What About Extra Virgin Olive Oil?

Oct 17 Olive Oil copy.jpeg

The relative paralysis of our arteries for hours after eating fast food and cheesecake may also occur after consuming olive oil. Olive oil was found to have the same impairment to endothelial function as high-fat foods like sausage and egg breakfast sandwiches. (See my Olive Oil and Artery Function video for an illustrative chart with different foods.)

Studies that have suggested endothelial benefits after olive oil consumption have measured something different: ischemia-induced dilation as opposed to flow-mediated dilation. There's just not good evidence that's actually an accurate index of endothelial function, which is what predicts heart disease. Hundreds of studies have shown that the ischemia-induced dilation test can give a false negative result.

Other oils have also been shown to have deleterious results on endothelial function. A significant and constant decrease in endothelial function appears within three hours after each meal, independent of the type of oil and whether the oil was fresh or deep fried. Olive oil may be better than omega-6-rich oils or saturated fats, but it still showed adverse effects. This was the case with regular, refined olive oil. But what about extra-virgin olive oil?

Extra-virgin olive oil retains a fraction of the anti-inflammatory phytonutrients found in the olive fruit, and so doesn't appear to induce the spike in inflammatory markers caused by regular olive oil. What does that mean for our arteries? Extra-virgin olive oil may have more of a neutral effect compared to butter, which exerted a noxious effect that lasted for up to six hours--basically right up until our next meal. In the largest prospective study ever to assess the relationship between olive oil consumption and cardiac events like heart attacks, there was a suggestion that virgin olive oil may be better than regular olive oil, but neither was found to significantly reduce heart attack rates after controlling for healthy dietary behaviors like vegetable intake, which tends to go hand-in-hand with olive oil intake.

There have also been studies showing that even extra-virgin olive oil, contrary to expectations, may significantly impair endothelial function. Why then do some studies suggest endothelial function improves on a Mediterranean diet, which is rich in olive oil? It may be because the Mediterranean diet is also rich in whole grains, fruits, vegetables, beans, and walnuts. Fruits and vegetables appear to provide some protection against the direct impairment of endothelial function produced by high-fat foods, including olive oil; therefore, improvements in health may be in spite of, rather than because of, the oil. In terms of their effects on post-meal endothelial function, the beneficial components of the Mediterranean diet may primarily be the antioxidant-rich foods, the vegetables, fruits, and their derivatives, such as balsamic vinegar. Adding some vegetables to a fatty meal may partially restore arterial functioning and blood flow.


If olive oil can impair our arterial function, Why Was Heart Disease Rare in the Mediterranean? I've got a whole series of videos on the Mediterranean diet that I invite you to check out.

Fatty Meals May Impair Artery Function so much that a single high-fat meal can trigger angina chest pain. But, whole-food sources of fat such as nuts appear to be the exception. See Extra Virgin Olive Oil vs. Nuts and Walnuts and Artery Function.

I've also examined artery function with several other foods: eggs, dark chocolate, coffee, vinegar, tea, and plant-based diets.

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

What About Extra Virgin Olive Oil?

Oct 17 Olive Oil copy.jpeg

The relative paralysis of our arteries for hours after eating fast food and cheesecake may also occur after consuming olive oil. Olive oil was found to have the same impairment to endothelial function as high-fat foods like sausage and egg breakfast sandwiches. (See my Olive Oil and Artery Function video for an illustrative chart with different foods.)

Studies that have suggested endothelial benefits after olive oil consumption have measured something different: ischemia-induced dilation as opposed to flow-mediated dilation. There's just not good evidence that's actually an accurate index of endothelial function, which is what predicts heart disease. Hundreds of studies have shown that the ischemia-induced dilation test can give a false negative result.

Other oils have also been shown to have deleterious results on endothelial function. A significant and constant decrease in endothelial function appears within three hours after each meal, independent of the type of oil and whether the oil was fresh or deep fried. Olive oil may be better than omega-6-rich oils or saturated fats, but it still showed adverse effects. This was the case with regular, refined olive oil. But what about extra-virgin olive oil?

Extra-virgin olive oil retains a fraction of the anti-inflammatory phytonutrients found in the olive fruit, and so doesn't appear to induce the spike in inflammatory markers caused by regular olive oil. What does that mean for our arteries? Extra-virgin olive oil may have more of a neutral effect compared to butter, which exerted a noxious effect that lasted for up to six hours--basically right up until our next meal. In the largest prospective study ever to assess the relationship between olive oil consumption and cardiac events like heart attacks, there was a suggestion that virgin olive oil may be better than regular olive oil, but neither was found to significantly reduce heart attack rates after controlling for healthy dietary behaviors like vegetable intake, which tends to go hand-in-hand with olive oil intake.

There have also been studies showing that even extra-virgin olive oil, contrary to expectations, may significantly impair endothelial function. Why then do some studies suggest endothelial function improves on a Mediterranean diet, which is rich in olive oil? It may be because the Mediterranean diet is also rich in whole grains, fruits, vegetables, beans, and walnuts. Fruits and vegetables appear to provide some protection against the direct impairment of endothelial function produced by high-fat foods, including olive oil; therefore, improvements in health may be in spite of, rather than because of, the oil. In terms of their effects on post-meal endothelial function, the beneficial components of the Mediterranean diet may primarily be the antioxidant-rich foods, the vegetables, fruits, and their derivatives, such as balsamic vinegar. Adding some vegetables to a fatty meal may partially restore arterial functioning and blood flow.


If olive oil can impair our arterial function, Why Was Heart Disease Rare in the Mediterranean? I've got a whole series of videos on the Mediterranean diet that I invite you to check out.

Fatty Meals May Impair Artery Function so much that a single high-fat meal can trigger angina chest pain. But, whole-food sources of fat such as nuts appear to be the exception. See Extra Virgin Olive Oil vs. Nuts and Walnuts and Artery Function.

I've also examined artery function with several other foods: eggs, dark chocolate, coffee, vinegar, tea, and plant-based diets.

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

What a Single Fatty Meal Can Do to Our Arteries

Oct12 Fatty Meal copy.jpeg

The phenomenon of postprandial angina was described more than 200 years ago: chest pain that occurs after a meal, even if you're just sitting down and resting. This could be intuitively attributed to redistribution of blood flow away from the heart to the gut during digestion. However, such a mechanism could not be demonstrated experimentally.

The problem appears to be within the coronary arteries themselves. The clue came in 1955 when researchers found they could induce angina in people with heart disease just by having them drink fat. My video Fatty Meals May Impair Artery Function includes a fascinating graph of so-called lactescence, or milkiness, over time. It shows how their blood became increasingly milky with fat over the next five hours, and each of the ten attacks of angina was found to occur about four-and-a-half to five hours after the fatty meal, right when blood milkiness was at or near its peak. After a nonfat meal with the same bulk and calories, but made out of starch, sugar, and protein, no anginal pain was elicited in any of the patients.

To understand how the mere presence of fat in the blood can affect blood flow to the heart, we need to understand the endothelium, the inner lining of all of our blood vessels. Our arteries are not just rigid pipes; they are living, breathing organs that actively dilate or constrict, thinning or thickening the blood and releasing hormones, depending on what's needed. This is all controlled by the single inner layer, the endothelium, which makes it the body's largest endocrine (hormone-secreting) organ. When it's all gathered up, the endothelium weighs a total of three pounds and has a combined surface area of 700 square yards.

We used to think the endothelium was just an inert layer lining our vascular tree, but now we know better:

Researchers found that low-fat meals tend to improve endothelial function, whereas high-fat meals tend to worsen it. This goes for animal fat, as well as isolated plant fats, such as sunflower oil. But, maybe it's just the digestion of fat rather than the fat itself? Our body can detect the presence of fat in the digestive tract and release a special group of hormones and enzymes. Researchers tried feeding people fake fat and found that the real fat deprived the heart of blood while the fake fat didn't. Is our body really smart enough to tell the difference?

A follow-up study settled the issue. Researchers tried infusing fat directly into people's bloodstream through an IV to sneak it past your mouth and brain. Within hours, their arteries stiffened, significantly crippling their ability to relax and dilate normally. So it was the fat after all! This decrease in the ability to vasodilate coronary arteries after a fatty meal, just when you need it, could explain the phenomenon of after-meal angina in patients with known coronary artery disease.


This effect could certainly help explain the findings in Low Carb Diets and Coronary Blood Flow. My video Olive Oil and Artery Function addresses less refined fats like extra virgin olive oil,.

For more on angina, see the beginning of my 2014 annual talk--From Table to Able: Combating Disabling Diseases with Food--and How Not to Die from Heart Disease.

Another consequence of endothelial dysfunction is lack of blood flow to other organs. Check out Survival of the Firmest: Erectile Dysfunction and Death and Atkins Diet: Trouble Keeping It Up.

Fat in the bloodstream can also impair our ability to control blood sugar levels. Learn more with What Causes Insulin Resistance?, The Spillover Effect Links Obesity to Diabetes, and Lipotoxicity: How Saturated Fat Raises Blood Sugar.

Finally, for more on how diet affects our arteries, check out Tea and Artery Function, Vinegar and Artery Function, and Plant-Based Diets and Artery Function.

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

What a Single Fatty Meal Can Do to Our Arteries

Oct12 Fatty Meal copy.jpeg

The phenomenon of postprandial angina was described more than 200 years ago: chest pain that occurs after a meal, even if you're just sitting down and resting. This could be intuitively attributed to redistribution of blood flow away from the heart to the gut during digestion. However, such a mechanism could not be demonstrated experimentally.

The problem appears to be within the coronary arteries themselves. The clue came in 1955 when researchers found they could induce angina in people with heart disease just by having them drink fat. My video Fatty Meals May Impair Artery Function includes a fascinating graph of so-called lactescence, or milkiness, over time. It shows how their blood became increasingly milky with fat over the next five hours, and each of the ten attacks of angina was found to occur about four-and-a-half to five hours after the fatty meal, right when blood milkiness was at or near its peak. After a nonfat meal with the same bulk and calories, but made out of starch, sugar, and protein, no anginal pain was elicited in any of the patients.

To understand how the mere presence of fat in the blood can affect blood flow to the heart, we need to understand the endothelium, the inner lining of all of our blood vessels. Our arteries are not just rigid pipes; they are living, breathing organs that actively dilate or constrict, thinning or thickening the blood and releasing hormones, depending on what's needed. This is all controlled by the single inner layer, the endothelium, which makes it the body's largest endocrine (hormone-secreting) organ. When it's all gathered up, the endothelium weighs a total of three pounds and has a combined surface area of 700 square yards.

We used to think the endothelium was just an inert layer lining our vascular tree, but now we know better:

Researchers found that low-fat meals tend to improve endothelial function, whereas high-fat meals tend to worsen it. This goes for animal fat, as well as isolated plant fats, such as sunflower oil. But, maybe it's just the digestion of fat rather than the fat itself? Our body can detect the presence of fat in the digestive tract and release a special group of hormones and enzymes. Researchers tried feeding people fake fat and found that the real fat deprived the heart of blood while the fake fat didn't. Is our body really smart enough to tell the difference?

A follow-up study settled the issue. Researchers tried infusing fat directly into people's bloodstream through an IV to sneak it past your mouth and brain. Within hours, their arteries stiffened, significantly crippling their ability to relax and dilate normally. So it was the fat after all! This decrease in the ability to vasodilate coronary arteries after a fatty meal, just when you need it, could explain the phenomenon of after-meal angina in patients with known coronary artery disease.


This effect could certainly help explain the findings in Low Carb Diets and Coronary Blood Flow. My video Olive Oil and Artery Function addresses less refined fats like extra virgin olive oil,.

For more on angina, see the beginning of my 2014 annual talk--From Table to Able: Combating Disabling Diseases with Food--and How Not to Die from Heart Disease.

Another consequence of endothelial dysfunction is lack of blood flow to other organs. Check out Survival of the Firmest: Erectile Dysfunction and Death and Atkins Diet: Trouble Keeping It Up.

Fat in the bloodstream can also impair our ability to control blood sugar levels. Learn more with What Causes Insulin Resistance?, The Spillover Effect Links Obesity to Diabetes, and Lipotoxicity: How Saturated Fat Raises Blood Sugar.

Finally, for more on how diet affects our arteries, check out Tea and Artery Function, Vinegar and Artery Function, and Plant-Based Diets and Artery Function.

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

Choosing to Have a Normal Blood Pressure

Oct 5 Blood Pressure copy.jpeg

For the first 90% of our evolution, humans ate diets containing less than a quarter teaspoon of salt a day. Why? Because we ate mostly plants. Since we went millions of years without salt shakers, our bodies evolved into salt-conserving machines, which served us well until we discovered salt could be used to preserve foods. Without refrigeration, this was a big boon to human civilization. Of course, this may have led to a general rise in blood pressure, but does that matter if the alternative is starving to death since all your food rotted away? But where does that leave us now, when we no longer have to live off pickles and jerky? We are genetically programmed to eat ten times less salt than we do now. Even many "low"-salt diets can be considered high-salt diets. That's why it's critical to understand what the concept of "normal" is when it comes to salt.

As I discuss in my video High Blood Pressure May Be a Choice, having a "normal" salt intake can lead to a "normal" blood pressure, which can help us to die from all the "normal" causes, like heart attacks and strokes.

Doctors used to be taught that a "normal" systolic blood pressure (the top number) is approximately 100 plus age. Babies start out with a blood pressure around 95 over 60, but then as we age that 95 can go to 120 by our 20s, then 140 in our 40s, and keep climbing as we age. (140 is the official cut-off above which one technically has high blood pressure.) That was considered normal, since everyone's blood pressure creeps up as we get older. And if that's normal, then heart attacks and strokes are normal too, since risk starts rising once we start getting above the 100 we had as a baby.

If blood pressures over 100 are associated with disease, maybe they should be considered abnormal. Were these elevated blood pressures caused by our abnormally high salt intake--ten times more than what our bodies were designed to handle? Maybe if we ate a natural amount of salt, our blood pressures would not go up with age and we'd be protected. Of course, to test that theory you'd have to find a population in modern times that doesn't use salt, eat processed food, or go out to eat. For that, you'd have to go deep into the Amazon rainforest.

Meet the Yanomamo people, a no-salt culture with the lowest salt intake ever reported. That is, they have a totally normal-for-our-species salt intake. So, what happens to their blood pressure on a no- or low-salt diet as they age? They start out with a blood pressure of about 100 over 60 and end up with a blood pressure of about 100 over 60. Though theirs is described as a salt-deficient diet, that's like saying they have a diet deficient in Twinkies. They're the ones, it seems, who are eating truly normal salt intakes, which leads to truly normal blood pressures. Those in their 50s have the blood pressure of a 20-year-old. What was the percentage of the population tested with high blood pressure? Zero. However, elsewhere in Brazil, up to 38% of the population may be affected. The Yanomamos probably represent the ultimate human example of the importance of salt on blood pressure.

Of course, there could have been other factors. They didn't drink alcohol, ate a high-fiber and plant-based diet, got lots of exercise, and had no obesity. There are a number of plant-based populations eating little salt who experience no rise of blood pressure with age, but how do we know what exactly is to blame? Ideally, we'd do an interventional trial. Imagine if we took people literally dying from out-of-control high blood pressure (so called malignant hypertension) where you go blind from bleeding into your eyes, your kidneys shut down, and your heart fails, and then we withhold from these patients blood pressure medications so their fate is certain death. Then, what if we put them on a Yanomamo level of salt intake--that is, a normal-for-the-human-species salt intake--and, if instead of dying, they walked away cured of their hypertension? That would pretty much seal the deal.

Enter Dr. Walter Kempner and his rice and fruit diet. Patients started with blood pressures of 210 over 140, which dropped down to 80 over 60. Amazing stuff, but how could he ethically withhold all modern blood pressure medications and treat with diet alone? This was back in the 1940s, and the drugs hadn't been invented yet.

His diet wasn't just extremely low salt, though; it was also strictly plant-based and extremely low in fat, protein, and calories. There is no doubt that Kempner's rice diet achieved remarkable results, and Kempner is now remembered as the person who demonstrated, beyond any shadow of doubt, that high blood pressure can often be lowered by a low enough salt diet.

Forty years ago, it was acknowledged that the evidence is very good, if not conclusive, that a low enough reduction of salt in the diet would result in the prevention of essential hypertension (the rising of blood pressure as we age) and its disappearance as a major public health problem. It looks like we knew how to stop this four decades ago. During this time, how many people have died? Today, high blood pressure may kill 400,000 Americans every year--causing a thousand unnecessary deaths every day.


I have a whole series of videos on salt, including Sprinkling Doubt: Taking Sodium Skeptics with a Pinch of Salt, The Evidence That Salt Raises Blood Pressure, Shaking the Salt Habit and Sodium & Autoimmune Disease: Rubbing Salt in the Wound.

Canned foods are infamous for their sodium content, but there are no-salt varieties. Learn more with my video Canned Beans or Cooked Beans?. Cutting down on sodium is one of the ways we could be Improving on the Mediterranean Diet. Beyond heart health, reducing salt intake could also help our kidneys (How to Treat Kidney Stones with Diet) but if you cut down on salt, won't everything taste like cardboard? See Changing Our Taste Buds.

For more on hypertension, see How to Prevent High Blood Pressure with Diet, How to Treat High Blood Pressure with Diet, and How Not to Die from High Blood Pressure. What if you already eat healthfully and still can't get your pressures down? Try adding hibiscus tea (Hibiscus Tea vs. Plant-Based Diets for Hypertension) and ground flaxseeds (Flax Seeds for Hypertension) to your diet, and, of course, make sure you're exercising regularly (Longer Life Within Walking Distance).

Dr. Kempner and his rice diet are so fascinating they warrant an entire video series. Check out Kempner Rice Diet: Whipping Us Into Shape, Drugs and the Demise of the Rice Diet, Can Diabetic Retinopathy Be Reversed?, and Can Morbid Obesity be Reversed Through Diet?.

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

Choosing to Have a Normal Blood Pressure

Oct 5 Blood Pressure copy.jpeg

For the first 90% of our evolution, humans ate diets containing less than a quarter teaspoon of salt a day. Why? Because we ate mostly plants. Since we went millions of years without salt shakers, our bodies evolved into salt-conserving machines, which served us well until we discovered salt could be used to preserve foods. Without refrigeration, this was a big boon to human civilization. Of course, this may have led to a general rise in blood pressure, but does that matter if the alternative is starving to death since all your food rotted away? But where does that leave us now, when we no longer have to live off pickles and jerky? We are genetically programmed to eat ten times less salt than we do now. Even many "low"-salt diets can be considered high-salt diets. That's why it's critical to understand what the concept of "normal" is when it comes to salt.

As I discuss in my video High Blood Pressure May Be a Choice, having a "normal" salt intake can lead to a "normal" blood pressure, which can help us to die from all the "normal" causes, like heart attacks and strokes.

Doctors used to be taught that a "normal" systolic blood pressure (the top number) is approximately 100 plus age. Babies start out with a blood pressure around 95 over 60, but then as we age that 95 can go to 120 by our 20s, then 140 in our 40s, and keep climbing as we age. (140 is the official cut-off above which one technically has high blood pressure.) That was considered normal, since everyone's blood pressure creeps up as we get older. And if that's normal, then heart attacks and strokes are normal too, since risk starts rising once we start getting above the 100 we had as a baby.

If blood pressures over 100 are associated with disease, maybe they should be considered abnormal. Were these elevated blood pressures caused by our abnormally high salt intake--ten times more than what our bodies were designed to handle? Maybe if we ate a natural amount of salt, our blood pressures would not go up with age and we'd be protected. Of course, to test that theory you'd have to find a population in modern times that doesn't use salt, eat processed food, or go out to eat. For that, you'd have to go deep into the Amazon rainforest.

Meet the Yanomamo people, a no-salt culture with the lowest salt intake ever reported. That is, they have a totally normal-for-our-species salt intake. So, what happens to their blood pressure on a no- or low-salt diet as they age? They start out with a blood pressure of about 100 over 60 and end up with a blood pressure of about 100 over 60. Though theirs is described as a salt-deficient diet, that's like saying they have a diet deficient in Twinkies. They're the ones, it seems, who are eating truly normal salt intakes, which leads to truly normal blood pressures. Those in their 50s have the blood pressure of a 20-year-old. What was the percentage of the population tested with high blood pressure? Zero. However, elsewhere in Brazil, up to 38% of the population may be affected. The Yanomamos probably represent the ultimate human example of the importance of salt on blood pressure.

Of course, there could have been other factors. They didn't drink alcohol, ate a high-fiber and plant-based diet, got lots of exercise, and had no obesity. There are a number of plant-based populations eating little salt who experience no rise of blood pressure with age, but how do we know what exactly is to blame? Ideally, we'd do an interventional trial. Imagine if we took people literally dying from out-of-control high blood pressure (so called malignant hypertension) where you go blind from bleeding into your eyes, your kidneys shut down, and your heart fails, and then we withhold from these patients blood pressure medications so their fate is certain death. Then, what if we put them on a Yanomamo level of salt intake--that is, a normal-for-the-human-species salt intake--and, if instead of dying, they walked away cured of their hypertension? That would pretty much seal the deal.

Enter Dr. Walter Kempner and his rice and fruit diet. Patients started with blood pressures of 210 over 140, which dropped down to 80 over 60. Amazing stuff, but how could he ethically withhold all modern blood pressure medications and treat with diet alone? This was back in the 1940s, and the drugs hadn't been invented yet.

His diet wasn't just extremely low salt, though; it was also strictly plant-based and extremely low in fat, protein, and calories. There is no doubt that Kempner's rice diet achieved remarkable results, and Kempner is now remembered as the person who demonstrated, beyond any shadow of doubt, that high blood pressure can often be lowered by a low enough salt diet.

Forty years ago, it was acknowledged that the evidence is very good, if not conclusive, that a low enough reduction of salt in the diet would result in the prevention of essential hypertension (the rising of blood pressure as we age) and its disappearance as a major public health problem. It looks like we knew how to stop this four decades ago. During this time, how many people have died? Today, high blood pressure may kill 400,000 Americans every year--causing a thousand unnecessary deaths every day.


I have a whole series of videos on salt, including Sprinkling Doubt: Taking Sodium Skeptics with a Pinch of Salt, The Evidence That Salt Raises Blood Pressure, Shaking the Salt Habit and Sodium & Autoimmune Disease: Rubbing Salt in the Wound.

Canned foods are infamous for their sodium content, but there are no-salt varieties. Learn more with my video Canned Beans or Cooked Beans?. Cutting down on sodium is one of the ways we could be Improving on the Mediterranean Diet. Beyond heart health, reducing salt intake could also help our kidneys (How to Treat Kidney Stones with Diet) but if you cut down on salt, won't everything taste like cardboard? See Changing Our Taste Buds.

For more on hypertension, see How to Prevent High Blood Pressure with Diet, How to Treat High Blood Pressure with Diet, and How Not to Die from High Blood Pressure. What if you already eat healthfully and still can't get your pressures down? Try adding hibiscus tea (Hibiscus Tea vs. Plant-Based Diets for Hypertension) and ground flaxseeds (Flax Seeds for Hypertension) to your diet, and, of course, make sure you're exercising regularly (Longer Life Within Walking Distance).

Dr. Kempner and his rice diet are so fascinating they warrant an entire video series. Check out Kempner Rice Diet: Whipping Us Into Shape, Drugs and the Demise of the Rice Diet, Can Diabetic Retinopathy Be Reversed?, and Can Morbid Obesity be Reversed Through Diet?.

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

Fish Consumption and Suicide

Sept 12 Fish Consumption copy.jpeg

Depression is a serious and common mental disorder responsible for the majority of suicides. As I've covered in Antioxidants & Depression, intake of fruits, vegetables, and naturally occurring antioxidants have been found to be protectively associated with depression. Therefore, researchers have considered that "it may be possible to prevent depression or to lessen its negative effects through dietary intervention."

But not so fast. Cross-sectional studies are snapshots in time, so we don't know "whether a poor dietary pattern precedes the development of depression or if depression causes poor dietary intake." Depression and even treatments for depression can affect appetite and dietary intake. Maybe people who feel crappier just eat crappier, instead of the other way around.

What we need is a prospective study (a study performed over time) where we start out with people who are not depressed and follow them for several years. In 2012, we got just such a study, which ran over six years. As you'll see in my video Fish Consumption and Suicide, those with higher carotenoid levels in their bloodstream, which is considered a good indicator of fruit and vegetable intake, had a 28% lower risk of becoming depressed within that time. The researchers conclude that having low blood levels of those healthy phytonutrients may predict the development of new depressive symptoms. What about suicide?

Worldwide, a million people kill themselves every year. Of all European countries, Greece appears to have the lowest rates of suicide. It may be the balmy weather, but it may also have something to do with their diet. Ten thousand people were followed for years, and those following a more Mediterranean diet pattern were less likely to be diagnosed with depression. What was it about the diet that was protective? It wasn't the red wine or fish; it was the fruit, nuts, beans, and effectively higher plant to animal fat ratio that appeared protective. Conversely, significant adverse trends were observed for dairy and meat consumption.

A similar protective dietary pattern was found in Japan. A high intake of vegetables, fruits, mushrooms, and soy products was associated with a decreased prevalence of depressive symptoms. The healthy dietary pattern was not characterized by a high intake of seafood. Similar results were found in a study of 100,000 Japanese men and women followed for up to 10 years. There was no evidence of a protective role of higher fish consumption or the long-chain omega 3s EPA and DHA against suicide. In fact, they found a significantly increased risk of suicide among male nondrinkers with high seafood omega 3 intake. This may have been by chance, but a similar result was found in the Mediterranean. High baseline fish consumption with an increase in consumption were associated with an increased risk of mental disorders.

One possible explanation could be the mercury content of fish. Could an accumulation of mercury compounds in the body increase the risk of depression? We know that mercury in fish can cause neurological damage, associated with increased risk of Alzheimer's disease, memory loss, and autism, but also depression. Therefore, "the increased risk of suicide among persons with a high fish intake might also be attributable to the harmful effects of mercury in fish."

Large Harvard University cohort studies found similar results. Hundreds of thousands were followed for up to 20 years, and no evidence was found that taking fish oil or eating fish lowered risk of suicide. There was even a trend towards higher suicide mortality.

What about fish consumption for the treatment of depression? When we put together all the trials done to date, neither the EPA nor DHA long-chain omega-3s appears more effective than sugar pills. We used to think omega-3 supplementation was useful, but several recent studies have tipped the balance the other way. It seems that "[n]early all of the treatment efficacy observed in the published literature may be attributable to publication bias," meaning the trials that showed no benefit tended not to get published at all. So, all doctors saw were a bunch of positive studies, but only because a bunch of the negative ones were buried.

This reminds me of my Is Fish Oil Just Snake Oil? video. Just like we thought omega-3 supplementation could help with mood, we also thought it could help with heart health, but the balance of evidence has decidedly shifted. I still recommend the consumption of pollutant-free sources of preformed long-chain omega 3s for cognitive health and explain my rationale in Should We Take DHA Supplements to Boost Brain Function? and Should Vegans Take DHA to Preserve Brain Function?


For more on the neurotoxic nature of mercury-contaminated seafood, see:

What can we do to help our mood? See:

What about antidepressant drugs? Sometimes they can be absolutely life-saving, but other times they may actually do more harm than good. See my controversial video Do Antidepressant Drugs Really Work?.

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

Fish Consumption and Suicide

Sept 12 Fish Consumption copy.jpeg

Depression is a serious and common mental disorder responsible for the majority of suicides. As I've covered in Antioxidants & Depression, intake of fruits, vegetables, and naturally occurring antioxidants have been found to be protectively associated with depression. Therefore, researchers have considered that "it may be possible to prevent depression or to lessen its negative effects through dietary intervention."

But not so fast. Cross-sectional studies are snapshots in time, so we don't know "whether a poor dietary pattern precedes the development of depression or if depression causes poor dietary intake." Depression and even treatments for depression can affect appetite and dietary intake. Maybe people who feel crappier just eat crappier, instead of the other way around.

What we need is a prospective study (a study performed over time) where we start out with people who are not depressed and follow them for several years. In 2012, we got just such a study, which ran over six years. As you'll see in my video Fish Consumption and Suicide, those with higher carotenoid levels in their bloodstream, which is considered a good indicator of fruit and vegetable intake, had a 28% lower risk of becoming depressed within that time. The researchers conclude that having low blood levels of those healthy phytonutrients may predict the development of new depressive symptoms. What about suicide?

Worldwide, a million people kill themselves every year. Of all European countries, Greece appears to have the lowest rates of suicide. It may be the balmy weather, but it may also have something to do with their diet. Ten thousand people were followed for years, and those following a more Mediterranean diet pattern were less likely to be diagnosed with depression. What was it about the diet that was protective? It wasn't the red wine or fish; it was the fruit, nuts, beans, and effectively higher plant to animal fat ratio that appeared protective. Conversely, significant adverse trends were observed for dairy and meat consumption.

A similar protective dietary pattern was found in Japan. A high intake of vegetables, fruits, mushrooms, and soy products was associated with a decreased prevalence of depressive symptoms. The healthy dietary pattern was not characterized by a high intake of seafood. Similar results were found in a study of 100,000 Japanese men and women followed for up to 10 years. There was no evidence of a protective role of higher fish consumption or the long-chain omega 3s EPA and DHA against suicide. In fact, they found a significantly increased risk of suicide among male nondrinkers with high seafood omega 3 intake. This may have been by chance, but a similar result was found in the Mediterranean. High baseline fish consumption with an increase in consumption were associated with an increased risk of mental disorders.

One possible explanation could be the mercury content of fish. Could an accumulation of mercury compounds in the body increase the risk of depression? We know that mercury in fish can cause neurological damage, associated with increased risk of Alzheimer's disease, memory loss, and autism, but also depression. Therefore, "the increased risk of suicide among persons with a high fish intake might also be attributable to the harmful effects of mercury in fish."

Large Harvard University cohort studies found similar results. Hundreds of thousands were followed for up to 20 years, and no evidence was found that taking fish oil or eating fish lowered risk of suicide. There was even a trend towards higher suicide mortality.

What about fish consumption for the treatment of depression? When we put together all the trials done to date, neither the EPA nor DHA long-chain omega-3s appears more effective than sugar pills. We used to think omega-3 supplementation was useful, but several recent studies have tipped the balance the other way. It seems that "[n]early all of the treatment efficacy observed in the published literature may be attributable to publication bias," meaning the trials that showed no benefit tended not to get published at all. So, all doctors saw were a bunch of positive studies, but only because a bunch of the negative ones were buried.

This reminds me of my Is Fish Oil Just Snake Oil? video. Just like we thought omega-3 supplementation could help with mood, we also thought it could help with heart health, but the balance of evidence has decidedly shifted. I still recommend the consumption of pollutant-free sources of preformed long-chain omega 3s for cognitive health and explain my rationale in Should We Take DHA Supplements to Boost Brain Function? and Should Vegans Take DHA to Preserve Brain Function?


For more on the neurotoxic nature of mercury-contaminated seafood, see:

What can we do to help our mood? See:

What about antidepressant drugs? Sometimes they can be absolutely life-saving, but other times they may actually do more harm than good. See my controversial video Do Antidepressant Drugs Really Work?.

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