Anthocyanins

Anthocyanins are a the largest group of water-soluble plant pigments (flavonoids). They are a group of dark blue pigmented antioxidants found especially in dark fruit such as blueberries and bilberries, aronia berries, dark blue grapes like Norton, Concord and Muscadine. There are also present in acai fruit, cranberries, black raspberry, cherries, and black currants. In vegetables they are found in the peel of eggplant and, in red cabbage, and in black rice. They are a type of flavonoid, odorless and barely astringent. In flowers they can vary from red to purple or blue depending on the pH of the soil in which the plant grows.

Bilberry is one of the best known anthocyanins. It is a small wild shrub growing in North America and northern Europe, traditionally used for diarrhea, urinary tract infections, and hemorrhoids. Over forty years of research establish this herb's value for vision health.^{1, 2, 3, 4} In addition to being powerful antioxidants, they support connective tissue, mitochondrial health,⁵ and reduce inflammation.⁶

Vision health Anthocyanins such as blueberry and bilberry extracts help counter oxidative stress in the retina⁷, help reduce inflammation in the tissues of the eye⁸, and also provide anti-allergic, anti-viral and microbial, anti-carcinogenic functions.³ They support blood circulation and the integrity of fine capillaries in the eye.⁹

Wet macular degeneration. Anthocyanidins inhibit growth of new extra blood vessels,¹⁰ which develop in the advanced version of macular degeneration and diabetic retinopathy.

Diabetic retinopathy. Researchers report that berry extracts and anthocyanins inhibit alpha-amylase and alpha-glucosidase in the gut, interacting with sugar transporters in the intestine, and ultimately slowing the rate of glucose entering the bloodstream. For this reason, they are important in helping to manage diabetes and diabetic retinopathy.¹¹

They are increasingly associated with non-vision conditions such as reducing chronic inflammation, hypertension and preventing atherosclerosis (antioxidants) [atherosclerosis (bilberry)].

Footnotes

1. Camire M.E. (2000). Herbs, Botanicals and Teas. Bilberries and blueberries as functional foods and nutraceuticals; pp. 289–319. Lancaster, PA: Technomic Publishing Company.
2. Chu, W.K., Cheung, S.C.M., Lau, R.A.W., Benzie, I.F.F. (2011). Chapter 4 Bilberry (Vaccinium myrtillus L.). Herbal Medicine: Biomecular and Clinical Aspects. 2nd ed. Boca Raton, FL: CRC Press/Taylor & Francis.
3. Kemper, K.J. (1965). Bilberry (Vaccinium myrtillus). Ann Ottalmol Clin Ocul,1965;91:371-86.
4. Upton, R, editor. (2001). Bilberry Fruit Vaccinium myrtillus L. Standards of Analysis, Quality Control, and Therapeutics. American Herbal Pharmacopoeia and Therapeutic Compendium. Santa Cruz, CA.
5. Yao, Y., Vieria, A. (2007). Protective activities of Vaccinium antioxidants with potential relevance to mitochondrial dysfunction and neurotoxicity. Neurotoxicology, Jan;28 93–100.
6. Park, S.J., Shin, W.H., Seo, J.W., Kim, E.J. (2007). Anthocyanins inhibit airway inflammation and hyperresponsiveness in a murine asthma model. Food Chem Toxicol, Aug;45(8):1459-67.
7. O.T.Mykkanen, et al, Bilberries potentially alleviate stress-related retinal gene expression induced by a high-fat diet in mice, Molecular Vision, September, 2012
8. S. Miyake, et al, Vision preservation during retinal inflammation by anthocyanin-rich bilberry extract: cellular and molecular mechanism, Laboratory Investigation, January, 2012
9. D. Ghosh, Anthocyanins and anthocyanin-rich extracts: role in diabetes and eye function, Asia Pacific Journal of Clinical Nurition, 2007.
10. Matsunaga, N., Tsuruma, D., Shimazawa, M., Yokota, S., Hara, H. (2010). Inhibitory actions of bilberry anthocyanidins on angiogenesis. Phytother Res, Jan;24 Suppl 1:S42-7.
11. Castro-Acosta, M.L., Lenihan-Geels, G.N., Corpe, C.P., Hall, W.L. (2016). Berries and anthocyanins: promising functional food ingredients with postprandial glycaemia-lowering effects. Proc Nutr Soc, Aug;75(3):342-55.
Also see the research discussed on the antioxidant/oxidative stress page and the inflammation page.