Moderate alcohol consumption could have a protective effect against diabetes mellitus and its complications such as diabetic retinopathy, caused by damage to the blood vessels of the tissue in the photosensitive part of the eye, the retina. This is what emerges from a study conducted by researchers from the Singapore Eye Research Institute and published in the British Journal of Ophthalmology. Diabetic retinopathy is today a growing disease in the world. It is estimated that it affects nearly 8 million Americans and that number could double by 2050. In Italy, it affects about 30% of patients with diabetes. It is estimated to cause about 1.9% of visual impairment and 2.6% of blindness.
Research
The study was conducted on 656 participants (a community of Singaporean Indians) with diabetes mellitus (of which 54% were men) with an average age of 59 and monitored over a six-year period. The incidence of diabetic retinopathy was assessed on the basis of medical questionnaires, while for alcohol consumption the participants were divided according to quantity and frequency (I drink alcohol: never, every day, once a week, twice, and so on).
The results
The researchers showed that compared to abstainers, there was a reduction in the incidence of diabetic retinopathy among regular alcohol users but also among those who consume moderate amounts. In fact, at the control, it was found that 16% of the participants developed diabetic retinopathy and 31% had had a worsening of the disease. Among those who consumed alcohol, the likelihood of developing diabetic retinopathy was 2/3 lower than those who did not drink. Even among study participants with infrequent alcohol consumption (less than twice a week) there was a reduction in the incidence of this disease while no link was found between alcohol consumption and progression of diabetic retinopathy.
The protective function of wine
Why this connection? There are several biological mechanisms through which alcohol can have a protective effect against diabetic retinopathy. Moderate alcohol intake, especially wine, is considered protective against cardiovascular diseases and since the latter are an important risk factor for the onset of ocular pathology, the benefit of moderate wine consumption could derive from reduction of cardiovascular risk.
Polyphenols and oxidative stress
Inflammation and oxidative stress are key factors in the development of diabetic retinopathy. Alcohol has a very high content of polyphenols essential to fight oxidative stress, but also to inhibit angiogenesis, prevent inflammation and promote vaso-relaxation, all elements that favor a greater blood flow to the retina. According to the researchers, these findings could provide the basis for encouraging physicians to also do counseling on foods and beverages that may play a protective role for patients with diabetes mellitus at risk for diabetic retinopathy.
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