Nature has presented us with a variety of berries and each berry provides different health benefits in a different manner. Nature has blessed human health with a special kind of berry called blueberry. However, all berries contain antioxidants and other health promoting compounds, but the concentration of antioxidants and health promoting compounds is higher in blueberries. As blueberry is native to America, Americans enjoy it from more than 100 years. Besides this, blueberries have even gained popularity in different parts of the world and today many food companies and manufacturers are incorporating blueberries in different food products because of its rich nutrient profile. No doubt, blueberry has an amazing nutrient profile and this has forced the researchers to throw some more light on different health benefits of blueberries.
Health Benefits of Blueberries
Blueberries provide a number of health properties such as anti-diabetic, anti-inflammatory, antioxidant, anti-hypertensive, anti-cancer, antihyperlipidemic and so on. It also boosts memory and improves concentration in older adults. Research has also shown that blueberries are liver-protective and gut-friendly. As it plays a protective and important role in every organ system, it is not less than a ‘super functional food’. Besides this, the action of blueberry in the prevention and treatment of certain diseases and disorders is similar to that of the drugs. Furthermore, the best part is that blueberries do not provide any side effects like many drugs do. Thus, for an overall good health it becomes very important to include blueberries in the daily diet.
Rich in Antioxidants
Blueberries contain a wide variety of powerful antioxidants that scavenge free radicals and reduce the level of oxidative stress. Research has found that the amounts of antioxidants in Lowbush blueberry are higher than that of Highbush blueberry species. Among all fruits and vegetables, blueberries have the highest antioxidant capacity. Blueberries contain flavonoids, anthocyanins and phytochemicals that possess antioxidant properties. However, some of the antioxidants are lost while processing such as drying, freezing and juicing. Even when blueberries are stored for a prolonged period, some of the antioxidants are lost. These antioxidants play an important role in the treatment and prevention of various diseases and disorders such as diabetes mellitus, heart diseases, liver diseases, gut problems, Alzheimer’s disease and cancer.
Rich in Anthocyanins
Blueberries are a very rich source of anthocyanins. Anthocyanins are responsible for the indigo color of blueberries. Besides providing a beautiful color, anthocyanins also provide a number of health benefits. Some of the most common anthocyanins found in blueberries include:
Out of all these, majority of anthocyanins present in blueberries are MALVIDIN and DELPHINIDIN. The anthocyanin composition of blueberries varies with different cultivars, environmental factors and stage of ripeness. Many studies have found that the content of anthocyanins is significantly higher in Lowbush blueberry as compared to Highbush blueberry. However, it has been found that the absorption of anthocyanins in humans is very low. Furthermore, the absorption of anthocyanins from blueberries depends upon the amount of blueberries eaten and other food sources eaten along with blueberries. Blueberry anthocyanins have shown to play an important role in weight loss, diabetes and insulin sensitivity.
Recently blueberry yogurt has gained a lot of popularity and it is easily available in the market but research has shown that storing blueberry yogurt for a long period may reduce the concentration of anthocyanins present in the yogurt. Therefore, in order to prevent loss of anthocyanins it is better not to store blueberries or any product made out of it for a long period.
Blueberry is very popular in clinical setting and it used extensively in the treatment of various ailments. Let’s have a look how blueberry protects the body against so many diseases and disorders:
Type-2 Diabetes Mellitus
With the increasing incidence of type 2 diabetes mellitus, special importance is given to different fruits for their anti-diabetic roles. Blueberry is one such fruit, which is loaded with goodness of anti-diabetic compounds. Blueberry possesses anti-diabetic activity. It has been used as a traditional medicine for the treatment of diabetic symptoms such as increased appetite or excessive hunger, increased thirst and frequent urination.
Blueberry has insulin-like property and it enhances the uptake of glucose by the cells. Therefore, more glucose enters the cells and less remains in the blood. In addition to this, blueberry increases the insulin sensitivity and reduces insulin resistance. It has a positive effect on pancreatic beta cells, that is, it improves the secretion of insulin from these cells.
Oxidative stress plays a very important role in promoting hyperglycemia or high blood sugar levels. Having high blood sugar levels for a prolonged period increases the risk of diabetic complications such as:
- Retinopathy (damage to eyes)
- Neuropathy (damage to nerves)
- Nephropathy (damage to kidney)
- Cardiovascular diseases
As blueberry is an abundant source of phytochemicals and antioxidants, it scavenges the free radicals and reduces oxidative stress. Such a decrease in the level of oxidative stress automatically reduces the hyperglycemia and helps to maintain blood sugar levels in normal range.
Besides this, blueberry leaf extract also plays an important role in lowering high blood sugar levels. Such a hypoglycemic property of blueberry is due to the presence of flavonoid ‘MYRTILLIN’. Other compounds present in blueberry leaf that possess similar properties include QUERCETIN and CHLOROGENIC ACID. Thus, through different mechanisms blueberry plays an important role in attenuating high blood sugar levels and hence, helps in the management of type 2 diabetes mellitus.
High Cholesterol Levels
Research has shown that treatment with blueberry has an ameliorating effect on high blood cholesterol levels. Blueberries reduced the level of cholesterol in the liver and aorta. It further reduced the production of cholesterol in the liver and increased the excretion of bile acids in the feces. Increased excretion of bile acid elevates the usage of cholesterol for synthesis of more bile acids. In such a way less cholesterol is stored in the body and less is present in the blood too. Besides this, blueberry suppresses the formation of fatty acids and increases the breakdown of fatty acid. It also increases the use of fatty acid as a source of energy, hence, less fat is stored in the body and less cholesterol is formed. Such a decrease reduced the overall risk of atherogenesis (formation of fatty clots in the arteries). Furthermore, research has also shown that blueberry also helps in weight loss that in turn helps in improving the lipid profile.
Hypertension or High Blood Pressure
Recent studies have shown that blueberry reduces high blood pressure and arterial stiffness and thus increases the production of nitric oxide. Reduction in nitric oxide induces constriction of blood vessels and increases the production of reactive oxygen species. Nitric oxide expands the blood vessels and helps the blood to flow smoothly all throughout the body. Blueberries are extremely rich in polyphenolic compounds including flavonoids, phenolic acid and stilbenes that further help in lowering high blood pressure.
One interesting study showed that consuming 50 grams of freeze-dried Highbush blueberry powder significantly lowered high blood pressure in obese men and women with metabolic syndrome in 8 weeks. Such a hypotensive role of blueberry is because of its ability to increase the availability of nitric oxide, a powerful vasodilator. It was further observed that daily incorporation of freeze-dried blueberry powder reduced the systolic blood pressure by 5.1% and diastolic blood pressure by 6.3%. Thus, it can be suggested that regular consumption of blueberry reduces blood pressure in hypertensive individuals and also reduces the risk of cardiovascular diseases associated with it.
As we age, our memory, concentration and other brain functions decline. Aging is the main cause of such a cognitive decline. As we age, the production of free radicals increases that attacks the brain and increases the level of oxidative stress. Such an interaction of free radicals with central nervous system contributes to cognitive decline. The first step that leads to the development of Alzheimer’s disease is oxidative stress. Therefore, with aging it becomes very important to increase intake of foods rich in antioxidants. Blueberry is one such fruit, which is completely packed with powerful antioxidants. These antioxidants neutralize the free radicals, reduce the level of oxidative stress and improve the antioxidant enzyme system. Such an effect helps to restore memory and concentration levels.
One study showed that supplementation with blueberry reversed the deleterious effect of aging on brain. Treatment with blueberry induced improvement in the memory and also improved neuronal signaling.
Another study showed that diet enriched with blueberry is an effective strategy to prevent or treat Alzheimer’s disease and other neurodegenerative disorders. It attenuates degenerative processes that may occur due to oxidative stress or inflammation. The powerful antioxidant properties of blueberries are due to the abundance of phytochemicals and flavonoids in it. Furthermore, the effectiveness of blueberry is similar to the pharmacologic treatment given during Alzheimer’s disease.
Research has shown that whole blueberry as well as blueberry juice is very effective in improving overall liver health. Increased exposure of liver to toxins, chemicals, drugs and alcohol may cause damage to the liver and may further lead to fibrosis of liver or even liver failure. Oxidative stress is the primary pathogenic factor (main cause) for liver diseases and thus, it can cause damage to the liver cells. Superoxide dismutase and catalase are important antioxidant enzymes that function as radical scavengers. Regular blueberry consumption significantly improves the activity of these antioxidant enzymes and thus protects the liver against damage.
It is found that proanthocyanidins (health promoting compound) present in blueberry leaves are able to inhibit replication of hepatitis C virus. A research showed that drinking blueberry juice reduced reactive oxygen species in the liver and improved the structure and function of the liver. In liver fibrosis, the structure of the liver changes and as the disease progresses, liver hardens. Thus, blueberry juice reduced the progression of the disease and thus lowered the level of liver enzymes that had increased due to fibrosis. Blueberry juice also had a stimulatory effect on metallothioneins expression in the liver. Metallothioneins are proteins that bind heavy metals and it also scavenges harmful free radicals and thus protects the liver.
A very easy way to increase the intake of antioxidants and to reduce oxidative stress is by increasing the intake of blueberries. A study showed that eating blueberries regularly reduced the level of inflammation and thus improved the health of liver cells. Thus, blueberries possess a therapeutic effect on liver fibrosis by inhibiting the level of inflammation as well as lipid peroxidation (oxidative degradation of lipids). Therefore, blueberry as well as blueberry juice can be successfully used in the treatment of liver diseases.
Many researchers have claimed that regular consumption of blueberry protects the gastrointestinal tract against various diseases. Lowbush blueberries possess antimicrobial properties that protect against the following:
- Escherichia coli (causes food borne illness)
- Listeria monocytogenes (causes listeriosis that resembles influenza)
- Salmonella Typhimurium (causes typhoid)
It was found that Lowbush blueberry inhibits intestinal pathogens and protects probiotics, live microorganisms that protect the gut and provides benefits.
Another study showed that blueberries reduce the translocation of the bacteria and thus, decrease the level of inflammation. It destroys the harmful bacteria that may otherwise give rise to gut diseases. Besides this, blueberry also conserves healthy and gut-friendly bacteria that improve overall gut health. Anthocyanins present in blueberries may also protect against free radicals that cause damage to the gut.
Inflammatory bowel disease is the inflammation of gastrointestinal tract that can even impair gastrointestinal structure and function. Research has showed that freeze-dried blueberry powder reduces the markers of inflammation and thus reduces the overall state of inflammation. A rat study found that anthocyanins present in blueberry effectively prevented the symptoms associated with inflammatory bowel disease such as diarrhea and abnormal bowel movements. It further improved the structure of colon and small intestine and reduced intestinal lesions. Anthocyanins also suppressed the production of free radicals and inflammatory markers. Thus, oral administration of anthocyanin extract from blueberries has a protective effect on inflammatory bowel disease.
Blueberries contain polyphenols, flavonoids and anthocyanins that have the strongest antioxidant capacity among all fruits and vegetables. Reactive oxygen species play an important role in the development of heart diseases. Therefore, it becomes very important to control the production of these reactive oxygen species. Blueberry enriched diet improved the overall health of cardiac cells and reduced the inflammatory cells to half. In addition to this, the ejection fraction (the amount of blood pumped by the heart during each contraction) also increased which was otherwise low in the diseased condition. It further reduced pro-inflammatory markers and thus, inhibited inflammatory stress pathway.
Uncontrolled blood sugar levels, high cholesterol levels and hypertension are the main risk factors for the development of heart diseases. Many studies have shown that blueberries are very effective in the management of diabetes, lipid profile and blood pressure. Thus, blueberries indirectly reduce the risk of heart disease by lowering its risk factors.
Research showed that consuming wild blueberry juice that provides 375 milligrams of anthocyanins for six weeks significantly lowered oxidative stress and improved endothelial function (inner lining of the blood vessels). Level of inflammatory biomarkers such as C-reactive protein (CRP), TNF-a and IL-6 also reduced. Thus, blueberries are an effective strategy for protecting heart health and improving its function.
A huge number of studies have shown that blueberries are very effective in the treatment and prevention of cancer. Such a role may be due to an amazing composition of blueberry fruits. They contain a vast variety of antioxidants, polyphenols, flavonoids and other health promoting compounds that inhibit the growth and spread of cancer cells to other parts of the body.
One research has shown that activities of phenolic compounds in rabbiteye blueberries have a great potential to suppress the multiplication and division of cancerous cells. Thus, blueberry phenolic compounds work by reducing the population of cancer-causing cells in the body. The presence of flavonols and tannins in blueberry extracts had the ability to inhibit the growth of cancer-causing cells by 50%. Anthocyanin fraction present in blueberry also increased the death of cancerous cells by 2-7 times. Such protective effects were specially observed in case of colon cancer.
Another mechanism by which blueberry reduces the risk of cancer is through its antioxidant potential. During cancer the state of inflammation and oxidative stress increases tremendously. The generation of free radicals during this stage is vast. Therefore, a diet rich in antioxidants is required to scavenge these free radicals and to inhibit further deterioration. It is very well known that among all fruits and vegetables, blueberries have the highest antioxidant potential. Hence, in simple words it can be said that blueberry is the perfect fruit for the treatment and prevention of cancer.
Blueberry & Drug Interaction
Anti-diabetic drugs: Blueberry fruit does not interact with any drug but some studies have shown that blueberry leaves may interact with anti-diabetic drugs. When blueberry leaf extract is consumed with anti-diabetic drugs or when less time gap is maintained between the two, blood sugar levels may fall beyond normal range and may lead to hypoglycemia.
Different Ways to Consume Blueberry
- Blueberry extract is available in the form of supplement or capsules
- Freeze-dried blueberry powder
- Blueberry leaf extract is also available in the form of pills or powder
- Whole blueberries
- Dried blueberries
- Frozen blueberries
- Blueberry juice
- Blueberry drink
- Blueberry yogurt
- Blueberry milkshake
- Blueberry smoothie
- Blueberry jam
- Blueberry puree or whole blueberry can be added to different bakery products such as pie, muffins etc.
Proper storage technique reduces the loss of nutrients in blueberries and maximizes its shelf life. Therefore, it becomes very important to store blueberries safely. Let’s have a look at the right storage techniques:
- While purchasing blueberries, check out for the moldy blueberries. If such blueberries are stored with fresh blueberries, it may spoil the fresh ones too.
- Blueberries that are very soft or mushy should be discarded, do not store them.
- Gently wash the blueberries before storing them and pat them dry completely with the help of a towel or a paper napkin. You can also spread the blueberries on a wide tray and let them dry naturally.
- Wet blueberries have high moisture content that cause the blueberries to mold too soon.
- Once they are completely dried, store them in a plastic or ceramic container. Avoid storing blueberries in metal container as it may lead to some undesirable reactions with the metal.
- Place a tissue or paper napkin at the bottom of the plastic or ceramic container so as to absorb excess moisture if any.
- Now place the container in the fridge.
- For frozen blueberries- Place the blueberries on a wide tray and make sure there is enough space between 2 berries. Keeping berries too close may lead to clumping.
- Now place this tray in the freezer for at least 2 to 3 hours.
- Once they are frozen transfer these berries into a plastic bag (Ziploc bag is the best)
- Again place this bag in the freezer. You can store them in the freezer for about a year.
Blueberries are flowering plants that belong to genus Vaccinium. Scientific name of blueberry is cyanococcus. Birth of blueberries took place in North America and from this place its cultivation was spread to the other parts of the world. Blueberry plants are shrubs that vary in size from 10 centimeters to 4 meters tall. Blueberries are classified into three types-
- Lowbush blueberries- they are smaller species and are also known as wild blueberries
- Highbush blueberries- they are larger species
- Rabbiteye blueberries
Blueberry leaves are oval in shape and are 1 to 8 centimeter long and 0.5 to 3 centimeter broad. Blueberry flowers are very beautiful bell-shaped flowers and are red, pale-pink or white in color. Blueberry fruits are 5 to 16 millimeter in diameter. Immature fruits are pale green in color. As they ripen, their color changes to reddish-purple. Once they are completely ripened, their color changes to indigo. Blueberries have a sweet taste and their level of acidity varies with their ripening stage.