One of the best things about learning the potential uses of plants is that it opens your eyes to a world of potential health benefits and remedies right on your doorstep.
No matter where you live in the United States, the chances are that you’ve come across a black walnut tree, whether you recognized the plant or not.
The black walnut, or Juglans Nigra, is striking to look at due to its height, growing up to 100 feet tall once the tree has matured. Its grooved bark might catch your eye, too.
What is really special about this deciduous tree, however, is that it has been incorporated into traditional Native American and Chinese medicinal treatments for centuries.
Read on to discover the scientific classification, identifying features, history, benefits, and possible side effects of the black walnut today.
Black Walnut: Taxonomy
Juglans Nigra, commonly known as the black walnut, is a deciduous tree belonging to the Juglandaceae (walnut) family.
The black walnut is a member of the Fagales order and the Rosanae superorder.
Identifying Black Walnut
As we have already mentioned, the black walnut is an easy tree to identify.
The tree can easily be distinguished from those around it by looking at the pattern of its bark and its interestingly shaped leaves.
The bark of the black walnut is very dark and has deep ridges running through it. The leaves, meanwhile, are large and consist of several long leaflets. Look for hair underneath the leaves to confirm that you have found a black walnut tree.
In the early summer, you might also be able to identify the black walnut by its flowers. Between the end of May and the beginning of June, black walnut trees grow flowers of both the male and female variety.
The scientific term for these flowers is ‘catkins.’ They resemble cylindrical clusters of green flowers that hang down approximately 8 to 10 centimeters (3.15 to 3.9 inches) from the branches.
Later in the year, during the Autumn months, the catkins will turn into fruit, which will be roughly spherical and somewhere between brown and green in color. Each fruit contains a walnut inside a tough shell.
A History of the Black Walnut
The historical significance of the black walnut tree begins with the traditional medicine of many Native American tribes, perhaps as early as the year 8000 BCE. Some Native American tribes used the plant as a repellent against mosquitos.
Black walnut is, in fact, an effective insect repellent because it contains juglone. Juglone is a powerful chemical, cleverly and naturally manufactured by the black walnut to repel insects from its leaves. It also grows in the tree’s roots and prevents the growth of other herbs, ensuring that this tall tree has all the room it needs to grow.
Native American medicine also sometimes involved the use of black walnut hulls as a treatment for parasites and certain skin conditions.
The use of black walnut to treat parasitic infections has since been backed by several scientific institutions, including the Pharmaceutical Society of Australia.
It was in Ancient China, however, that parts of the black walnut became integrated into treatments for kidney ailments.
During the final years of the 18th century, the wood of the black walnut tree, striking for its dark pigmentation and hard-wearing properties, would become a popular material for home furnishings.
Between 1914 and 1918, during the First World War, the black walnut husks were actually employed as gas mask filters.
It wasn’t until the middle of the 20th century that the chemical properties of the black walnut began to be actively utilized outside of traditional medicine. Herbicide and insecticide products began to be manufactured using parts of the tree that contain juglone.
The Benefits and Uses of Black Walnut
Today, in the 21st century, we have more knowledge about the potential benefits and uses of black walnut than ever before.
While some research is still needed to officially confirm many of the benefits that black walnut supplements claim to have, several scientific studies into the black walnut have been carried out with interesting and encouraging results.
Black walnut is considered to be a superfood because of its many nutritional benefits.
First and foremost, it is worth noting that the nuts of the black walnut tree have the highest protein content of any tree-grown nut worldwide.
Black walnuts also score highly in comparison to other walnut varieties, including the English walnut. They have a higher concentration of antioxidants and healthful fatty acids than other walnuts, for example. If you’re looking for a solid source of fiber, iron, and Vitamin A in a single mouthful, the black walnut is definitely a good option.
The antioxidants in black walnuts may be effective in fighting diseases such as cancer, diabetes, and heart disease. Because black walnut is also an anti-inflammatory, it is often used as a treatment for inflammatory and fungal conditions.
According to recent studies, the consumption of black walnut can help to make blood vessels more responsive to changes in other areas of the body while decreasing levels of bad cholesterol. These effects combined can significantly reduce the risk of inflammation and blood clots in the cardiovascular system.
Studies have also shown that people who consume black walnuts in moderate quantities are generally less prone to obesity than those who do not.
Black walnut has also been shown to have positive effects on digestive health. Studies have measured this by examining the levels of healthy gut bacteria in participants.
Findings suggest that eating black walnuts on a regular basis may help to promote the production of good bacteria in the gut. Not only will this help to ensure healthy and regular digestion, but a healthy gut can significantly lower the risk of diseases such as colon cancer.
If you struggle to regulate your high blood sugar levels, research suggests that black walnut may be able to help. The antioxidants in the walnut have been shown to lower glucose levels in the blood, meaning it could be an effective treatment for hyperglycaemic patients.
While the practice of using black walnut to treat parasitic infection dates back to the establishment of traditional Native American medicine, black walnut is still used as a treatment for certain parasites today. As of yet, however, there isn’t enough scientific evidence to conclusively back claims of its effectiveness for this purpose.
Some people also use black walnut as a treatment for Diphtheria and syphilis, although more research is needed to confirm whether this treatment is beneficial.
Potential Side Effects of Black Walnut
Whether or not black walnut is likely to produce any adverse side effects depends on a few factors, including which part of the plant you consume and any pre-existing health conditions you may have.
In terms of which parts of the tree are most likely to induce side effects, you can rest assured that consuming the nut itself in normal quantities is unlikely to be harmful.
There is, of course, the potential for allergic reactions when consuming any kind of nut. So, if you know that you have a history of reacting negatively to nut products, black walnut is better avoided.
If you have no experience with nut products, proceed with caution and remain alert for any allergy symptoms. As with all types of walnuts, these symptoms may range from mild to severe and can encompass dermatological symptoms (itching, swelling, or a rash), digestive issues (stomach ache and nausea), and respiratory problems (difficulty breathing, tightness of the throat).
At its most severe, an allergic reaction to black walnut can result in anaphylactic shock, which is a potentially fatal reaction involving a sudden drop in blood pressure accompanied by a blockage of the airways. Anaphylactic shock may also produce symptoms such as a rash, nausea or vomiting, and a pulse that is either weak, rapid, or both. Any combination of these symptoms should be treated as a medical emergency, and medical assistance should be sought urgently.
Aside from allergic reactions, negative symptoms as a result of consuming black walnut will most often occur when parts of the tree or fruit other than the nut itself are ingested.
Consumption of the bark of the black walnut tree, for example, has been linked to a higher incidence of certain cancers, specifically of the tongue or lips.
Moreover, the leaves of the black walnut and the fruit’s shell are not recommended for consumption. These parts of the plant are also not generally recommended for medicinal purposes because of their tannin content, high levels of which have been linked to diseases of the kidneys and liver.
Medical professionals do not recommend applying black walnut directly to the skin as a dermatological treatment. This is because black walnut contains juglone, which is a chemical compound known to cause irritation in some cases.
Frequently Asked Questions
How should I consume black walnut?
The simplest way to take black walnut is to integrate some of these nutritional nuts into your diet.
The great thing about walnuts is that they are easy to introduce into your diet. A handful of walnuts makes a filling and nourishing snack, but walnuts also work well in a variety of dishes, including black walnut bread, cookies, and even salads.
Alternatively, black walnut capsules and tinctures are sold in many pharmacies.
How many black walnuts should I eat?
Dieticians recommend the consumption of 28 grams of nuts (not specifically limited to black walnuts) per day in order to see positive results in terms of blood pressure.
Given that black walnuts are so nutritionally beneficial, there is no reason why consuming 28 grams of black walnuts per day in lieu of other types of nuts should be harmful. If anything, you would be ensuring that you are getting as much protein from your daily nut allowance as possible.
Walnuts weigh about 5 grams each, so 28 grams of walnuts only comes to about 6 walnuts per day. This is very easy to incorporate into your diet as a quick snack.
Be careful not to significantly exceed the recommended amount of walnuts per day. You can have too much of a good thing, as they say, and consuming too many walnuts might leave you with excess fiber. This, in turn, can cause digestive problems.
Why do black walnuts stain my hands?
If you have noticed that shelling black walnuts leaves dark stains on your fingers, this is a result of the juglone in the fruit of the walnut.
Juglone is an irritant, so it’s best not to come into contact with it if you can avoid it. Exposure to juglone can cause painful blistering on the skin. Therefore, we would always recommend wearing protective gloves when shelling black walnuts.
Hindsight is 20/20, so if you’ve already handled black walnuts and stained your hands, don’t panic. Wash your hands thoroughly with soap and water. This won’t remove the staining, which is likely to stick around for a few weeks, but it will remove any excess juglone and prevent any potential reaction from getting worse due to prolonged exposure.
If blistering occurs, do not touch the blisters. If a blister bursts, you can apply an antibiotic ointment and bandage the area. For particularly large or painful blisters, a visit to your primary care practitioner may be necessary. A steroid cream may help to minimize itching.
Generally speaking, black walnut is a highly beneficial superfood that is high in protein, fiber, iron, Vitamin A, antioxidants, and fatty acids.
Studies have shown that black walnut has health benefits for the cardiovascular system as well as on blood sugar levels.
The black walnut is also thought to reduce the risk of obesity. Certain types of cancer, as well as inflammatory and fungal health issues, may also be reduced by black walnut treatment.
More scientific research must be conducted before the effectiveness of black walnut against parasitic infections, Diphtheria, and syphilis can be proven.
The consumption of any part of the black walnut other than the nut itself is not medically recommended. The rest of the fruit, the leaves, the bark, and the roots of the tree all contain juglone, which is a known irritant.
When shelling black walnuts, wear protective gloves and handle with care.