A plethora of studies have shown anti-oxidants help slow progression of eye diseases such as macular degeneration, light sensitivity (we call it photophobia), with age related eye disease study (AREDS for short) being the most famous, so much so supplements use its name in marketing. Cold water or oily fish contain Omega-3 Fatty Acids, and foods rich in Vitamins A, C and lutein include spinach, kale, strawberries and tomatoes, but not all nutrients are created equally. Vitamin A is critical for basic function of the eye, but rarely do we struggle with patients getting enough of that anymore; optometrists usually spend time discussing how to get optimal sight from your eyes and how to prevent or slow diseases.
In recent years, you may have heard your eye doctor talking about nutrients that are helpful for eye health and beta-carotene, a type of vitamin A, is usually absent from that list. How did we come to think of carrots, which are rich in beta-carotene, as the food of choice for eye health when things like lutein, found in dark lefty greens, are much more helpful?
Brief history lesson on Vitamin A
To find out, we go back to England during World War 2. During the war, they developed radar technology and it allowed pilots to “see” where they were going and where enemies were. Through a propaganda campaign, the Ministry of Food attributed their success by declaring their pilots could see a lot better at night due to all the carrots they ate. With research about micronutrients just starting, the public was hungry for this type of information and fed into the campaign, perpetuating the myth to this day. (Vitamin A was the first vitamin discovered, they were all given names in order… confirm details)
Beta-carotene is helpful for the eyes in that it can be converted (albeit poorly) to a form of vitamin A that prevents night blindness, but without a deficient level of this vitamin, we benefit very little from this nutrient. It’s important but not the best choice. If you could have just food that is great for your sight, I’d choose spinach, bar none.
Lutein assists the retina
Besides not smoking, eating spinach (or Swiss chard) is the best thing you can do to keep the retina functioning at peak performance. Since we can’t make carotenoids ourselves, we need to get them in our diet, and spinach and kale are packed full of them. Lutein and zeaxanthin (types of carotenoids) are both present over the more light sensitive part of the retina, aka the macula, in abundance. These micronutrients act like sunglasses absorbing excess blue light reducing glare and supporting the retinal tissue from oxidative stress from the cascade of events that allow the photoceptors to process light into a brain signal. This tissue needs a lot to go right for you to see well and getting enough lutein is crucial.
In the last decade, optometrists have been able to monitor the level of these nutrients by evaluating the macular pigment density (MPOD score). With the vast majority of people in the US below optimal levels, we don’t have to measure this to know if you’re on the low end. If you’re having issues with glare, you likely need more of these carotenoids in your diet. The general daily recommendation is to get about 10mg of Lutein and about 2mg of Zeaxanthin.
Check your multi vitamin closely as both of these are routinely included but in very small amounts; 100ug (microgram) is only 0.1mg (milligram), or about 100 times less than the recommendation. A study tried to test the toxic dosage by giving people 100mg a day of Lutein, but there were no ill effects. I don’t recommend taking that amount regularly, but you can safely take supplements and still eat kale and spinach without worry.
Some common foods high in lutein can be found here. Generally cooked dark leafy greens are better than eaten raw (it’s made more bioavailable that way) and include collards, kale, mustard greens, beet and turnip greens, as well as powerhouses spinach and Swiss chard. Don’t like those, green pea, yellow squash and pumpkin can be good choices also; other veggies to consider include broccoli, Brussel sprouts and asparagus. Low on the list are carrots and pistachios.
Other beneficial micronutrients: Vitamin C & Omega 3
Vitamin C greatly benefits our eye health though supporting the lens; it contains the highest density of vitamin C (ascorbic acid) in the body and ensuring you get enough of it can slow down the formation of cataracts. Since cataracts or the gradual discoloration of the lens, occurs primarily for oxidative stress, this powerful anti-oxidant slows it down; it may not help much once cataracts are interfering with your vision, but those who take enough regularly have a delayed onset of cataract and delayed need for surgery. Sadly, if you live long enough, cataracts are one of those things that do eventually happen to everyone.
Lots of foods are high in vitamin C including spinach (20% of your daily value). Other foods rich in vitamin C include kiwifruit, snow peas, broccoli, tomatoes and strawberries; powerhouse choices include guava, oranges and red bell peppers. The daily recommendation for vitamin C is about 90mg daily but much more is safe.
Omega 3s and Omega 6s are beneficial for reducing inflammation in all parts of the eye from reducing dry eye symptoms to lower risk of macular degeneration. Seeds are rich in both of these but flax and chia seeds have much more Omega 3 than 6. Oily or cold water fish are also good choices for getting highly absorbable Omega 3s. Remember that DHA and EPA are easy for the body to absorb and put to use in our bodies, but ALA is hard to process into a usable form; because of this, I recommend sticking to fish (or algae) based sources as I don’t have to subtract the ALA from the total Omega 3 in the food.
The jury is out on the ideal ratio of DHA to EPA or even Omega 3 to 6, but I find that 2000mg of combined DHA and EPA work well for my patients who want to reduce their dry eye symptoms or keep their retina healthy. Find some other foods here.
Next best thing to micronutrients: exercise!
The next best thing you can do to keep your retinas in top shape is by taking care of your heart (and cardiovascular system). If your blood vessels aren’t able to keep oxygen rich blood flowing to the capillaries throughout your body, tissue won’t be able to function as well as it should and the retina just like many parts of the brain are greedy for what blood can supply and small imbalances over time can lead to devastating outcomes.
When optometrists view inside your eyes (usually after being dilated), we are looking at the retina for areas that might be compromised. One such detail we can see areas of capillary bed death. They look like pedals on a flower and typically are close to the macula. When capillaries die, they can’t get nutrients and oxygen to the retina it supports and this leads to small blind spots. If they are very small or a further from the macula, it’s easy to adapt to, but often times this occurs right below our detailed vision, leaving your vision significantly reduced. The rest of the tissue can be healthy and functional, but your vision will never be the same.
Small changes in nutrition really helps vision
If this advice sounds familiar, you’re right: eat brightly colored vegetables and fruit (like spinach), exercise to keep your blood vessels nimble, the opposite of smoking (which hardens vessels). The part we don’t always share with our patients how ever if that little changes matter. Think about the law of diminishing returns, the first action does more than the second, which does more than the third and so on.
For example someone who doesn’t get much lutein in their diet, your brain, skin and eyes are hungry for this nutrient and it will make marked improvements over someone who commits to eating leafy greens everyday when they were already eating them a few times a week; both are beneficial, but the first more so. Another example, for someone who doesn’t exercise much who starts walking 30 minutes per week, they reap significant cardiovascular benefits from where they were before. Don’t underestimate the value of even small adjustments to your diet or activity level on your over all health.
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Posted in May 2021 by Laura Nennig, OD; she specializes in contact lens fittings, with advanced training with scleral lenses and has a passion for ocular wellness.