Black Radish: How This Humble Bitter Can Support Digestive Health

Published on April 19, 2023

By Kristen Boye BS, Natural Health

Kristen Boye

Kristen Boye is a natural health expert, writer, copywriter, and editor. Kristen was raised on an organic farm in British Columbia which inspired her life’s work. She holds a Bachelor’s Degree in Natural Health, is a Certified Natural Foods Chef, co-owner of a medicinal herb farm, and is a natural foods and children’s health advocate. Kristen lives with her husband and two children on their medicinal herb farm in Western North Carolina.

In Western culture, Radishes are typically red and eaten occasionally in salads, sales, or salsas.

However, did you know dozens of Radish varieties are enjoyed as food and a traditional herb worldwide?

One such variety is the Black Radish, also known as Spanish Black Radish or the Erfurter radish.

This larger and spicier round radish has black skin and white flesh and is typical in Mexican, Spanish, Asian, and Mediterranean cuisine.

It also has a history of traditional use in Asian, African, and Mexican folklore for supporting the liver, gallbladder, and digestion.

This article will explore the history, traditional use, science, and benefits behind Black Radish and how it may help support your health and culinary repertoire.

What is Black Radish?

Also known as Erfurter radish, Spanish Black Radish, or Raphanus sativus, Black Radish is a type of radish with black or purple skin and white flesh belonging to the Brassica family.REF#1331 

The nutritious root and leaves of Black Radish—and other radish varieties—have been consumed worldwide as pickles and in salads, fresh sauces, and curries.

Black Radishes are generally larger than their red, pink, or white cousins. They’re also spicier, more pungent, and have slightly tougher flesh, making them suitable for eating raw or roasted.

Extracts prepared from the leaves and roots of radishes have been traditionally used in folklore for:

  • Stomach and digestive health 
  • Urinary tract health 
  • Liver health
  • Cardiac health
  • Radishes have also been consumed as “bitters” to help support healthy digestion.

Today, Black Radishes can be found fresh in specialty stores or various supplements and tinctures.

How Black Radish Supports Various Aspects Of Health

Like all Brassicas, Black Radish is rich in nutrients that support various organs, systems, and aspects of well-being.

Some of the nutrients found in Black Radish leaves and roots include:REF#1332 

  • Fiber
  • B-vitamins
  • Iron
  • Vitamin C
  • Vitamin K
  • Zinc
  • Copper
  • Anthocyandins (a type of antioxidant)
  • Quercetin
  • Manganese
  • Calcium
  • Magnesium
  • Phosphorus

Black Radish is also a good source of water and contains just 20 calories per serving.

The health-supportive potential of Black Radish is attributed to the presence of specific beneficial plant compounds known as secondary metabolites.REF#1333

Secondary metabolites occur in lower abundance and distribution than primary metabolites and are deposited in specialized cells and organelles.

They act as microbial-balancing and antioxidant (cell-protecting) compounds and include: 

  • Glucosinolates: Which give Black radish its signature bitter flavor.REF#1334 Black radishes have four times the Glucosinolates of any other radish variety.
  • Polyphenols: A type of antioxidant that has insulin-like properties.
  • Isothiocyanates: These are products of Glucosinolates that give Black Radish its pungent or spicy flavor and scent.REF#1334 

Let’s explore how these Black Radish nutrients help support and protect various organs and systems.

#1: Black Radish Is A Bitter

Bitters have been used across cultures as far back as ancient Egypt to promote strong and healthy digestion.*

New research supports this, showing different types of bitters may work on various aspects of digestive function, including saliva and stomach acid production.REF#1335

Their bitter taste comes from the plant's alkaloids and glycosides, which cause our salivary glands to become active.

Some examples of common bitters include:

  • Artichoke
  • Black Walnut
  • Bitter Melon
  • Chicory
  • Dark Leafy greens
  • Radishes
  • Dandelion
  • Gentian
  • Sarsaparilla
  • Sweedish Bitters

In herbalism, bitters are also given to support the normal production of bile* which aids in digestion.

#2: Black Radish Supports Gut Health

In addition to its digestive health benefits as a bitter, Black Radish has also demonstrated potential benefits to the gut.

In an animal study entitled: “Effects of black radish root (Raphanus sativus L. var niger) on the colon mucosa in rats fed a fat-rich diet” researchers tested the effects of Black Radish on rats with various disruptions in their gut lining due to a high-fat diet.

All the subjects showed improvement after taking the Black Radish, including enhanced numbers of healthy cells and more balanced inflammation.

More research is needed to determine how Black Radish may influence gut health.

However, given the number of studies showing brassica vegetables support gut health, digestion, and more REF#1336, it is likely Black Radish is a gut-friendly food.

Learn more about the gut microbiome from a naturopath and medical herbalist in: Understanding The Microbiome & Tips To Maintain A Healthy Gut.

#3: Black Radish Supports Balanced Blood Sugar

Earlier, we discussed the three secondary metabolites in Black Radish believed to be responsible for its various health benefits.

One of the most notable is Polyphenols, a type of antioxidant that has demonstrated insulin-like properties.

Black Radish also contains glucose-inhibiting compounds, making it potentially helpful for supporting balanced blood sugar.

Several studies on Black Radish and Black Radish sprouts have demonstrated the plant’s supportive properties for blood sugar balance and metabolic health.REF#1337 

Scientists believe this is due to its ability to:

  • Support glucose-related hormones
  • Reduce oxidative stress, and promote cellular health through its antioxidant properties
  • Support balanced glucose uptake and absorption
  • Support normal synthesis of adiponectin, a central regulatory protein involved in the regulation of lipid and glucose metabolism secreted by adipose (fat) tissue

In addition to its secondary metabolite benefits, Black Radish is a low-carb, low-sugar, and fiber-rich food, making it a great addition to snacks and meals to support balanced blood sugar and metabolic health.

#4: Black Radish Supports Gallbladder Health

In various systems of traditional herbalism, the liver, and gallbladder are often treated as one, with herbs given for liver support also benefitting the gallbladder and vice versa.

Therefore, it’s not surprising that Black Radish has shown gallbladder-supportive benefits.

In an animal study published in the Journal of Biomedicine and Biotechnology, mice were given Black Radish juice to mice with diet-induced cholesterol gallstones.REF#1338

This diet also increased cholesterol and triglycerides levels, gallbladder wall thickness, intestinal problems, and liver weight while decreasing HDL levels.

After treatment with Black Radish juice for six days, the cholesterol gallstones were eradicated significantly, cholesterol and triglycerides levels decreased, and HDL levels increased.

This small, non-human study shows the potential for Black Radish to be a healthy gallbladder- and cholesterol-supportive food.

If you have gallbladder concerns, adding some black radish to your next green juice may also be a good reason.

#5: Black Radish Supports Liver Detoxification

Traditional herbalists worldwide have long recommended Black Radish, and other Radishes, for liver support.*

New research has finally validated this ancient wisdom, and the findings are impressive.

A study published in BMC Complementary and Alternative Medicine found that Black Radish's unique combination of the plant compounds glucosinolates, sulfates, and high-cysteine-proteins made it beneficial for supporting liver detoxification.REF#1339 

The liver is considered one of our master organs of detoxification, playing a role in transforming, neutralizing, breaking down, storing, and eliminating various internal, external, and environmental toxins. 

Additional research shows Black Radish supports Phase 1 and Phase 2 liver detoxification by promoting the healthy activity of crucial detoxification enzymes.REF#1340

A proper balance between Phase 1 and Phase 2 detoxification reactions is critical to preventing the redistribution of toxins before they enter Phase 3, the final stage of excretion.

Black Radish has also demonstrated liver-protective and decongestive properties in animal studies.REF#1337 

These small studies give a glimpse into the potential of Black Radish as a detox-supportive functional food and traditional herb.

Gaia Herbs Liver Cleanse contains Black Radish and other herbs to support optimal liver detox and health.

#6: Black Radish Promotes Kidney Health

Unless we become ill or have a family history of kidney problems, most of us pay little mind to these organs. 

However, the kidneys are two of the body’s most essential organs for detoxification and keeping you alive.

Your kidneys take care of you by: 

  • Filtering over 150 quarts of blood per day
  • Playing an essential role in maintaining fluid and electrolyte balance
  • Participating in hormone activation
  • Synthesizing vitamin D
  • And filtering various toxins such as ammonia, creatine, hormone metabolites, and heavy metals.REF#1341

Unfortunately, very few of us have learned how to care for our kidneys using nutrition, lifestyle, and herbs.

Black Radish extract has been shown helpful for supporting kidney function by promoting optimal urine pH, urine volume, uric acid, and oxalate levels.REF#1342

When these levels are suboptimal, it can lead to issues such as kidney stones or excess uric acid.

In this study, Black Radish did not affect creatinine or calcium levels.

Discover more natural ways to support kidney health in:

Black Radish Side Effects & Contraindications

No significant side effects have been reported from consuming Black Radish.

Some people may experience stomach upset from excessive consumption or due to the spiciness of the herb.

Allergic reactions are rare but could occur.

Some experts believe Brassica vegetables, such as radishes, should be avoided by those with thyroid conditions because they can have a goitrogenic effect (Goitrogens are substances that disrupt the production of thyroid hormones).

However, not all thyroid health experts recommend avoiding Brassicas. 

Talk to your healthcare professional for individual recommendations.

How To Start Reaping The Benefits Of Black Radish & Other Bitter Herbs

Black Radish can be enjoyed in salads, salsas, as a side dish, as a garnish, or roasted to reduce its pungency and bring out its natural sweetness.

Supplements are also a popular way to get a more concentrated dose of Black Radish.

Although 100% Black Radish extracts are available, Black Radish is often combined with other bitter herbs that support the liver, gallbladder, and digestion.

Gaia Herbs offers Black Radish in our Liver Cleanse formula. 

This product combines Black Radish with Milk Thistle, Turmeric, Dandelion, Yellow Dock, Artichoke, Gentian, Figwort, Fenugreek, Ginger, and Burdock for broad-spectrum detoxification support.

Discover more ways to support liver, gallbladder, and digestive function in:


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