Chocolate is Finally Put to the Test

Oct 10 Chocolate copy.jpeg

Botanically speaking, seeds are small embryonic plants--the whole plant stuffed into a tiny seed and surrounded by an outer layer packed with vitamins, minerals, and phytochemicals to protect the seedling plant's DNA from free radicals. No wonder they're so healthy. By seeds, using the formal definition, we're talking all whole grains; grains are seeds--you plant them and they grow. Nuts are just dry fruits with one or two seeds. Legumes (beans, peas, and lentils) are seeds, too, as are cocoa and coffee beans. So, finding health-promoting effects in something like cocoa or coffee should not be all that surprising. There is substantial evidence that increased consumption of all these little plants is associated with lower risk of cardiovascular disease.

Of course, much of chocolate research is just on how to get consumers to eat more. While it didn't seem to matter what kind of music people were listening to when it came to the flavor intensity, pleasantness, or texture of a bell pepper, people liked chocolate more when listening to jazz than classical, rock, or hip hop. Why is this important? So food industries can "integrate specific musical stimuli" in order to maximize their profits. For example, purveyors may play jazz in the background to increase consumers' acceptance of their chocolates. Along these lines, another study demonstrated that people rated the oyster eaten "more pleasant in the presence of the 'sound of the sea' than in the presence of 'farmyard noises.'"

You'd think chocolate would just sell itself, given that it's considered the most commonly craved food in the world. The same degree of interest doesn't seem to exist as to whether or not Brussels sprouts might provide similar cardiovascular protection. So, it's understandable to hope chocolate provides health benefits. Meanwhile, despite their known benefits, Brussels sprouts don't get the love they deserve.

One of the potential downsides of chocolate is weight gain, which is the subject of my Does Chocolate Cause Weight Gain? video. Though cocoa hardly has any calories, chocolate is one of the most calorie-dense foods. For example: A hundred calories of chocolate is less than a quarter of a bar, compared to a hundred calories of strawberries, which is more than two cups..

A few years ago, a study funded by the National Confectioners Association--an organization that, among other things, runs the website voteforcandy.com--reported that Americans who eat chocolate weigh, on average, four pounds less than those who don't. But maybe chocolate-eaters exercise more or eat more fruits and vegetables. The researchers didn't control for any of that.

The findings of a more recent study published in the Archives of Internal Medicine were less easy to dismiss and there were no apparent ties to Big Chocolate. The researchers reported that out of a thousand men and women they studied in San Diego, those who frequently consumed chocolate had a lower BMI--actually weighed less--than those who ate chocolate less often. And this was even after adjusting for physical activity and diet quality. But, it was a cross-sectional study, meaning a snapshot in time, so you can't prove cause and effect. Maybe not eating chocolate leads to being fatter, or maybe being fatter leads to not eating chocolate. Maybe people who are overweight are trying to cut down on sweets. What we need is a study in which people are followed over time.

There was no such prospective study, until now. More than 10,000 people were followed for six years, and a chocolate habit was associated with long-term weight gain in a dose-response manner. This means the greatest weight gain over time was seen in those with the highest frequency of chocolate intake. It appears the reason the cross-sectional studies found the opposite is that subjects diagnosed with obesity-related illnesses tended to reduce their intake of things like chocolate in an attempt to improve their prognosis. This explains why heavier people may, on average, eat less chocolate.

To bolster this finding came the strongest type of evidence--an interventional trial--in which you split people up into two groups and change half their diets. Indeed, adding four squares of chocolate to peoples' daily diets does appear to add a few pounds.

So, what do we tell our patients? In 2013, researchers wrote in the American Family Physician journal that "because many cocoa products are high in sugar and saturated fat, family physicians should refrain from recommending cocoa...." That's a little patronizing, though. You can get the benefits of chocolate without any sugar or fat by adding cocoa powder to a smoothie, for example. Too often, doctors think patients can't handle the truth. Case in point: If your patients inquire, one medical journal editorial suggest, ask them what type of chocolate they prefer. If they respond with milk chocolate, then it is best to answer that it is not good for them. If the answer is dark chocolate, then you can lay out the evidence.


Even better than dark chocolate would be cocoa powder, which contains the phytonutrients without the saturated fat. I've happily (and deliciously) created other videos on cocoa and chocolate, so check out Update on Chocolate, Healthiest Chocolate Fix, A Treatment for Chronic Fatigue Syndrome, and Dark Chocolate and Artery Function.

Whether with Big Candy, Big Chocolate, or some other player, you always have to be careful about conflict of interest. For more information, watch my Food Industry Funded Research Bias video.

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

Chocolate is Finally Put to the Test

Oct 10 Chocolate copy.jpeg

Botanically speaking, seeds are small embryonic plants--the whole plant stuffed into a tiny seed and surrounded by an outer layer packed with vitamins, minerals, and phytochemicals to protect the seedling plant's DNA from free radicals. No wonder they're so healthy. By seeds, using the formal definition, we're talking all whole grains; grains are seeds--you plant them and they grow. Nuts are just dry fruits with one or two seeds. Legumes (beans, peas, and lentils) are seeds, too, as are cocoa and coffee beans. So, finding health-promoting effects in something like cocoa or coffee should not be all that surprising. There is substantial evidence that increased consumption of all these little plants is associated with lower risk of cardiovascular disease.

Of course, much of chocolate research is just on how to get consumers to eat more. While it didn't seem to matter what kind of music people were listening to when it came to the flavor intensity, pleasantness, or texture of a bell pepper, people liked chocolate more when listening to jazz than classical, rock, or hip hop. Why is this important? So food industries can "integrate specific musical stimuli" in order to maximize their profits. For example, purveyors may play jazz in the background to increase consumers' acceptance of their chocolates. Along these lines, another study demonstrated that people rated the oyster eaten "more pleasant in the presence of the 'sound of the sea' than in the presence of 'farmyard noises.'"

You'd think chocolate would just sell itself, given that it's considered the most commonly craved food in the world. The same degree of interest doesn't seem to exist as to whether or not Brussels sprouts might provide similar cardiovascular protection. So, it's understandable to hope chocolate provides health benefits. Meanwhile, despite their known benefits, Brussels sprouts don't get the love they deserve.

One of the potential downsides of chocolate is weight gain, which is the subject of my Does Chocolate Cause Weight Gain? video. Though cocoa hardly has any calories, chocolate is one of the most calorie-dense foods. For example: A hundred calories of chocolate is less than a quarter of a bar, compared to a hundred calories of strawberries, which is more than two cups..

A few years ago, a study funded by the National Confectioners Association--an organization that, among other things, runs the website voteforcandy.com--reported that Americans who eat chocolate weigh, on average, four pounds less than those who don't. But maybe chocolate-eaters exercise more or eat more fruits and vegetables. The researchers didn't control for any of that.

The findings of a more recent study published in the Archives of Internal Medicine were less easy to dismiss and there were no apparent ties to Big Chocolate. The researchers reported that out of a thousand men and women they studied in San Diego, those who frequently consumed chocolate had a lower BMI--actually weighed less--than those who ate chocolate less often. And this was even after adjusting for physical activity and diet quality. But, it was a cross-sectional study, meaning a snapshot in time, so you can't prove cause and effect. Maybe not eating chocolate leads to being fatter, or maybe being fatter leads to not eating chocolate. Maybe people who are overweight are trying to cut down on sweets. What we need is a study in which people are followed over time.

There was no such prospective study, until now. More than 10,000 people were followed for six years, and a chocolate habit was associated with long-term weight gain in a dose-response manner. This means the greatest weight gain over time was seen in those with the highest frequency of chocolate intake. It appears the reason the cross-sectional studies found the opposite is that subjects diagnosed with obesity-related illnesses tended to reduce their intake of things like chocolate in an attempt to improve their prognosis. This explains why heavier people may, on average, eat less chocolate.

To bolster this finding came the strongest type of evidence--an interventional trial--in which you split people up into two groups and change half their diets. Indeed, adding four squares of chocolate to peoples' daily diets does appear to add a few pounds.

So, what do we tell our patients? In 2013, researchers wrote in the American Family Physician journal that "because many cocoa products are high in sugar and saturated fat, family physicians should refrain from recommending cocoa...." That's a little patronizing, though. You can get the benefits of chocolate without any sugar or fat by adding cocoa powder to a smoothie, for example. Too often, doctors think patients can't handle the truth. Case in point: If your patients inquire, one medical journal editorial suggest, ask them what type of chocolate they prefer. If they respond with milk chocolate, then it is best to answer that it is not good for them. If the answer is dark chocolate, then you can lay out the evidence.


Even better than dark chocolate would be cocoa powder, which contains the phytonutrients without the saturated fat. I've happily (and deliciously) created other videos on cocoa and chocolate, so check out Update on Chocolate, Healthiest Chocolate Fix, A Treatment for Chronic Fatigue Syndrome, and Dark Chocolate and Artery Function.

Whether with Big Candy, Big Chocolate, or some other player, you always have to be careful about conflict of interest. For more information, watch my Food Industry Funded Research Bias video.

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

Boosting Brown Fat Through Diet

Sept 26 Boosting Brown Fat copy.jpeg

Until about ten years ago, brown adipose tissue (BAT) was considered to be biologically active only in babies and small children where it generates heat by burning fat. But now, there is no doubt that active brown fat is present in adult humans and is involved in cold-induced increases in whole-body calorie expenditure and, thereby, helps control of not only body temperature but also how fat we are.

In 2013, researchers showed that one could activate brown adipose tissue if you chill out people long enough, specifically, by exposing them to two hours of cold every day for six weeks, which can lead to a significant reduction in body fat. You can see an illustrative graph in my video Boosting Brown Fat Through Diet. Although researchers demonstrated the effective recruitment of human brown fat, it would seem difficult to increase exposure to cold in daily life. Thankfully, our brown fat can also be activated by some food ingredients, such as capsaicin, the compound that makes hot peppers hot.

While physical activity is usually recommended to increase energy expenditure, there are specific food components, such as capsaicin, that are known to burn off calories. For example, one study found that there was a significant rise in energy expenditure within 30 minutes of eating the equivalent of a jalapeño pepper.

Normally when we cut down on calories, our metabolism slows down, undercutting our weight loss attempts; but sprinkling a third of a teaspoon of red chili pepper powder onto our meals counteracts that metabolic slow down and promotes fat burning. Researchers wanted to try giving participants more chili pepper in order to try to match some of the studies done in Asia, but the Caucasian subjects couldn't take it. But by adding more than a tablespoon of red pepper powder to a high-fat meal, Japanese women burned significantly more fat.

We've known for decades that cayenne pepper increases metabolic rate, but we didn't know how. But studies show that this class of compounds increases energy expenditure in human individuals with brown fat, but not in those without it, indicating that individuals increase expenditure right off the BAT. Additionally, there is a variety of structurally similar flavor molecules in other foods, like black pepper and ginger, that may activate thermogenesis as well, but they haven't been directly tested.

All these results suggest that the anti-obesity effects of pepper compounds are based on the heat-generating activity of recruited brown fat. Thus, repeated ingestion can mimic the chronic effects of cold exposure without having to freeze ourselves.

Consumption of spicy foods may help us lose weight, but what about the sensory burn and pain on our tongues and sometimes in our stomachs as well as further on down? Are our only two options for boosting brown fat to freeze our legs or burn our butts?

Arginine-rich foods may also stimulate brown adipose tissue growth and development through a variety of mechanisms, which is achieved by consuming more soy foods, seeds, nuts, and beans.


For more on brown adipose tissue, see Brown Fat: Losing Weight Through Thermogenesis.

What about arginine? Check out Fat Burning Via Arginine. And, did you know arginine may also play a role in the effects nuts may have on penile blood flow? I discuss this in Pistachio Nuts for Erectile Dysfunction.

For more on spicy foods, see my videos Cayenne Pepper for Irritable Bowel Syndrome and Chronic Indigestion to learn how digestive disorders may be helped and Hot Sauce in the Nose for Cluster Headaches? for information on how the hot pepper compound can be a lifesaver for people suffering from "suicide" headaches.

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

Boosting Brown Fat Through Diet

Sept 26 Boosting Brown Fat copy.jpeg

Until about ten years ago, brown adipose tissue (BAT) was considered to be biologically active only in babies and small children where it generates heat by burning fat. But now, there is no doubt that active brown fat is present in adult humans and is involved in cold-induced increases in whole-body calorie expenditure and, thereby, helps control of not only body temperature but also how fat we are.

In 2013, researchers showed that one could activate brown adipose tissue if you chill out people long enough, specifically, by exposing them to two hours of cold every day for six weeks, which can lead to a significant reduction in body fat. You can see an illustrative graph in my video Boosting Brown Fat Through Diet. Although researchers demonstrated the effective recruitment of human brown fat, it would seem difficult to increase exposure to cold in daily life. Thankfully, our brown fat can also be activated by some food ingredients, such as capsaicin, the compound that makes hot peppers hot.

While physical activity is usually recommended to increase energy expenditure, there are specific food components, such as capsaicin, that are known to burn off calories. For example, one study found that there was a significant rise in energy expenditure within 30 minutes of eating the equivalent of a jalapeño pepper.

Normally when we cut down on calories, our metabolism slows down, undercutting our weight loss attempts; but sprinkling a third of a teaspoon of red chili pepper powder onto our meals counteracts that metabolic slow down and promotes fat burning. Researchers wanted to try giving participants more chili pepper in order to try to match some of the studies done in Asia, but the Caucasian subjects couldn't take it. But by adding more than a tablespoon of red pepper powder to a high-fat meal, Japanese women burned significantly more fat.

We've known for decades that cayenne pepper increases metabolic rate, but we didn't know how. But studies show that this class of compounds increases energy expenditure in human individuals with brown fat, but not in those without it, indicating that individuals increase expenditure right off the BAT. Additionally, there is a variety of structurally similar flavor molecules in other foods, like black pepper and ginger, that may activate thermogenesis as well, but they haven't been directly tested.

All these results suggest that the anti-obesity effects of pepper compounds are based on the heat-generating activity of recruited brown fat. Thus, repeated ingestion can mimic the chronic effects of cold exposure without having to freeze ourselves.

Consumption of spicy foods may help us lose weight, but what about the sensory burn and pain on our tongues and sometimes in our stomachs as well as further on down? Are our only two options for boosting brown fat to freeze our legs or burn our butts?

Arginine-rich foods may also stimulate brown adipose tissue growth and development through a variety of mechanisms, which is achieved by consuming more soy foods, seeds, nuts, and beans.


For more on brown adipose tissue, see Brown Fat: Losing Weight Through Thermogenesis.

What about arginine? Check out Fat Burning Via Arginine. And, did you know arginine may also play a role in the effects nuts may have on penile blood flow? I discuss this in Pistachio Nuts for Erectile Dysfunction.

For more on spicy foods, see my videos Cayenne Pepper for Irritable Bowel Syndrome and Chronic Indigestion to learn how digestive disorders may be helped and Hot Sauce in the Nose for Cluster Headaches? for information on how the hot pepper compound can be a lifesaver for people suffering from "suicide" headaches.

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

Brown Fat: Losing Weight Through Thermogenesis

Sept 21 Brown Fat Thermo copy.jpeg

During World War I, it was discovered that many of the chemicals for new explosives had toxic or even lethal effects on the workers in the munitions factories. Chemicals such as di-nitro-phenol (DNP) can boost metabolism so much that workers were too often found wandering along the road after work, covered in sweat with temperatures of 106 to 109 degrees Fahrenheit before they died. Even after death, their temperatures kept going up, as if they were having a total body meltdown. At subacute doses, however, workers claimed to have grown thin to a notable extent after several months working with the chemical.

That got some Stanford pharmacologists excited about the "promising metabolic applications" of DNP. Our resting metabolic rate jumps up 30% after one dose of DNP, and therefore, it becomes an actual fat-burning drug. People started losing weight, as you can see in my video Brown Fat: Losing Weight Through Thermogenesis, with no apparent side effects. They felt great... and then thousands of people started going blind and users started dropping dead from hyperpyrexia, fatal fever due to the heat created by the burning fat. Of course, it continued to be sold. Ad copy read:

"Here, at last, is a [weight] reducing remedy that will bring you a figure men admire and women envy, without danger to your health or change in your regular mode of living....No diet, no exercise!"

It did work, but the therapeutic index--the difference between the effective dose and the deadly dose--was razor thin. It was not until thousands suffered irreversible harm that it got pulled from the market and remained unavailable. Unavailable, that is, until it was brought back by the internet for those dying to be thin.

There is, however, a way our body naturally burns fat to create heat. When we're born, we go from a nice tropical 98.6 in our mother's womb straight to room temperature, just when we're still all wet and slimy. As an adaptive mechanism to maintain warmth, the appearance of a unique organ around 150 million years ago allowed mammals to maintain our high body temperatures.

That unique organ is called brown adipose tissue, or BAT, and its role is to consume fat calories by generating heat in response to cold exposure. The white fat in our bellies stores fat, but the brown fat, located up between our shoulder blades, burns fat. BAT is essential for thermogenesis, the creation of heat in newborns, but has been considered unnecessary in adults who have higher metabolic rates and increased muscle mass for shivering to warm us up when we get chilled. We used to think brown tissue just shrank away when we grew up, but, if it was there, then it could potentially make a big difference for how many calories we burn every day.

When PET scans were invented to detect metabolically active tissues like cancer, oncologists kept finding hot spots in the neck and shoulder regions that on CT scans turned out not to be cancer, just fat. Then, some observant radiologists noticed they appeared in patients mostly during the cold winter months. When they looked closer at tissue samples taken from people who had undergone neck surgery, they found it: brown fat in adults.

The common message from a number of studies is that BAT is present and active in adults, and the more we have and the more active it is, the thinner we are. And we can rapidly activate our fat-burning brown fat by exposure to cold temperatures. For example, if you hang out in a cold room for two hours in your undies and put your legs on a block of ice for four minutes every five minutes, you can elicit a marked increase in energy expenditure, thanks to brown fat activation. So, the studies point to a potential "natural" intervention to stimulate energy expenditure: Turn down the heat to burn calories (and reduce the carbon footprint in the process).

Thankfully, for those of us who would rather not lay our bare legs on blocks of ice, our brown fat can also be activated by some food ingredients such as those that are covered in my Boosting Brown Fat Through Diet video.


I briefly touch on the role cold temperatures can play in weight loss in The Ice Diet and talk more about calories in (Nutrient-Dense Approach to Weight Management) and calories out (How Much Exercise to Sustain Weight Loss).

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

Brown Fat: Losing Weight Through Thermogenesis

Sept 21 Brown Fat Thermo copy.jpeg

During World War I, it was discovered that many of the chemicals for new explosives had toxic or even lethal effects on the workers in the munitions factories. Chemicals such as di-nitro-phenol (DNP) can boost metabolism so much that workers were too often found wandering along the road after work, covered in sweat with temperatures of 106 to 109 degrees Fahrenheit before they died. Even after death, their temperatures kept going up, as if they were having a total body meltdown. At subacute doses, however, workers claimed to have grown thin to a notable extent after several months working with the chemical.

That got some Stanford pharmacologists excited about the "promising metabolic applications" of DNP. Our resting metabolic rate jumps up 30% after one dose of DNP, and therefore, it becomes an actual fat-burning drug. People started losing weight, as you can see in my video Brown Fat: Losing Weight Through Thermogenesis, with no apparent side effects. They felt great... and then thousands of people started going blind and users started dropping dead from hyperpyrexia, fatal fever due to the heat created by the burning fat. Of course, it continued to be sold. Ad copy read:

"Here, at last, is a [weight] reducing remedy that will bring you a figure men admire and women envy, without danger to your health or change in your regular mode of living....No diet, no exercise!"

It did work, but the therapeutic index--the difference between the effective dose and the deadly dose--was razor thin. It was not until thousands suffered irreversible harm that it got pulled from the market and remained unavailable. Unavailable, that is, until it was brought back by the internet for those dying to be thin.

There is, however, a way our body naturally burns fat to create heat. When we're born, we go from a nice tropical 98.6 in our mother's womb straight to room temperature, just when we're still all wet and slimy. As an adaptive mechanism to maintain warmth, the appearance of a unique organ around 150 million years ago allowed mammals to maintain our high body temperatures.

That unique organ is called brown adipose tissue, or BAT, and its role is to consume fat calories by generating heat in response to cold exposure. The white fat in our bellies stores fat, but the brown fat, located up between our shoulder blades, burns fat. BAT is essential for thermogenesis, the creation of heat in newborns, but has been considered unnecessary in adults who have higher metabolic rates and increased muscle mass for shivering to warm us up when we get chilled. We used to think brown tissue just shrank away when we grew up, but, if it was there, then it could potentially make a big difference for how many calories we burn every day.

When PET scans were invented to detect metabolically active tissues like cancer, oncologists kept finding hot spots in the neck and shoulder regions that on CT scans turned out not to be cancer, just fat. Then, some observant radiologists noticed they appeared in patients mostly during the cold winter months. When they looked closer at tissue samples taken from people who had undergone neck surgery, they found it: brown fat in adults.

The common message from a number of studies is that BAT is present and active in adults, and the more we have and the more active it is, the thinner we are. And we can rapidly activate our fat-burning brown fat by exposure to cold temperatures. For example, if you hang out in a cold room for two hours in your undies and put your legs on a block of ice for four minutes every five minutes, you can elicit a marked increase in energy expenditure, thanks to brown fat activation. So, the studies point to a potential "natural" intervention to stimulate energy expenditure: Turn down the heat to burn calories (and reduce the carbon footprint in the process).

Thankfully, for those of us who would rather not lay our bare legs on blocks of ice, our brown fat can also be activated by some food ingredients such as those that are covered in my Boosting Brown Fat Through Diet video.


I briefly touch on the role cold temperatures can play in weight loss in The Ice Diet and talk more about calories in (Nutrient-Dense Approach to Weight Management) and calories out (How Much Exercise to Sustain Weight Loss).

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:

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Heart of Gold: Turmeric vs. Exercise

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The endothelium is the inner lining of our blood vessels. Laid end-to-end, endothelial cells from a single human would wrap more than four times around the world. And it's not just an inert layer; it's highly metabolically active. I've talked before about how sensitive our endothelium is to oxidation (The Power of NO) and inflammation (The Leaky Gut Theory). If we don't take care of it, endothelial dysfunction may set us up for heart disease or a stroke. Are we ready to heed our endothelium's early warning signal?

If it's all about oxidation and inflammation, then fruits and vegetables should help. And indeed it appears they do. Each daily serving of fruits or vegetables was associated with a 6% improvement in endothelial function. These fruit- and vegetable-associated improvements in endothelial function are in contrast to several negative vitamin C pill studies that failed to show a benefit. It can be concluded that the positive findings of the fruit and vegetable study are not just because of any one nutrient in fruits and veggies. Rather than searching for the single magic bullet micronutrient, a more practical approach is likely to consider whole foods. Increasing fruit and vegetable consumption is likely to have numerous benefits due to synergistic effects of the plethora of wonderful nutrients in plants.

Exercise helps our endothelial cells, too, but what type of exercise helps best? Patients were randomized into four groups: aerobic exercise (cycling for an hour a day), resistance training (using weights and elastic bands), both, or neither. The aerobic group kicked butt. The resistance group kicked butt. The aerobic and resistance group kicked butt, too. The only group who didn't kick butt was the group who sat on their butts. Our endothelium doesn't care if we're on a bike or lifting weights, as long as we're getting physical activity regularly. If we stop exercising, our endothelial function plummets.

Antioxidant pills don't help, but drug companies aren't going to give up that easy. They're currently looking into anti-inflammatory pills. After all, there's only so much you can make selling salad. For those who prefer plants to pills, one of the most anti-inflammatory foods is the spice turmeric. Researchers in Japan recently compared the endothelial benefits of exercise to that of curcumin, the yellow pigment in turmeric and curry powder. About a teaspoon a day's worth of turmeric for eight weeks was compared to 30 to 60 minutes of aerobic exercise a day.

Which group improved their endothelial function more? The group who did neither experienced no benefit, but both the exercise and the curcumin groups significantly boosted endothelial function. The researchers reported: "The magnitude of the improvement achieved by curcumin treatment was comparable to that obtained with exercise. Therefore, regular ingestion of curcumin could be a preventive measure against cardiovascular disease" at least in postmenopausal women, who were the subjects of this study. "Furthermore, [their] results suggest that curcumin may be a potential alternative treatment for patients who are unable to exercise."

Ideally, we'd both eat curcumin and exercise. One study looked at central arterial hemodynamics. Basically, if our endothelium is impaired, our arteries stiffen, making it harder for our heart to pump. Compared to placebo, we can drop down the pressure with turmeric curcumin or exercise. However, if we combine both, then we really start rocking and rolling, as you can see in the chart about 4 minutes into my video Heart of Gold: Turmeric vs. Exercise. The researchers conclude that these findings suggest that regular endurance exercise combined with daily curcumin ingestion may reduce the pressure against which our hearts have to figh. We want both healthy eating and exertion for our endothelium.


This entry is a follow-up to Turmeric Curcumin vs. Exercise for Artery Function.

Endothelial dysfunction is at the heart (pun intended) of many of our deadliest diseases. Pledge to save your endothelial cells and check out some of these other videos about the effects of food on our endothelial function:

For more on the concept of nutrient synergy, see Garden Variety Anti-Inflammation and Cranberries vs. Cancer.

Regardless what you do or don't eat, exercise is critical:

I must have dozens of turmeric videos by now, but here are a few to get you started:

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:

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