Berries, a natural source of antioxidants
One of the main properties of berries is their potent anti-oxidant effect because they are a very rich source of plant chemicals (phytochemicals) that neutralize free radicals.
The compounds found in berries not only include Vitamin C but also phenolic compounds called polyphenols. There are over 8,000 different types of polyphenols ( falvonoids, phenolic acids, tannins, stilbenes and diferuloylmethanes). The key ingredient in berries are the flavonoids which encompass chemicals called "anthocyanins".
Anthocyanins (from the Greek words "anthos" (flower) and "kyanous" (dark blue") are the pigments that give berries their red, blue and purple tint.
All of these phytochemicals have anti-oxidant and anti-inflammatory properties.
But, what are anti-oxidant compounds? and, what do they do?
Free radicals, which are also known as "reactive oxygen species" (or ROS) are chemicals produced naturally by our body during its normal day-to-day metabolic processes.
External factors such as air pollutants, the UV radiation from the sun, smoking, alcohol, industrial chemicals and agrochemicals also trigger the production of free radicals.
Dangers of Free Radicals
Free Radicals are highly reactive chemical compounds and their main feature is that they are molecules with "unpaired electrons". Molecules seek stability and require "paired" electrons so these free radicals snatch an electron from another molecule to become stable. This process is known as "oxidation".
But oxidation causes damage to the second molecule, turning it into a new free radical. This begins a vicious circle of free radicals damaging otherwise stable molecules and converting them into free radicals or ROS.
The whole cycle provokes "oxidative stress" to the body, which reacts with different methods to neutralize free radicals and restore order, and also becomes inflammed.
The problem arises when these ROS are produced in quantites that overwhelm your body's natural antioxidant mechanisms.
ROS are capable of causing damage to our DNA and the proteins and fats in our cells walls and nucleus.
This damage disrupts the way cells work and is harmful for our health.
Free radicals are produced by external factors such as smoking, air pollutants, X-rays, UV radiation from sunlight and industrial chemicals and pesticides.
As their name indicates, they neutralize the activity and inhibit free radicals, blocking the the chain reaction of "oxidation". They do so by "trapping" the ROS or reacting with the chemicals that produce free radicals.
A balanced diet and a healthy lifestyle can minimize the presence of free radicals and enhance the activity of antioxidants.
Antioxidants include compounds such as vitamins (A, E and C) and also phytochemicals: flavonoids and polyphenols.
Inflammation caused by oxidative stress has a negative impact on human health:
If not strictly controlled with antioxidants, oxidative stress can induce several diseases, both chronic and degenerative, it also speeds up the body aging process.
Kidney disease, rheumatoid arthritis, cardiovascula disease and even neurological diseases (dementia, multiple scelrosis, Alzheimer's) and cancer have been linked to oxidative stress ( 1 ).
As we will see below, berries are an interesting "natural" source of antioxidants and can help boost your health and counteract the negative health effects of free radicals and oxidative stress.
Berries and their health benefits
What is a berry anyway?
Even a child knows what a berry is: a small sweet and fleshy fruit, with seeds, with a color that ranges from red to purple and blue, which can be easily picked off bushes or trees.
But common knowledge and scientific classification don't usually go hand in hand, and berries are a good example:
Botanical classification of Berries
A botanist will tell you that a berry is a fruit that develops from a flower that has one single ovary. It's seeds are surrounded by a fleshy pericarp, which consists of three distinct layers: an inner layer, or "endocarp", a middle layer, or "mesocarp" and an outer layer, the "exocarp".
To be a berry, it must have at least two seeds, that is why a cherry (with only one seed or pip) is not considered a berry by botanists, intsead it is a drupe.
Based on this classification, strawberries, raspberries and blackberries aren't berries either but a banana, an eggplant, the kiwi fruit, tomatoes and even citrus such as oranges and lemons are all berries.
In the case of bananas and oranges (as well as watermelons) the exocarp is tough and not edible.
Strawberries and raspberries don't make the berry cut because they come from flowers that have more than one ovary, and each ovary produces a small "druplet", each one with its seed. These druplets combine to form an aggregate fruit: like a strawberry or a black berry.
But, for the purpose of this article, and the scientific papers cited in it, berries are in fact what we all consider them to be: small juicy red - purple - dark blue fruits belonging to many different families of plants:
- Rosaceae: such as the black chokeberry (Aronia melanocarpa), strawberry (Fragaria ananassa), red raspberry (Rubus ideaus), black raspberry (Rubus occidentalis), blackberry (Rubus fruticosus), cherry (Prunus sp.) and cloudberry (Rubus chamaemorus).
- Ericaceae: which include the cranberry (Vaccinium macrocarpon), bilberry (Vaccinium myritillus), lowbush blueberry (Vaccinium angustifolium), highbush blueberry (Vaccinium corymbosum)
- Other families: blackcurrants (Ribes nigrum - family: Grossulariaceae), sea buckthorn (Elaaagnus rhamnoides - family: Elaeagnaceae) and grapes (Vitis - family: Vitaceae), mulberry (Morus sp. - family: Moraceae), maqui or Chilean wineberry (Aristotelia chilensis - family: Elaeocarpaceae).
Having clarified the classification of berries, let's look into their healthy properties:
A review of scientific studies regarding the health benefits of cherries ( 2 ) found that consuming them reduced oxidative stress, inflammation, exercise induced muscle soreness (exercise generates free radicals) and blood pressure. Cherries also improved sleep, arthritis and decreased "bad" cholesterol (LDL) and triglycerides in diabetic women and obese subjects. Furthermore some studies showed that cherry consumption was beneficial for diabetes, cognitive functions and mood.
However these benefits were reported in studies that used very large doses of cherries (equivalent to eating between 45 and 270 cherries per day).
The high content of anthocyanines makes blueberries great for promoting eye health according to a study by Huang et al., (2018) ( 3 ).
That study found that the antioxidant and anti-inflammatory properties of blueberries protected the retinal capillary endothelial cells from damage caused by high levels of glucose in patients suffering from diabetic retinopathy.
Blackberry feeding significantly increased fat oxidation and insulin sensitivity in overweight or obese men Solverson et al. (2018)
Source of Fiber and Vitamin C
Blueberries are also a good source of dietary fiber (roughtly 3.5% content). Also 4 ounces of blueberries provide, on average, 10 mg Vitamin C, equal to 1 ⁄ 3 of the daily recommended intake. ( 9 ).
This fiber plus Vitamin C effect is found in all berries:
Fiber and Vitamin C content per 100 g raw fruit
2.0 g fiber - 58.8 mg Vitamin C
5.3 g fiber - 21.0 mg Vitamin C
6.5 g fiber - 26.2 mg Vitamin C
3.6 g fiber - 14.0 mg Vitamin C
2.1 g fiber - 7.0 mg Vitamin C
1.7 g fiber - 36.4 mg Vitamin C
Source: National Nutrient Database for Standard Reference. Legacy Release, USDA
A study involving 27 overweight and obese men ( 4 ) revealed that eating 600 grams per day (1.3 pounds) of blackberries -equivalent to 1,500 mg ⁄ day of flavonoids- increased fat oxidation and insulin sensitivity.
Fat oxidation means that your body is using fat as fuel and "burning" it in the cells' powerhouses, the mitochondria. By burning fat, you shed weight.
Improving insulin sensitivity reduces the risk of developing type 2 diabetes.
Gopalan et al., (2012) ( 6 ) describe the properties of its anthocyanines (such as delphinidin-3-O-glucoside, delphinidin-3-O-rutinoside, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside), phenolic acids and flavonols.
They report that it has positive effects treating diabetes, high blood pressure and cardiovascular, eye, kidney and neurodegenerative diseases.
These berries contain alkaloids and flavonoids both of which act as antioxidants. The main compound found in mulberries are anthocyanines. They have anti-obesity, anti-cholesterol properties and also help protect the liver (Zhang et al., 2018) ( 5 ).
Cancer and Berries,: a protective effect
A a review by Kristo, Klimis-Zacasa and Sikalidis (2016) ( 7 ) on the protective effects of berries against cancer found the following:
The antioxidant properties of berries protect DNA from damage and also regulate the growth -or proliferation rates of malignant and premalignant cells (this is known as apoptosis).
By acting upon premalignant cells and causing them to regress they help prevent cancer initiation and even delay its progression into full blown cancer.
The exact mode of action is not yet clear, but some pathways by which antioxidants found in edible berries act upon cancer have been identified.
The authors conclude that: "Edible berries have been demonstrated to extend chemoprevention in cancer primarily of the Gastrointestinal tract as well as breast and to a lesser degree of liver, prostate, pancreas and lung."
Additionally, being a natural food, administrated as part of a balanced diet, it has no negative side effects.
Berry administration [is] a plausible and potentially useful dietary strategy to reduce risk of cancer and help cancer patients with disease prognosis Kristo et al. (2016)
Definitiely include berries in your daily diet
Incorporating natural antioxidants into your diet by adding a handfull of berries seems a very sensible choice.
They appear to have a significant effect on many diseases, especially those related to oxidative stress.
Their natural phenolic compounds plus Vitamin C and fiber makes them ideal as a part of your balanced daily diet.
A wide variety of berries whether fresh or frozen (frozen berries have the same content of polyphenols and vitamins as fresh ones - and are an ideal way to eat them off-season during the long winter months) ( 8 )
Measurement of the antioxidant activity of anthocyanin extracts from blueberries showed there was no significant difference between fresh, dried, and frozen blueberries. Lohachoompol (2004) (8)
They have no toxic side effects and they are a tasty and healthy option for desserts, breakfast or even part of your salads.
Cite this article:
A. Whittall. ©2019. The Health Benefits of Berries. Patagonia Wellness, 04 Jan. 2019. http://www.patagoniawellness.com/diet-food/berries-health-benefits.html
Subject: The health benefits of berries. rich in antioxidants and fiber, berries keep free radicals under control, combat inflammation and have a positive effect on several chronic disases, from cardiovascular, renal and retinal ailments to diabetes, obesity, neurological diseases and cancer.
References and Further Reading
(1) Pizzino G, Irrera N, Cucinotta M, et al. (2017). Oxidative Stress: Harms and Benefits for Human Health. Oxid Med Cell Longev. 2017;2017:8416763
(2) Kelley DS, Adkins Y, Laugero KD., (2018). A Review of the Health Benefits of Cherries. Nutrients. 10(3):368. Published 2018 Mar 17. doi:10.3390/nu10030368
(3) Huang W, Yan Z, Li D, Ma Y, Zhou J, Sui Z., (2018). Antioxidant and Anti-Inflammatory Effects of Blueberry Anthocyanins on High Glucose-Induced Human Retinal Capillary Endothelial Cells. Oxid Med Cell Longev. 2018;2018:1862462. Published 2018 Feb 22. doi:10.1155/2018/1862462
(4) Solverson PM, Rumpler WV, Leger JL, et al. (2018). Blackberry Feeding Increases Fat Oxidation and Improves Insulin Sensitivity in Overweight and Obese Males. Nutrients. 2018;10(8):1048. Published 2018 Aug 9. doi:10.3390/nu10081048
(5) Zhang H, Ma ZF, Luo X, Li X, (2018). Effects of Mulberry Fruit (Morus alba L.) Consumption on Health Outcomes: A Mini-Review. Antioxidants (Basel). 2018;7(5):69. Published 2018 May 21. doi:10.3390/antiox7050069
(6) Ashwin Gopalan et al., (2012). The health benefits of blackcurrants. Issue 8, 2012 Food & Function
(7) Kristo AS, Klimis-Zacas D, Sikalidis AK, (2016). Protective Role of Dietary Berries in Cancer. Antioxidants (Basel). 2016;5(4):37. Published 2016 Oct 19. doi:10.3390/antiox5040037
(8) Virachnee Lohachoompol, George Srzednicki, John Craske, (2004). The Change of Total Anthocyanins in Blueberries and Their Antioxidant Effect After Drying and Freezing. Journal of Biomedicine and Biotechnology, vol. 2004, no. 5, pp. 248-252
(9) Michalska A, Lysiak G, (2015). Bioactive Compounds of Blueberries: Post-Harvest Factors Influencing the Nutritional Value of Products. Int J Mol Sci. 2015;16(8):18642-63. Published 2015 Aug 10. doi:10.3390/ijms160818642