The truth about eating eggs - MUST READ - BBC

 

The truth about eating eggs

22 MARCH 2021|FOOD & DRINK

Are eggs helpful to our health… or a cause of heart disease? Experts advise egg consumption should be part of a healthy lifestyle to be beneficial. But fears that eggs can be bad for us appear to have been laid to rest.

Based on the BBC Future article 'The truth about eating eggs' by Jessica Brown. (see article below)

Video by Howard Timberlake

https://www.bbc.com/reel/playlist/the-truth-about-food?vpid=p08ngz2x

The truth about eating eggs

Are eggs helpful to our health… or a cause of heart disease? BBC Future examines the evidence.

By Jessica Brown24th April 2020

A

As many countries urge populations to stay at home, many of us are paying more attention to our diets and how the food we eat can support our health. To help sort out the fact from the fiction, BBC Future is updating some of our most popular nutrition stories from our archive.

Our colleagues at BBC Good Food are focusing on practical solutions for ingredient swaps, nutritious storecupboard recipes and all aspects of cooking and eating during lockdown.

If there was such a thing as a perfect food, eggs would be a contender. They’re readily available, easy to cook, affordable and packed with protein.

“The egg is meant to be something that has all the right ingredients to grow an organism, so obviously it’s very nutrient dense,” says Christopher Blesso, associate professor of nutritional science at the University of Connecticut in the US.

Eating eggs alongside other food can help our bodies absorb more vitamins, too. For example, one study found that adding an egg to salad can increase how much vitamin E we get from the salad.

But for decades, eating eggs has also been controversial due to their high cholesterol content – which some studies have linked to an increased risk of heart disease. One egg yolk contains around 185 milligrams of cholesterol, which is more than half of the 300mg daily amount of cholesterol that the US dietary guidelines recommended until recently.  

Additionally, there have been scientifically unsupported claims the eggs can guard against coronavirus, or that they have even been responsible for its outbreak. There has even been one outlandish theory that spitting in an egg before cooking it creates antibodies which can guard against the disease. (There's no evidence to support this.)

Does that mean eggs, rather than being an ideal food, might actually be doing us harm?

You might also like:
• Can chicken soup cure the common cold?
• Are you eating enough salt?
• How much water should you drink a day?

Cholesterol, a yellowish fat produced in our liver and intestines, can be found in every one of our body’s cells. We normally think of it as “bad”. But cholesterol is a crucial building block in our cell membranes. It also is needed for the body to make vitamin D, and the hormones testosterone and oestrogen. 

We produce all the cholesterol we need on our own, but it’s also found in animal produce we consume, including beef, prawns and eggs, as well as cheese and butter.

Cholesterol is found in animal products like beef as well as eggs (Credit: Getty Images)

Cholesterol is transported around our body by lipoprotein molecules in the blood. Every person has a different combination of various types of lipoproteins, and our individual make-up plays a role in determining our risk of developing heart disease.

Low-density lipoprotein (LDL) cholesterol – referred to as “bad” cholesterol – is transported from the liver to arteries and body tissues. Researchers say that this can result in a build-up of cholesterol in the blood vessels and increase the risk of cardiovascular disease.

But researchers haven’t definitively linked consumption of cholesterol to an increased risk of cardiovascular disease. As a result, US dietary guidelines no longer have a cholesterol restriction; nor does the UK. Instead, emphasis is placed on limiting how much saturated fat we consume, which can increase the risk of developing cardiovascular disease. Foods containing trans fats, in particular, increase our LDL levels. Although some trans fats occur naturally in animal products, most are made artificially and are found in highest levels in margarines, snacks, and some deep-fried and baked foods, such as pastry, doughnuts and cake. (Read more about whether diets encouraging people to eat more saturated fat are good for you.)

Some deep-fried foods, which contain trans fats, can increase our LDL (or "bad") cholesterol levels (Credit: Getty Images)

Meanwhile, along with prawns, eggs are the only food high in cholesterol that are low in saturated fat. 

“While the cholesterol in eggs is much higher than in meat and other animal products, saturated fat increases blood cholesterol. This has been demonstrated by lots of studies for many years,” says Maria Luz Fernandez, professor of nutritional sciences at the University of Connecticut in the US, whose latest research found no relationship between eating eggs and an increased risk of cardiovascular disease.

The discussion on the health effects of eggs has shifted partly because our bodies can compensate for the cholesterol we consume.

“There are systems in place so that, for most people, dietary cholesterol isn’t a problem,” says Elizabeth Johnson, research associate professor of nutritional sciences at Tufts University in Boston, US.

In a 2015 review of 40 studies, Johnson and a team of researchers couldn’t find any conclusive evidence on the relationship between dietary cholesterol and heart disease.

“Humans have good regulation when consuming dietary cholesterol, and will make less cholesterol themselves,” she says.

And when it comes to eggs, cholesterol may pose even less of a health risk. Cholesterol is more harmful when oxidised in our arteries, but oxidisation doesn’t happen to the cholesterol in eggs, says Blesso.

“When cholesterol is oxidised, it may be more inflammatory, and there are all kinds of antioxidants in eggs that protect it from being oxidised,” he says.

Also, some cholesterol may actually be good for us. High-density lipoprotein (HDL) cholesterol travels to the liver, where it’s broken down and removed from the body. HDL is thought to have a protective effect against cardiovascular disease by preventing cholesterol from building up in the blood.

“People should be concerned about cholesterol that circulates in their blood, which is the one that leads to heart disease,” says Fernandez.

What matters is the ratio of HDL to LDL in our bodies, as elevated HDL counteracts the effects of LDL.

However, while most of us are able to buffer the cholesterol we consume with the cholesterol we synthesise in our livers, Blesso says around a third of us will experience an increase in blood cholesterol by 10% to 15% after consuming it.

Trials have found that lean and healthy people are more likely to see an increase in LDL after eating eggs. Those who are overweight, obese or diabetic will see a smaller increase in LDL and more HDL molecules, Blesso says. So, if you’re healthier to begin with, eggs potentially could have a more negative effect than if you’re overweight – but if you’re healthier, you’re also more likely to have good HDL levels, so an increase in LDL probably isn’t very harmful.

One study found that an additional half egg per day was linked to a higher risk of heart disease... (Credit: Getty Images)

Research published earlier this year, though, challenged the recent consensus that eggs pose no harm to our health. Researchers looked at data from 30,000 adults followed for an average of 17 years and found that each additional half an egg per day was significantly linked to a higher risk of heart disease and death. (They controlled for the subjects’ diet patterns, overall health and physical activity to try to isolate the effects of eggs.)

“We found that, for every additional 300mg cholesterol person consumed, regardless of the food it came from, they had a 17% increased risk of cardiovascular disease, and 18% increased risk of all-cause mortality,” says Norrina Allen, one of the study’s authors and associate professor of preventive medicine at Northwestern University in Illinois, US.

You might also like:

• How meal timings affect your waisteline
• Is breakfast the most important meal of the day?
• Why humans have evolved to drink milk

“We also found that each half egg per day led to a 6% increased risk of heart disease and 8% increased risk of mortality.”

Despite the study being one of the largest of its kind to address this specific relationship between eggs and heart disease, it was observational, giving no indication of cause and effect. It also relied upon a single set of self-reported data – participants were asked what they ate over the previous month or year, then followed up their health outcomes for up to 31 years. This means the researchers only got a single snapshot of what the participants were eating, even though our diets can change over time.

…but other studies have found that eggs are associated with a lower risk of heart disease (Credit: Getty Images)

And the study conflicts with past results. Numerous studies suggest eggs are good for heart health. One previous analysis of half a million adults in China, published in 2018, even found the exact opposite: egg consumption was associated with lower risk of heart disease. Those who ate eggs every day had an 18% lower risk of death from heart disease and 28% lower risk of stroke death compared to those who didn’t eat eggs.

Like the previous study, it too was observational – meaning it’s impossible to tease out cause and effect. (Do healthier adults in China simply eat more eggs, or do the eggs make them healthier?). That, of course, may be a big part of the confusion.

Good egg

While these studies have reignited the debate on the impact of cholesterol in eggs on our health, we do know some ways in which eggs could affect our risk of disease.

One way is through a compound in eggs called choline, which may help protect us against Alzheimer’s disease. It also protects the liver. (Find out if eggs are a good way of stopping a hangover.)

Choline, which is found in eggs, may protect us against Alzheimer’s disease (Credit: Getty Images)

But it may have negative effects, too. Choline is metabolised by gut microbiota into a molecule called TMO, which is then absorbed into people’s livers and converted to TMAO, a molecule associated with an increased risk of cardiovascular disease. Blasso has wondered if eating a lot of choline from eggs could lead to elevations of TMAO: he found studies where people were observed to have elevated TMAO levels up to 12 hours after eating eggs.

Research measuring egg consumption and TMAO has so far only found transient increases in TMAO. However, TMAO is measured as a marker for heart disease only at a baseline level, which can be detected when people are fasting. Blasso likens this to how our blood sugar levels increase temporarily after eating carbohydrates, but elevated blood sugar levels are only associated with diabetes when these levels are continuous.

This may be because when we eat eggs, we might only get choline’s beneficial effects, he says.

“The problem is when, instead of being absorbed into the blood, choline continues to the large intestine, where it can become TMA and then TMAO,” says Fernandez.

“But in eggs, choline is absorbed and doesn’t go to the large intestine, so it doesn’t increase the risk of heart disease.”

Meanwhile, scientists are beginning to understand other health benefits of eggs. Egg yolks are one of the best sources of lutein, a pigment that has been linked to better eyesight and lower risk of eye disease, for example.

Egg yolks are an excellent source of lutein, which has been linked to better eyesight (Credit: Getty Images)

“There are two types of lutein found the retina of the eye, where it can protect the retina from light damage by working as a blue light filter, as exposure to light makes the eye deteriorate,” says Johnson.

While researchers are a long way from understanding why eggs affect us differently, the vast majority of recent research suggests they pose no risk to our health, and are much more likely to provide health benefits.

Even so, having eggs for breakfast every day probably isn’t healthiest option, either – at least as it’s recommended we have a varied diet… rather than put all our eggs in one basket.

https://www.bbc.com/future/article/20190916-are-eggs-good-for-you

BBC: The truth about eating eggs

Are eggs helpful to our health… or a cause of heart disease? BBC Future examines the evidence.

• By Jessica Brown

17 September 2019

If there was such a thing as a perfect food, eggs would be a contender. They’re readily available, easy to cook, affordable and packed with protein.

“The egg is meant to be something that has all the right ingredients to grow an organism, so obviously it’s very nutrient dense,” says Christopher Blesso, associate professor of nutritional science at the University of Connecticut in the US.

Eating eggs alongside other food can help our bodies absorb more vitamins, too. For example, one study found that adding an egg to salad can increase how much vitamin E we get from the salad.

But for decades, eating eggs has also been controversial due to their high cholesterol content – which some studies have linked to an increased risk of heart disease. One egg yolk contains around 185 milligrams of cholesterol, which is more than half of the 300mg daily amount of cholesterol that the US dietary guidelines recommended until recently.  

Does that mean eggs, rather than an ideal food, might actually be doing us harm?

You might also like:
• Can chicken soup cure the common cold?
• Are you eating enough salt?
• How much water should you drink a day?

Cholesterol, a yellowish fat produced in our liver and intestines, can be found in every one of our body’s cells. We normally think of it as “bad”. But cholesterol is a crucial building block in our cell membranes. It also is needed for the body to make vitamin D, and the hormones testosterone and oestrogen. 

We produce all the cholesterol we need on our own, but it’s also found in animal produce we consume, including beef, prawns and eggs, as well as cheese and butter.

Cholesterol is found in animal products like beef as well as eggs (Credit: Getty Images)

Cholesterol is transported around our body by lipoprotein molecules in the blood. Every person has a different combination of various types of lipoproteins, and our individual make-up plays a role in determining our risk of developing heart disease.

Low-density lipoprotein (LDL) cholesterol – referred to as “bad” cholesterol – is transported from the liver to arteries and body tissues. Researchers say that this can result in a build-up of cholesterol in the blood vessels and increase the risk of cardiovascular disease.

But researchers haven’t definitively linked consumption of cholesterol to an increased risk of cardiovascular disease. As a result, US dietary guidelines no longer have a cholesterol restriction; nor does the UK. Instead, emphasis is placed on limiting how much saturated fat we consume, which can increase the risk of developing cardiovascular disease. Foods containing trans fats, in particular, increase our LDL levels. Although some trans fats occur naturally in animal products, most are made artificially and are found in highest levels in margarines, snacks, and some deep-fried and baked foods, such as pastry, doughnuts and cake.

Some deep-fried foods, which contain trans fats, can increase our LDL (or "bad") cholesterol levels (Credit: Getty Images)

Meanwhile, along with prawns, eggs are the only food high in cholesterol that are low in saturated fat. 

“While the cholesterol in eggs is much higher than in meat and other animal products, saturated fat increases blood cholesterol. This has been demonstrated by lots of studies for many years,” says Maria Luz Fernandez, professor of nutritional sciences at the University of Connecticut in the US, whose latest research found no relationship between eating eggs and an increased risk of cardiovascular disease.

The discussion on the health effects of eggs has shifted partly because our bodies can compensate for the cholesterol we consume.

“There are systems in place so that, for most people, dietary cholesterol isn’t a problem,” says Elizabeth Johnson, research associate professor of nutritional sciences at Tufts University in Boston, US.

In a 2015 review of 40 studies, Johnson and a team of researchers couldn’t find any conclusive evidence on the relationship between dietary cholesterol and heart disease.

“Humans have good regulation when consuming dietary cholesterol, and will make less cholesterol themselves,” she says.

Cholesterol is harmful when it is oxidised – but the antioxidants in eggs prevent that process from happening (Credit: Getty Images)

And when it comes to eggs, cholesterol may pose even less of a health risk. Cholesterol is more harmful when oxidised in our arteries, but oxidisation doesn’t happen to the cholesterol in eggs, says Blesso.

“When cholesterol is oxidised, it may be more inflammatory, and there are all kinds of antioxidants in eggs that protect it from being oxidised,” he says.

Also, some cholesterol may actually be good for us. High-density lipoprotein (HDL) cholesterol travels to the liver, where it’s broken down and removed from the body. HDL is thought to have a protective effect against cardiovascular disease by preventing cholesterol from building up in the blood.

“People should be concerned about cholesterol that circulates in their blood, which is the one that leads to heart disease,” says Fernandez.

What matters is the ratio of HDL to LDL in our bodies, as elevated HDL counteracts the effects of LDL.

However, while most of us are able to buffer the cholesterol we consume with the cholesterol we synthesise in our livers, Blesso says around a third of us will experience an increase in blood cholesterol by 10% to 15% after consuming it.

Trials have found that lean and healthy people are more likely to see an increase in LDL after eating eggs. Those who are overweight, obese or diabetic will see a smaller increase in LDL and more HDL molecules, Blesso says. So, if you’re healthier to begin with, eggs potentially could have a more negative effect than if you’re overweight – but if you’re healthier, you’re also more likely to have good HDL levels, so an increase in LDL probably isn’t very harmful.

One study found that an additional half egg per day was linked to a higher risk of heart disease... (Credit: Getty Images)

Research published earlier this year, though, challenged the recent consensus that eggs pose no harm to our health. Researchers looked at data from 30,000 adults followed for an average of 17 years and found that each additional half an egg per day was significantly linked to a higher risk of heart disease and death. (They controlled for the subjects’ diet patterns, overall health and physical activity to try to isolate the effects of eggs.)

“We found that, for every additional 300mg cholesterol person consumed, regardless of the food it came from, they had a 17% increased risk of cardiovascular disease, and 18% increased risk of all-cause mortality,” says Norrina Allen, one of the study’s authors and associate professor of preventive medicine at Northwestern University in Illinois, US.

“We also found that each half egg per day led to a 6% increased risk of heart disease and 8% increased risk of mortality.”

Despite the study being one of the largest of its kind to address this specific relationship between eggs and heart disease, it was observational, giving no indication of cause and effect. It also relied upon a single set of self-reported data – participants were asked what they ate over the previous month or year, then followed up their health outcomes for up to 31 years. This means the researchers only got a single snapshot of what the participants were eating, even though our diets can change over time.

…but other studies have found that eggs are associated with a lower risk of heart disease (Credit: Getty Images)

And the study conflicts with past results. Numerous studies suggest eggs are good for heart health. One previous analysis of half a million adults in China, published in 2018, even found the exact opposite: egg consumption was associated with lower risk of heart disease. Those who ate eggs every day had an 18% lower risk of death from heart disease and 28% lower risk of stroke death compared to those who didn’t eat eggs.

Like the previous study, it too was observational – meaning it’s impossible to tease out cause and effect. (Do healthier adults in China simply eat more eggs, or do the eggs make them healthier?). That, of course, may be a big part of the confusion.

Good egg

While these studies have reignited the debate on the impact of cholesterol in eggs on our health, we do know some ways in which eggs could affect our risk of disease.

One way is through a compound in eggs called choline, which may help protect us against Alzheimer’s disease. It also protects the liver.

Choline, which is found in eggs, may protect us against Alzheimer’s disease (Credit: Getty Images)

But it may have negative effects, too. Choline is metabolised by gut microbiota into a molecule called TMO, which is then absorbed into people’s livers and converted to TMAO, a molecule associated with an increased risk of cardiovascular disease. Blasso has wondered if eating a lot of choline from eggs could lead to elevations of TMAO: he found studies where people were observed to have elevated TMAO levels up to 12 hours after eating eggs.

Research measuring egg consumption and TMAO has so far only found transient increases in TMAO. However, TMAO is measured as a marker for heart disease only at a baseline level, which can be detected when people are fasting. Blasso likens this to how our blood sugar levels increase temporarily after eating carbohydrates, but elevated blood sugar levels are only associated with diabetes when these levels are continuous.

This may be because when we eat eggs, we might only get choline’s beneficial effects, he says.

“The problem is when, instead of being absorbed into the blood, choline continues to the large intestine, where it can become TMA and then TMAO,” says Fernandez.

“But in eggs, choline is absorbed and doesn’t go to the large intestine, so it doesn’t increase the risk of heart disease.”

Meanwhile, scientists are beginning to understand other health benefits of eggs. Egg yolks are one of the best sources of lutein, a pigment that has been linked to better eyesight and lower risk of eye disease, for example.

Egg yolks are an excellent source of lutein, which has been linked to better eyesight (Credit: Getty Images)

“There are two types of lutein found the retina of the eye, where it can protect the retina from light damage by working as a blue light filter, as exposure to light makes the eye deteriorate,” says Johnson.

While researchers are a long way from understanding why eggs affect us differently, the vast majority of recent research suggests they pose no risk to our health, and are much more likely to provide health benefits.

Even so, having eggs for breakfast every day probably isn’t healthiest option, either – at least as it’s recommended we have a varied diet… rather than put all our eggs in one basket.

http://www.bbc.com/future/story/20190916-are-eggs-good-for-you

Protect Eyes from Computer Blue Light

Our round-the-clock use of smartphones and computers exposes our eyes to an unnaturally high amount of blue light. Research shows that blue light is damaging to the retina and other parts of our eye.1

February 2017

By Ronnie Cortez

Exposure to ultraviolet solar rays accelerates age-related visual loss. Enlightened individuals wear UV protection sunglasses outdoors to minimize sunray-induced ocular damage.

A new vision-robbing culprit has emerged that is more prevalent than sunlight exposure. Our round-the-clock use of smartphones and computers exposes our eyes to an unnaturally high amount of blue light. Research shows that blue light is damaging to the retina and other parts of our eye.1

Chronic exposure to blue light is associated with increased risk of developing age-related macular degeneration,1-4 a leading cause of blindness in older adults.5

Supplementing with multivitamins and xanthophyll carotenoids that include lutein, zeaxanthin, and meso-zeaxanthin have demonstrated intriguing effects for preventing or mitigating macular degeneration.6

If you use a smartphone or a computer on a daily basis, it is important to ingest xanthophyll carotenoids to protect your eyes from the damaging risks of blue light.

THE CATASTROPHIC CONSEQUENCES OF CHRONIC BLUE LIGHT EXPOSURE

While most of us know the dangers of ultraviolet light and take steps to avoid it, blue light is in some ways a more insidious problem.

Blue-violet rays that emanate from our ubiquitous screens can penetrate into the retina, where they induce photochemical stress that directly damages retinal cells and indirectly leads them to self-destruct.1,2,4,29

Nature provided us with powerful protection against blue light, in the form of pigments in our retinas that absorb light in the blue wavelengths.

But while sunlight, to which we are directly exposed only during the day contains about 25% blue light, our screens, particularly those powered by light-emitting diodes, or LEDs, can contain about 35% of retina-threatening blue light.1 And LEDs, increasingly in use for interior lighting, produce still higher proportions of blue light the “cooler” the LED’s emissions are.1

A recent publication summed the situation up by saying that “…our exposure to blue light is everywhere and only increasing.”1 That’s why supplementation with carotenoid nutrients like lutein, zeaxanthin, and meso-zeaxanthin is so essential, even for those who spend little time in the sun.

Preventing Blue Light-Associated Eye Diseases

Evidence that supplementing with lutein and zeaxanthin provides retina-protecting effects has been accumulating for years, even since before the explosion of blue light exposure now facing modern populations. As that threat has grown, however, so has the importance of knowing how best to protect our eyes against retinal damage, and particularly age-related macular degeneration.

Our natural protection against damaging light of all wavelengths, primarily ultraviolet (UV) and blue, comes from a layer of pigmented cells called the retinal pigment epithelium.7,8 These pigmented cells are rich in lutein, zeaxanthin, and other carotenoids derived from our diet.7,8

Carotenoids have a unique molecular structure that enables them to soak up intense blue wavelengths, thus sparing the delicate rod and cone cells in our eyes that convert light energy into electrical impulses.7 Once those cells burn out, they are gone for good—retinal cells cannot normally regenerate.9,10

Ophthalmologists now recognize that the density of pigmented cells in the macula, or central portion of the retina, is closely associated with the degree of protection provided to retinal cells. This measure, called macular pigment optical density, is now considered a strong indicator of retinal health, and is therefore the main outcome measure in most studies of natural supplements with protective properties.

To date, studies reveal strong and consistent benefits of lutein, zeaxanthin, and meso-zeaxanthin on retinal health and resistance to development of age-related macular degeneration, as measured by improvements in macular pigment optical density. The strongest evidence, as is usually the case, comes from studies of early age-related macular degeneration, reinforcing the idea that early prevention is vastly superior to late attempts at cures.

Studies of early age-related macular degeneration have shown that lutein, zeaxanthin, and meso-zeaxanthin increase macular pigment optical density with continued supplementation (generally one or more years).11-14This increase in macular pigment optical density is presumed to account for most of the protective effect of these nutrients.

A growing body of evidence reveals that boosting one’s intake of omega-3s and carotenoids like lutein helps maintain healthy eyes.

In a 2013 study, patients with early/mild age-related macular degeneration were supplemented once- or twice-daily with lutein, zeaxanthin, low-dose omega-3s (100 mg DHA, 30 mg EPA), and antioxidant nutrients for one year. The result showed improved macular pigment optical density, while macular pigment optical density was reduced in unsupplemented placebo recipients.15

By 2016, sufficient data from many studies on this subject have been published to allow for a powerful meta-analysis, in which results from multiple small studies are analyzed as one large group. This study evaluated 20 clinical trials involving 938 patients with macular degeneration and 826 control subjects.16 It showed that supplementation with the xanthophyll carotenoids, including lutein, zeaxanthin, and meso-zeaxanthin, was consistently associated with significant increases in macular pigment optical density. This benefit was found in patients with macular degeneration and in currently healthy subjects. This meta-analysis showed that trials using meso-zeaxanthin produced the greatest increases in macular pigment optical density, suggesting that this nutrient is an important addition to lutein/zeaxanthin supplements for eye health.

WHAT YOU NEED TO KNOW

The Importance of Retinal Protection

• Energetic wavelengths of blue light are powerfully destructive of the eye’s most essential components, the vision receptors in the retina, which are most highly concentrated in the macula, or central portion.
• Human eyes contain adequate protection against natural levels of blue light, but that protection wanes with age, as the light-absorbing pigments lutein and zeaxanthin fade out of the retinal pigment layer.27
• Excessive blue light exposure is expected to cause increased rates of age-related macular degeneration as the baby-boom generation ages, the first in history to be bathed in such intense blue light.1
• Replacing the carotenoid pigments in the eye’s protective layer, however, is an effective means of quenching much of the photochemical damage done by blue light.
• Studies show that the progression of age-related macular degeneration can be effectively slowed with regular supplementation with lutein, zeaxanthin, and meso-zeaxanthin.28
• Retinal damage is irreversible, so early and powerful protection is our only hope, and supplementation with these carotenoid nutrients is a clinically-validated means of gaining that protection.

Improving Vision

When blue light strikes the
retina, a variety of
photochemical reactions
take place.

Improvements in macular pigment optical density provide protection against blue light damage. But is it possible lutein, zeaxanthin, and other carotenoids can also improve vision?

Vision can be measured in a number of ways. Visual acuity is derived from some version of the familiar Snellen eye chart (the chart of letters used by doctors to test your eyes), and indicates how well a subject sees objects at fixed distances.

Visual acuity has now been shown to be increased in at least one study of lutein, zeaxanthin, and omega-3 fatty acids, along with the expected increases in protective pigment density, in those with early age-related macular degeneration.15Indeed, a landmark 2015 meta-analysis of eight such studies reported improvements in visual acuity in response to lutein and zeaxanthin supplementation in people with age-related macular degeneration.17 This analysis also revealed a close association between supplement-induced increases in macular pigment optical density and visual performance.

Another, higher-tech approach to determining visual responses to supplementation is to use an electroretinogram. This device measures the minute electrical impulses produced by retinal cells in response to light.

A 2016 study demonstrated that, in addition to significant increases in macular pigment optical density with lutein supplementation, there was also a significant increase in how quickly retinal cells responded to light stimuli, as measured by the electroretinogram.18

All of the data point to one conclusion—that the combination of lutein, zeaxanthin, and, ideally, meso-zeaxanthin has real effectiveness at restoring the eye’s natural blue light shield, the macular pigment epithelium, which should protect against progression of age-related macular degeneration. Indeed, this large body of evidence has resulted in a change in ophthalmologists’ recommendations about eye-protective supplements.

While the supplement formula recommended by the original Age-Related Eye Disease Study (AREDS) included beta carotene as the only carotenoid, subsequent studies, including the more recent AREDS-2, found that replacing beta carotene with the combination of lutein and zeaxanthin produces superior risk reduction for developing the most serious forms of macular degeneration. That replacement alone produced an 18% reduction in the risk of developing late age-related macular degeneration, and a 22% reduction in risk of developing the blindness-inducing “wet,” or neovascular, macular degeneration.19

How the Carotenoids Protect Eyes Against Blue Light Damage

 

When blue light strikes the retina, a variety of photochemical reactions take place.20These include intense oxidative damage, as light photons energetically interact with oxygen-rich blood, producing reactive oxygen species. These caustic compounds then attack the vital fats that form nerve and light-receptor cell membranes, impairing their function.21,22

Worse, all of this chemical reactivity triggers inflammatory signals and changes in gene expression that perpetuate the retinal injury, which, in turn, triggers further oxidative stress in a vicious cycle.21

The carotenoids lutein and zeaxanthin are already well known for their ability to absorb energetic blue light radiation, and for preventing development, and promoting scavenging of, reactive oxygen species.23,24 Recent studies have found that these compounds also promote an anti-inflammatory environment in retinal cells.21,23

In fact, those studies show that retinal cells have an active mechanism for concentrating lutein and zeaxanthin within their cytoplasm, producing up to 14-fold higher concentrations within the cell than in the medium surrounding them.21

Other studies have shown that the anti-inflammatory effect of these nutrients extends beyond the local environment of the eye, producing what seem to be body-wide effects.25

In the specific context of age-related macular degeneration, these same carotenoids have been shown to prevent the development of overgrown blood vessels that produce the blindness-inducing “wet” form of macular degeneration. This again is a consequence of the ability of these vegetable-derived carotenoids to shield eye structures from blue light damage.23,26

Summary

 

Modern technology has increased the risk of retinal damage and macular degeneration with a host of electronic devices whose screens project blue light.

Scientists are just now beginning to recognize the threats posed by chronic blue light exposure at work, at home, and even during recreational activities throughout the day and night.

A clinically-validated means of mitigating this blue light-induced retinal damage is to supplement with carotenoid nutrients, particularly lutein, zeaxanthin, and meso-zeaxanthin.

As with so many nutrients, the multiple mechanisms by which carotenoids like lutein and zeaxanthin operate to protect tissue is a direct mirror of the multiple mechanisms that nature has created to protect our eyes. These nutrients provide protection from the moment a blue light photon enters the eye, shielding the irreplaceable light-sensing cells from photochemical damage. We now recognize that these compounds also act to slow the inflammatory reactions that aggravate light-induced damage, and they can prevent development of blood vessel overgrowth that produces “wet” macular degeneration, the leading cause of age-related blindness.

Those who spend a significant amount of time in front of a television, computer, tablet, or smartphone should ensure adequate intake of lutein, zeaxanthin and meso-zeaxanthin to reduce their risk of catastrophic vision loss.

Readers of this publication have been using lutein, zeaxanthin and meso-zeaxanthin supplements for many years to protect against solar eye damage. It’s comforting to know these same nutrients also afford protection against indoor blue light.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.

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