Blackberries And Cognitive Function

Introduction

In the realm of nutrition and cognitive well-being, blackberries deserve your attention. While it may seem that everything is a 'superfood', it can be easy to lose sight of the benefits of a healthy and balanced diet – but the blackberry should not be overlooked. It is an edible fruit that grows in woodland and hedgerows from late summer until mid-autumn in the UK, and it is known to have an array of health benefits – from improved immune function to cardiovascular health.¹ Aside from these well-known attributes, blackberries may also enhance cognitive function due to their high level of antioxidants, fibre, and other essential nutrients.

It goes without saying that proper cognitive function is essential, dictating such processes as learning, memory, decision-making, and language abilities. Tailoring our diet to support brain health is something that we should all strive for and blackberries are a great place to start.

Nutritional composition of blackberries

Rich in antioxidants

Antioxidants are at the forefront of blackberries’ nutritional qualities. Antioxidants help protect cells from oxidative stress, a process linked to ageing and cognitive dysfunction.² Two of the most abundant antioxidants in blackberries are vitamin C and vitamin E.

• Vitamin C – one cup (144g) of blackberries contains 30.2mg of vitamin C, which equates to 34% of the recommended dietary allowance (RDA)
• Vitamin E – one cup of blackberries contains 1.68mg of vitamin E. This accounts for 11% of the recommended daily allowance (RDA)

As well as vitamins C and E, blackberries contain high levels of plant compounds with strong antioxidant properties known as polyphenols. Examples of polyphenols present in blackberries are anthocyanins and flavonols.

High in fibre

Blackberries are also high in dietary fibre. One cup of blackberries provides 7.63g, which is 27% of the RDA. This sets blackberries ahead of other common fruits such as apples and grapes which only contain 3g and 1.36g of fibre per portion, respectively. While fibre may seem irrelevant to cognitive function, fibre plays a well-known role in digestive health and evidence suggests a link between these two systems. This link centres on what is known as the gut-brain axis which enables communication between the gut and the brain.

Other essential nutrients

Besides antioxidants and fibre, blackberries house a variety of other essential nutrients. These include, but are not limited to –

• Vitamin K – low dietary intake of vitamin K has been linked with poor cognitive function.³ One cup of blackberries contains 24% of the RDA of vitamin K. Consuming these berries is likely to reduce the risk of cognitive decline
• Copper – copper is essential for the proper functioning of the nervous system. Copper is involved in the synthesis of brain chemicals known as neurotransmitters which are vital for communication between brain cells. One cup of blackberries provides 27% of the RDA of this mineral
• Manganese – manganese is another essential mineral found in blackberries and is necessary for normal brain and nervous system function. One cup of blackberries contains 40% of the RDA of manganese

The impact of antioxidants on cognitive function

Oxidative stress and the role of antioxidants

Oxidative stress occurs when there is an accumulation of reactive oxygen species (a subset of free radicals) that cannot be neutralised by the body. These free radicals cause damage to cells and tissues, potentially resulting in the development of various diseases. Antioxidants play a crucial role in this process through neutralising free radicals and averting oxidative stress.

The brain is highly susceptible to oxidative stress due to its high oxygen consumption and abundant lipid content⁴ (lipids are one of the main macromolecules targeted by free radicals). When oxidative stress does occur, it can lead to the onset of neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD).⁵ Therefore, antioxidants are essential for preventing these diseases and supporting brain health.

Specific antioxidants and their influence on the brain

Vitamin C

Vitamin C is regarded as the most important antioxidant in brain tissue, vitamin C is crucial in counteracting oxidative stress and its effects. Several studies have presented evidence to indicate a therapeutic role of vitamin C in AD. One of these focused on beta-amyloid, the main component of the amyloid plaques that accumulate in the brains of AD patients.

The results of this study showed that pre-loading neurons with vitamin C prevented cell death and reduced the production of beta-amyloid.⁶ Consequently, this suggests that vitamin C plays a protective role against the development of AD. Given the high vitamin C content in blackberries, this highlights another potential benefit of the fruit.

Vitamin E

Much like vitamin C, vitamin E is a powerful antioxidant that protects the brain against oxidative stress and is high in blackberries. A randomised clinical trial involving 613 patients with mild to moderate AD demonstrated that administration of a type of vitamin E (alpha-tocopherol) slowed functional decline and a delay in disease progression.⁷

Polyphenols

Dietary polyphenols, such as anthocyanins and flavonols are present in high levels in blackberries and have been shown to exert various neuroprotective effects. These include protection against neurotoxins (including free radicals) and suppression of inflammation in the brain.⁸ On top of this, polyphenols may improve cognitive functions like memory and learning. In one study using aged rats, it was found that a blackberry-supplemented diet improved cognitive performance with researchers suggesting this was due to the high polyphenol content of the berries.⁹

Fibre and its role in cognitive function

The digestive system is a complex network. Recent research uncovered a significant connection between gut health and the brain through the gut-brain axis. This connection facilitates bidirectional communication, meaning digestive health affects brain health and vice versa (stress, for example, can have wide-reaching effects on the gut).

With their high fibre content, blackberries contribute positively to this interplay. A critical aspect relates to the gut microbiota, the community of microorganisms in the digestive tract. Dietary fibre has prebiotic qualities meaning fibre encourages the growth and activity of beneficial microorganisms. As a consequence, the gut microbiota can exert its influence on the brain by regulating systems associated with stress response, anxiety, and memory.¹⁰

Furthermore, a well-functioning digestive system enables the absorption of nutrients, including those crucial for brain health, such as vitamins C and E. Therefore, consuming sufficient fibre is essential for supporting cognitive function.

Incorporating blackberries into a brain-boosting diet

Blackberries are a versatile fruit that can be combined with a range of other foods for a brain-boosting snack or meal. Certain foods also complement blackberries, enhancing the cognitive benefits by providing additional nutrients to aid in brain function. Here are some examples of complementary foods –

• Greek yoghurt – Greek yoghurt is a good source of protein and calcium. Protein helps stabilise blood sugar levels to ensure a steady supply of energy to the brain. Calcium is essential for many functions of the nervous system.¹¹ Add blackberries as a topping for Greek yoghurt, or blend the two together along with milk and other fruits to create a smoothie
• Oats – Oats are a good source of complex carbohydrates, which provide a steady release of glucose to the brain. Mix blackberries with porridge for a breakfast that will kick-start your brain for the day
• Nuts and seeds – Almonds, walnuts, chia seeds, and flaxseeds contain antioxidants and essential nutrients and are high in omega-3 fatty acids, which are crucial for brain health.¹² Enjoy a handful of nuts and blackberries for the perfect brain-boosting snack, or add chia and flaxseed to smoothies, yoghurts, and porridge
• Leafy greens – Spinach, kale, and other leafy greens are rich in vitamins such as folate, which is necessary for healthy brain function. Include blackberries in a leafy green salad or green smoothie (add some Greek yoghurt for the ultimate boost!)
• Salmon – Similar to nuts and seeds, fatty fish like salmon are high in omega-3 fatty acids. Prepare salmon with a blackberry glaze for a cognitive-enhancing meal

While combining blackberries with the foods listed above will provide optimal cognitive benefits, the fruit can also be enjoyed alongside sweet treats such as ice cream and frozen yoghurt, or in desserts such as parfaits, sorbets, and crumbles. The key is to incorporate blackberries as part of a diverse and balanced diet while maintaining variety in your food choices. This way, these brain-boosting dietary changes will be sustainable in the long run.

Potential considerations and precautions

There are very few risks associated with eating blackberries. However, here are some things to keep in mind –

• Allergies or sensitivities – blackberries have low allergenicity, so the chance of an allergic reaction is minimal. Nonetheless, symptoms of food allergies such as itching, skin rash, and nasal congestion can occur in sensitised individuals. Caution is advised if you have a history of allergies or reactions to similar berries
• Stomach discomfort – the high fibre content of blackberries means they can cause stomach discomfort when consumed in high quantities. Keep servings small if you have a sensitive stomach

FAQs

Which berries are good for cognition?

Besides blackberries, blueberries are known for their cognitive benefits due to high levels of antioxidants. Strawberries also contain nutrients that may support cognitive function.

Is it okay to eat blackberries every day?

Yes, blackberries make a healthy addition to your diet, and it is generally okay to eat them every day. However, as with any food, moderation is key. Be mindful of their high fibre content and any sensitivities that you may have to similar berries.

How can I improve my cognitive function?

Maintain a balanced diet rich in fruits, vegetables, and whole grains. Stay physically active, get enough sleep, manage stress, and engage in mental activities like puzzles. Stay socially connected and consider incorporating brain-boosting foods like berries into your diet.

How do you know if your brain is unhealthy?

Signs of an unhealthy brain may include persistent memory problems, difficulty concentrating, changes in mood or behaviour, and impaired decision-making. If you are concerned about these symptoms, consult a healthcare professional.

Summary

Blackberries have the power to exert a positive influence on cognitive function. This is due in part to their high antioxidant content with vitamin C, vitamin E, and polyphenols defending the brain against oxidative stress and reducing the risk of neurodegeneration. Additionally, the abundance of fibre in blackberries plays a dual role in fostering gut and brain health via the gut-brain axis.

Incorporating blackberries into a balanced diet is likely to enhance cognitive function, supporting processes such as learning and memory and minimising the risk of developing diseases like AD. The versatility of these berries allows for variety in their consumption, making the experience of boosting your brain health simple and enjoyable.