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

Can Dehydration Affect Our Mood?

Sept 7 Dehydration copy.jpeg

Water is by far the number-one nutrient in our diet. Studies have suggested that proper hydration may lower our risk of heart disease and cancer, and may even make us better kissers. Brushing artificial skin against the lips of young women, researchers found that hydrated lips showed greater sensitivity to light touch.

Although it is well known that water is essential for human survival, it's only recently that we have begun to understand its role in the maintenance of brain function. It makes sense. Our brain is 75% water. When we get dehydrated, our brain actually shrinks. Even mild dehydration, which can be caused by simply exercising on a hot day, has been shown to change brain function.

I've talked about the role of hydration for cognitive function in Does a Drink of Water Make Children Smarter?, but current findings suggest that our mood states may also be positively influenced by water consumption.

The effects of dehydration in real life have not been not well documented. It wasn't until 2013 that the first study to investigate the effects of mild dehydration on a variety of feelings was published. What did the researchers find? The most important effects of fluid deprivation were increased sleepiness and fatigue, lower levels of vigor and alertness, and increased confusion. But as soon as they gave the subjects some water, the deleterious effects on alertness, happiness, and confusion were immediately reversed.

Water absorption actually happens very rapidly, within 5 minutes from mouth to bloodstream, peaking around minute 20. Interestingly, the temperature of the water appears to affect this speed. Which do you think is absorbed more rapidly--cold water or warm, body temperature water? It turns out cold water gets sucked in about 20% faster!

How can we tell if we're dehydrated or not? Well, why don't we ask our bodies? If we chug down some water and then turn around and just pee it all out, presumably that would be our body's way of saying, "I'm good, all topped off." But if we drink a bunch of water and our body keeps most of it, then presumably our tank was low. Researchers from the University of Connecticut formalized the technique. You empty your bladder, chug down 11 milliliters per kilogram of body weight (about 3 three cups of water for an average-sized person) and then an hour later see how much you pee. Basically, if you drink 3 cups and pee out less than 1, there's a good chance you were dehydrated. You can see the findings of this chug-and-pee test around minute 3 in my Can Dehydration Affect Our Mood? video.


For more on water, see my How Many Glasses of Water Should We Drink a Day?, Does a Drink Of Water Make Children Smarter?, and Treating Dry Eyes with Diet: Just Add Water?

Other healthy beverages include hibiscus tea (Hibiscus Tea vs. Plant-Based Diets for Hypertension) and green tea (Dietary Brain Wave Alteration and Benefits of Green Tea for Boosting Antiviral Immune Function).

What else can affect our mood?

What about the omega-3s in fish? That's the subject of another video: Fish Consumption and Suicide.

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

Can Dehydration Affect Our Mood?

Sept 7 Dehydration copy.jpeg

Water is by far the number-one nutrient in our diet. Studies have suggested that proper hydration may lower our risk of heart disease and cancer, and may even make us better kissers. Brushing artificial skin against the lips of young women, researchers found that hydrated lips showed greater sensitivity to light touch.

Although it is well known that water is essential for human survival, it's only recently that we have begun to understand its role in the maintenance of brain function. It makes sense. Our brain is 75% water. When we get dehydrated, our brain actually shrinks. Even mild dehydration, which can be caused by simply exercising on a hot day, has been shown to change brain function.

I've talked about the role of hydration for cognitive function in Does a Drink of Water Make Children Smarter?, but current findings suggest that our mood states may also be positively influenced by water consumption.

The effects of dehydration in real life have not been not well documented. It wasn't until 2013 that the first study to investigate the effects of mild dehydration on a variety of feelings was published. What did the researchers find? The most important effects of fluid deprivation were increased sleepiness and fatigue, lower levels of vigor and alertness, and increased confusion. But as soon as they gave the subjects some water, the deleterious effects on alertness, happiness, and confusion were immediately reversed.

Water absorption actually happens very rapidly, within 5 minutes from mouth to bloodstream, peaking around minute 20. Interestingly, the temperature of the water appears to affect this speed. Which do you think is absorbed more rapidly--cold water or warm, body temperature water? It turns out cold water gets sucked in about 20% faster!

How can we tell if we're dehydrated or not? Well, why don't we ask our bodies? If we chug down some water and then turn around and just pee it all out, presumably that would be our body's way of saying, "I'm good, all topped off." But if we drink a bunch of water and our body keeps most of it, then presumably our tank was low. Researchers from the University of Connecticut formalized the technique. You empty your bladder, chug down 11 milliliters per kilogram of body weight (about 3 three cups of water for an average-sized person) and then an hour later see how much you pee. Basically, if you drink 3 cups and pee out less than 1, there's a good chance you were dehydrated. You can see the findings of this chug-and-pee test around minute 3 in my Can Dehydration Affect Our Mood? video.


For more on water, see my How Many Glasses of Water Should We Drink a Day?, Does a Drink Of Water Make Children Smarter?, and Treating Dry Eyes with Diet: Just Add Water?

Other healthy beverages include hibiscus tea (Hibiscus Tea vs. Plant-Based Diets for Hypertension) and green tea (Dietary Brain Wave Alteration and Benefits of Green Tea for Boosting Antiviral Immune Function).

What else can affect our mood?

What about the omega-3s in fish? That's the subject of another video: Fish Consumption and Suicide.

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

Can Dehydration Affect Our Mood?

Sept 7 Dehydration copy.jpeg

Water is by far the number-one nutrient in our diet. Studies have suggested that proper hydration may lower our risk of heart disease and cancer, and may even make us better kissers. Brushing artificial skin against the lips of young women, researchers found that hydrated lips showed greater sensitivity to light touch.

Although it is well known that water is essential for human survival, it's only recently that we have begun to understand its role in the maintenance of brain function. It makes sense. Our brain is 75% water. When we get dehydrated, our brain actually shrinks. Even mild dehydration, which can be caused by simply exercising on a hot day, has been shown to change brain function.

I've talked about the role of hydration for cognitive function in Does a Drink of Water Make Children Smarter?, but current findings suggest that our mood states may also be positively influenced by water consumption.

The effects of dehydration in real life have not been not well documented. It wasn't until 2013 that the first study to investigate the effects of mild dehydration on a variety of feelings was published. What did the researchers find? The most important effects of fluid deprivation were increased sleepiness and fatigue, lower levels of vigor and alertness, and increased confusion. But as soon as they gave the subjects some water, the deleterious effects on alertness, happiness, and confusion were immediately reversed.

Water absorption actually happens very rapidly, within 5 minutes from mouth to bloodstream, peaking around minute 20. Interestingly, the temperature of the water appears to affect this speed. Which do you think is absorbed more rapidly--cold water or warm, body temperature water? It turns out cold water gets sucked in about 20% faster!

How can we tell if we're dehydrated or not? Well, why don't we ask our bodies? If we chug down some water and then turn around and just pee it all out, presumably that would be our body's way of saying, "I'm good, all topped off." But if we drink a bunch of water and our body keeps most of it, then presumably our tank was low. Researchers from the University of Connecticut formalized the technique. You empty your bladder, chug down 11 milliliters per kilogram of body weight (about 3 three cups of water for an average-sized person) and then an hour later see how much you pee. Basically, if you drink 3 cups and pee out less than 1, there's a good chance you were dehydrated. You can see the findings of this chug-and-pee test around minute 3 in my Can Dehydration Affect Our Mood? video.


For more on water, see my How Many Glasses of Water Should We Drink a Day?, Does a Drink Of Water Make Children Smarter?, and Treating Dry Eyes with Diet: Just Add Water?

Other healthy beverages include hibiscus tea (Hibiscus Tea vs. Plant-Based Diets for Hypertension) and green tea (Dietary Brain Wave Alteration and Benefits of Green Tea for Boosting Antiviral Immune Function).

What else can affect our mood?

What about the omega-3s in fish? That's the subject of another video: Fish Consumption and Suicide.

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 Much Water Should We Drink Every Day?

How Much Water Should We Drink Every Day?.jpeg

More than 2000 years ago Hippocrates (460-377 BCE) said, "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." What does that mean when it comes to water? Water has been described as a neglected, unappreciated, and under-researched subject, and further complicating the issue, a lot of the papers extolling the need for proper hydration are funded by the bottled water industry.

It turns out the often quoted "drink at least eight glasses of water a day" dictum has little underpinning scientific evidence . Where did that idea come from? The recommendation was traced to a 1921 paper, in which the author measured his own pee and sweat and determined we lose about 3% of our body weight in water a day, or about 8 cups (see How Many Glasses of Water Should We Drink in a Day?). Consequently, for the longest time, water requirement guidelines for humanity were based on just one person.

There is evidence that not drinking enough may be associated with falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancer, urinary tract infections, constipation, dry mouth, cavities, decreased immune function and cataract formation. The problem with many of these studies is that low water intake is associated with several unhealthy behaviors, such as low fruit and vegetable intake, more fast-food, less shopping at farmers markets. And who drinks lots of water? People who exercise a lot. No wonder they tend to have lower disease rates!

Only large and expensive randomized trials could settle these questions definitively. Given that water cannot be patented, such trials seem unlikely; who's going to pay for them? We're left with studies that find an association between disease and low water intake. But are people sick because they drink less, or are they drinking less because they're sick? There have been a few large prospective studies in which fluid intake is measured before disease develops. For example, a Harvard study of 48,000 men found that the risk of bladder cancer decreased by 7% for every extra daily cup of fluid we drink. Therefore, a high intake of water--like 8 cups a day--may reduce the risk of bladder cancer by about 50%, potentially saving thousands of lives.

The accompanying editorial commented that strategies to prevent the most prevalent cancers in the West are remarkably straightforward in principle. To prevent lung cancer, quit smoking; to prevent breast cancer, maintain your ideal body weight and exercise; and to prevent skin cancer, stay out of the sun. Now comes this seemingly simple way to reduce the risk of bladder cancer: drink more fluids.

Probably the best evidence we have for a cut off of water intake comes from the Adventist Health Study, in which 20,000 men and women were studied. About one-half were vegetarian, so they were also getting extra water by eating more fruits and vegetables. Those drinking 5 or more glasses of water a day had about half the risk of dying from heart disease compared to those who drank 2 or fewer glasses a day. Like the Harvard study, this protection was found after controlling for other factors such as diet and exercise. These data suggest that it was the water itself that was decreasing risk, perhaps by lowering blood viscosity (blood thickness).

Based on all the best evidence to date, authorities from Europe, the U.S. Institute of Medicine, and the World Health Organization recommend between 2.0 and 2.7 liters (8 to 11 cups) of water a day for women, and 2.5 to 3.7 liters (10 to 15 cups) a day for men. This includes water from all sources, not just beverages. We get about a liter from food and the water our body makes. So this translates into a recommendation for women to drink 4 to 7 cups of water a day and men 6 to 11 cups, assuming only moderate physical activity at moderate ambient temperatures.

We can also get water from all the other drinks we consume, including caffeinated drinks, with the exception of stronger alcoholic drinks like wines and spirits. Beer can leave you with more water than you started with, but wine actively dehydrates you. However, in the cancer and heart disease studies I mentioned above, the benefits were only found with increased water consumption, not other beverages.

I've previously touched on the cognitive benefits of proper hydration here: Does a Drink Of Water Make Children Smarter?

Surprised tea is hydrating? See my video Is Caffeinated Tea Dehydrating?

Surprised that the 8-a-day rested on such flimsy evidence? Unfortunately, so much of what we do in medicine has shaky underpinnings. That's the impetus behind the idea of evidence-based medicine (what a concept!). Ironically, this new movement may itself undermine some of the most effective treatments. See Evidence-Based Medicine or Evidence-Biased?

How else can we reduce our risk of bladder cancer? See Raw Broccoli and Bladder Cancer Survival.

What kind of water? I recommend tap water, which tends to be preferable from a chemical and microbial contamination standpoint. What about buying one of those fancy alkalizing machines? See Alkaline Water: a Scam?

It's so nice to have data on such a fundamental question. We have much to thank the Adventists for. You will see their studies cropping up frequently. See, for example, Plant-Based Diets and Diabetes, The Okinawa Diet: Living to 100, and Evidence-Based Eating.

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 / Flickr. Image has been modified.

Original Link

How Much Water Should We Drink Every Day?

How Much Water Should We Drink Every Day?.jpeg

More than 2000 years ago Hippocrates (460-377 BCE) said, "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." What does that mean when it comes to water? Water has been described as a neglected, unappreciated, and under-researched subject, and further complicating the issue, a lot of the papers extolling the need for proper hydration are funded by the bottled water industry.

It turns out the often quoted "drink at least eight glasses of water a day" dictum has little underpinning scientific evidence . Where did that idea come from? The recommendation was traced to a 1921 paper, in which the author measured his own pee and sweat and determined we lose about 3% of our body weight in water a day, or about 8 cups (see How Many Glasses of Water Should We Drink in a Day?). Consequently, for the longest time, water requirement guidelines for humanity were based on just one person.

There is evidence that not drinking enough may be associated with falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancer, urinary tract infections, constipation, dry mouth, cavities, decreased immune function and cataract formation. The problem with many of these studies is that low water intake is associated with several unhealthy behaviors, such as low fruit and vegetable intake, more fast-food, less shopping at farmers markets. And who drinks lots of water? People who exercise a lot. No wonder they tend to have lower disease rates!

Only large and expensive randomized trials could settle these questions definitively. Given that water cannot be patented, such trials seem unlikely; who's going to pay for them? We're left with studies that find an association between disease and low water intake. But are people sick because they drink less, or are they drinking less because they're sick? There have been a few large prospective studies in which fluid intake is measured before disease develops. For example, a Harvard study of 48,000 men found that the risk of bladder cancer decreased by 7% for every extra daily cup of fluid we drink. Therefore, a high intake of water--like 8 cups a day--may reduce the risk of bladder cancer by about 50%, potentially saving thousands of lives.

The accompanying editorial commented that strategies to prevent the most prevalent cancers in the West are remarkably straightforward in principle. To prevent lung cancer, quit smoking; to prevent breast cancer, maintain your ideal body weight and exercise; and to prevent skin cancer, stay out of the sun. Now comes this seemingly simple way to reduce the risk of bladder cancer: drink more fluids.

Probably the best evidence we have for a cut off of water intake comes from the Adventist Health Study, in which 20,000 men and women were studied. About one-half were vegetarian, so they were also getting extra water by eating more fruits and vegetables. Those drinking 5 or more glasses of water a day had about half the risk of dying from heart disease compared to those who drank 2 or fewer glasses a day. Like the Harvard study, this protection was found after controlling for other factors such as diet and exercise. These data suggest that it was the water itself that was decreasing risk, perhaps by lowering blood viscosity (blood thickness).

Based on all the best evidence to date, authorities from Europe, the U.S. Institute of Medicine, and the World Health Organization recommend between 2.0 and 2.7 liters (8 to 11 cups) of water a day for women, and 2.5 to 3.7 liters (10 to 15 cups) a day for men. This includes water from all sources, not just beverages. We get about a liter from food and the water our body makes. So this translates into a recommendation for women to drink 4 to 7 cups of water a day and men 6 to 11 cups, assuming only moderate physical activity at moderate ambient temperatures.

We can also get water from all the other drinks we consume, including caffeinated drinks, with the exception of stronger alcoholic drinks like wines and spirits. Beer can leave you with more water than you started with, but wine actively dehydrates you. However, in the cancer and heart disease studies I mentioned above, the benefits were only found with increased water consumption, not other beverages.

I've previously touched on the cognitive benefits of proper hydration here: Does a Drink Of Water Make Children Smarter?

Surprised tea is hydrating? See my video Is Caffeinated Tea Dehydrating?

Surprised that the 8-a-day rested on such flimsy evidence? Unfortunately, so much of what we do in medicine has shaky underpinnings. That's the impetus behind the idea of evidence-based medicine (what a concept!). Ironically, this new movement may itself undermine some of the most effective treatments. See Evidence-Based Medicine or Evidence-Biased?

How else can we reduce our risk of bladder cancer? See Raw Broccoli and Bladder Cancer Survival.

What kind of water? I recommend tap water, which tends to be preferable from a chemical and microbial contamination standpoint. What about buying one of those fancy alkalizing machines? See Alkaline Water: a Scam?

It's so nice to have data on such a fundamental question. We have much to thank the Adventists for. You will see their studies cropping up frequently. See, for example, Plant-Based Diets and Diabetes, The Okinawa Diet: Living to 100, and Evidence-Based Eating.

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 / Flickr. Image has been modified.

Original Link

Tea and Flouride Risk

 

 

 

 

 

 

 

 

Childhood Tea Drinking May Increase Fluorosis Risk

If cranberries are so good at keeping bacteria from sticking to the wall of the bladder (see my video Can Cranberry Juice Treat Bladder Infections?), what about keeping bacteria from sticking to other places? There is in vitro research suggesting cranberry phytonutrients may reduce adhesion of H. pylori bacteria in the wall of the stomach, so maybe cranberries should be given along with antibiotics to help eradicate the ulcer-causing bacteria. But hey, what about our teeth?

Dental plaque is bacteria sticking to our teeth, particularly Streptococcus mutans. We’ve known that those with different drinking habits—be they coffee, tea, barley coffee, or wine—have about 10 times less of these plaque bacteria. Since those are all beverages from plants, maybe phytonutrients are fighting back at plaque.

If bacteria cause plaque and cavities, why not just swish with some antibiotic solution? There are downsides to just indiscriminately wiping out bacteria both good and bad, as I detailed in my Don’t Use Antiseptic Mouthwash video. So maybe it would be better if we just stop the bad bugs from sticking to our teeth.

There is some evidence that cranberries might affect the adhesion of bacteria to fake teeth in a petri dish, but nothing yet definitive. Green tea also appears to help prevent cavities, but that may be because of its natural fluoride content in the tea plant. I have a video about a woman who developed fluoride toxicity drinking up to the equivalent of about five dozen cups a day, but what about just regular consumption?

During the tooth development years, up to about age 9, children exposed to too much fluoride can develop dental fluorosis, a mottled discoloration of the teeth. It’s just a cosmetic issue and usually just manifests as faint white spots, but it’s the main reason the EPA is reconsidering current tap water fluoridation levels. If you watch my 3-min video Childhood Tea Drinking May Increase Fluorosis Risk, you’ll see that herbal teas are fine–about 100 fold under the limit–but caffeinated teas exceed the suggested limit, and decaf teas exceed the mandatory limit. Those limits are for tap water, though, so tea drinking would only pose much of a risk if drank all day long as one’s primary beverage. Kids who primarily drink non-herbal tea as a source of hydration would be at risk for dental fluorosis.

What may be the best source of hydration for kids? Might tea also cause dehydration? Find the answers to these beverage-related questions in my videos Does a Drink of Water Make Children Smarter? and Is Caffeinated Tea Dehydrating?

What about all those folks that say fluoride is a poison to be avoided at all costs? I offer my brief two cents in the Q&A The Dangers of Fluoride? There are elements for which there is no safe level of exposure, though. I explore a few in my video Fukushima and Radioactivity in Seafood.

Beyond cosmetic issues, what should we eat and drink to keep our mouth healthy? See my videos Plant-Based Diets: Oral Health and Plant-Based Diets: Dental 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 and More Than an Apple a Day.

Image credit: Josconklin / Wikimedia Commons

Original Link

Schoolchildren Should Drink More Water

 

 

 

 

 

 

 

 

Does a Drink of Water Make Kids Smarter?

Most children arrive at school in a state of mild dehydration that may negatively affect scholastic performance.

Preventing cellular dehydration is integral to hormonal, immune, neurological, cardiovascular, gastrointestinal, muscle and skeletal function. So researchers recently set out to determine the hydration status of healthy children in the United States. Urine samples were obtained from groups of 9 to 11 year olds in Los Angeles and Manhattan on their way to school to see how they were doing.

The study was motivated by recent studies in Israel showing children did not seem to be hydrated enough. But Israel’s in a desert, so they wanted to repeat the study under cooler and less arid conditions. It turns out the U.S. kids did just as bad as the Israelis.

As I show in my video Does a Drink Of Water Make Children Smarter?, urine from nearly two-thirds of the U.S. kids studied was considered too concentrated, an indicator that they were dehydrated. Why? They weren’t drinking enough water. Three-quarters of the kids did not drink water between the time they woke up and when they went off to school.

But most ate breakfast, so they must have been drinking something. The problem is that other beverages are not as hydrating. The levels of sodium, sugars, and amino acids in milk and juice can shrink cells and trigger the release of the hormone that spurs dehydration.

So what, though? Is there any actual negative impact of mild dehydration on one’s ability to function at school? Historically, most of the studies on hydration and mental functioning were done on adults under extreme conditions, like having people exercise in 113 degree heat, or giving people powerful diuretics like Lasix and putting them on a treadmill. Most of the studies on hydration and cognitive performance have been performed on military personnel to evaluate soldiers’ ability to function in extreme circumstances. It is easy to imagine that a soldier fighting in the desert with a heavy rucksack and a protective suit must be physically and cognitively at his best. It is, however, very difficult to translate this knowledge to normal real-life circumstances. Three new studies changed that.

They were simple studies. Researchers took a group of schoolchildren, randomly allocated them to drink a cup of water or not, and then gave them all a test to see who did better. And the winner was… the cup-of-water group. Conclusion: “The results of the present study suggest that even children in a state of mild dehydration, not induced by intentional water deprivation or by heat stress and living in a cold climate, can benefit from drinking more water and improve their cognitive performance.”

So water worked for 2nd and 3rd graders, what about 1st grade? Same experimental design but this time instead of forcing kids in the water group to drink a cup, the water group was just given some water and told to drink as much they wanted, and again found significant improvement in the performance of various tasks, leading to the same conclusion: “[E]ven under conditions of mild dehydration…children’s cognitive performance can be improved by having a drink of water.”

The latest study that just came out is the largest to date.  It too found a remarkable proportion of children were in a state of mild, voluntary dehydration at the beginning of the school day and a significant negative correlation between dehydration and, for example, the ability to remember numbers. The researchers offered a randomized group some water, and those kids on average felt better and performed better. “To conclude…[mild dehydration] is an adverse state that might render the school day more challenging for children.”

Even doctors often apparently fail to realize the connection. A recent survey found that healthcare professionals under-recognized the importance of proper hydration for mental health. Who would care enough about the importance of human hydration to even do a survey? A “Hydration Institute” founded in part by…The Coca-Cola company.

These three new studies found drinking resulted in a significant improvement in cognitive performance, but not with Coke. And not with Ritalin or some new drug, either. Just plain water. Think how much drug companies could make if they could sell sugar pills but just tell kids to take the fake pill with… a glass of water.

This is one of those groundbreaking findings (like my gargling video) that will likely never see the light of day because there’s no profit motive for promotion. We’re guaranteed to be assailed about all the new drugs and surgical advances because there’s big business behind getting the word out. But who profits from tap water? Or even broccoli for that matter? That’s one of the reasons I created NutritionFacts.org, to bring to light all the findings that would otherwise just get buried in medical library basements (or, increasingly, vast private databases).

The water content of plant foods may help explain why those eating plant-based diets are, on average, so slim. Like fiber, water is a source of Nutrition Without Calories. See Dietary Guidelines: It’s All Greek to the USDA for a country with the guts to suggest water might be preferable to drinking soda.

Juice and milk may not be as hydrating as water. What about tea? See my video Is Caffeinated Tea Dehydrating? What about Bottled Water vs. Tap?

More on children’s health in videos such as:

-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 and More Than an Apple a Day.

Image credit: JefferyTurner / Flickr

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