Blueberries are one of the most popular berries across the globe, which is good news because they are one of the highest ranking fruits in terms of antioxidants, which help to combat free radicals that damage cellular structures and DNA in our bodies. Consuming blueberries in their raw state is best, as this will help preserve the enzymes and beneficial compounds in the berries, giving you the biggest bang for your buck. To read more on how the antioxidants in blueberries can benefit you, please read on.
Blueberry Benefits: What Blueberry Antioxidants Mean For You!
1. Brain Strengthening
The antioxidants in blueberries help protect the nerve cells in your brain from oxygen damage and thus improve cognitive functioning. Studies have found that blueberry extracts are particularly effective in reversing age-related deficits in neuronal signalling (1) – rats fed the blueberry rich diet (but not the controls) were found to have several anthocyanin concentrations located in the cerebellum, cortex, hippocampus and striatum (areas of the brain). This suggests that antioxidants have the ability to cross the blood-brain barrier and can localize in brain regions important for learning and memory!
2. Eye Health
Blueberry anthocyanins help ensure our retinas are protected from unwanted oxygen damage and UV rays from the sun. In 2008, researchers at the University of Paris used blueberry antioxidants to test on a human retinal cell model that had been subject to oxidative stress (2). The retina is located in a highly oxygenated environment and thus is incredibly susceptible to oxidative damage. The blueberry extracts actually helped protect the human retinal cells from tBHP-induced cytotoxicity (which is just a fancy name for cells that are treated with a harsh chemical to induce cellular apoptosis – or in other words, cellular death). The extracts helped to increase cell viability, and decrease oxidative stress and mitochondrial apoptosis. After 24-hours the blueberry treatment, tBHP-induced cytotoxicity had been completely inhibited!
UV-B rays from the sun induce oxidative stress on the eyes (for extended periods of time that is – the sun is good for our bodies don’t forget!), so understanding the mechanisms of blueberry antioxidants and the effects they have on our retinas is important in helping prevent retinal damage – the natural way.
3. Muscle & Injury Repair
When we perform exercises that are extremely rough on our bodies, we risk the chance of injuring our muscles. The antioxidants in blueberries actually help repair our muscles after such strenuous exercise which helps reduce post-exercise injuries. Researchers at the Appalachian State University examined whether blueberries or vitamin C consumed for 7 days would limit the amount of oxidative stress and cytokine changes following extreme exercise. Although exercising is highly beneficial, intense or long duration aerobic exercise, as well as heat stress, have been found to greatly increase oxidative stress. Subjects exercised in the heat, in a controlled study. Blueberry polyphenols were most effective in reducing the amount of reactive oxygen species in the blood serum, with vitamin C having little to no effects (3).
In addition, strenuous exercise and its ability to generate oxidative stress (in individuals who ran for 2.5 hours), was found, in another study, to be greatly inhibited by consumption of blueberries for extended periods (250grams of blueberries, daily, for six weeks). Natural killer cell counts increased (this is a good thing – natural killer cells are critical to the innate immune system) as well as concentrations of anti-inflammatory cytokines with the diets rich in blueberries, compared to controls (not fed blueberries) (4).
4. Cancer Prevention
The antioxidants in blueberries also help reduce the chance of developing cancers such as breast, colon, esophageal and intestinal cancer. Flavonoid-rich fruits and diets that are in high consumption of these fruits have the ability to limit the development and severity of certain cancers and vascular diseases. Phytochemicals in berries (and other fruits), especially the blueberry (such as flavonoids like anthocyanins, flavonols, and proanthcyanidins), can decrease inflammation, counteract oxidative stress, and modulate interactions and expression of genes in the body associated with the disease process (5).
Among the variety of studies showing the effects of blueberry polyphenols and their ability to combat cancer, one particular study caught my eye. This study was conducted at the Center for Human Nutrition at the University of California. Researchers at this university found that blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts (all incredibly rich in antioxidants) inhibited the growth and stimulated apoptosis (cell death) of human cancer cells in vitro (6). Cancer cells normally proliferate at an incredibly fast rate (depending on the cancer type), however, these berry extracts were enough to increase the inhibition of cell proliferation of all cancer cell lines used (breast, oral, colon and prostate tumour cell lines)! Berry extracts also stimulated apoptosis of the cancer cell lines, meaning that the polyphenols in berries are strong enough to combat and kill cancer cells!
Sources:
(1) Andres-Lacueva, C., Shukitt-Hale, B., Galli, R., Jauregui, O., Lamuela-Raventos, R., & Joseph, J. (2005) Anthocyanins in aged blueberry-fed rats are found centrally and may enhance memory. Nutritional Neuroscience, 8, 111-120.
(2) Dutot, M., Rambaux, L., Warnet, J., & Rat, P. (2008) Oxidative stress modulation using polyphenol-rich blueberries: application on a human retinal cell model. Journal Francais, D’ophtalmologie, 31, 975-980.
(3) McAnulty, S., McAnulty, L., Nieman, D., Dumke, C., Morrow, J., Utter, A., Henson, D., Proulx, W., & George, G. (2003) Consumption of blueberry polyphenols reduces exercise-induced oxidative stress compared to vitamin C. Nutrition Research, 24, 209-221.
(4) McAnulty, L., Nieman, D., Dumke, C., Shooter, L., Henson, D., Utter, A., Milne, G., McAnulty, S. (2011) Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running. Applied Physiology, Nutrition, and Metabolism, 36, 976-984.
(5) Neto, C. (2007) Cranberry and blueberry: Evidence for protective effects against cancer and vascular diseases. Molecular Nutrition & Food Research, 51, 652-664.
(6) Seeram, N., Adams, L., Zhang, Y., Lee, R., Sand, D., Scheuller, H., & Heber, D. (2006) Blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts inhibit growth and stimulate apoptosis of human cancer cells in vitro. Journal of Agricultural and Food Chemistry, 54, 9329-9339.
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