This week’s blog on The Importance of Nutrition to Your Eyes has been contributed by Dr Luisa Sastre, Specialist Ophthalmologist in Medical Retina
When faced with a diagnosis such as macular degeneration or diabetic retinopathy, many of my patients ask me: “Doctor, is there anything else, apart from the conventional treatments that I can do to stop the progression of my eye disease or to prevent it in my other eye?”
Almost every other day, I hear questions such as: “Doctor, I have heard that goji berries have a huge amount of zeaxanthin which can be very good for my macula; should I start eating them?”
Well, macular degeneration is the leading cause of blindness in men and women over the age of 60, in Europe and the US. And unfortunately (but not surprisingly) diabetic retinopathy is the leading cause of the loss of vision among the populations in the GCC countries. So, whatever we can add to the medical and surgical classical approaches to help reduce this problem will be more than welcome.
Although there is some confusion about the relationship between nutrition, lifestyle and eye care (and more high quality research is required), we do have some good evidence available to help guide us on our lifestyle choices.
The main risk factor for macular degeneration is aging (for good reason the full name of the disease is ´age-related macular degeneration´ – AMD). However, we know that a healthy diet could play a significant role in the development of the disease, especially in people who are genetically predisposed to it. There is evidence that certain nutrients protect our body from damaging substances called oxidants. These nutrients are called antioxidants. The antioxidant vitamins that play a role in the health of your retina are:
- Carotenoids (Lutein and Zeaxanthin) are a natural sunblock for the macula (the central area of the retina), absorbing the damaging blue wavelengths of light. They are pigments present in some yellow plants (zeaxanthin can be found in orange, sweetcorn and orange peppers while kale, red pepper, spinach or lettuce, are rich in lutein). These foods containing antioxidant vitamins need to be consumed in our diet, as the human body does not produce them naturally. They should be very lightly cooked because over-cooking them may destroy the pigments. Zeaxanthin is present in eggs and is thought to be more easily absorbed by the body thanks to the fat in the egg.
- Vitamins (C and E) – Many of the nutrients mentioned above are also rich in vitamins C and E. Vitamin C is a powerful antioxidant present not only in citrus fruits but also in strawberries and brussels sprouts which, along with grapefruit, are among the top sources of vitamin C. Vitamin E can be found in seeds, nuts, and wheat germ oil.
Other nutrients important for your macula are:
- Omega 3 fatty acids (DHA and EPA) – They have a powerful anti-inflammatory effect that will help your heart and brain stay healthy, as well as your retina. The recommendation is to eat at least two servings of cold-water fish per week. Salmon, sardines, and herring are top sources of omega-3s; halibut and tuna are also good sources.
- Minerals like zinc (which is present in oysters and meat – beef, turkey, veal, pork, lamb) and copper (found in organic meats, nuts and seeds, chocolate and shellfish) are essential for important biochemical functions in the body and could play a role in maintaining a healthy retina.
Several studies (AREDS1 and AREDS2 studies), suggest that certain nutritional supplements can slow down the progression of AMD by about 25%. Many ophthalmologists may recommend taking these supplements, if you are diagnosed with dry AMD with medium size or large drusen, or wet AMD. However, it is also widely agreed that if you eat a healthy diet including at least five portions of fruit and vegetables a day, you should not need a supplement.
I want to emphasise 3 important points:
Firstly, that no supplement is going to ‘cure’ macular degeneration. Supplements are just complementary to the main treatment, which in the case of wet AMD is the injection of certain medications into the eye.
Secondly, that supplements should not be used as a substitute for a healthy and varied diet.
Thirdly, taking antioxidant vitamin C, E or beta-carotene (vitamin A) supplements will not prevent the onset of AMD in people who do not have symptoms of the condition. There is no evidence for the benefit of other supplements, such as lutein and zeaxanthin.
Other measures to be considered in AMD are:
- Quit smoking: Smoking increases the production of damaging free radicals (oxidants) and people who smoke are up to four times more likely to develop AMD than those who don’t, regardless of genetic risk. By the way, if you are a smoker or you have recently quit, you should not take supplements with beta carotene (vitamin A), as this type of supplement is related to an increase in the incidence of lung cancer in smokers. None of the latest versions of supplements (based on the latest study AREDS 2) come with vitamin A.
- Wear sunglasses: Just as you need to protect your skin from UV exposure, you also need to protect your eyes. Excessive UV exposure can damage your cornea, your retina and can cause cataracts. Choose sunglasses with 100% protection against both UVA and UVB or glasses with 100% protection against UV 400. It is also important for children to get used to wearing sunglasses early in life, as it is the cumulative damage over a lifetime that puts you at risk of developing sight-threatening eye disease.
- Join a Support group: Support groups offer the opportunity to talk to other people suffering the same frustrations and concerns. They can help in finding solutions to your vision-related problems.
And lastly, when it comes to diabetic retinopathy, nutrition and lifestyle are simply one of the basic pillars of the treatment. Diet and exercise are mandatory in order to maintain good control of sugar levels and this will help prevent serious complications such as macular edema or retinal bleedings. Your endocrinologist or primary care doctor should definitely guide you in this journey.
Live a healthy life!
It is more important to promote health positively rather than to prevent disease.