The role of the eye care provider is to optimise eye health and ultimately maintain sight. But is there more we can do to provide support or even preventthe development and progression of eye disease?
In practice, we often see patients presenting with a clinical history of chronic disease, manifesting as a range of eye disorders. Alongside rising rates of obesity, diabetes, hypertension and metabolic disease, has been an increase in the prevalence of age-related eye diseases.1 There is growing evidence in support of the association between metabolic conditions and eye health,1,2 and as such, attention is being directed at changing their shared risk factors, including diet and nutrition.
Although the actual mechanisms between metabolic syndrome and eye disorders are not yet fully understood, some correlations have been identified. It is suggested that raised noradrenaline, in turn producing chronic inflammation and immunesystem dysfunction, is responsible for the correlation between metabolic syndrome and age-related macular degeneration (AMD)1. There are links between metabolic syndrome and glaucoma, with diabetes and hypertension positionedas responsible by increasing intraocular pressure.1 Population based studies have highlighted the association between metabolic syndrome and retinopathy, with evidence pointing to hyperglycaemia and hypertension as being key contributing factors.1 Insulin resistance and inflammation appear to be the mechanisms by which retinopathy can develop.1
there are circumstances where diet is suboptimal or there are other health issues preventing adequate absorption of nutrients in which supplementation may be more appropriate
All of this suggests that there are indeed modifiable risk factors with the potential to slow or even prevent these eye diseases from developing.1,2 Therefore, it should be argued that now is the time to actively think more about the important role nutritioncan play in the prevention of metabolic problems and eye disease, such as AMD, glaucoma and retinopathy. Moreover, it is imperative to be critical of the current medical model whereby clinical cut-off values exclude patients presenting with mild visual changes and/or impairment from receiving further treatment for suggestive glycaemic dysfunction. Signs of pre-diabetes and insulin resistance can be identifiedwell before medical conditions arise, which should be our focus in moving towards a preventative and targeted approach.
While some studies examining eye health and nutrition are inconclusive, there are some prominent studies including the Age-Related Eye Disease Study (AREDS)3Rotterdam,4 the Blue Mountains Eye Study5, and prospective analysis fromthe Nurse’s Health Study and the Health Professional Follow-up Study,6 which show the benefit of nutritional interventions.
The common recommendation between most of the available studies is the emphasis placed upon adequate dietary intake of fruit and vegetable, from which important micro-nutrients for eye health are derived. The eye is susceptible to oxidative damage (high metabolic rate and light- exposure) and therefore, antioxidants are particularly relevant for the oxidative stress- related eye diseases including cataracts, glaucoma, and AMD.
The purpose of this article is to provide a framework to eye care providers regarding some simple things that can be applied to patient care.
NUTRIENTS, EYE DISEASE AND DIETARY FOOD SOURCES
As previously described, there are multiple studies examining the benefit of dietary change with or without supplementation. While intuitively, changes in dietary food practices would provide the most benefit, there are circumstances where diet is suboptimal or there are other health issues preventing adequate absorption of nutrients in which supplementation may be more appropriate.
Table 1 provides a guide based on current evidence of nutrition and related eye health and disease. It cites the most commonly researched nutrients and their associated health benefits as well as their recommendations. It may be a useful adjunct when advising patientson supporting eye health.
When using the guide, it is important to remain mindful of a couple of points:
- While there have been numerous studies on the various nutrients and their effect in eye health, only a small sample show good evidence.
- Further, certain micro-nutrients work well with other micro-nutrients or require them as a co-factor, which allow nutrients to act synergistically. Therefore, a combination of nutrients is helpful. A diet that is varied and containing plenty of different types of fruit and vegetables, as well as the appropriate quantities of lean meats, nuts, legumes, dairy and fats is important. Additionally, the avoidance of frequent (more than daily) consumption of red meat is advised, as it has been linked to an increase risk of AMD.7
For all chronic disease, the earlier that treatment – including nutritional support – is initiated, the better. It may be that for some ocular disease processes early nutrition support translates to better long term outcomes. However, this should not deter encouraging patients from making healthy choices.For diabetic retinopathy, early glycaemic control is the best preventative measure and supplementation with antioxidants is a useful adjunct.
TO SUPPLEMENT OR NOT TO SUPPLEMENT?
Table 1 presents the possible micronutrients that can benefit eye health, including nutrient sources and effects. It highlights the benefits of nutrition support as adjunct therapy while treating eye disease, either as preventative or during treatment. However, It is important to use this table with caution as, although Table 1 shows the RDI and suggested therapeutic dosages, there is still much to learn in this regard.
IMPLICATIONS FOR THE FUTURE
Together with the findings of functional nutrients, and evidence of the integrated nature of metabolic and eye health, health professionals should seek to transform the current system of care. Health professionals caring for patients at metabolic risk should be working collaboratively, to provide screening, dietary and lifestyle support, and to comprehensively care for patients’ wellbeing. For those in need of ongoing disease management, such as patients with chronic eye disease and insulin resistance, diabetes or hypertension, a move towards a highly integrated, collaborative care approach is even more essential in ensuring positive outcomes for their health overall.Although not touched on throughout this article, the interaction between genes, environmental factors, diet and lifestyle, and importantly, the gut microbiome, are all likely to be key factors in supporting optimal health. With future research, clinical practice should come to reflect the growing evidence behind these factors to prevent poor metabolic and eye health.Dr. Stephanie Hyams BMedSc (Hons), MBBS (U.Syd Hons), FACAM, FRACGP is a general practitioner with a wide range of experience and interests spanning her 20 years of medical practice. She has a focus on preventative health and wellness and has a particular interest in metabolic disease prevention and aesthetic intervention related to chronic disease. Dr Hyams is currently affiliated with multi-disciplinary teams across Sydney, working along-side other specialists, includingophthalmologists and optometrists, to deliver comprehensive and integrated patient care.
Geraldine Georgeou is an experienced Accredited Practising Dietitian with over 20 years’ in the industry, from Prince of Wales Hospital, the Australian Navy and consulting to Diabetes Australia. She is a familiar face in the media. She runs two Sydney clinics: Designer Diets in Kogarah and Bondi Junction and the EllaWell Diabetes Prevention Management program, a multidisciplinary diabetes care team that tailors medical and dietary advice and support for people with metabolic health risk and diabetes.
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