What is the nutritional value of sloe berries and their health benefits?

January 11, 2026 •

4 min read

According to several analyses, fresh sloes contain notable levels of vitamin C, E, potassium, and magnesium. But what is the full nutritional value of sloe berries, and what do these tiny, tart fruits offer for your health?

Quick Summary

Sloe berries, from the blackthorn bush, offer a nutrient-rich profile high in antioxidants like flavonoids and phenols, along with essential vitamins and minerals. They are rarely eaten raw due to their astringent taste, but are prized for making liqueurs, jams, and jellies.

Key Points

Rich in Antioxidants: Sloe berries are packed with phenols and flavonoids, such as anthocyanins, which offer strong antioxidant and anti-inflammatory benefits.
Good Source of Vitamins: The fresh berries provide a notable amount of vitamins C and E, supporting immune function and protecting against cell damage.
High in Essential Minerals: Sloes contain significant levels of potassium, magnesium, calcium, and iron, crucial for nerve, muscle, and bone health.
Requires Processing: Due to a bitter, astringent taste from tannins, sloes are rarely eaten raw and are best consumed in jams, jellies, or liqueurs after being processed.
Potential Digestive Aid: In traditional medicine, sloes have been used for digestive issues, with the fruits acting as an antidiarrheal and the flowers as a laxative.
Seeds are Toxic: The seeds of sloe berries contain amygdalin, which is toxic in large quantities and should be removed before preparation, especially when serving to children.

The sloe berry, or Prunus spinosa, is a small, dark-blue fruit from the thorny blackthorn bush, native to parts of Europe, western Asia, and northwest Africa. Often foraged from hedgerows, this fruit is notoriously astringent and bitter when raw, leading most foragers to process it into jams, jellies, and the famous sloe gin. Despite its challenging raw flavor, the sloe berry contains a concentrated nutritional punch that offers several health benefits when prepared correctly.

The Core Nutritional Profile of Sloe Berries

Beyond their reputation for flavoring alcohol, sloes are a genuine source of vitamins, minerals, and other bioactive compounds. These nutrients are more potent in the fresh fruit, with some content potentially lost during high-heat processing like jam-making.

Vitamins and Minerals Per 100g

Based on available data, a 100g serving of fresh sloe berries provides a healthy dose of several micronutrients:

Vitamin C: Approx. 9.5 to 10 mg. This antioxidant is vital for immune function and skin health.
Vitamin E: Approx. 5 mg. Another powerful antioxidant that protects cells from damage.
Potassium: Approx. 250 to 453 mg. Essential for nerve function, muscle contraction, and maintaining normal blood pressure.
Magnesium: Approx. 20 to 22 mg. Important for energy metabolism and regulating muscle and nerve function.
Calcium: Approx. 10 to 37 mg. Crucial for bone health and proper blood clotting.
Iron: Approx. 0.7 to 2.1 mg. Necessary for creating red blood cells and for oxygen transport.
Fiber: Approx. 1.4 g. Supports digestive health.
Carbohydrates: Approx. 11.42 g.
Calories: Approx. 46-69 kcal.

Antioxidants: The Powerhouse in Sloe Berries

Sloe berries are especially celebrated for their high concentration of antioxidants, particularly phenols and flavonoids. These compounds combat oxidative stress in the body by neutralizing harmful free radicals, which helps reduce the risk of chronic and degenerative diseases.

Polyphenols found in blackthorn fruit include:

Anthocyanins: The pigments that give sloes their deep purple-blue color. They have strong antioxidant and anti-inflammatory properties.
Flavonoids: A class of antioxidants including quercetin, rutin, and myricetin. Studies have linked them to potential antihypertensive and anti-diabetic activity.
Phenolic Acids: Such as caffeic acid and gallic acid, which contribute significantly to the berry's overall antioxidant capacity.
Tannins: These compounds are responsible for the berry's distinct astringent flavor. Tannins are also known for their antidiarrheal and antioxidant properties.

Health Benefits Backed by Research and Tradition

The rich nutritional composition of sloe berries supports a variety of health-promoting effects, some of which are backed by modern science while others come from traditional folk medicine.

Antioxidant Effects: The potent combination of anthocyanins, flavonoids, and other phenolic compounds helps protect the body's cells from damage caused by free radicals.
Immune System Support: The high vitamin C content provides a natural boost to the immune system, aiding the body in fighting off infections.
Digestive Aid: Historically, the astringent fruits were used to treat diarrhea, while the flowers were steeped in tea as a laxative. The fruit's fiber content also aids in promoting healthy intestinal transit.
Cardiovascular Health: Flavonoids like quercetin and rutin, along with potassium, have been associated with positive effects on blood pressure and cholesterol regulation, supporting overall heart health.
Anti-inflammatory Properties: Research indicates that sloe extracts possess significant anti-inflammatory activities, which may help mitigate symptoms of inflammatory conditions.

Sloe's Nutritional Profile vs. Other Common Berries

To better understand the nutritional value of sloe berries, here is a comparison of key nutrients per 100g of fresh fruit against other popular berries:


Nutrient	Sloe (100g)	Blueberries (100g)	Blackberries (100g)
Energy (kcal)	46–69	57	43
Vitamin C (mg)	9.5–10	9.7	21
Fiber (g)	1.4	2.4	5.3
Potassium (mg)	250–453	77	162
Magnesium (mg)	20–22	6	20

This comparison highlights that sloes, while lower in fiber than blackberries, are a significantly richer source of minerals like potassium and magnesium compared to both blueberries and blackberries. Their vitamin C content is comparable to blueberries but less than blackberries.

How to Incorporate Sloe Berries into Your Diet Safely

Due to their intense tartness and astringent flavor, raw sloe berries are not widely consumed. The seeds also contain amygdalin, which converts to a small amount of toxic cyanide in the body, so consuming large quantities raw is not recommended, especially for children. Proper preparation, however, makes them delicious and safe.

Popular Uses

Sloe Gin: This is perhaps the most famous use, involving infusing sloes with sugar and gin to create a sweet liqueur.
Jams and Jellies: The berries have high pectin content, making them ideal for setting preserves.
Syrups and Cordials: Sloe syrup can be used to flavor drinks or poured over desserts.
Wine: Sloes can be used to produce a rich, spicy fruit wine.

Preparation Tip

For most recipes, it is traditional to pick sloes after the first frost, which helps mellow their flavor and split the skins. Alternatively, you can freeze the berries for 24 hours to achieve the same effect.

Conclusion

The nutritional value of sloe berries is a hidden treasure within a naturally unpalatable fruit. Packed with powerful antioxidants like phenols and anthocyanins, along with important vitamins and minerals such as potassium and magnesium, they offer a host of potential health benefits, from combating oxidative stress to supporting cardiovascular health. While they are not a fruit for fresh consumption, their role in traditional preserves, liqueurs, and syrups provides a delicious way to enjoy their unique flavor and nutritional advantages. The proper processing, including a freezing step to reduce astringency, unlocks the best of what these humble, thorny berries have to offer. For a deeper dive into the phytochemical composition of Prunus spinosa and its various bioactive compounds, numerous research studies are available.

Frequently Asked Questions

Raw sloe berries are safe in small quantities for adults, but their bitter, astringent taste makes them unpleasant to eat. The seeds contain small amounts of amygdalin, which is toxic, so it is safer to spit them out and consume the berries after processing.

The most common preparation involves freezing the berries first to mimic a frost. This helps break the skins and mellow the flavor. They are then used to make sloe gin, jams, jellies, and syrups.

While blueberries are often consumed fresh, sloes offer a richer source of minerals like potassium and magnesium. The vitamin C content is comparable, but blueberries generally contain more fiber.

Historically, sloes were used as an antidiarrheal agent due to their tannins, while the flowers were used as a laxative. The fruit's fiber content can also support healthy digestion.

The antioxidant power of sloe berries comes from their high levels of polyphenolic compounds, including anthocyanins, flavonoids like quercetin, and phenolic acids such as caffeic acid.

Children should avoid eating raw sloe berries. The presence of amygdalin in the seeds, which can be toxic when ingested, and the unpleasant taste mean sloes are not suitable for children unless properly prepared and cooked.

While sloe berries themselves are nutrient-rich, the berries lose some nutrients when steeped, and sloe gin is primarily an alcoholic beverage mixed with a significant amount of sugar. Its health effects are more tied to the alcohol and sugar content than the fruit itself.