Why are blueberries good for you?

Why are blueberries good for you?
August 21, 2015 8:00 PM

You might have heard about blueberries and might have some information regarding them, but do you want to know much more about them? If so, then you need to read this article as it will tell you about blueberries, their health benefits, their side effects and why they are good for your health.

What Are Blueberries?

Blue berries belong to the genus Vaccinium. They have indigo color and are perennial flowering plants. The place where blueberries are most commonly found is the North America. They are the species Cyanococcus and are sold as blueberries. The size of a blueberry can vary ranging from 10 centimeters to 4 meters in height. ‘High-bush blueberries’ is the name of the larger species, whereas ‘low-bush blueberries’ is the name of the smaller species.

The leaves of blueberries are of various forms and sizes. They can either be deciduous, evergreen, or lanceolate. The width of these leaves is 0.5-3.5 cm, whereas the height is 1-8 cm long. These flowers are usually bell-shaped, which can be red or sometimes, pink in color. These flowers are covered with a coating of epicuticular. This makes their taste a whole lot sweeter when they are fully ripe. The fruits come from blueberries in the growing season. The factors which affect the growing are some local conditions, like latitude and altitude. Due to this, the best time of the crop can vary from May to August.

Now let us look at the place of origin of blueberries. Various different species of blueberries are present in Europe, Asia, Africa and North America. Blueberries are grown commercially in the Southern American nations, and the Southern Hemisphere of New Zealand and Australia. There are many other eatable blue berries present in the genus Vaccinium. The European bilberries and Vaccinium myrtillus are the most dominantly found species of blueberries.

Species of blueberries

Some of the popular species of blueberries are mentioned below:

  • One of the popular species of blueberries is Vaccinium alaskaense. It is a dominant species of blueberries, usually found in the coastal forests of Alaska and British Columbia.
  • Another popular species of blueberries is Vaccinium boreale. These include Labrador, Quebec, and peaty barrens. They are present in the southern parts of Massachusetts and New York.
  • Vaccinium angustifolium is a popular species of blueberries. They usually include bogs, clearings and acidic barrens. They are present in the south of Nova Scotia in USA and are also found in Virginia.
  • Other popular species of blueberries include:
    • Vaccinium caesariense, which is also known as the New Jersey Blueberry.
    • Vaccinium constablaei, which is also known as hillside blueberry.
    • Vaccinium corymbosum; it is also known as northern highbush blueberry.
    • Vaccinium ellliottii. These are also known as Elliot Blueberry.
    • Vaccinium darrowii, which is also known as evergreen blueberry.
    • Vaccinium fuscatum. Another name given to this species is Black highbush blueberry.
    • Vaccinium formosum, which is also known as Southern blueberry.
    • Vaccinium myrsinites, also known as shiny blueberry.
    • Vaccinium hirsutum; they are also known as hairy-fruited blueberry.
    • Vaccinium myrtilloides. It is known by many other names such as Canadian blueberry, velvet leaf and sour top.
    • Vaccinium pallidum, which is also known as dryland blueberry.
    • Vaccinium operium. Cyan-fruited blueberry is another name given to this blueberry species.
    • Vaccinium tenellum, which is also known as southern blueberry.
    • Vaccinium tenellum. It is also known by another name, southern blueberry.
    • Vaccinium virgatum. The other name for this species is rabbiteye blueberry.
    • Some other species of blue fruit blueberries include vaccinium myrtillus, vaccinium koreanum and vaccinium uliginosum.

Identification of blueberries

The commercially prepared blueberries can be obtained from North-central, North and Eastern America. Some other species of this shrub are in the Pacific Northwest and Southern United States, Europe, Asia and South America. There are also some other species of this shrub which include whortleberries, huckleberries and bilberries. The name ‘blueberry’ is generally given to these species and they are sold as jam products.

The many different names used for blueberries in other languages, actually mean blueberries. These include Norwegian Blaeberry, Scots Blaeberry and French myrtilles. All of these words mean bilberry, which translates to blueberry. The Russian Onokoya is not another name for blueberries. However, they are similar in meaning to another species, bog bilberries. You can judge the difference between cyanococcus bilberries and other bilberries just by seeing the color and the cuts. The color of bilberries is generally partially or whole purple, whereas the flesh color of light blueberries are light green flesh.

Cultivation of blueberries

Blueberries can either be picked from wild bushes or can be cultivated in farms. The most commonly cultivated species of blueberries in the North America is V. corymbosum; these are known as northern bushes. On the other hand, the name of the hybrids of Vaccinium species southern highbush blueberries. The wild blueberries, also known as lowbush blueberries, are usually cultivated for their color. The lowbush blue berries are found in the Atlantic Provinces, present west to Quebec. West Virginia and Michigan are the places in the Southern regions, where it can be found. Natural blueberries barrens are produced by this species, in which large areas are covered by this species. The wild blueberries are a major part of investment in several First Nation communities in Ontario. The term ‘wild’ is generally is usually used to get more market for low bush blueberries. The bushes of blueberries are burnt after every two years and the pests are removed and managed.

Benefits of blueberries

Now there are two ways to view the benefits of blueberries. Firstly, we can talk about the benefits of blueberries specific to the substances contained in it. Next, we can also talk about the general health benefits of blueberries. Both these ways to describe the benefits of blueberries are mentioned in the next two sections.

Benefits of individual substances contained in blueberries

Let us first look at the benefits of blueberries with regards to the substances contained in it. The highest quantity and quality of antioxidants are present in blueberries in comparison to any other fruit. The level of antioxidants present in blueberries is equal to those present in vegetables, like kale and spinach. Some of the substances contained in blueberries, along with their benefits have been mentioned below:

1. Anthocyanins

Anthocyanins are actually the antioxidants present in blueberries; these give the blueberries their color. There are many benefits of this pigmented substance contained in blueberries. For example, the risks of certain kinds of cancers can be lowered due to this substance. The healthy aging and memory functioning are other two factors in which this color pigment substance is quite helpful. Recent research has also found that anthocyanins are quite beneficial for controlling obesity and the prevention of cardiovascular diseases (1).

2. Antioxidants

There are a large number of antioxidants present in blueberries. The main function of antioxidants is actually to neutralize the oxygen molecules and the free radicals. These antioxidants have the power to ward off diseases and have cleansing properties. Antioxidants are also quite helpful against the accumulation of pathogens and ultraviolent radiations (2).

3. Catechins

The defense system of the antioxidants is facilitated by catechins. One of the main benefits of catechins is that they prevent cancer. The catechins found in green teas and those in berries are quite similar to each other. The quantity of catechins in 100 g of red raspberries is 0.83 milligrams, and the Evergreen berries is 1.4 milligrams.

4. Ellagic acid

Ellagic acid is a phenolic compound, present in blueberries, which has antibacterial and antiviral properties. Research has proven that Ellagic acid plays an important role in the reversal of certain tumors and in the prevention of cancer.

5. Fiber

Fiber is a substance just like carbohydrates and is found only in plants. Different kinds of cancers can be prevented by fibers and it also helps in the maintenance of gastrointestinal tract. The heart attack risk and the blood pressure risk is also lowered due to fibers. There is a long list of the health benefits of fiber. Hypertension, stroke and obesity is also reduced by the intake of fiber (3).

6. Gallic acid

Gallic acid is mostly present in red wine and black tea. It is a potent antioxidant. Different studies have shown that gallic acid might be helpful in fighting the cancerous cells in the body. The rapid increase in the cell numbers is also prevented by gallic acid.

7. Oxygen Radiance Absorbance Capacity (ORAC)

The term used to measure the antioxidant activities of different antioxidants is ORAC. The time and length needed to stop the oxidizing action of an agent is measured by OPAC. The process of oxidation is stopped by antioxidants. This damages the tissues very much. The aging process can be slowed down by the intake of fruits and vegetables which have a high ORAC value. The antioxidants work best when they are in combined form. The health benefits of antioxidants are further increased by the presence of plant compounds and different fibers. This is probably the reason that a nutraceutical source is more beneficial as compared to a dietary supplement. An average of 800 units are obtained from one serving of vegetables or fruits. Experts suggest that approximately 5000 units of ORAC per day is needed in order to increase the tissue antioxidant activities and the serum activities. This is quite beneficial for the overall health of the body.

8. Phytochemicals

The flavor and scent to the blueberries is due to the phytochemicals present in them. Phytochemicals are naturally occurring substances in most plants. The amount of phytochemicals is high in different fruits and vegetables, like berries. A special type of phytochemical is present in blueberries and they have antioxidant and disease fighting properties. Research has shown that phytochemicals are quite beneficial against cancer and cardiovascular problems (4).

9. Quercetin

Quercetin is another substance present in blueberries, which is actually a flavonol. Many anti-carcinogenic properties are associated with quercetin. Quercetin is also quite beneficial against heart diseases and cancer.

10. Rutin

Rutin is a bioflavonoid. The vascular health is promoted by rutin. It is also helpful against cancer because it prevents the gathering of the cancerous cells in one place. There are also many anti-allergic and anti-inflammatory properties present in rutin.

11. Salicylic acid

Salicylic acid is usually found in Oregon caneberries. Salicylic acid has a protective effect against different heart diseases, such as aspirin, the commonly known salicylic acid product is Aspirin. Salicylic acid obtained from fruit and vegetable resources has many health benefits because it is quite beneficial as a medication. Only a small amount of raspberries are present in salicylic acid, like about 5 mg in 100 g of red raspberries. Research has shown that salicylic acid is quite beneficial against dandruff, warts, and sore feet and hands.

12. Vitamin C

Vitamin C is also present in blueberries. It functions as a powerful antioxidant.

General health benefits of blueberries

Now that you know about the health benefit of each substance present in blueberries, it is a good idea to know about the individual health benefits of blueberries. Some individual benefits of blue berries have been mentioned below:

1. Antioxidant support

Many antioxidant nutrients are present in blueberries. Therefore, blueberries are quite beneficial in the cardiovascular system, against oxidative stress. Research has shown that the benefits of blueberries aren’t just restricted to the cardiovascular system. Every system of the body is strengthened by the intake of blueberries and that includes cardiovascular system too. New and concrete research has supported the fact that the laxative effect of muscles vanishes due to the intake of blueberries. Due to the consumption of blueberries, the nervous system of the body can also be saved from stress. The risk of neurodegenerative diseases in younger and middle aged adults is significantly reduced due to the consumption of antioxidants. The digestive tract is also strengthened and the blood sugar is regulated due to the antioxidant properties of blueberries.

2. Cardiovascular properties

The blueberries have shown their effect in the cardiovascular system. Blueberries support the cardiovascular system in a variety of ways. For example, by the consumption of blueberries, the fats in the body are balanced, the HDL (good cholesterol) level is increased, and the levels of triglycerides is lowered. Different blood components in the body are also protected from oxygen damage. Protection is also provided in the blood vessel walls. Blood fats and the blood vessel structures are also improved, which leads to antioxidant properties in the blood too. The intake of blueberries goes up on every day level. Some studies have also shown that more benefits are obtained when blueberries are consumed in larger quantities.

Some research has been done recently with regards to the relationship between cardiovascular properties and blue berries. The enzyme, nitric oxide synthase (NOS) is involved in these studies. Inducible NOS has been the main point of focus of most studies. The risk of inflammation is increased when the inducible NOS or iNOS is in excess. Endogenous NOS is another type of NOS. The cardiovascular properties of the body are improved when the endogenous NOS or eNOS levels in the body are quite high. The eNOS is increased due to daily blueberry intake, according to recent research. A whole new world of health benefits of blueberries for the cardiovascular system have been opened through this research.

3. Mental health benefits

Another interesting area of research is the mental health benefits provided by blueberries. Recently, a study was done to know the effects of blueberries on mind. In the research, old aged people, with an average age of 75, were given blueberries for 12 straight weeks. The results of the study showed that the scores of respondents improved on intelligence tests. The researchers also said in the results that it isn’t only memory which is improved by the use of blueberries. The research said that the mental conditions are also controlled by the intake of blueberries.

4. Benefits of blueberries to the blood sugar levels

Balancing the sugar levels can be quite a challenging task for insulin resistance and type 2 diabetes patients. The blood sugar level of obese people also shoots to dangerous levels, in some cases. It is inevitable that the blood sugar levels of these people will shoot to abnormal levels if they don’t take appropriate measures. There are many researches regarding blueberries and the levels of blood sugar levels and these researches haven’t been disappointing. These researches suggest that blueberries are quite beneficial in people already diagnosed with high blood sugar levels. The glycemic index (GI) value of blueberries quite good in comparison to other fruits.

5.  Health of eyes

You might not know it but the fact of the matter is that the retina present in the eye is the most prone part to oxidative stress. Different foods containing phytonutrients are recommended by doctors to give protection to retina from oxygen damage. One such food are blueberries. There have been many researches regarding the benefits of blueberries for eye health. One interesting research was done on Israeli fighters (5). The research showed that the Israeli pilots who consumed blueberries had a better night vision.

Side effects of eating too many blueberries

Although blueberries are quite beneficial for health, they have a downside to them too. Eating too many blueberries can pose dangerous risks to the body like hypoglycemia, gastrointestinal distress, and increasing the bleeding risks. It’s more likely that a healthy person won’t be much affected by the intake of blueberries. However, an unhealthy person can be affected by the intake of blueberries, especially if he has a certain health condition. Some side effects of eating too many blueberries have been mentioned below:

1. Problems in gastrointestinal tract

You read in the previous section that blueberries are high in salicylic content. It is a good thing in ordinary people. However, the intake of blueberries can pose a problem in people who are sensitive salicylic acid. Constipation, vomiting, nausea, bloating and gas are just some symptoms faced by people who are sensitive to salicylic acid. People sensitive to salicylic acid should especially avoid blueberry juices because they contain high salicylate content in them. Remember, you will suffer these gastrointestinal problems only if you consume blueberries in excess quantities. Blueberries can be beneficial when consumed in moderate quantities.

2. Leading to hypoglycemia

Hypoglycemia is defined as a health condition in which the blood sugar levels in the body is quite low. The diabetic patients experience a drop in their blood sugar levels when they consume blueberries. The intake of blueberries is recommended for diabetic patients to get a drop in the blood sugar level. However, one should be careful because it can, sometimes, lead to hypoglycemia. Therefore, it is recommended to constantly measure your blood sugar level if you are diabetic and are taking blueberries on regular basis.

3. Risk of bleeding

About 29 micrograms of vitamin K is present in one serving of blueberries. Thus, you can classify blueberries as a vitamin K food. There are a number benefits of consuming vitamin K, like maintaining the density of bones and controlling the blood clotting system in the body. Vitamin K is generally recommended for people who have thin blood. These people should consume vitamin K to increase the blood density. However, it is best to consult a doctor before adding or subtracting vitamin K from your diet because it can make you more prone to bleeding.

Conclusion

This post provided you with some interesting information and facts about health benefits and side effects of blueberries. Benefits are described both in general as well as per substance. You also learnt various information about cultivation and species of blueberries. While it can be said that blueberries are beneficial for you, some side effects are associated with them so one should be careful and not to eat too much of them.

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Written by: Michal Vilímovský (EN)
Education: Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
Article resources: See numbered references within the article.
Image resources: Dollarphotoclub.com
Published: August 21, 2015 8:00 PM
Next scheduled update: August 21, 2017 8:00 PM
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