In 2019, 463 million people were diagnosed with diabetes worldwide. Diabetes is a metabolic disease characterized by chronic hyperglycemia resulting from problems in the secretion of insulin, in a poor action of insulin itself or both. Diabetes carries with it several consequences, including a complication called diabetic retinopathy. It is estimated that after 20 years of diabetes, almost all patients with type 1 diabetes and 60% of patients with type 2 diabetes will have this condition, which leads to damage to the blood vessels of the retina and consequent loss of vision. Scientists therefore wondered whether, through diet or supplements, it may be possible to prevent or mitigate diabetic retinopathy. Well, a key role seems to be played by flavonoids, powerful antioxidant substances, as emerges from a recent research published in the journal Nutrients by a team of Portuguese researchers (Matos et al, Nutrients, Sep 2020).
High levels of blood sugar induces oxidative stress and inflammation of the retina, already in the early stages of diabetes. These conditions cause the death of neurons in the retina and alterations in its blood vessels, which, over time, can close and cause edema in the central area of ??the retina, the macula, the proliferation of new blood vessels and eventually detachment of the retina. However, thanks to their antioxidant and anti-inflammatory action, flavonoids have been found to be beneficial in both the prevention and treatment of retinal damage caused by hyperglycemia. Flavonoids are substances that can be taken either through supplements or, even better, with the diet. There are several types of flavonoids, such as anthocyanins. Anthocyanins are contained in high quantities in berries and cherries. It has been observed that the anthocyanins of blueberries are able to prevent the damage caused by hyperglycemia on the endothelial cells of the capillaries of the retina. Not only that, it has also been shown that blueberries can delay or even prevent diabetic retinopathy. Other types of flavonoids are the catechins contained in cocoa, tea and grapes. The catechins counteract inflammation, which promotes the onset of retinopathy. Moreover, catechins counteract the formation of new blood vessels and reduce the formation of some substances, called advanced glycation end products, which have a direct role in the initial and progression of diabetic retinopathy. Then don’t forget also the flavanones of citrus fruits, such as orange, lemon and grapefruit with a protective vessel action, antioxidant on the retina, also useful in counteracting retinal inflammation. Soy isoflavones counteract the death of retinal cells, are antioxidant and can act by delaying retinopathy.
Therefore, enriching your diet with foods rich in flavonoids or, on the advice of your doctor, using supplements of these substances can help counteract some of the damage caused by hyperglycemia on the eyes. However, as pointed out by the authors of the study themselves, flavonoids should not be seen as magical substances capable of solving problems but should be included within a varied and balanced diet and a healthy lifestyle.
