Podcast: Protecting Our Vision

Summary

In this episode of the Nutrition Facts Podcast, Dr. Michael Greger explores how nutrition can protect and enhance eye health. He highlights the role of plant pigments like zeaxanthin and lutein in preventing age-related macular degeneration and glaucoma. Dr. Greger explains how certain foods, such as goji berries, kale, and collard greens, can help preserve vision, while cautioning against relying on eggs or supplements for eye protection. He also discusses how proper diet can reduce eye strain from screen use and improve overall visual health.

Takeaways

• 🌿 Dietary plant pigments, like zeaxanthin, protect against age-related macular degeneration.
• ☀️ UV rays from sunlight can damage the retina, but plant pigments help absorb blue light and reduce photo-oxidative damage.
• 🥚 Eggs, despite being a source of lutein, have minimal impact on increasing protective eye pigments compared to vegetables like corn and spinach.
• 🍇 Goji berries are an excellent cholesterol-free source of zeaxanthin, which helps maintain eye health and prevent macular degeneration.
• 👁️ Blue and green eyes are more vulnerable to light damage, making a diet rich in leafy greens particularly important for people with lighter eye colors.
• 🍑 Fresh fruits, especially oranges and peaches, have been linked to reduced glaucoma risk, while their processed forms, like juice or canned, don't offer the same benefits.
• 🥬 Kale and collard greens are potent in eye-protecting phytonutrients, reducing the risk of glaucoma, especially in African-American women.
• 🧠 Carrots may not protect against eye diseases equally across ethnicities due to differences in preparation and nutrient absorption.
• 🍒 Berries like black currants and bilberries have been shown to reduce eye strain from prolonged computer use.
• 📚 Supplements are often unreliable in content and quality, making whole foods a safer and more effective source of nutrients for eye health.

Q & A

What is the main focus of this podcast episode?

The podcast focuses on how dietary choices, particularly the consumption of specific plant pigments like zeaxanthin, can protect eyesight and reduce the risk of age-related macular degeneration (AMD) and other eye conditions.

How does sunlight affect the retina, and how does the body protect against this damage?

Sunlight, particularly UV rays, can damage the retina. The body protects against this by building up yellow plant pigments like zeaxanthin in the retinal pigment epithelium, which absorbs blue light and reduces photo-oxidative damage.

Why is macular pigment important, and how can diet help maintain it?

Macular pigment, derived entirely from diet, protects the eyes from damage that can lead to age-related macular degeneration. Increasing the intake of foods rich in lutein and zeaxanthin, such as spinach, corn, and goji berries, can help maintain this protective layer.

What foods are better sources of zeaxanthin compared to eggs?

While eggs are often touted as a source of zeaxanthin, they are less effective in boosting eye pigment compared to plant-based sources like spinach, corn, and goji berries, which have much higher concentrations of zeaxanthin.

Why are blue-eyed individuals at a higher risk for eye damage compared to brown-eyed individuals?

Blue eyes allow up to 100 times more light through compared to brown eyes, making individuals with lighter eye colors more vulnerable to retinal damage from sunlight. As a result, they may benefit from eating more greens like kale and spinach, which protect the eyes.

What role do goji berries play in protecting against age-related macular degeneration?

Goji berries, rich in zeaxanthin, can help protect the eyes by increasing pigment levels and reducing the buildup of soft drusen, a type of debris associated with age-related macular degeneration. Just 15 berries a day can have protective effects.

What connection exists between fruit and vegetable consumption and the risk of glaucoma?

Certain fruits and vegetables, particularly those rich in phytonutrients like kale and collard greens, have been shown to reduce the risk of glaucoma, particularly among African-American women. However, not all fruits and vegetables have the same protective effects.

Why might supplements like zeaxanthin pills or iron supplements not be recommended for eye health?

Whole foods are preferred over supplements because they contain a range of beneficial compounds, not just isolated nutrients. Additionally, supplements like calcium or iron pills may increase the risk of glaucoma, making a balanced diet a safer approach.

What is nearwork-induced transient myopia, and how can it affect eye health?

Nearwork-induced transient myopia occurs when staring at a screen for prolonged periods causes eye strain and temporary blurriness when looking at distant objects. Over time, this can lead to long-term damage, but certain foods, like black currants, may help alleviate eye strain symptoms.

What alternative sources of zeaxanthin are suggested in place of eggs?

In place of eggs, which also raise cholesterol levels, healthier sources like goji berries, kale, collard greens, and spinach are recommended for boosting zeaxanthin levels without the associated risks of heart disease.

Outlines

00:00

👁️ Protecting Your Eyes with Diet

This paragraph introduces the topic of protecting eyesight, specifically focusing on the importance of plant pigments like zeaxanthin in preventing age-related macular degeneration. Dr. Michael Greger explains how sunlight can damage our retinas and how dietary pigments, such as those found in spinach and corn, help protect against this damage. He highlights the limited effectiveness of eggs in increasing these pigments and suggests better alternatives like goji berries.

05:01

🍊 The Best Fruits and Vegetables for Eye Health

This section emphasizes the difference between various fruits and vegetables in reducing glaucoma risk. Dr. Greger points out that while bananas don't significantly affect eye health, oranges and fresh peaches do. Interestingly, the consumption of vegetables as a whole didn't seem to matter much, but specific leafy greens like kale and collard greens showed significant benefits, especially in African-American women, who tend to consume them more than white women.

10:05

🧑‍💻 Managing Eye Strain from Screens

This paragraph focuses on eye strain caused by prolonged screen time and explores how nutrition can alleviate the symptoms. Black currants, rich in anthocyanins, are highlighted for their ability to reduce eye strain, with a study showing significant improvement in refractive values. Dr. Greger cautions against relying on supplements, as their effectiveness is often questionable, and instead advocates for whole foods like currants or bilberries.

💡 Transforming Health Through Nutrition

In the final paragraph, Dr. Greger invites listeners to share their stories of improved health through evidence-based nutrition. He directs them to the NutritionFacts website for additional resources, including research, graphics, and videos. He also promotes his latest books, 'How Not to Diet' and 'How to Survive a Pandemic,' emphasizing that all profits go to charity. He underscores that NutritionFacts.org is a nonprofit organization dedicated to sharing free, science-backed nutrition information.

Keywords

💡Zeaxanthin

Zeaxanthin is a yellow plant pigment found in certain foods, which plays a crucial role in protecting the retina from photo-oxidative damage caused by sunlight. In the video, it is highlighted as essential for preventing age-related macular degeneration by absorbing harmful blue light. The video emphasizes that dietary intake of zeaxanthin, rather than from supplements or egg yolks, is the best way to protect our eyesight.

💡Macular Pigment

Macular pigment refers to the yellow pigments, like zeaxanthin and lutein, that accumulate in the macula, a part of the retina, and protect the eyes from light-induced damage. The video explains that a healthy diet can significantly boost this pigment, reducing the risk of blindness from conditions like age-related macular degeneration. It underscores how diet can preserve vision by maintaining pigment levels.

💡Age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness in older adults, caused by damage to the macula in the retina. The video discusses how dietary changes, particularly the intake of zeaxanthin-rich foods like spinach and goji berries, can help prevent or delay the onset of this condition, making it a key concern for those aiming to protect their eyesight as they age.

💡Goji berries

Goji berries are identified in the video as a potent source of zeaxanthin, with up to 60 times more than eggs, making them highly effective in boosting eye health. The video explains that consuming as few as 15 goji berries per day for three months can protect against pigment loss and prevent debris buildup in the eye associated with age-related macular degeneration.

💡Photo-oxidative damage

Photo-oxidative damage occurs when light, particularly blue light, causes oxidative stress and harm to the cells in the retina. The video explains that this damage can be mitigated by dietary pigments like zeaxanthin, which absorb blue light and act as a defense mechanism for the retina, preventing conditions like macular degeneration.

💡Retinal pigment epithelium

The retinal pigment epithelium is a layer of cells in the eye that protects the retina from damage and supports visual function. In the video, this layer is described as benefiting from pigments like zeaxanthin absorbed from the diet, which help defend the eye from harmful light exposure and oxidative stress, reducing the risk of vision impairment.

💡Soft drusen

Soft drusen are deposits of debris that accumulate in the retina and are associated with the development of age-related macular degeneration. The video discusses how dietary interventions, particularly the consumption of zeaxanthin-rich foods like goji berries, can prevent the buildup of soft drusen, thereby lowering the risk of vision loss.

💡Cholesterol-free dietary strategies

Cholesterol-free dietary strategies refer to avoiding foods like eggs, which may raise bad cholesterol levels while seeking alternative sources of nutrients like zeaxanthin. The video recommends goji berries as a cholesterol-free option to increase zeaxanthin levels, in contrast to egg yolk-based strategies, which come with cardiovascular risks.

💡Glaucoma

Glaucoma is the second leading cause of blindness globally and is particularly common in African American women. The video highlights how a diet rich in dark leafy greens like kale and collard greens, which are high in eye-protecting phytonutrients such as zeaxanthin, can lower the risk of developing glaucoma, demonstrating the link between diet and eye health.

💡Nearwork-induced transient myopia

Nearwork-induced transient myopia is a temporary blurring of distant objects caused by prolonged close-up work, such as staring at a computer screen. The video explains how this condition can be mitigated through dietary changes, like consuming anthocyanin-rich foods such as black currants, which have been shown to reduce eye strain and visual fatigue in clinical studies.

Highlights

Plant pigments such as zeaxanthin can help protect the retina from photo-oxidative damage and reduce the risk of age-related macular degeneration.

The yellowing of corneas due to cataracts may be a defense mechanism to protect the retina, but surgically removing cataracts can increase the risk of blindness.

A diet rich in yellow plant pigments can help build macular pigment, which protects against vision loss from macular degeneration.

Eggs are often marketed as a good source of lutein, but even high lutein, organic, free-range eggs do not significantly increase eye pigmentation.

Corn and spinach can dramatically boost protective eye pigment when consumed daily for three months, unlike eggs.

Goji berries contain 60 times more zeaxanthin than eggs and are an effective, cholesterol-free way to increase zeaxanthin levels in the body.

A daily intake of 15 goji berries for three months was shown to protect against pigment loss and prevent the buildup of soft drusen, a risk factor for macular degeneration.

A study involving African-American women found that kale and collard greens, rich in zeaxanthin, reduced the risk of glaucoma, especially in high-risk populations.

People with lighter eye colors like blue or gray need to consume more greens to protect their eyes, as they let in more light compared to darker eye colors.

Carrot consumption appeared to have a greater protective effect on glaucoma in white women compared to black women, potentially due to differences in food preparation methods.

Eating fruits like oranges and peaches, but not canned peaches or orange juice, was associated with a lower risk of glaucoma.

Black currants, and other anthocyanin-rich berries, were found to significantly reduce eye strain in people who spend long hours in front of computer screens.

Supplements like zeaxanthin pills may not be as effective as whole foods because of the complexity and reliability of nutrients in whole foods.

Calcium and iron supplements may increase the risk of glaucoma, highlighting the importance of obtaining nutrients from whole foods rather than pills.

Bilberries, once believed to improve night vision during WWII, may have gained their reputation from a false narrative aimed at concealing the invention of radar technology.

Transcripts

We all want to eat the kinds of foods

that make us feel better and live longer.

But there’s so much conflicting information out there,

so many nutrition opinions.

Welcome to the Nutrition Facts Podcast,

I’m your host, Dr. Michael Greger.

It’s my job to give you the information you need

to make the healthiest choices possible.

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 has ever got a sunburn knows

how damaging the UV rays in sunlight can be.

Imagine what those rays are doing

to the back of our eyeballs, our retinas?

The eye’s 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 zeaxantin,

which absorbs blue light and protects the retina from photo-oxidative damage.

The yellowing of our corneas when we get cataracts

may actually be our bodies’ defense mechanism to protect our retinas.

In fact when we go and surgically remove those cataracts,

our risk of blindness from macular degeneration shoots up

since we’ve removed that protection.

Instead of trading one type of vision loss for another,

instead of pigmenting the front of our eye with cataracts,

better to pigment the back of eyes with diet.

The pigment in the back of our eye 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 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 the supermarket, but from a local farm.

Instead of getting phytonutrients

from the egg that came from the chicken

that came from the corn and blades of grass you 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 also so neat about this study is that it went back

and measured the levels three months after the study stopped,

and the levels were still way up here.

So once we build our macular pigment up

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 out until we get back.

Yes, eyes can increase zeaxantin 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 zeaxantin cannot be recommended.

An alternative, you know, a cholesterol-free food source is desirable,

like goji berries for example, which have

up to 60 times more zeaxantin than eggs.

A modest dose markedly increases levels in our body.

An inexpensive, effective, safe, whole foods strategy

to increase the zeaxantin in our blood stream.

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 15 berries a day for three months.

But still found it could protect against loss of pigment

and prevent the buildup of what’s called soft drusen,

which is just debris that builds up in the back of our 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 10 million Americans.

Now note they gave the berries with milk in this study,

so the butterfat could increase the absorption of the carotenoid pigments.

A healthier way to get the same effect would be to just 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 1 in 10 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 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 a difference

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 sauce or something.

Why not just take a zeaxanthin pill?

Well, we don't know what exactly is in

these wonderful foods that's working their wonders

so it may be better to just recommend folks eat them,

rather than supplements.

And 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 lenses 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 eye strain 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 that they might spread a plant disease that affects white pine,

which we hardly even harvest any more.

They are, however, currant-ly [cough] are 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, 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 most herbal supplement labels lie.

And who wouldn't want to eat this, rather than this?

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 the 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.

We would love it if you could share with us your stories

about reinventing your health through evidence-based nutrition.

Go to nutritionfacts.org/testimonials.

We may share it on our social media to help inspire others.

To see any graphs, charts, graphics, images, or studies mentioned here,

go to the NutritionFacts Podcast landing page.

There you’ll find all the detailed information you need –

plus, links to all of the sources we cite for each of these topics.

My last two books are “How to Survive a Pandemic”

and my “How Not to Diet Cookbook”.

Get ready this year for the launch of How Not to Age.

And, of course, all the proceeds I receive from the sales

of all my books goes directly to charity.

NutritionFacts.org is a nonprofit, science-based public service,

where you can sign up for free daily updates

on the latest in nutrition research with bite-sized videos and articles

uploaded nearly every day.

Everything on the website is free.

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It’s strictly non-commercial. I’m not selling anything.

I just put it up as a public service, as a labor of love,

as a tribute to my grandmother,

whose own life was saved with evidence-based nutrition.