We know that legumes, nuts and seeds can be some of the healthiest superfoods around when consumed in moderation, and one of the better nuts for health is the walnut. Walnuts nutrition has been shown to help fight depression, improve brain health, boost heart health and more. But did you know there’s a type of walnut in particular, the black walnut, that provides some remarkable benefits of its own?
The black walnut (Juglans nigra) has been a nutritious addition to the diets of individuals since ancient times, from the Native American to Asian cultures. Studies have focused on the constituents, flavonoids, quinones and polyphenols found in the kernels, which are known for their antineoplastic, anti-inflammatory, antioxidant, antiatherogenic and neuroprotective properties.
Given that, black walnuts are a popular superfood, and modern research is only just scratching the surface when it comes to uncovering the powerful nutritional components these unique nuts contain, as I describe below.
Black Walnut Benefits
1. Expels Parasites
One of the key active components of the black walnut hull is juglone. Juglone exerts its effect by inhibiting certain enzymes needed for metabolic function. It’s highly toxic to many insect herbivores — it’s often used by organic gardeners as a natural pesticide — and researchers have observed that black walnut can expel parasitic worms from the body.
According to the Pharmaceutical Society of Australia, black walnut is effective against ringworm, tapeworm, pin or thread worm, and other parasites of the intestine. This is why black walnut makes a great addition to any parasite cleanse.
2. Promotes Healthy Skin
The tannins in black walnut have an astringent effect, which is used to tighten the epidermis, mucous membranes and relieve irritation. Dermatological applications associated with black walnut include viral warts, eczema, acne, psoriasis, xerosis, tinea pedis and poison ivy.
3. Improves Cardiovascular Health
Black walnuts are an excellent source of alpha-linolenic acid (ALA), with 100 grams of the walnuts containing 3.3 grams of ALA. Walnuts are an excellent staple of the Mediterranean diet, a diet thought to be healthy in reducing mortality rates from coronary artery disease, which is low in Mediterranean populations.
Recent epidemiological studies suggest that frequent consumption of walnuts may have protective effects against coronary heart disease because of the promising effects on blood lipid profiles. In clinical studies, diets supplemented with walnuts decreased serum concentration of low-density lipoprotein and cholesterol. Other potential protective constituents include high amounts of magnesium, vitamin E, protein, dietary fiber, potassium and alpha-linolenic acid.
4. Holds Antifungal and Antimicrobial Activity
The juice from unripe black walnut hulls has been used in folk medicine for many years as a treatment for topical, localized dermatophytic fungal infections, such as ringworm. These fungal infections usually involve the keratinized tissues, such as hair, skin and nails. Such infections may be chronic and resistant to treatment but rarely affect the general health of the patient.
It’s been suggested that the biological activity of the black walnut hull is due to the naphthoquinone, juglone (5-hydroxy-1,4 naphthoquinone). The antifungal activity of juglone has also been compared to other known antifungal agents, such as griseofulvin, clotrimazole, tolnaftate, triacetin, zinc undecylenate, selenium sulfide, liriodenine and liriodenine methionine. In a study, it was determined that juglone exhibited moderate antifungal activity similar to zinc undecylenate and selenium sulfide, which are commercially available antifungal agents. Internally, black walnut is also used for chronic constipation, intestinal toxemia, portal congestion, hemorrhoids and giardia.
The derivatives of 1,4-naphthoquinons have been of great clinical interest since these compounds exhibit strong activity as antibacterial and antifungal agents. A series of 50 naphthoquinone derivatives was synthesized and evaluated for antibacterial and antifungal properties, with highest activity against S. aureus and candida symptoms and moderate activity against gram-positive and acid-fast bacteria.
Another study showed that juglone potentially can inhibit three key enzymes from Helicobacter pylori, a gram-negative bacterium that causes several human gastrointestinal diseases. Several algae species, including Anabaena variabilis and Anabaena flos-aquae, were inhibited significantly by juglone as well.
5. Helps Protect Against Cancer
Quinones have been associated with anticancer activity. Juglone is a quinone found in the leaves, roots and bark of black walnut trees. The exocarp of immature green fruit, bark and branches has been used in China to treat liver, lung and gastric cancer. Juglone blocks potassium channels, promotes the generation of hydrogen peroxide and inhibits transcription in cancer cells.
In a recent study, it was shown to promote cell death in human colorectal cells, and given black walnuts juglone content, it could make the black walnut a potential cancer-fighting food.