Introduction

Hundreds of blackberry species have been identified and are widely available worldwide. Whether wild or cultivated, these tasty fruits belonging to the thorny shrubs group (Rubus genus), are packed with a rich nutritional blend made up of vitamins, minerals, and bioactive compounds.¹ 

Blackberries have a high polyphenol, flavonoids and anthocyanin content, all of which are powerful antioxidants contributing to the berries’ numerous health benefits.¹ These superfoods are also a rich source of fibres, folate, vitamin C, E and K, potassium and calcium.²   

Thanks to their impressive nutritional profile, the consumption of blackberries has been associated with:^1,2  

• Antioxidant properties
• Protection against certain types of cancers
• Anti-inflammatory properties
• Immune system support 
• Digestive system support
• Contribution to cardiovascular health
• Contribution to skin health 

Read on to learn more about the nutritional content of blackberries, their wide range of benefits and potential risks associated with their consumption.  

Nutritional composition of blackberries

The nutritional content of blackberries may vary from one species to another. However, they remain an important source of vitamins, minerals and essential compounds, particularly polyphenols.¹    

Key vitamins and minerals present in blackberries

According to the United States Department of Agriculture (USDA), the nutritional value of 1 cup of raw blackberry serving (144 grams) is as follows: 

Raw blackberries are low on calories, low on fat and have no cholesterol content. These fruits are a good source of fibre, vitamins and minerals. Potassium is the most prevalent mineral, followed by calcium, phosphorus, manganese and iron. As for their vitamin content, they are rich in folate, vitamins C, E, K, and A and beta-carotene.

Folate, or vitamin B9, is essential for DNA synthesis and the production of healthy red blood cells. Adequate folate consumption is particularly crucial during pregnancy to reduce the risk of neural tube birth defects called spina bifida. One cup of blackberries covers around 9% of your daily recommended folate needs. 

Vitamin C or ascorbic acid, is an antioxidant that supports the immune system, helps heal wounds and maintains healthy skin, cartilage and other body tissues. Additionally, vitamin C enhances the absorption of iron.³ One cup of blackberries provides around 34% of your recommended daily vitamin C needs. 

Vitamin K plays a crucial role in regulating blood clotting and promoting bone health. One cup of blackberries provides around 24% of your daily recommended vitamin K needs. 

Potassium is important for muscle contraction, heart contraction and maintaining fluid balance in the body. One cup of blackberries covers 5% of your daily recommended potassium needs. 

Manganese is involved in blood clotting, bone growth, metabolism of fat and carbohydrates, production of sex hormones, calcium absorption, and brain and nerve function. One cup of blackberries is enough to cover 40% of your recommended daily needs. 

Overview of bioactive compounds in blackberries

Polyphenols, the most varied type of phytochemicals found in plants, are bioactive compounds believed to be the main reason behind the health protective effects and benefits associated with blackberries.⁴ 

Lately, phytochemicals have gained special interest and extensive research has been conducted on the polyphenolic content of blackberries, especially phenolic acids, flavonoids and anthocyanins, to better understand their properties. Studies have shown that polyphenols:⁴

• Have anti-inflammatory properties
• Lower your risk of cardiovascular diseases
• Improve brain function
• Supports your immune system
• Have antioxidant properties
• Lower your risk of developing certain types of cancer

Blackberries stand out from other fruits because of their high polyphenol content. In a 2021 study evaluating the anthocyanin content in five different berry species: raspberry, blackberry, red currant, blackcurrant, and highbush blueberry, blackberries were found to have significantly the highest levels.⁵

Health benefits of vitamin-packed blackberries

Having explored the nutritional composition of blackberries, it's time to highlight their health benefits.

Antioxidant properties

Blackberries owe their vibrant colour to anthocyanins, a subgroup of flavonoids with potent antioxidant properties.⁴ Free radicals are produced if we are exposed to certain situations such as air pollution or cigarette smoking. They attack and harm our cells causing numerous illnesses. Possessing powerful antioxidant properties, anthocyanins fight and neutralise free radicals, lowering our risk of developing chronic conditions such as diabetes, cardiac diseases, and certain types of cancers.⁴

Let us not forget that blackberries are vitamin-packed - their antioxidant and disease fighting properties are also partly due to their richness in vitamins C and E.

Anti-inflammatory properties

Many studies, mostly conducted on rodents, identified the anti-inflammatory properties of phenolic acids and flavonoids found in blackberries. Such studies showed that the consumption of blackberries reduces inflammation, lowers inflammatory markers such as C-reactive protein (CRP), and inhibits COX-2, an enzyme responsible for the synthesis of molecules mediating inflammation.^6,7

Immune system support

With their vitamin C and zinc content, blackberries contribute to supporting the immune system. Their deficiency will weaken our immunity. Vitamin C plays a pivotal role in the immune response by stimulating white blood cell production, mediating their function and the body’s immune response. Supplementing with vitamin C will reduce the duration of respiratory infections such as the common cold.^8,9 

In addition, antibacterial and antiviral properties have been attributed to the bioactive compounds found in blackberries.¹⁰

Cardiovascular health

Role of folate in reducing cardiovascular risks

Blackberries contain a fair amount of folate. Adequate folate intake is associated with a lower risk of cardiovascular illnesses, as it helps regulate homocysteine levels - a compound linked to heart disease.¹¹ 

Antioxidants' impact on heart health

A review of 59 studies evaluating the effects of anthocyanins and anthocyanin-rich berries, including blackberries, showed that consuming high amounts of anthocyanins in your diet was linked to a lower risk of coronary heart disease, a lower risk of total cardiac disease incidence and a lower risk of cardiac disease-related deaths.¹² 

Furthermore, a review of 66 trials assessing the effects of anthocyanins on blood pressure showed that they may help reduce blood pressure. Inconsistencies in the reported results were due to several factors such as the type of anthocyanin, dose used, duration of the trial, and patients' characteristics.¹³  

Digestive health

Blackberries are a particularly good source of fibres, both soluble and insoluble. One cup of blackberries provides you with 7.63 grams of fibre, covering around 30% of your daily recommended needs. 

Blackberries’ richness in fibre contributes in many ways towards your digestive health. When consumed, blackberries

• bind to cholesterol and reduce its absorption and consequently its levels in your blood
• help control your blood sugar level
• help control your body weight
• help food move through your gut, relieving and preventing constipation 

Skin health

As mentioned above, consuming 1 cup of blackberries provides a significant amount of vitamin C, and covers 2% of your daily vitamin A needs, and 11% of that of vitamin E.

The antioxidant properties of these vitamins allow them to fight free radicals, preventing their harmful effects on our skin cells. Vitamin E nurtures the skin, slows down skin ageing and may also prevent wrinkles.  

In vitro (test tube experiments) and animal studies confirm the role of vitamin C in collagen synthesis, which is needed for skin elasticity and skin cell health. Vitamins C and E were also found to protect the skin from photodamage.¹⁴  

Risks and considerations

Consuming blackberries is generally safe. Reports on blackberry allergies are limited, however do exist. You should always look out for and report signs of allergy such as itching, rash, or swelling of the lips or eyes, and difficulty breathing.¹⁵ 

If you are intolerant to a medication called salicylate or aspirin, you might develop a reaction to blackberries because of their salicylate content.  

Summary

Blackberries have been recently marketed as nutrient-packed superfoods. Their health benefits are numerous and are mostly linked to their unique blend of nutrients, bioactive compounds and powerful antioxidant properties. 

Their potent antioxidant effects have been well-established by numerous research. However, most studies evaluating blackberries and their phytochemical contents were conducted in vitro and on animals using significantly high doses. Because of this, further investigations on humans are required to confidently affirm their antimicrobial, antidiabetic, anti-inflammatory, anticancer, glucose-lowering, lipid-lowering and blood pressure-lowering effects.

Incorporating blackberries into your diet is beneficial, may improve your overall health and reduce your risk of chronic illnesses. Always remember that eating a balanced and colourful diet is key to a healthy body.