Blueberries And Their Natural Mood Enhancers

Overview 

Blueberries are a small but mighty fruit packed full of antioxidants, vitamins and fibre whilst being low in calories. They are known as a ‘superfood’ due to their range of health benefits, including blood sugar regulation, immune system support, eye health maintenance, reduced risk of heart disease and overall contribution to healthy ageing. 

As well as their benefits for physical health, blueberries have been reported to have mood-boosting properties, mainly due to their high vitamin C and fibre content. Read on to discover how incorporating blueberries into your diet can boost your overall well-being. 

Nutritional content of blueberries

Rich in antioxidants

Antioxidants are chemicals found in plants that prevent the oxidation of food when it is broken down in our bodies. Oxidation is a chemical reaction that produces compounds called free radicals (highly reactive molecules). Free radicals damage our cells, and a buildup of free radicals causes oxidative stress in the body, which can lead to several side effects such as fatigue, memory loss, a lack of concentration, digestive issues, headaches, and an increased risk of cardiovascular, neurological, inflammatory and respiratory diseases.¹ The high antioxidant levels in blueberries can help prevent these, making us feel alert and healthy, which can help contribute to a better mood. 

The main antioxidants present in blueberries are a specific type of flavonoids called anthocyanins. Flavonoids are a type of polyphenol (plant compound) found in many plant products, and they give blueberries their characteristic colour. Of the various chemicals found in blueberries, anthocyanins seem to have the greatest health benefits, most notably with their neuroprotective effects (protecting the brain and nervous system), which human clinical trials have shown.² Additionally, out of all foods, blueberries are one of the highest ranking for anthocyanin content.³

Importance of antioxidants for overall health

Blueberries are an ideal part of the diet for everyone. The free-radical fighting effect of antioxidants helps protect against many diseases. Specifically, human clinical trial research has shown that anthocyanins are associated with a reduced risk of cardiovascular disease and type 2 diabetes, as well as improved weight maintenance and protection of the brain. Being overweight can majorly increase the risk of cardiovascular disease and hypertension (high blood pressure). A high anthocyanin intake has been proven to help keep off excess weight, therefore contributing to overall disease reduction.²

Anthocyanins also contribute to gut health and help boost the gut microbiota, which contributes to our overall health, for example, by protecting against degenerative diseases and ageing.² In recent years, there has been increasing research into the link between gut flora and mental wellbeing. It is well known that anthocyanins, found in high concentrations in blueberries, are important for a healthy gut microbiota. A balanced microbiota has also been associated with improved psychological well-being.^3,4

High levels of vitamins and minerals

Vitamin C

One serving of blueberries contains 25% of the daily recommended level of vitamin C. Note that vitamin C is not stored in the body, it has to be gained from our diet every day. Vitamin C has numerous health benefits, including protecting our cells from damage, keeping skin, bone, cartilage and blood vessels healthy, and helping the wound healing process. 

In addition, vitamin C also has a range of benefits for our brains. Out of all the body tissues, the brain has the highest concentration of vitamin C. As well as its roles in neuroprotection and synthesis of neurotransmitters allowing brain communication, vitamin C has been found to improve motivation, focus, psychological function and reduce anxiety, therefore it is thought to be important for maintaining normal mental health.⁵ 

Other essential nutrients in blueberries 

As well as vitamin C, blueberries are high in vitamin K, vitamin B6, folate, thiamine, manganese, and dietary fibre. 

One portion of blueberries contains approximately 14% of the recommended daily fibre intake. Consuming plenty of fibre has been shown to enhance psychological well-being, lower the risk of depression, and even help to reduce the severity of autism.⁴ A high-fibre diet also has the benefits of improving gut health and weight management, which can have positive knock-on effects on psychological well-being, as previously discussed. Some studies have even reported that the fibre content in fruits and vegetables is more beneficial to the gut microflora than polyphenols (such as flavonoids like anthocyanin in blueberries).⁶ Fibre helps to balance the gut microbiota, which in turn helps the function of the vagus nerve connecting the gut and the brain. This causes better responses to stress and a more balanced mood.⁴ 

Fibre also directly benefits psychological health due to its conversion into short-chain fatty acids (SCFAs) in the body. SCFAs promote cells in the brain, such as microglia and astrocytes, to reduce inflammation and remove damaged neurons, contributing to better brain health.⁴ 

Increased fibre intake has been shown to improve psychological well-being for all ages, as early as when a baby is developing in the mother’s womb. Babies of individuals assigned female at birth (AFABs) who consumed more raw fruits during pregnancy had better cognitive development during the first year.⁷ An Australian study on adolescents observed that depression and aggression were associated with Western diets (famously low in fibre), and positive behaviours were linked with a higher intake of fresh fruits.⁸ For adults, evidence suggests that a higher intake of fibre-rich foods contributes to lower anxiety and higher levels of happiness, life satisfaction, and emotional well-being. One study observed that adults with high-quality diets had 67% better psychological well-being than those with low-quality diets. Interestingly, that difference was only observed when people had a high intake of fruits and vegetables in their diets.⁸ 

More specifically, fruit fibre has been shown to lower the risk of depression, anxiety, and psychological distress, especially for AFABs. A study of AFAB people found that those with the highest fruit intake had reduced odds of depression, anxiety, and distress by over 50% each compared to those with the lowest fruit intake.⁹ Another study on both AMABs and AFABs showed that for every 100g serving of fruit consumed, there was a 3% lower risk of depression.¹⁰ These results, alongside the other evidence of health benefits gained from blueberries, show that blueberries are a good way to boost mental well-being simply by incorporating them into your diet. 

Blueberries and brain health

Impact on cognitive function

The cognitive benefits of blueberries have been supported by numerous studies, making them a smart choice if you want to boost your brain function. Luckily, their effects seem to benefit all ages. Studies on school children have found that both short-term and long-term memory was improved after consumption of blueberry powder. Moreover, the more blueberry powder was consumed, the better the performance in the cognitive task. Studies on older adults have also shown improvements in memory and task switching.² 

The high vitamin C content in blueberries contributes greatly to brain health. People with low vitamin C often feel fatigued and depressed, and these symptoms often precede the disease called scurvy, which is caused by vitamin C deficiency.¹¹ Studies have shown that when people with vitamin C deficiency are given vitamin C, their mood improves. The same is true even for people with normal levels of vitamin C, reporting that their anxiety decreased after consuming more vitamin C.¹² 

Reducing oxidative stress in the brain

Due to their high antioxidant levels, blueberries can help reduce oxidative stress in the brain. Oxidative stress damages neurons, activating inflammation down the line. Damage to brain cells has been shown to contribute to depression and anxiety; thus, preventing oxidative stress in the brain can help improve symptoms.¹³

Blueberries and neurotransmitters

Vitamin C is required for the synthesis and release of several neurotransmitters in the brain. Neurotransmitters are chemicals that carry messages between cells in the brain to keep our brains and bodies functioning. One of the main ways that vitamin C helps to boost mood is by aiding in the production of the neurotransmitter dopamine, known as the ‘reward and motivation’ chemical. Vitamin C found in blueberries is also important in the production of noradrenaline (norepinephrine), a neurotransmitter with roles in arousal, attention and cognitive function.¹²

Blueberries also contain tryptophan, a specific amino acid which is necessary for the production of proteins. Tryptophan is a key ingredient in the production of serotonin, a neurotransmitter involved in mood regulation, cognition, reward, learning, and memory, among other physiological processes. Vitamin C could contribute to the production of serotonin, although evidence for that is limited.¹¹

Deficiencies and dysregulation of neurotransmitters so important for the brain - dopamine, noradrenaline and serotonin - have been hypothesised to contribute to depression. Getting plenty of vitamin C from blueberries may help to maintain healthy levels of these neurotransmitters, contributing to a better mood.¹¹ 

Anti-inflammatory properties of blueberries 

Inflammation and its effects on mood

Inflammation is linked to various health issues, including mood disorders such as depression. Research has found that people with bipolar depression have higher levels of inflammatory mediators in their brain, molecules triggering the inflammation. Additionally, people with systemic autoimmune diseases (a group of diseases characterised by unusually high levels of inflammation and tissue damage caused by the immune system attacking healthy cells) are at higher risk of developing bipolar depression.^{14, 15}

Blueberries as natural anti-inflammatory agents

Blueberries are known for their powerful anti-inflammatory properties. This is down to the anthocyanins, which help to fight inflammation directly, as well as helping to regulate the immune system, which can reduce chronic inflammation. Inflammation can have a detrimental effect on a person’s overall well-being, for example, by causing stiffness and pain, which can make the person unwilling to carry out daily tasks and social events. Letting chores pile up and missing out on social interactions are both detrimental to mental health, so reducing inflammation could help to improve quality of life. 

The anti-inflammatory effects of blueberries have been tested in various studies and experimental models. One study used a human skin model to test the effects of blueberry extract on artificially induced inflammation. The skin was exposed to ozone, which is a toxic pollutant that causes inflammation and impairs wound healing. Wound healing was recovered by administering blueberry extract, which activated antioxidant defence systems.¹⁶

Blueberries and stress reduction

Stress is a natural human response to a difficult or threatening situation. Everyone experiences stress to some degree, but unhealthy levels can cause uncontrollable anxiety, mental tension, mood swings and despair. Many people experience unhealthy levels of stress due to the pressures of modern-day life, especially when we feel under a lot of pressure or in a situation that is out of our control. Consuming blueberries may be able to alleviate stress due to their high levels of antioxidants. Not only do antioxidants benefit brain function, but they also help to lower blood pressure, which is a key marker of stress. 

Anxiety is often a symptom of stress, and as previously discussed, compounds found in blueberries, such as vitamin C, fibre, and anthocyanins, can help to ease feelings of anxiety. 

The anthocyanins found in blueberries also have natural stress-reducing properties due to their benefits to the gut microbiota, which aids the functioning of the vagus nerve. The vagus nerve is the main nerve in the ‘rest and digest’ system. This system works in balance with the sympathetic nervous system, which is involved in fight or flight behaviours (the body’s response to stress). Aiding the function of the vagus nerve by boosting our gut microbiota with the high anthocyanin and fibre content in blueberries could potentially help with stress response behaviours and help to maintain a more balanced mood.⁴ 

Blueberries can be incorporated into an overall stress-relief routine, for example, by taking time out of your day to make a tasty and satisfying smoothie or by using them in baking, which is a mindful and therapeutic activity. 

Incorporating blueberries into the diet

Fresh vs. frozen blueberries

Frozen blueberries are a good way to get more bang for your buck. Research has proved that frozen blueberries retain nearly all of their nutritional value, with no decrease in the level of antioxidants. They also contain the same amount (and sometimes even more) of fibre, thiamine, vitamin B6 and folate. Interestingly, the only downside to frozen blueberries is the loss of vitamin C content, losing over two-thirds of their vitamin C upon freezing. 

Frozen blueberries are now sold in most supermarkets, making them easy to get your hands on, even when fresh blueberries are out of season. Additionally, many people prefer the taste of frozen blueberries. They can be defrosted in the microwave to soften them and release their juices, which makes for a nice topping on yoghurt or ice cream. Frozen blueberries also tend to be more cost-effective. A 350g bag of frozen blueberries costs anywhere from £2.25 to £2.75 from the main supermarket chains, which works out at 64p-78p per 100g, compared to roughly £1 per 100g for fresh blueberries. 

Creative ways to consume blueberries

Blueberries are extremely versatile and can be easily enjoyed as they are, but if you fancy switching it up, you can try incorporating them into smoothies and baked goods. Both fresh and frozen blueberries work well in smoothies and can go well with any other fruit and vegetables. For an easy smoothie, try blending a banana with 175g of blueberries, a tablespoon of Greek yoghurt and some apple juice. You can try adding things like fresh mint to switch it up. Blueberries work well in muffins and crumbles to make a sweet treat. Try adding some blueberries to a standard cupcake recipe for an easy dessert.

Blueberry powder is also a good way to gain all the nutrients of blueberries and is especially useful if you do not enjoy the taste or texture of raw blueberries. Blueberry powder is usually made from grinding up freeze-dried blueberries, which can be done at home to save costs, as ready-made blueberry powder tends to be expensive, and is usually only sold in whole food shops. Blueberry powder can be added to yoghurt, smoothies, porridge, protein shakes, dips, and even ice cream! This is a useful way to get the key nutrients of blueberries into children's diets by disguising them in a tasty dessert. 

Summary

Blueberries are touted as a superfood due to their wide-ranging health benefits. One of the lesser spoken-about benefits is their mood-enhancing properties. Consuming blueberries helps to maintain a healthy internal environment, especially a healthy gut, which can potentially contribute to a more stable mood. The high levels of vitamin C and fibre found in blueberries help to improve cognitive function, reduce the risk of anxiety and depression, and fight inflammation, which can have negative effects on mental well-being. 

Blueberries are easily incorporated into the diet; however, their cost can be a setback. Frozen blueberries are a good option for saving money while still gaining all the nutritional benefits. A couple of handfuls of blueberries count as one of your 5-a-day, which is low in calories and sugar and contains 4 grams of dietary fibre (about 14% of the daily recommended intake) and one-quarter of the daily recommended vitamin C intake. It is important to remember that individual responses to blueberries may vary, and eating a varied and balanced diet and maintaining a healthy lifestyle overall is vital for looking after your mental health.