Are Black Walnuts Good For You?

Written by Sindhu Koganti

Black walnuts (Juglans nigra) are known for their distinct taste and are native to North America. They have long been used in herbal medicine for their antioxidant, anti-inflammatory, antibacterial, and anti-cancer properties. Their high vitamin, mineral, unsaturated fat, and polyphenol content help treat many ailments. They improve heart health, fight cancer, aid weight loss, and support digestive health. In this article, we explore the health benefits of black walnuts, their nutrition profile, and possible side effects. Keep reading!

Health Benefits Of Black Walnuts

1. Improves Heart Health

Research states that increased intake of nuts has protective benefits over cardiovascular diseases (1). The presence of omega-3 alpha-linolenic acid in black walnuts improves heart health. A study conducted by the Pennsylvania State University (USA) found that dietary alpha-linolenic acid, which is abundant in black walnuts, reduces the inflammatory and lipid cardiovascular risk factors in people with high cholesterol (2). It has a lipid-lowering effect and helps reduces LDL cholesterol levels. Also, a walnut-enriched diet is rich in ellagic acid, which is said to have a cardioprotective effect (3).

Another study states that the intake of walnuts helps improve blood circulation which, in turn, results in proper heart functioning (4). Also, walnut seeds contain high amounts of phenolic compounds and antioxidants, and their regular intake can reduce the risk of cardiovascular diseases (5).

2. Fights Cancer

Black walnuts contain certain antitumor compounds like ellagic acid and juglone that have shown anti-cancer potential and suppressed tumor growth in mice (6). A study conducted by the University of Michigan Medical School (USA) found that juglone (a natural toxin) reduces programmed cell death in the case of human gastric cancer (7), (8).

The presence of gamma-tocopherol in walnuts was found effective in treating cancer, and their increased intake helps lower the risk of cancer (1). Also, the kernels of black walnuts have antioxidant and anti-cancer properties (9). However, more studies are needed to understand this benefit of black walnuts in humans.

3. Antibacterial Properties

The hulls of black walnuts were tested for their ability to inhibit fungal and bacterial activities of certain bacterial species like Candida albicans, Trichophyton rubrum, and Streptococcus mutans (10). Also, the tannins in black walnuts exhibit antibacterial effects (11). A study also found that green walnut husk has high polyphenol content and antioxidant and antimicrobial effects (12).

Black walnut extracts have six bioactive compounds that are responsible for their antibacterial effects (13). A review published in the International Journal of Dentistry suggests that the aqueous extracts of black walnut bark have an antimicrobial effect (14).

The unripe hulls of black walnuts have been used in the treatment of topical fungal infections (15). They have also shown an inhibitory effect on bacteria such as Staphylococcus aureus (16).

4. Aids Weight Loss

The unsaturated fatty acids in black walnuts increase satiety. A study conducted by the University Hospital Maastricht (Netherlands) found that the intake of foods high in unsaturated fats can reduce hunger and increase fullness (17). A small-scale study conducted on 20 men and women found that walnut consumption for four days increased satiety by the third day (18). 

Also, the consumption of 30 grams of walnuts per day promotes weight loss. However, more studies are needed to prove this benefit of black walnuts (19).

5. Supports Digestive Health

The leaves of black walnut trees have been used for treating diarrhea, bilious, and intestinal colic (cramp-like pain that originates in the small and large intestine) by Native Americans (20). Also, walnut oil contains linoleic and linolenic acids that are said to possess anti-inflammatory properties. It helps in treating intestinal inflammation, diarrhea, and other gastrointestinal tract disorders (21).

Balck walnuts may help in calming an upset stomach and relieve constipation. However, more studies are needed to understand this effect of black walnuts in humans.

6. Lowers Blood Sugar Levels

A review published in the African Journal Of Traditional, Complementary, and Alternative Medicine found that black walnuts have a hypoglycemic effect (22). They were found to lower blood sugar levels in diabetic rats.

Also, black walnut kernels have bioactive compounds such as quercetin-3-O-glucoside that exhibit anti-diabetic properties. However, more studies are warranted to prove the same.

7. Improves Sleep

Walnuts are a rich source of antioxidants like melatonin, which can be used as an alternative treatment for sleep disorders (23). A study has shown that melatonin is effective in improving the duration and quality of sleep (24).

8. Promotes Skin Health

The anti-inflammatory properties of black walnuts help in treating many inflammatory skin diseases like acne (25). Also, its antibacterial effect can act against certain bacterial strains like S. aureus that helps in treating several skin infections. Anecdotal evidence suggests that the fine powder of black walnut husks can be made into a paste and used on the skin, which can clear up skin conditions like eczema, psoriasis, blemishes, and pimples.

Also, the arginine in black walnuts helps in lowering blood pressure (1). And, polyphenols like tannins help prevent certain neurodegenerative diseases like Alzheimer’s and Parkinson’s diseases. These tannins may also help calm hyperactive sweat glands (26).

These are the potential health benefits of black walnuts. They are rich in a wide variety of vitamins and minerals. Check out the nutrition profile of black walnuts below.

Black Walnut Nutrition

According to the U.S. Department of Agriculture, 100 grams of dried black walnut contains (27):

  • Energy: 619 kcal
  • Protein: 24.1 g
  • Fat: 59.3 g
  • Carbohydrates: 58 g
  • Fiber: 6.8 g
  • Calcium: 61 mg
  • Iron: 3.12 mg
  • Magnesium: 201 mg
  • Phosphorous: 513 mg
  • Potassium: 523 mg
  • Zinc: 3. 37 mg
  • Copper: 1.36 mg
  • Manganese: 3.9 mg
  • Selenium: 17 mcg

Black walnuts also contain antioxidants, polyphenols, and essential fats that help in improving your overall health. English walnuts are the commonly available tree nuts with many nutrients. But, what is the difference between English walnuts and black walnuts? Scroll down to find out.

Black Walnuts Vs. English Walnuts

Black walnuts have a bolder, earthier flavor, while English walnuts have a milder taste. The shells of black walnuts are thick and tough to crack, whereas English walnuts have thinner, easier-to-crack shells. English walnuts contain more omega-3 fats than black walnuts. Black walnuts are used mostly for making flavorings and extracts. English walnuts are used in cooking, baking, and making ice cream.

The hulls of black walnuts are available in the form of tinctures, powders, capsules, or liquid drops. They are also used as a natural remedy for treating many parasitic infections. Some people use the extract as a gargle to kill bacteria in their mouth. Also, the hull extracts of black walnuts are used in hair dyes.

Are you wondering how to add black walnuts to your diet? Scroll down to learn more!

How To Add Black Walnuts To Your Diet

These crunchy tree nuts have a unique and natural flavor. They are used in cookies, cakes, pies, salads, pasta, and fudge. You can also make black walnut ice cream.

How To Prepare Black Walnut Ice Cream

What You Need

  • Black walnut extract – ½ teaspoon
  • Superfine sugar – ½ cup
  • Half-and-half cream – 1 cup
  • Light cream – 2 cups
  • Chopped black walnuts – ½ cup

Process

  1. Stir together the sugar, light cream, half-and-half, and black walnut extract in a medium bowl.
  2. Pour the mixture into the container of an ice cream maker and freeze it according to the manufacturer’s instructions.
  3. When the ice cream is done, fold in the black walnuts and transfer it to a freezer container.
  4. Freeze the ice cream until solid.

Black walnuts are generally considered safe for most people. But, people with nut allergies and the ones who eat these nuts excessively may experience some side effects. Learn about the possible side effects of black walnuts in the next section.

What Are The Possible Side Effects Of Black Walnuts?

Black walnuts are generally considered safe when eaten in limited quantities. However, some people exhibit side effects such as stomach upset and allergic reactions. People with nut allergies should avoid the intake of black walnuts.

Supplements made of black walnuts are not regulated by the U.S. Food and Drug Administration as research on them is very limited, and there are no recorded side effects of black walnuts. Avoid eating these nuts if you are pregnant or breastfeeding, and consult your doctor before consuming them or their supplements.

How do you select and store black walnuts? Find out the process in the following section.

Selection And Storage

If you preserve black walnuts along with their shells, they won’t lose their freshness. Keep them in the refrigerator in case you de-shell them or in the freezer for long-term storage.

You can easily identify black walnuts that have gone rancid due to their paint thinner-like smell. Try to store them in a dry, cool place to avoid damage.

Conclusion

Black walnuts are edible and shelled tree nuts with a hard surface. They are high in nutrition and have many antibacterial and anti-inflammatory properties. These tree nuts are also rich in plant compounds that help in treating many ailments. From improving heart function to supporting skin health, black walnuts offer several health benefits. Also, black walnut hulls have medicinal properties and are used in supplements. However, their excess consumption leads to side effects. If you are pregnant or lactating, consult your doctor before eating them.

Sources

Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. A Review on the Potential Human Health Benefits of the Black Walnut: A Comparison with the English Walnuts and Other Tree Nuts
    https://www.tandfonline.com/doi/full/10.1080/10942912.2015.1114951
  2. Dietary alpha-linolenic acid reduces inflammatory and lipid cardiovascular risk factors in hypercholesterolemic men and women
    https://pubmed.ncbi.nlm.nih.gov/15514264/
  3. Walnut extract (Juglans regia L.) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483
    https://pubmed.ncbi.nlm.nih.gov/17916277/
  4. Antioxidant potential of Juglans nigra black walnut husks extracted using supercritical carbon dioxide with an ethanol modifier
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5332255/
  5. A Comprehensive Review on the Chemical Constituents and Functional Uses of Walnut (Juglans spp.) Husk
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719079/
  6. Antitumor activity of Juglans nigra(black walnut) extractives
    https://onlinelibrary.wiley.com/doi/abs/10.1002/jps.2600571009
  7. The natural toxin juglone causes degradation of p53 and induces rapid H2AX phosphorylation and cell death in human fibroblasts
    https://pubmed.ncbi.nlm.nih.gov/16271620/
  8. Juglone-induced apoptosis in human gastric cancer SGC-7901 cells via the mitochondrial pathway
    https://pubmed.ncbi.nlm.nih.gov/19815401/
  9. Profiling Anticancer and Antioxidant Activities of Phenolic Compounds Present in Black Walnuts (Juglans nigra) Using a High-Throughput Screening Approach
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7583942/
  10. Antimicrobial effects of plant extracts on Streptococcus mutans Candida albicans Trichophyton rubrumand other micro-organisms
    https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/j.1472-765X.1992.tb00668.x
  11. Antibacterial activity of tannin constituents from Phaseolus vulgaris Fagoypyrum esculentum Corylus avellana and Juglans nigra
    https://pubmed.ncbi.nlm.nih.gov/18325686/
  12. Characterization of Microcapsule Containing Walnut ( Juglans regiaL.) Green Husk Extract as Preventive Antioxidant and Antimicrobial Agent
    https://pubmed.ncbi.nlm.nih.gov/30598739/
  13. Identifying Antibacterial Compounds in Black Walnuts ( Juglans nigra) Using a Metabolomics Approach
    https://pubmed.ncbi.nlm.nih.gov/30274312/
  14. Antibacterial Effect of Juglans Regia Bark against Oral Pathologic Bacteria
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708447/
  15. Antimicrobial activity of juglone
    https://onlinelibrary.wiley.com/doi/abs/10.1002/ptr.2650040104
  16. An overview of phytochemicals and potential health-promoting properties of black walnut
    https://pubs.rsc.org/en/content/articlehtml/2020/ra/d0ra05714b
  17. Effect of fat saturation on satiety hormone release and food intake
    https://pubmed.ncbi.nlm.nih.gov/19225118/
  18. Walnut consumption increases satiation but has no effect on insulin resistance or the metabolic profile over a 4-day period
    https://pubmed.ncbi.nlm.nih.gov/19910942/
  19. Impact of providing walnut samples in a lifestyle intervention for weight loss: a secondary analysis of the HealthTrack trial
    https://pubmed.ncbi.nlm.nih.gov/28747865/
  20. Black Walnut (Juglans nigra) Extracts Inhibit Proinflammatory Cytokine Production From Lipopolysaccharide-Stimulated Human Promonocytic Cell Line U-937
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761373/
  21. Walnut Oil Alleviates Intestinal Inflammation and Restores Intestinal Barrier Function in Mice
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284466/
  22. Effect of Walnut Leaf Coriander and Pomegranate on Blood Glucose and Histopathology of Pancreas of Alloxan Induced Diabetic Rats
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2816491/
  23. Walnuts Have Potential for Cancer Prevention and Treatment in Mice
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3952627/
  24. A review of sleep disorders and melatonin
    https://pubmed.ncbi.nlm.nih.gov/28460563/
  25. Black Walnut (Juglans nigra) Extracts Inhibit Proinflammatory Cytokine Production From Lipopolysaccharide-Stimulated Human Promonocytic Cell Line U-937
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761373/
  26. Health benefits of walnut polyphenols: An exploration beyond their lipid profile
    https://www.tandfonline.com/doi/full/10.1080/10408398.2015.1126218?src=recsys
  27. Nuts walnuts black dried
    https://fdc.nal.usda.gov/fdc-app.html#/food-details/170186/nutrients

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Sindhu Koganti is a Biotechnology graduate and has been in the writing field for over 4 years now. She specializes in writing on Health and Wellness. She has hands-on experience in writing articles and press releases on Life Sciences and Healthcare, Food and Beverages, and Chemicals and Materials. When she’s not writing, she loves watching movies and listening to music. She also enjoys traveling.