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Antioxidants may prevent AMD in people with high genetic risk

July 1, 2011

According to a new Dutch study, adequate dietary intakes of micronutrients with antioxidant properties can reduce the risk of early age-related macular degeneration (AMD) in those at high genetic risk.

In the case-control study, the dietary intake of micronutrients was assessed in 2167 individuals (aged over 55 years) at risk of AMD, using a food frequency questionnaire (1). In addition, genetic variants (polymorphisms) related to a high risk of developing AMD were determined. The study results showed that during the follow-up (median, 8.6 years) the 517 participants who developed early AMD were slightly older (mean age 68.1 years), had a higher frequency of high risk genotypes, and lower intakes of beta-carotene, lutein and zeaxanthin, omega-3 fatty acids (eicosapentaenoic and docosahexaenoic acid) and zinc.

The researchers concluded that higher dietary intake of antioxidants, zinc and omega-3 fatty acids can attenuate the incidence of early AMD in those carrying important genetic risk variants. To achieve this benefit, it would not appear necessary to consume excessive amounts of these nutrients; the recommended dietary allowance will suffice. Given that there are no other interventions that are readily available, or offer prevention at such low cost, the findings would stress the importance of sufficient intake of these nutrients in young susceptible individuals to postpone or prevent the devastating effects of AMD. Therefore, clinicians should provide dietary advice.

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries, accounting for 50% of blindness. Approximately 2.5 million elderly individuals are affected by late AMD in Europe and
21 million worldwide. The development of AMD is complex, with both genetic and environmental factors contributing. Inflammation and oxidative stress are known to be fundamental pathways. Two genetic variants have been identified to be linked significantly to a higher risk of AMD: together, these variants contribute to late AMD in more than 80% of cases. The only protective factors for AMD known to date are nutrients.

References

  1. Ho L. et al. Reducing the genetic risk of age-related macular degeneration with dietary antioxidants, zinc, and omega-3 fatty acids. Arch Ophthalmol. 2011; 129(6):758–766.