Have you ever wondered if there’s a natural way to lower your high blood pressure, guard against Alzheimer's, lose weight, and feel better? Well as it turns out there is. Michael Greger, M.D. FACLM, founder of NutritionFacts.org, and author of the instant New York Times bestseller “How Not to Die” celebrates evidence-based nutrition to add years to our life and life to our years.

Protecting Our Vision

Dietary remedies for keeping our eyes healthy. This episode features audio from:

Visit the video pages for all sources and doctor’s notes related to this podcast.


What’s the best way to protect one of our most important senses?

We start with the story of two very important plant pigments – that help guard against age-related macular degeneration. 

Anyone who’s ever got a sunburn knows how damaging the UV rays in sunlight can be. Imagine what those same rays are doing to the back of our eyeballs, our retinas. The eye is designed to take sunlight and focus it like a magnifying glass into the back of our eyes. Thankfully, we have a layer of cells in our eye, called the retinal pigment epithelium, that supports and protects our delicate retinal eyesight machinery. This layer builds up yellow plant pigments from our diet, like zeaxanthin, which absorbs blue light and protects the retina from the photo-oxidative damage.

The yellowing of the lenses in our eyes when we get cataracts may actually be our body’s defense mechanism to protect our retinas. In fact, when you go and surgically remove those cataracts, your risk of blindness from macular generation shoots up, since you removed that protection. Instead of trading one type of vision loss for another, instead of pigmenting the front of your eyes with cataracts, better to pigment the back of our eyes with diet. The pigment in the back of our eyes is entirely of dietary origin—thus suggesting that the most common cause of going blind in the Western world could be delayed, or even averted, with appropriate dietary modification.

Where in our diet do we get it? Well, the egg industry brags that eggs are a good source. But, have an egg nearly every day—six eggs a week—for three months and the pigmentation in our eyes barely moves. And, these were the high-lutein, free-range, certified organic eggs—not purchased at a supermarket, but a local farm.

Instead of getting the phytonutrients from the egg, that came from the chicken, that came from the corn and blades of grass she pecked on, what about getting it from the source? A cup of corn and a half-cup of spinach a day for three months: a dramatic boost in protective eye pigment.

What’s neat about this study is that they went back and measured the levels three months after the study stopped, and the levels were still way up here. So, once we build up our macular pigment with a healthy diet, our eyeballs really try to hold on to it. So, even if we go on vacation, and end up eating more iceberg lettuce than spinach, our eyes will hold on until we get back.

Yes, eggs can increase zeaxanthin levels in the blood, but they also raise bad cholesterol levels and risk of heart disease. “Therefore, an egg yolk-based dietary strategy to increase plasma zeaxanthin cannot be recommended, and an alternative, cholesterol-free, food source is desirable”—like goji berries, for example, which have up to 60 times more zeaxanthin than eggs. A modest dose markedly increases levels in our body: an inexpensive, effective, safe, whole food strategy to increase zeaxanthin in the bloodstream. But we don’t need it in our blood; we need it in our eyes.

So, how about a double-blind, randomized, placebo-controlled trial? To preserve eyesight in the elderly in traditional Chinese medicine, people are often prescribed 40 to 100 goji berries a day. But here, they just used about 15 berries a day for three months, but still found it could protect against loss of pigment and prevent the build-up of what’s called “soft drusen,” which is just debris that builds up in the back of the eye—both of which are associated with age-related macular degeneration, “the leading cause of legal blindness” in older men and women, affecting more than ten million Americans. Note they gave the berries with milk in this study; so, the butterfat could increase the absorption of these carotenoid pigments. A healthier way to get the same effect would just be to eat goji berries with nuts or seeds—in other words, goji trail mix.

In our next story – Kale and collard greens play a starring role in the prevention of glaucoma.

Glaucoma is the second leading cause of legal blindness in white women, but the #1 cause of blindness in African-American women. That’s one reason researchers chose a population of African-American women to study the effects of fruit and vegetable consumption on glaucoma risk. But, the other reason is because they were specifically interested in foods with the highest concentration of those eye-protecting phytonutrients like zeaxanthin—kale and collard greens. But, you’d be lucky if you could find one in ten white people eating even a single serving a month, whereas that was a no-brainer for African-Americans.

What’d they find? Well, as I’ve stressed over the years, all fruits and vegetables are not the same. Whether you hardly ever ate bananas or had one or more bananas every day didn’t seem to matter much. But, eating a couple oranges every week was associated with dramatically lower risk. Not orange juice, though. You can drink orange juice every day, and it didn’t seem to matter. A similar finding with peaches: fresh peaches seemed to work, but canned peaches didn’t.

Similarly, vegetables in general, as a catch-all term, didn’t seem to matter. For example, whether you ate a green salad twice a week, once a week, or zero times a week didn’t seem to matter when it came to reducing glaucoma risk. But, you know how pitiful most people’s salads are.

White people, take note, as you may need it even more. The lighter our eye color, the more greens we need to eat. Blue eyes let 100 times more light through; so, people with blue or gray eyes appear significantly more vulnerable to damage compared to brown or black, with green and hazel somewhere in the middle.

It’s interesting; carrots appeared to be less protective in black women compared to white women. They suggest it could be differences in food preparation methods. Perhaps the African-American subjects tended to eat carrots raw, limiting the absorption of certain nutrients, while they chopped and prepared their collard greens with oil, making the nutrients more bioavailable—because the absorption of carotenoid phytonutrients depends on the presence of fat, which is why I encourage people to eat nuts or seeds with their greens: a little tahini sauceor something.

Why not just take a zeaxanthin pill? Well, we don’t know what exactly it is in these wonderful foods that’s working their wonders; so, it may be better to just recommend folks eat them, rather than supplements. In fact, people that take calcium or iron supplements may be doubling, quadrupling, or septupling their odds of glaucoma. Better to just get most of our nutrients from produce, not pills. 

Finally, today – we look at the best dietary treatments…for eye strain.

What happens to our eyesight if we sit in front of a computer all day? In previous years, “the rapid spread of computers…in the home and workplace has led to an increase in ocular and visual problems, including eye discomfort, blurring of distant objects, eye strain, and…(visual fatigue),” so called “nearwork-induced transient myopia.” That’s when, after staring at a computer screen for a while, you look out the window, and things start out all blurry. That’s because our poor little ciliary muscles pulling at the lens in our eyes are locked in this constant state of contraction to keep that near focus. Over time, this can have long-term adverse consequences. Yes, we could waste 4 to 12 minutes an hour taking breaks staring out the window, but what if you’ve got nutrition videos to make?

The “Effects of Black Currant Intake on Video Display Terminal Work-induced Transient Refractive Alteration in Healthy Humans, a double-blind, placebo-controlled, crossover study” finding a significant improvement in refractive values and eyestrain symptoms compared to placebo. Note what passes for currants in the U.S. are actually champagne grape raisins, not actual black currants—which were banned in the U.S. a century ago, at the behest of the lumber industry, for fear they might spread a plant disease that affects white pine, which we hardly even harvest any more. They are, however, currant-ly making a comeback, though any anthocyanin-rich berry might have similar benefits. For example, there was a previous study done on bilberries. Why didn’t I report on it when it came out? Because I can’t read Japanese.

Why not just take bilberry powder capsules? Because, as we’ve seen over and over, when you test supplements, you’re lucky if they have any of what it says on the label. “Furthermore, even for products actually containing [bilberries] at all, labeling was often uninformative, misleading, or both”—something the herbal supplement market is infamous for. The largest study to date found that it appears that most herbal supplement labels lie.

It’s interesting; bilberries gained notoriety during World War II, when it was said that pilots in the British Royal Air force were “eating bilberry jam to improve their night vision.” Turns out this may have been a story concocted to fool the Germans. The real reason the Brits were able to, all of a sudden, target Nazi bombers in the middle of the night, before they even made it to the English Channel was likely not because of bilberries, but because of a top-secret new invention they needed to keep quiet, called radar.

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