How to Treat Dry Eye Disease Naturally with Diet

Oct 31 Dry Eyes copy.jpeg

One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water? video. That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

  • increase complex carbohydrates;
  • increase vitamin A content (by eating red, orange, yellow, and dark green leafy vegetables);
  • increase zinc and folate intake (by eating whole grains, beans, and raw vegetables, especially spinach);
  • ensure sufficient vitamin B6 and potassium intake (by eating nuts, bananas, and beans);
  • ensure sufficient vitamin C intake (by eating citrus);
  • eliminate alcohol and caffeine;
  • reduce sugar and salt intake; and
  • consume six to eight glasses of water per day.

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.


Find more on the importance of proper hydration in my How Many Glasses of Water Should We Drink a Day?, Does a Drink Of Water Make Children Smarter?, and Can Dehydration Affect Our Mood? videos.

To learn more on other topics related to eye health, check out:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Original Link

How to Treat Dry Eye Disease Naturally with Diet

Oct 31 Dry Eyes copy.jpeg

One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water? video. That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

  • increase complex carbohydrates;
  • increase vitamin A content (by eating red, orange, yellow, and dark green leafy vegetables);
  • increase zinc and folate intake (by eating whole grains, beans, and raw vegetables, especially spinach);
  • ensure sufficient vitamin B6 and potassium intake (by eating nuts, bananas, and beans);
  • ensure sufficient vitamin C intake (by eating citrus);
  • eliminate alcohol and caffeine;
  • reduce sugar and salt intake; and
  • consume six to eight glasses of water per day.

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.


Find more on the importance of proper hydration in my How Many Glasses of Water Should We Drink a Day?, Does a Drink Of Water Make Children Smarter?, and Can Dehydration Affect Our Mood? videos.

To learn more on other topics related to eye health, check out:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Original Link

Plant versus Animal Iron

Plant versus Animal Iron.jpeg

It is commonly thought that those who eat plant-based diets may be more prone to iron deficiency, but it turns out that they're no more likely to suffer from iron deficiency anemia than anybody else. This may be because not only do those eating meat-free diets tend to get more fiber, magnesium, and vitamins like A, C, and E, but they also get more iron.

The iron found predominantly in plants is non-heme iron, which isn't absorbed as well as the heme iron found in blood and muscle, but this may be a good thing. As seen in my video, The Safety of Heme vs. Non-Heme Iron, avoidance of heme iron may be one of the key elements of plant-based protection against metabolic syndrome, and may also be beneficial in lowering the risk from other chronic diseases such as heart disease.

The data linking coronary heart disease and the intake of iron, in general, has been mixed. This inconsistency of evidence may be because of where the iron comes from. The majority of total dietary iron is non-heme iron, coming mostly from plants. So, total iron intake is associated with lower heart disease risk, but iron intake from meat is associated with significantly higher risk for heart disease. This is thought to be because iron can act as a pro-oxidant, contributing to the development of atherosclerosis by oxidizing cholesterol with free radicals. The risk has been quantified as a 27% increase in coronary heart disease risk for every 1 milligram of heme iron consumed daily.

The same has been found for stroke risk. The studies on iron intake and stroke have had conflicting results, but that may be because they had never separated out heme iron from non-heme iron... until now. Researchers found that the intake of meat (heme) iron, but not plant (non-heme) iron, was associated with an increased risk of stroke.

The researchers also found that higher intake of heme iron--but not total or plant (non-heme) iron--was significantly associated with greater risk for type 2 diabetes. There may be a 16% increase in risk for type 2 diabetes for every 1 milligram of heme iron consumed daily.

The same has also been found for cancer, with up to 12% increased risk for every milligram of daily heme iron exposure. In fact, we can actually tell how much meat someone is eating by looking at their tumors. To characterize the mechanisms underlying meat-related lung cancer development, researchers asked lung cancer patients how much meat they ate and examined the gene expression patterns in their tumors. They identified a signature pattern of heme-related gene expression. Although they looked specifically at lung cancer, they expect these meat-related gene expression changes may occur in other cancers as well.

We do need to get enough iron, but only about 3% of premenopausal white women have iron deficiency anemia these days. However, the rates are worse in African and Mexican Americans. Taking into account our leading killers--heart disease, cancer, and diabetes--the healthiest source of iron appears to be non-heme iron, found naturally in abundance in whole grains, beans, split peas, chickpeas, lentils, dark green leafy vegetables, dried fruits, nuts, and seeds.

But how much money can be made on beans, though? The processed food industry came up with a blood-based crisp bread, made out of rye flour and blood from cattle and pigs, which is one of the most concentrated sources of heme iron, about two-thirds more than blood from chickens. If blood-based crackers don't sound particularly appetizing, you can always snack on cow blood cookies. And there are always blood-filled biscuits, whose filling has been described as "a dark-colored, chocolate flavored paste with a very pleasant taste." (It's dark-colored because spray-dried pig blood can have a darkening effect on the food product's color.) The worry is not the color or taste, it's the heme iron, which, because of its potential cancer risk, is not considered safe to add to foods intended for the general population.

Previously, I've touched on the double-edged iron sword in Risk Associated With Iron Supplements and Phytates for the Prevention of Cancer. It may also help answer Why Was Heart Disease Rare in the Mediterranean?

Those eating plant-based diets get more of most nutrients since whole plant foods are so nutrient dense. See Nutrient-Dense Approach to Weight Management.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank

Original Link

Plant versus Animal Iron

Plant versus Animal Iron.jpeg

It is commonly thought that those who eat plant-based diets may be more prone to iron deficiency, but it turns out that they're no more likely to suffer from iron deficiency anemia than anybody else. This may be because not only do those eating meat-free diets tend to get more fiber, magnesium, and vitamins like A, C, and E, but they also get more iron.

The iron found predominantly in plants is non-heme iron, which isn't absorbed as well as the heme iron found in blood and muscle, but this may be a good thing. As seen in my video, The Safety of Heme vs. Non-Heme Iron, avoidance of heme iron may be one of the key elements of plant-based protection against metabolic syndrome, and may also be beneficial in lowering the risk from other chronic diseases such as heart disease.

The data linking coronary heart disease and the intake of iron, in general, has been mixed. This inconsistency of evidence may be because of where the iron comes from. The majority of total dietary iron is non-heme iron, coming mostly from plants. So, total iron intake is associated with lower heart disease risk, but iron intake from meat is associated with significantly higher risk for heart disease. This is thought to be because iron can act as a pro-oxidant, contributing to the development of atherosclerosis by oxidizing cholesterol with free radicals. The risk has been quantified as a 27% increase in coronary heart disease risk for every 1 milligram of heme iron consumed daily.

The same has been found for stroke risk. The studies on iron intake and stroke have had conflicting results, but that may be because they had never separated out heme iron from non-heme iron... until now. Researchers found that the intake of meat (heme) iron, but not plant (non-heme) iron, was associated with an increased risk of stroke.

The researchers also found that higher intake of heme iron--but not total or plant (non-heme) iron--was significantly associated with greater risk for type 2 diabetes. There may be a 16% increase in risk for type 2 diabetes for every 1 milligram of heme iron consumed daily.

The same has also been found for cancer, with up to 12% increased risk for every milligram of daily heme iron exposure. In fact, we can actually tell how much meat someone is eating by looking at their tumors. To characterize the mechanisms underlying meat-related lung cancer development, researchers asked lung cancer patients how much meat they ate and examined the gene expression patterns in their tumors. They identified a signature pattern of heme-related gene expression. Although they looked specifically at lung cancer, they expect these meat-related gene expression changes may occur in other cancers as well.

We do need to get enough iron, but only about 3% of premenopausal white women have iron deficiency anemia these days. However, the rates are worse in African and Mexican Americans. Taking into account our leading killers--heart disease, cancer, and diabetes--the healthiest source of iron appears to be non-heme iron, found naturally in abundance in whole grains, beans, split peas, chickpeas, lentils, dark green leafy vegetables, dried fruits, nuts, and seeds.

But how much money can be made on beans, though? The processed food industry came up with a blood-based crisp bread, made out of rye flour and blood from cattle and pigs, which is one of the most concentrated sources of heme iron, about two-thirds more than blood from chickens. If blood-based crackers don't sound particularly appetizing, you can always snack on cow blood cookies. And there are always blood-filled biscuits, whose filling has been described as "a dark-colored, chocolate flavored paste with a very pleasant taste." (It's dark-colored because spray-dried pig blood can have a darkening effect on the food product's color.) The worry is not the color or taste, it's the heme iron, which, because of its potential cancer risk, is not considered safe to add to foods intended for the general population.

Previously, I've touched on the double-edged iron sword in Risk Associated With Iron Supplements and Phytates for the Prevention of Cancer. It may also help answer Why Was Heart Disease Rare in the Mediterranean?

Those eating plant-based diets get more of most nutrients since whole plant foods are so nutrient dense. See Nutrient-Dense Approach to Weight Management.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sally Plank

Original Link

Children’s Supplements Found Contaminated With Pollutants

NF-May19 PCBs in Children's Fish Oil Supplements.jpeg

A number of case-control studies have found that giving kids cod liver oil supplements may increase their risk of asthma later in life. Case-control studies are done by asking about past behavior in cases (those with asthma) versus controls (those without asthma) to see if certain past behaviors are more likely among the disease group. The problem is that asking people to remember what they were doing years ago, when most people can't remember what they had for breakfast last week, is unreliable. When interpreting the results from case-control studies, we also can't rule out something called reverse causation. Maybe cod liver oil doesn't lead to asthma, but asthma led to the use of cod liver oil.

It would therefore be nice to see a cohort study. In a cohort study, researchers would take people without asthma and follow them over time to see if those taking cod liver oil are more likely to develop it. Because people without the disease and their diets are followed over time, cohort studies bypass the problems of recall bias and reverse causation.

In 2013, we finally got one such study. 17,000 people free of asthma were followed over 11 years. Researchers knew who was taking cod liver oil and who wasn't, and then sat back and watched to see who got asthma over the subsequent 11 years. The researchers found that cod liver oil intake was indeed significantly associated with the development of asthma. They thought it might be the excessive vitamin A in the cod liver oil that was causing the problem, but there are also a number of substances in fish oil we may not want our children exposed to.

Researchers from Philadelphia University, highlighted in my video PCBs in Children's Fish Oil Supplements, recently looked at 13 over-the-counter children's dietary supplements containing fish oil to assess potential exposure to PCBs, toxic industrial pollutants that have contaminated our oceans. PCBs were detected in all products. Could we just stick to the supplements made from small, short-lived fish like anchovies instead of big predator fish like tuna to reduce the impact of biomagnification? Or use purified fish oils? No, the researchers found no significant difference in PCB levels whether the supplements were labeled as molecularly distilled or how high up the food chain the fish were.

The researchers concluded that while children's dietary supplements containing the long-chain omega-3's from fish oils may claim to benefit young consumers, "daily ingestion of these products may provide a vector for contaminant exposure that may off-set the positive health effects." What positive health benefits are they talking about?

Researchers publishing in the journal, Early Human Development, found that infants given DHA-fortified formula may have better development of their eyes and brains compared to infants getting non DHA-fortified formula. What was the source of the DHA? Not fish, but algae-derived DHA. In that way we can get the benefits of omega 3's without the contaminant risks. But of course, breast milk is the gold standard, significantly better than either of the formula fed infants. So the best source of omega-3's is mom.

It's bad enough when supplement manufacturers exploit adults when they're sick and vulnerable with pills that are often useless or worse, but taking advantage of our parental drive to do what's best for our children with contaminated products that may make them sick, makes me sick.

More on supplements in:

And speaking of which, Is Fish Oil Just Snake Oil?

Also check out these videos on fish oil and DHA: Omega-3's and the Eskimo Fish Tale and Should We Take EPA and DHA Omega-3 For Our Heart?

What about omega 3's for our child's growing brain? See my video Mercury vs. Omega-3s for Brain Development

We can also be exposed to PCBs in food. See Food Sources of PCB Chemical Pollutants.

More on the polluted aquatic food chain in:

What can we do to lower the risk of childhood asthma and other allergic-type diseases? See:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Lars Plougmann / Flickr

Original Link

Is it Better to Bake, Boil, or Steam Sweet Potatoes?

NF-Nov19 best method for cooking sweet potatoes.jpg

I previously talked about the cancer fighting properties of sweet potatoes (See Anti-Cancer Potential of Sweet Potato Proteins) and what would happen if you centered your diet around them (The Okinawa Diet: Living to 100). It seems that the only potential downside to eating too many sweet potatoes is that you could get yellow palms (or nose as you can see in the video, The Best Way to Cook Sweet Potatoes), a harmless condition called "carotenemia." Caused by elevated levels of beta carotene in the blood, it was first noticed a century ago when carrots were introduce into infant diets. It's treated mostly by just reassuring parents that it's harmless, but if we don't want our child's nose to be yellow, we can decrease their beta carotene intake and in a few months it will be gone.

When picking out varieties at the supermarket, the intensity of the yellow or orange flesh color of the sweet potato is directly correlated to its nutritional content, so the more intense the better. Though if you really want intensity, sweet potato varieties don't just range from white to yellow and orange, but from pink to deep purple. The natural pigments that cause these colors may have special anticancer effects.

What is the best way to cook sweet potatoes? Boiling may actually retain most of the antioxidant power of sweet potatoes, compared to roasting and steaming. If we compare baking to boiling microscopically, boiling helps thin out the cell walls and gelatinize the starch, which may enhance the bioavailability of nutrients. At the same time, the glycemic index of boiled sweet potatoes was found to be about half that of baking or roasting, so boiled sweet potatoes give us less of a blood sugar spike.

Make sure to keep the skin on, though. The peel of a sweet potato has nearly ten times the antioxidant power as the flesh (an antioxidant capacity comparable to that of blueberries). However, the peel's nutrition really takes a hit when baked, which wipes out over two thirds of the antioxidants, whereas microwaving or boiling are comparatively much gentler. The same is true for the rest of the sweet potato. Baking can also cause an 80% drop in vitamin A levels, twice as much as boiling. Therefore, from a nutritional standpoint, boiling rather than baking should be recommended for cooking sweet potato.

Boiling may theoretically be best, but sweet potatoes are so incredibly healthy that the actual best way to prepare them is whichever way will get you to eat the most of them! The exception is deep frying, which can lead to the formation of acrylamide, a potential human carcinogen.

What about cooking methods for other vegetables? See my video Best Cooking Method.

Want more information about acrylamide, the potential crispy carb carcinogen? See my video Cancer Risk from French Fries. And for why deep frying in general might not be good, Deep Frying Toxins and Carcinogens in the Smell of Frying Bacon.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Avital Pinnick / Flickr

Original Link

The Healthiest Diet for Weight Control

NF-Sep4 Why Plant-Based Might be the Healthiest Diet for Weight Control.jpg

We know that vegetarians tend to be slimmer, but there's a perception that veg diets may somehow be deficient in nutrients. So how's this for a simple study, profiled in my video Nutrient-Dense Approach to Weight Management: an analysis of the diets of 13,000 people, comparing the nutrient intake of those eating meat to those eating meat-free.

They found that those eating vegetarian were getting higher intakes of nearly every nutrient: more fiber, more vitamin A, more vitamin C, more vitamin E, more of the B vitamins (thiamin, riboflavin, & folate), more calcium, more magnesium, more iron, and more potassium. At the same time, they were also eating less of the harmful stuff like saturated fat and cholesterol. And yes, they got enough protein.

And some of those nutrients are the ones Americans really struggle to get enough of--like fiber, vitamins A, C, and E, calcium, magnesium, potassium--and those eating vegetarian got more of all of them. Even so, just because they did better than the standard American diet isn't saying much--they still didn't get as much as they should have. Those eating vegetarian ate significantly more dark green leafy vegetables, but that comes out to just two more teaspoons of greens than meat eaters on average every day.

In terms of weight management, the vegetarians were consuming, on average, 363 fewer calories every day. That's what people do when they go on a diet and restrict their food intake--but it seemed like that is how vegetarians just ate normally.

How sustainable are more plant-based diets long term? They are among the only type of diet that has been shown to be sustainable long-term, perhaps because not only do people lose weight but they often feel so much better.

And there's no calorie counting or portion control. In fact, vegetarians may burn more calories in their sleep. Those eating more plant-based diets appear to have an 11% higher resting metabolic rate. Both vegetarians and vegans seem to have a naturally revved up metabolism compared to those eating meat.

Having said that, the vegetarians in the first study mentioned were also eating eggs and dairy, so while they were significantly slimmer than those eating meat, they were still, on average, overweight. As profiled in my video, Thousands of Vegans Studied, the only dietary pattern associated on average with an ideal body weight was a strictly plant-based one. But at least the study helps to dispel the myth that meat-free diets are somehow nutrient-deficient. In fact, the editor-in-chief of the Journal of the American Dietetic Association asked, "What could be more nutrient dense than a vegetarian diet?"

Anyone can lose weight in the short term on nearly any diet, but diets don't seem to work in the long-term. That's because we don't need a "diet"; we need a new way of eating that we can comfortably stick with throughout our lives. If that's the case, then we better choose to eat in a way that will most healthfully sustain us. That's why a plant-based diet may offer the best of both worlds. It's the only diet, for example, shown to reverse heart disease-our number one killer-in the majority of patients, as described in my video: One in a Thousand: Ending the Heart Disease Epidemic.

There are a number of theories offered as to why those eating plant-based are, on average, so much slimmer. Check out these videos for more information:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Original Link