Which of your five senses would you most regret losing? More than 70% of Americans say it’s their sense of sight. But did you know your vision is more than a quality of life issue—and that your eyes reveal a lot about your cardiovascular health?
That’s because some of the same conditions that promote heart disease also promote vision problems.
- Diabetes: Chronically high blood sugar damages the tiny blood vessels in the retina and can lead to vision-robbing diabetic retinopathy. Diabetes increases the risk of developing cataracts and glaucoma as well heart disease.
- Hypertension: High blood pressure also injures blood vessels in the retina and, over time, may cause hypertensive retinopathy and permanent damage to the eyes.
- Obesity: Obesity is linked with an increased risk of glaucoma, age-related macular degeneration, and cataracts. Excess weight is also a primary contributor to type 2 diabetes and hypertension, which further increases risk.
When an ophthalmologist examines your eyes, one of the things they’re looking at are the blood vessels in the back of your eyes, called the retina vasculature. Its shape and structure can signal heart disease, diabetes, and hypertension. In fact, these conditions are often picked up on routine eye exams, making your eyes a window on your overall health.
Unfortunately, Vision Loss Is on the Rise
The CDC reports that over 4.2 million people aged 40 and older are either legally blind or have impaired vision, even with corrective lenses. And that number is expected to more than double to nearly 9 million over the next 30 years.
Much of this increase is related to the aging of our population. Age-related macular degeneration is a leading cause of vision impairment, and cataracts and glaucoma are more common as we get older. Among younger adults, retinopathy is the #1 cause of blindness, and it too is on the rise as rates of diabetes and hypertension climb.
The good news is that vision loss can be prevented or delayed—not with drugs or high-tech procedures but with good old-fashioned nutrition. Better yet, that same nutritional support also benefits your heart and overall quality of life.
Vitamin A, Beta-Carotene & Eye Health
For generations, mothers have told their children that eating carrots will help them see better in the dark. Although this is a bit of exaggeration—carrots do not improve night vision—they are a good source of beta-carotene, a carotenoid in orange/yellow produce and leafy green vegetables.
Beta-carotene is converted in the body into vitamin A, which is essential for the development and proper functioning of the eyes. Vitamin A deficiency is the major cause of blindness in children in developing countries, affecting hundreds of thousands of kids under age five every year. Deficiency is blessedly rare in the developed world, but it does occur, and symptoms include dry eyes and night blindness.
Top food sources of vitamin A and beta-carotene include beef liver, sweet potatoes, pumpkin, butternut squash, spinach, kale, collards, and, of course, carrots. Vitamin A (much of it sourced as beta-carotene) is also included in multivitamin supplements. The recommended dose is 900 mcg RAE (retinol activity equivalents) per day.
Benefits of Lutein & Zeaxanthin
Although most Americans get enough vitamin A and beta-carotene from food and multivitamins, many fall short when it comes to other important carotenoids.
Lutein and zeaxanthin are carotenoids that accumulate in the retina, the light-sensitive tissue in the back of the eyes, and the macula, a small area in the retina responsible for central vision. Like internal sunglasses, they filter out blue light—high-energy wavelengths of light that can damage the macula and retina. Blue light is of particular concern today because it is not only part of the natural spectrum of sunlight but also emitted by fluorescent and LED lights, computer screens, smartphones, tablets, and TVs. So, protecting our eyes with lutein and zeaxanthin is more important now than ever.
The benefits of lutein and zeaxanthin for the eyes were revealed in the Age-Related Eye Disease Study 2 (AREDS2). This long-term, government-sponsored clinical trial found that supplements containing 10 mg of lutein and 2 mg of zeaxanthin plus other nutrients slowed the progression of macular degeneration by about 25%. These carotenoids have also been shown to reduce sensitivity to glare and eye fatigue and improve light/dark adaptation, which makes driving at night easier. Recent research reveals that lutein and zeaxanthin, which are also abundant in the brain, enhance cognitive function and brain health as well.
Concentrations of lutein and zeaxanthin can be determined by a noninvasive test that measures “macular pigment optical density” (MPOD). A high MPOD, indicative of a greater accumulation of lutein and zeaxanthin, means more robust protection. A dense MPOD can absorb as much as 90% of the blue light entering your eyes. Plus, it also supports brain function.
How can you raise your MPOD? By increasing your intake of lutein and zeaxanthin! The average daily intake of lutein and zeaxanthin combined is just 1–3 mg—and even lower in many older adults, who may need them the most. This is a drop in the bucket compared to the 12 mg used in the AREDS2 protocol and 25 mg or more in other studies. You can boost your levels by eating more leafy greens such as kale, spinach, turnip greens, and collards, but I also recommend supplements.
A few high-quality multivitamins contain lutein and zeaxanthin, but most multis do not, so you may need to add a vision supplement to your regimen. The recommended daily intake of lutein and zeaxanthin is 10 mg and 2 mg, respectively.
Other Essential Nutrients for Vision Support
Vitamins C & E are potent antioxidants that protect proteins, lipids, and other molecules against oxidative damage. Both vitamins are included in the AREDS2 protocol, underscoring their ability to slow age-related macular degeneration. They also guard against cataracts, which are caused by free radical damage to the lenses of the eyes. Vitamin C is particularly important, as studies reveal links between a higher intake of C and a lower risk of developing cataracts.
Good sources of vitamin E include nuts, seeds, and vegetable oils. Vitamin C is found in citrus, berries, red peppers, and other produce. All multivitamins contain C and E. Aim for a daily dose of 500 mg of vitamin C between foods and supplements combined and 130–180 mg of natural vitamin E.
Zinc, a mineral found in high concentrations in areas of the retina, is another component of the AREDS recommendations. Even on its own without the other nutrients, high-dose zinc has been shown to reduce the risk of developing advanced age-related macular degeneration.
Oysters contain far more zinc than any other food, but beef, turkey, and pork are more common sources. If you are vegetarian or have an intestinal problem that decreases absorption, make sure you get enough zinc from supplements. Although the AREDS studies used a very large dose of zinc (80 mg), I believe that 10–15 mg, which is the amount in many multivitamin and mineral supplements, is fine for most people.
CoQ10, which I highly recommend for heart health, also shows promise for retinal protection. Plus, adding astaxanthin to the mix may offer a significant upside for vision health.
Diet for Eye Health
As a cardiologist, I place a lot of emphasis on diet for the prevention and treatment of cardiovascular disorders. Adopting a healthy, nutrient-rich diet will not only reduce your risk of heart disease but also help prevent vision loss.
Add a good daily multivitamin plus lutein and zeaxanthin—which are hard to get in adequate amounts even with a good diet—and you’re well on your way to seeing clearly into the future.