Flavonoids and Vision: Can They Boost My Eye Health
Flavonoids – also called bioflavonoids – are a group of powerful antioxidants derived from plants. Scientists find them particularly interesting because it’s believed that their antioxidant properties can help to protect against harmful chemicals made in the body called free radicals. Antioxidants like flavinoids are also thought to be important for your vision, with the American Optometric Association suggesting that adding antioxidants to your diet can improve your eye health.i However, despite these claims, there is still conflicting information on the reliability of these powerful antioxidants.ii To provide some clarity, we’ve broken down research into flavinoids and their potential benefits on eye health.
What are the different types of flavonoid?
There are thousands of known varieties of flavonoids – they’re thought to be the largest group of plant chemicals. Flavonoids are also sometimes called vitamin P, but they aren’t technically vitamins because vitamins are essential compounds for human health, and as far as we know, not all flavonoids are essential. However, that does not mean that they aren’t extremely beneficial. They fall into different groups, including:
Since flavonoids are found in almost all fruits and vegetables, scientists believe that this might be some of the reason why a diet rich in fruit and veg is essential for good health. Several specific flavonoids have also been studied for their potential health benefits. Quercetin, for example, is a type of flavonol that has been much investigated for its role in reducing allergies; resveratrol has been examined for its ability to reduce the risk of heart disease; and hesperidin for its anti-inflammatory properties. For more information on this, see our guide to antioxidants and eye health.
Which flavonoids help to improve eye health?
Experts have conducted research into a number flavonoids thought to improve eye health. These range from nutrients in everyday food, to more obscure ones that you may need to consume through supplementation.
Anthocyanins and anthocyanidins
Anthocyanins and anthocyanidins are flavonoids responsible for the blue, purple and red pigments of many plants. Many believe they may support small blood vessel health by repairing damaged collagen in blood vessel walls and capillaries – including those in the eyes. In the past decade, however, a number of studies have been conducted into anthocyanins and anthocyanidins and their relationship to eye function. One particular piece of research suggests that anthocyanins may help prevent damage to the eye caused by diabetes, a condition called diabetic retinopathy.v More recently, one study found that anthocyanins in blueberries may inhibit the start and progression of AMD by way of their antioxidant capabilities.vi
Anthocyanins and anthocyanidins can be found in a range of blue, purple and red fruits, including blueberries, bilberries, grapes, currants and aubergine. However, if you find it difficult to consume the right amount through diet alone, it might be a good choice to consider supplementation. Our high-quality Colladeen® Original supplements contain a powerful amount of anthocyanidins to help support eye health.
Belonging to the flavonol group of flavonoids, quercetin is often used in nutritional supplements to help relieve the symptoms of allergies such as hay fever. But they may also play a part in protecting against the development of AMD. In one study, quercetin – along with a number of other flavonoids– was found to protect human retinal pigment epithelial (RPE) cells from damage, reducing the overall risk of developing AMD.vii However, more clinical trials on humans is required to confirm these results. If you’re looking to boost your quercetin intake, our high-quality Quercetin 500mg might be a good place to start.
While vitamin C isn’t a flavonoid as such, but most foods that contain vitamin C also contain flavonoids. in fact, the two are thought to work together in the body to support a range of conditions. Vitamin C is essential for forming and maintaining collagen, including the collagen found in the cornea, the transparent front part of the eye. It’s also important for keeping your blood vessels healthy, which also includes the blood vessels in your eyes. According to the American Optometric Association, studies suggest vitamin C may lower the risk of developing cataracts – one of the most common causes of vision loss – as well as an eye condition called age-related macular degeneration (AMD).i In one European study, researchers found those with the highest blood levels of vitamin C were 64 per cent less likely to develop cataracts than those eating fewer vitamin C-rich foods.iv Additionally, more recently researchers writing in the American Journal of Clinical Nutrition discovered people who regularly eat oranges – which are arguably the best-known source of vitamin C and flavonoids – are less likely to develop AMD in later life.iv According to the researchers, it was the flavonoids in oranges that appeared to provide the protective effect.
Ways to consume more flavonoids
Flavonoids are widely-available in a range of fruits and vegetables, including; apples, bananas, strawberries, tomatoes, peppers, chillies, kale, sweet potatoes, watermelons cocoa, and quinoa. There is currently no recommended daily intake for flavonoids, although experts recommend getting your flavonoids from as many different food sources as possible, rather than just a few of the same foods every day. This means you’ll be getting a wide range of the many different types of flavonoids in your diet.
Cooking and storing can reduce the level of flavonoids in food, however, so if you’re getting yours through your diet rather than in a supplement, try to eat flavonoid-rich foods raw whenever you can, and make sure they’re as fresh as possible. Once a fruit or vegetable begins losing its colour, it also starts to lose its flavonoid content. As a way of increasing the number of flavinoids you consume through diet, one really simple way would be to add a handful of fresh or dried mixed berries to your cereal in the morning. We’d recommend a sprinkling of dried cranberries, for a boost of vitamin C and anthocyanidins. Meanwhile, you can also top up your flavonoid levels by taking a supplement that contains specific eye-healthy ingredients – try one that contains vitamin C with flavonoids, anthocyanidins or quercetin.
No doubt there are promising results from the effects of flavonoids in improving eye health. For more information on a range of common eye conditions, as well as advice on how to improve your overall eye health, feel free to visit our Vision Health Hub.
American Optometric Association. Diet and Nutrition. (2018). Available online: https://www.aoa.org/patients-and-public/caring-for-your-vision/diet-and-nutrition
Milbury, P.E. Flavonoid intake and eye health. J Nutr Gerontol Geriatr. (2012). ;31(3):254-68. Available online: https://www.ncbi.nlm.nih.gov/pubmed/22888841
Valero, M.P., et al. Vitamin C Is Associated with Reduced Risk of Cataract in a Mediterranean Population. J Nutr. (2002 Jun) ;32(6):1299-306. Available online: https://www.ncbi.nlm.nih.gov/pubmed/12042450
Gopinath, B, et al. Dietary flavonoids and the prevalence and 15-y incidence of age-related macular degeneration. Am J Clin Nutr. (2018 Aug 1) ;108(2):381-387. Available online: https://www.ncbi.nlm.nih.gov/pubmed/?term=Dietary+flavonoids+and+the+prevalence+and+15-y+incidence+of+age-related+macular+degeneration
Scharrer, A., Ober, M. Anthocyanosides in the treatment of retinopathies. Klin Monatsbl Augenheilkd. (1981) ;1178:386-389. Available online: https://europepmc.org/abstract/med/7253530
Huang, W.Y., et al. Protective Effects of Blueberry Anthocyanins against H2O2-Induced Oxidative Injuries in Human Retinal Pigment Epithelial Cells. J Agric Food Chem. (2018 Feb 21) ;66(7):1638-1648.
Hanneken, A., et al. Flavonoids protect human retinal pigment epithelial cells from oxidative stress-induced death. Inv Ophthalmol Vis Sci. (2006) ;47:3164-77.