto
Serve this simple but delicious grill item with organic brown rice and grilled zucchini for a perfect late-summer dinner!
1 1/2 lbs. large fresh sea scallops
6 large shiitake mushrooms, stemmed and halved
2 tablespoons good olive oil
4 wooden skewers, soaked in water
1 cup fresh mint leaves
1 cup Italian parsley leaves
1/2 cup walnut pieces
1/3 cup safflower oil
1 teaspoon walnut oil
1/4 teaspoon ground coriander
1 tablespoon fresh lemon juice
1 teaspoon microplaned lemon zest (optional)
Combine all pesto ingredients in food processor, pulse/process just until coarsely pureed. (Can be prepared in advance and refrigerated.)
Heat grill to medium-high.
Toss sea scallops and shiitakes with olive oil to lightly coat. Divide among four skewers. Grill for about 2-3 minutes per side, until scallops are barely cooked through and slightly opaque. Plate and top with a generous spoonful of pesto, serve the rest of the pesto on the side.
Red Fruit Compote w/ Toasted Black Walnuts
An ideal coda to your sea scallop dinner...
2 cups watermelon, cut into 1-inch squares
2 cups strawberries, halved
1 cup raspberries
2 tablespoons organic wild honey
1 tablespoon cherry fruit syrup
2 teaspoons fresh lemon juice
1/4 cup toasted chopped black walnuts*
Combine fruits in a large glass bowl. Toss gently with honey, lemon juice & fruit syrup. Sprinkle walnuts over the top and serve.
Makes 5 cups.
* to toast walnuts: heat in a dry skillet over medium-high heat, shaking constantly, for about 1 minute. Remove from pan and cool.
A version of this post appears in my "Eat Smart" column in the September issue of Better Nutrition magazine.