The Two Most Active Ingredients of the Mediterranean Diet

Which Parts of the Mediterranean Diet Extended Life.jpg

Olives and nuts are plant foods, and as such, are packed with antioxidants, raising the antioxidant level of our bloodstream resulting in lower fat oxidation and free radical DNA damage, but what's happening inside people's arteries?

Researchers measured the amount of atherosclerotic plaque in the neck arteries going to the brain in folks who for years were eating added nuts, added extra virgin olive oil or neither to their daily diets. In the control group, the plaque got worse, which is what happens when one continues to eat an artery-clogging diet, but there were no significant changes in the added extra virgin olive oil group, and the plaque in the added nut group appeared to get better. The nuts appeared to induce a regression of the disease, or at least a significant delay in the progression. The nut group was still suffering strokes, but only half as many, perhaps because the reduction in plaque height within the arteries on extra nuts was indicating a stabilization of the plaque, rendering them less likely to rupture. You can see these results in my video Which Parts of the Mediterranean Diet Extended Life?

Adding nuts to our diet may also improve endothelial function, boosting the ability of our arteries to dilate naturally by about 30 percent. If you look at the baseline adherence to Mediterranean diet principles and control for things like smoking and exercise, there were only two factors significantly associated with reduced heart attack and stroke risk: more vegetables and more nuts. No significant association with the olive oil, wine, fish or cutting back on soda and cookies. Among the individual components, only increased consumption of vegetables and nuts were related to reduced cardiovascular events.

On the one hand, cutting stroke risk in half just by eating a handful of nuts a day is pretty amazing, but those in the added nut group didn't appear to live any longer overall. This is in contrast to other studies that suggested that frequent nut consumption may extend life. For example, the Harvard health professionals studies, involving a whopping three million person-years of follow-up over decades, found nut consumption associated with fewer deaths from cancer, heart disease, respiratory disease and most importantly fewer deaths overall. This was confirmed by all the other big major prospective studies in a recent review.

So what's going on here with the study showing no longevity benefit from nuts? Did they just not wait long enough? Just because people were randomized to the nut group didn't mean they actually ate more nuts, and those randomized to the other groups didn't necessarily stay away.

If you re-analyze the data comparing the death rates of those who actually ate more nuts to those who actually didn't, nut consumption was indeed associated with significantly reduced risk of death. If you do the same kind of post hoc analysis with olive oil, even with the extra virgin, there is no benefit in terms of living longer. This is consistent with how Ancel Keys, the so-called Father of the Mediterranean diet, viewed olive oil. He thought of its benefit more as a way of just replacing animal fats; anything to get people to eat less lard and butter.

What is the best kind of nut? The greatest benefits were attributed to walnuts, particularly for preventing cancer deaths. Those eating more than three servings of walnuts a week appeared to cut their risk of dying from cancer in half.

Now it's just a matter of communicating the research to the public. All the major cancer groups emphasize a more plant-based diet, remarkably consistent with the World Health Organization guidelines for healthy eating. The far-reaching positive effects of a plant-based diet--including walnuts--may be the most critical message for the public.

Here are some of my previous videos on the Mediterranean diet:

Think the effects of adding a few nuts to one's daily diet are too good to believe? Check out my video Four Nuts Once a Month. For more on Walnuts and Artery Function check out the video, and for more on nuts and cancer prevention, see Which Nut Fights Cancer Better?

Nuts May Help Prevent Death and so may beans; see Increased Lifespan from Beans. What about Fruits and Longevity: How Many Minutes per Mouthful?

More on protecting ourselves from "brain attacks" in Preventing Strokes with 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:

Image Credit: garlandcannon / Flickr. This image has been modified.

Original Link

The Two Most Active Ingredients of the Mediterranean Diet

Which Parts of the Mediterranean Diet Extended Life.jpg

Olives and nuts are plant foods, and as such, are packed with antioxidants, raising the antioxidant level of our bloodstream resulting in lower fat oxidation and free radical DNA damage, but what's happening inside people's arteries?

Researchers measured the amount of atherosclerotic plaque in the neck arteries going to the brain in folks who for years were eating added nuts, added extra virgin olive oil or neither to their daily diets. In the control group, the plaque got worse, which is what happens when one continues to eat an artery-clogging diet, but there were no significant changes in the added extra virgin olive oil group, and the plaque in the added nut group appeared to get better. The nuts appeared to induce a regression of the disease, or at least a significant delay in the progression. The nut group was still suffering strokes, but only half as many, perhaps because the reduction in plaque height within the arteries on extra nuts was indicating a stabilization of the plaque, rendering them less likely to rupture. You can see these results in my video Which Parts of the Mediterranean Diet Extended Life?

Adding nuts to our diet may also improve endothelial function, boosting the ability of our arteries to dilate naturally by about 30 percent. If you look at the baseline adherence to Mediterranean diet principles and control for things like smoking and exercise, there were only two factors significantly associated with reduced heart attack and stroke risk: more vegetables and more nuts. No significant association with the olive oil, wine, fish or cutting back on soda and cookies. Among the individual components, only increased consumption of vegetables and nuts were related to reduced cardiovascular events.

On the one hand, cutting stroke risk in half just by eating a handful of nuts a day is pretty amazing, but those in the added nut group didn't appear to live any longer overall. This is in contrast to other studies that suggested that frequent nut consumption may extend life. For example, the Harvard health professionals studies, involving a whopping three million person-years of follow-up over decades, found nut consumption associated with fewer deaths from cancer, heart disease, respiratory disease and most importantly fewer deaths overall. This was confirmed by all the other big major prospective studies in a recent review.

So what's going on here with the study showing no longevity benefit from nuts? Did they just not wait long enough? Just because people were randomized to the nut group didn't mean they actually ate more nuts, and those randomized to the other groups didn't necessarily stay away.

If you re-analyze the data comparing the death rates of those who actually ate more nuts to those who actually didn't, nut consumption was indeed associated with significantly reduced risk of death. If you do the same kind of post hoc analysis with olive oil, even with the extra virgin, there is no benefit in terms of living longer. This is consistent with how Ancel Keys, the so-called Father of the Mediterranean diet, viewed olive oil. He thought of its benefit more as a way of just replacing animal fats; anything to get people to eat less lard and butter.

What is the best kind of nut? The greatest benefits were attributed to walnuts, particularly for preventing cancer deaths. Those eating more than three servings of walnuts a week appeared to cut their risk of dying from cancer in half.

Now it's just a matter of communicating the research to the public. All the major cancer groups emphasize a more plant-based diet, remarkably consistent with the World Health Organization guidelines for healthy eating. The far-reaching positive effects of a plant-based diet--including walnuts--may be the most critical message for the public.

Here are some of my previous videos on the Mediterranean diet:

Think the effects of adding a few nuts to one's daily diet are too good to believe? Check out my video Four Nuts Once a Month. For more on Walnuts and Artery Function check out the video, and for more on nuts and cancer prevention, see Which Nut Fights Cancer Better?

Nuts May Help Prevent Death and so may beans; see Increased Lifespan from Beans. What about Fruits and Longevity: How Many Minutes per Mouthful?

More on protecting ourselves from "brain attacks" in Preventing Strokes with 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:

Image Credit: garlandcannon / Flickr. This image has been modified.

Original Link

Benefits of Nuts for Stroke Prevention

PREDIMED - Does Eating Nuts Prevent Strokes.jpg

In the PREDIMED study, from the Spanish "PREvencio ́n con DIeta MEDiterranea," a whopping 7,447 patients were randomized into three groups. These were folks at high risk for a heart attack, about half were obese, diabetic and most had high blood pressure and high cholesterol, but they had not yet had their first heart attack or stroke. A third were told to eat a Mediterranean diet and given a free quart of extra virgin olive oil every week. The second group were told to eat a Mediterranean diet and given a half pound of free nuts every week, and the last third were told to follow the American Heart Association guidelines and reduce their fat intake. No portion control or exercise advice was given, and they were followed for about five years. The results were published in the New England Journal of Medicine.

The first thing you do when you look at a diet intervention trial is see what the groups actually ended up eating, which can be very different from what they were told to eat. For example, the so-called low-fat group started out at 39 percent of calories from fat, and ended up getting 37 percent of calories from fat, which is high fat even compared to the Standard American Diet which comes in at 33 percent, something the researchers plainly acknowledged. In fact, the control group didn't change much at all over the years, so can be thought of as the what-if-you-don't-do-anything group, which is still an important control group to have. Though the two Mediterranean diet groups didn't get much more Mediterranean. You can see the charts in my video PREDIMED: Does Eating Nuts Prevent Strokes?

The two Mediterranean groups were told to eat more fruits and vegetables, for example, and less meat and dairy, but didn't accomplish any of those compared to control. The biggest changes recorded were, not surprisingly, in the consumption of the freebies. The group that got a free jug of extra-virgin olive oil delivered to their home every week really did start increasing their consumption, in part by replacing some of the refined olive oil they had been using. And those that got a half pound of free nuts sent to them every week for four years straight did start eating more nuts.

Basically the researchers designed a study to test two different Mediterranean diets versus a low fat diet, but ended up studying something very different. In essence, they studied what happens when thousands of people switch from consuming about three tablespoons of olive oil a day (half virgin) to four tablespoons of all virgin, compared to thousands of people who all the sudden go from eating about a half an ounce of nuts a day to a whole ounce, compared to thousands of people who don't make much of a change at all. It may not have been what they were hoping for, but these are important research questions in and of themselves.

With no significant differences in meat and dairy intake, there were no significant differences in saturated fat or cholesterol intake, so no surprise there was no significant differences in their blood cholesterol levels, and so no difference in their subsequent number of heart attacks. In the five or so years the study ran, there were 37 heart attacks in the olive oil group, 31 in the nut group and 38 in the neither group. No significant difference. Same with dying from a heart attack or stroke or from any cause--but, those in the olive oil and especially the nut group had significantly fewer strokes. All three groups were eating stroke-promoting diets; some people in all three groups had strokes after eating these diets for years, and so ideally we'd choose diets that can stop or reverse the disease process, but the diet with added extra virgin olive oil caused about a third fewer strokes, and adding nuts seemed to cut their stroke risk nearly in half. If this worked as well in the general population, in the U.S. alone that would mean preventing 89,000 strokes a year. That's would be like ten strokes an hour around the clock prevented simply by adding half an ounce of nuts to one's daily diet.

Here are some of my previous videos on the Mediterranean diet:

The PREDIMED study got a bad rap because of how it was reported, but it's an extraordinary trial that continues to churn out useful results.

More on nuts in:

But what about nuts and weight gain? See Nuts and Obesity: The Weight of Evidence .

For videos on olive oil, see Extra Virgin Olive Oil vs. Nuts and Olive Oil & 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:

Image Credit: Sally Plank / Flickr. This image has been modified.

Original Link

Benefits of Nuts for Stroke Prevention

PREDIMED - Does Eating Nuts Prevent Strokes.jpg

In the PREDIMED study, from the Spanish "PREvencio ́n con DIeta MEDiterranea," a whopping 7,447 patients were randomized into three groups. These were folks at high risk for a heart attack, about half were obese, diabetic and most had high blood pressure and high cholesterol, but they had not yet had their first heart attack or stroke. A third were told to eat a Mediterranean diet and given a free quart of extra virgin olive oil every week. The second group were told to eat a Mediterranean diet and given a half pound of free nuts every week, and the last third were told to follow the American Heart Association guidelines and reduce their fat intake. No portion control or exercise advice was given, and they were followed for about five years. The results were published in the New England Journal of Medicine.

The first thing you do when you look at a diet intervention trial is see what the groups actually ended up eating, which can be very different from what they were told to eat. For example, the so-called low-fat group started out at 39 percent of calories from fat, and ended up getting 37 percent of calories from fat, which is high fat even compared to the Standard American Diet which comes in at 33 percent, something the researchers plainly acknowledged. In fact, the control group didn't change much at all over the years, so can be thought of as the what-if-you-don't-do-anything group, which is still an important control group to have. Though the two Mediterranean diet groups didn't get much more Mediterranean. You can see the charts in my video PREDIMED: Does Eating Nuts Prevent Strokes?

The two Mediterranean groups were told to eat more fruits and vegetables, for example, and less meat and dairy, but didn't accomplish any of those compared to control. The biggest changes recorded were, not surprisingly, in the consumption of the freebies. The group that got a free jug of extra-virgin olive oil delivered to their home every week really did start increasing their consumption, in part by replacing some of the refined olive oil they had been using. And those that got a half pound of free nuts sent to them every week for four years straight did start eating more nuts.

Basically the researchers designed a study to test two different Mediterranean diets versus a low fat diet, but ended up studying something very different. In essence, they studied what happens when thousands of people switch from consuming about three tablespoons of olive oil a day (half virgin) to four tablespoons of all virgin, compared to thousands of people who all the sudden go from eating about a half an ounce of nuts a day to a whole ounce, compared to thousands of people who don't make much of a change at all. It may not have been what they were hoping for, but these are important research questions in and of themselves.

With no significant differences in meat and dairy intake, there were no significant differences in saturated fat or cholesterol intake, so no surprise there was no significant differences in their blood cholesterol levels, and so no difference in their subsequent number of heart attacks. In the five or so years the study ran, there were 37 heart attacks in the olive oil group, 31 in the nut group and 38 in the neither group. No significant difference. Same with dying from a heart attack or stroke or from any cause--but, those in the olive oil and especially the nut group had significantly fewer strokes. All three groups were eating stroke-promoting diets; some people in all three groups had strokes after eating these diets for years, and so ideally we'd choose diets that can stop or reverse the disease process, but the diet with added extra virgin olive oil caused about a third fewer strokes, and adding nuts seemed to cut their stroke risk nearly in half. If this worked as well in the general population, in the U.S. alone that would mean preventing 89,000 strokes a year. That's would be like ten strokes an hour around the clock prevented simply by adding half an ounce of nuts to one's daily diet.

Here are some of my previous videos on the Mediterranean diet:

The PREDIMED study got a bad rap because of how it was reported, but it's an extraordinary trial that continues to churn out useful results.

More on nuts in:

But what about nuts and weight gain? See Nuts and Obesity: The Weight of Evidence .

For videos on olive oil, see Extra Virgin Olive Oil vs. Nuts and Olive Oil & 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:

Image Credit: Sally Plank / Flickr. This image has been modified.

Original Link

Improving Employee Diets Could Save Companies Millions

Plant-Based Workplace Intervention.jpg

The food, alcohol, and tobacco industries have been blamed for "manufacturing epidemics" of chronic disease, but they're just trying to sell more product like everyone else. And so if that means distorting science, creating front groups, compromising scientists, blocking public health policies... they're just trying to protect their business.

It's not about customer satisfaction, but shareholder satisfaction. How else could we have tobacco companies, for example, "continuing to produce products that kill one in two of their most loyal customers?"

Civil society organizations concerned with public health have earned a reputation for being "anti-industry," but the issue is not industry, but that sector of industry whose products are harmful to public health. We like the broccoli industry. In fact, the corporate world might end up leading the lifestyle medicine revolution.

As shown in my video, Plant-Based Workplace Intervention, the annual cost attributable to obesity alone among full-time employees is estimated at 70 billion dollars, primarily because obese employees are not as productive on the job. Having healthy employees is good for the bottom-line. Every dollar spent on wellness programs may offer a $3 return on investment. And if you track the market performance of companies that strive to nurture a culture of health, they appear to outperform their competition.

That's why companies like GEICO are exploring workplace dietary interventions (see my video, Slimming the Gecko). The remarkable success at GEICO headquarters led to an expansion of the program at corporate offices across the country, with test sites from San Diego to Macon, Georgia. Given that previous workplace studies have found that workers who ate a lot of animal protein had nearly five times the odds of obesity, whereas those that ate mostly plant protein appeared protected, obese and diabetic employees were asked to follow a plant-based diet of whole grains, vegetables, beans, and fruit while avoiding meat, dairy, and eggs. Compliance wasn't great. Fewer than half really got their animal product consumption down, but there were definitely improvements such as significant reductions in saturated fat, an increase in protective nutrients, and even noted weight loss, lower blood cholesterol levers, and better blood sugar control in diabetics.

And this was with no calorie counting, no portion control, and no exercise component. The weight reduction appears to result from feeling fuller earlier, due to higher dietary fiber intake. The difference in weight loss could also be the result of an increase in the thermic effect of food, allowing a small extra edge for weight loss in the vegan group. Those eating plant-based diets tend to burn off more calories in heat.

Eating plants appears to boost metabolism. This may be due to increased insulin sensitivity in cells, allowing cells to metabolize carbohydrates more quickly rather than storing them as body fat. "As a result, vegan diets have been shown to increase postprandial calorie burn by about 16%, up to three hours after consuming a meal."

Imagine how much money companies that self-insure their employees could save! See, for example:

Find out more on some of the potential downsides of corporate influence in videos like

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: Ryan McGuire / Pixabay. This image has been modified.

Original Link

Improving Employee Diets Could Save Companies Millions

Plant-Based Workplace Intervention.jpg

The food, alcohol, and tobacco industries have been blamed for "manufacturing epidemics" of chronic disease, but they're just trying to sell more product like everyone else. And so if that means distorting science, creating front groups, compromising scientists, blocking public health policies... they're just trying to protect their business.

It's not about customer satisfaction, but shareholder satisfaction. How else could we have tobacco companies, for example, "continuing to produce products that kill one in two of their most loyal customers?"

Civil society organizations concerned with public health have earned a reputation for being "anti-industry," but the issue is not industry, but that sector of industry whose products are harmful to public health. We like the broccoli industry. In fact, the corporate world might end up leading the lifestyle medicine revolution.

As shown in my video, Plant-Based Workplace Intervention, the annual cost attributable to obesity alone among full-time employees is estimated at 70 billion dollars, primarily because obese employees are not as productive on the job. Having healthy employees is good for the bottom-line. Every dollar spent on wellness programs may offer a $3 return on investment. And if you track the market performance of companies that strive to nurture a culture of health, they appear to outperform their competition.

That's why companies like GEICO are exploring workplace dietary interventions (see my video, Slimming the Gecko). The remarkable success at GEICO headquarters led to an expansion of the program at corporate offices across the country, with test sites from San Diego to Macon, Georgia. Given that previous workplace studies have found that workers who ate a lot of animal protein had nearly five times the odds of obesity, whereas those that ate mostly plant protein appeared protected, obese and diabetic employees were asked to follow a plant-based diet of whole grains, vegetables, beans, and fruit while avoiding meat, dairy, and eggs. Compliance wasn't great. Fewer than half really got their animal product consumption down, but there were definitely improvements such as significant reductions in saturated fat, an increase in protective nutrients, and even noted weight loss, lower blood cholesterol levers, and better blood sugar control in diabetics.

And this was with no calorie counting, no portion control, and no exercise component. The weight reduction appears to result from feeling fuller earlier, due to higher dietary fiber intake. The difference in weight loss could also be the result of an increase in the thermic effect of food, allowing a small extra edge for weight loss in the vegan group. Those eating plant-based diets tend to burn off more calories in heat.

Eating plants appears to boost metabolism. This may be due to increased insulin sensitivity in cells, allowing cells to metabolize carbohydrates more quickly rather than storing them as body fat. "As a result, vegan diets have been shown to increase postprandial calorie burn by about 16%, up to three hours after consuming a meal."

Imagine how much money companies that self-insure their employees could save! See, for example:

Find out more on some of the potential downsides of corporate influence in videos like

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: Ryan McGuire / Pixabay. This image has been modified.

Original Link

Lipotoxicity: How Saturated Fat Raises Blood Sugar

NF-Nov24 Lipotoxicity How Saturated Fat Raises Blood Sugar copy.jpg

The reason those eating plant-based diets have less fat buildup in their muscle cells and less insulin resistance may be because saturated fats appear to impair blood sugar control the most.

The association between fat and insulin resistance is now widely accepted. Insulin resistance is due to so-called ectopic fat accumulation, the buildup of fat in places it's not supposed to be, like within our muscle cells. But not all fats affect the muscles the same. The type of fat, saturated vs. unsaturated, is critical. Saturated fats like palmitate, found mostly in meat, dairy and eggs, cause insulin resistance, but oleate, found mostly in nuts, olives and avocados may actually improve insulin sensitivity.

What makes saturated fat bad? Saturated fat causes more toxic breakdown products and mitochondrial dysfunction, and increases oxidative stress, free radicals and inflammation, establishing a vicious cycle of events in which saturated fat induces free radicals, causes dysfunction in the little power plants within our muscle cells (mitochondria), which then causes an increase in free radical production and an impairment of insulin signaling. I explain this in my video Lipotoxicity: How Saturated Fat Raises Blood Sugar.

Fat cells filled with saturated fat activate an inflammatory response to a far greater extent. This increased inflammation from saturated fat has been demonstrated to raise insulin resistance through free radical production. Saturated fat also has been shown to have a direct effect on skeletal muscle insulin resistance. Accumulation of saturated fat increases the amount of diacyl-glycerol in the muscles, which has been demonstrated to have a potent effect on muscle insulin resistance. You can take muscle biopsies from people and correlate the saturated fat buildup in their muscles with insulin resistance.

While monounsaturated fats are more likely to be detoxified or safely stored away, saturated fats create those toxic breakdown products like ceramide that causes lipotoxicity. Lipo- meaning fat, as in liposuction. This fat toxicity in our muscles is a well-known concept in the explanation of trigger for insulin resistance.

I've talked about the role saturated and trans fats contribute to the progression of other diseases, like autoimmune diseases, cancer and heart disease, but they can also cause insulin resistance, the underlying cause of prediabetes and type 2 diabetes. In the human diet, saturated fats are derived from animal sources while trans fats originate in meat and milk in addition to partially hydrogenated and refined vegetable oils.

That's why experimentally shifting people from animal fats to plant fats can improve insulin sensitivity. In a study done by Swedish researchers, insulin sensitivity was impaired on the diet with added butterfat, but not on the diet with added olive fat.

We know prolonged exposure of our muscles to high levels of fat leads to severe insulin resistance, with saturated fats demonstrated to be the worst, but they don't just lead to inhibition of insulin signaling, the activation of inflammatory pathways and the increase in free radicals, they also cause an alteration in gene expression. This can lead to a suppression of key mitochondrial enzymes like carnitine palmitoyltransferase, which finally solves the mystery of why those eating vegetarian have a 60 percent higher expression of that fat burning enzyme. They're eating less saturated fat.

So do those eating plant-based diets have less fat clogging their muscles and less insulin resistance too? There hasn't been any data available regarding the insulin sensitivity or inside muscle cell fat of those eating vegan or vegetarian... until now. Researchers at the Imperial College of London compared the insulin resistance and muscle fat of vegans versus omnivores. Those eating plant-based diets have the unfair advantage of being much slimmer, so they found omnivores who were as skinny as vegans to see if plant-based diets had a direct benefit, as opposed to indirectly pulling fat out of the muscles by helping people lose weight in general.

They found significantly less fat trapped in the muscle cells of vegans compared to omnivores at the same body weight, better insulin sensitivity, better blood sugar levels, better insulin levels and, excitingly, significantly improved beta-cell function (the cells in the pancreas that make the insulin). They conclude that eating plant-based is not only expected to be cardioprotective, helping prevent our #1 killer, heart disease, but that plant-based diets are beta-cell protective as well, helping also to prevent our seventh leading cause of death, diabetes.

This is the third of a three-part series, starting with What Causes Insulin Resistance? and The Spillover Effect Links Obesity to Diabetes.

Even if saturated fat weren't associated with heart disease, its effects on pancreatic function and insulin resistance in the muscles would be enough to warrant avoiding it. Despite popular press accounts, saturated fat intake remains the primary modifiable determinant of LDL cholesterol, the #1 risk factor for our #1 killer-heart disease. See The Saturated Fat Studies: Buttering Up the Public and The Saturated Fat Studies: Set Up to Fail.

How low should we shoot for in terms of saturated fat intake? As low as possible, according to the U.S. National Academies of Science Institute of Medicine: Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

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: Andrew Malone / Flickr

Original Link

Lipotoxicity: How Saturated Fat Raises Blood Sugar

NF-Nov24 Lipotoxicity How Saturated Fat Raises Blood Sugar copy.jpg

The reason those eating plant-based diets have less fat buildup in their muscle cells and less insulin resistance may be because saturated fats appear to impair blood sugar control the most.

The association between fat and insulin resistance is now widely accepted. Insulin resistance is due to so-called ectopic fat accumulation, the buildup of fat in places it's not supposed to be, like within our muscle cells. But not all fats affect the muscles the same. The type of fat, saturated vs. unsaturated, is critical. Saturated fats like palmitate, found mostly in meat, dairy and eggs, cause insulin resistance, but oleate, found mostly in nuts, olives and avocados may actually improve insulin sensitivity.

What makes saturated fat bad? Saturated fat causes more toxic breakdown products and mitochondrial dysfunction, and increases oxidative stress, free radicals and inflammation, establishing a vicious cycle of events in which saturated fat induces free radicals, causes dysfunction in the little power plants within our muscle cells (mitochondria), which then causes an increase in free radical production and an impairment of insulin signaling. I explain this in my video Lipotoxicity: How Saturated Fat Raises Blood Sugar.

Fat cells filled with saturated fat activate an inflammatory response to a far greater extent. This increased inflammation from saturated fat has been demonstrated to raise insulin resistance through free radical production. Saturated fat also has been shown to have a direct effect on skeletal muscle insulin resistance. Accumulation of saturated fat increases the amount of diacyl-glycerol in the muscles, which has been demonstrated to have a potent effect on muscle insulin resistance. You can take muscle biopsies from people and correlate the saturated fat buildup in their muscles with insulin resistance.

While monounsaturated fats are more likely to be detoxified or safely stored away, saturated fats create those toxic breakdown products like ceramide that causes lipotoxicity. Lipo- meaning fat, as in liposuction. This fat toxicity in our muscles is a well-known concept in the explanation of trigger for insulin resistance.

I've talked about the role saturated and trans fats contribute to the progression of other diseases, like autoimmune diseases, cancer and heart disease, but they can also cause insulin resistance, the underlying cause of prediabetes and type 2 diabetes. In the human diet, saturated fats are derived from animal sources while trans fats originate in meat and milk in addition to partially hydrogenated and refined vegetable oils.

That's why experimentally shifting people from animal fats to plant fats can improve insulin sensitivity. In a study done by Swedish researchers, insulin sensitivity was impaired on the diet with added butterfat, but not on the diet with added olive fat.

We know prolonged exposure of our muscles to high levels of fat leads to severe insulin resistance, with saturated fats demonstrated to be the worst, but they don't just lead to inhibition of insulin signaling, the activation of inflammatory pathways and the increase in free radicals, they also cause an alteration in gene expression. This can lead to a suppression of key mitochondrial enzymes like carnitine palmitoyltransferase, which finally solves the mystery of why those eating vegetarian have a 60 percent higher expression of that fat burning enzyme. They're eating less saturated fat.

So do those eating plant-based diets have less fat clogging their muscles and less insulin resistance too? There hasn't been any data available regarding the insulin sensitivity or inside muscle cell fat of those eating vegan or vegetarian... until now. Researchers at the Imperial College of London compared the insulin resistance and muscle fat of vegans versus omnivores. Those eating plant-based diets have the unfair advantage of being much slimmer, so they found omnivores who were as skinny as vegans to see if plant-based diets had a direct benefit, as opposed to indirectly pulling fat out of the muscles by helping people lose weight in general.

They found significantly less fat trapped in the muscle cells of vegans compared to omnivores at the same body weight, better insulin sensitivity, better blood sugar levels, better insulin levels and, excitingly, significantly improved beta-cell function (the cells in the pancreas that make the insulin). They conclude that eating plant-based is not only expected to be cardioprotective, helping prevent our #1 killer, heart disease, but that plant-based diets are beta-cell protective as well, helping also to prevent our seventh leading cause of death, diabetes.

This is the third of a three-part series, starting with What Causes Insulin Resistance? and The Spillover Effect Links Obesity to Diabetes.

Even if saturated fat weren't associated with heart disease, its effects on pancreatic function and insulin resistance in the muscles would be enough to warrant avoiding it. Despite popular press accounts, saturated fat intake remains the primary modifiable determinant of LDL cholesterol, the #1 risk factor for our #1 killer-heart disease. See The Saturated Fat Studies: Buttering Up the Public and The Saturated Fat Studies: Set Up to Fail.

How low should we shoot for in terms of saturated fat intake? As low as possible, according to the U.S. National Academies of Science Institute of Medicine: Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

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: Andrew Malone / Flickr

Original Link

How a Low-Carb Diet is Metabolically Like Being Obese

NF-Nov22 The Spillover Effect copy.jpg

Free fatty acids (meaning fat circulating in the bloodstream not packaged into triglycerides) result in inflammation, toxic fat breakdown products, and oxidative stress, which can gum up the insulin receptor pathway and lead to insulin resistance in our muscles. Insulin resistance is what causes prediabetes and type 2 diabetes. I explain the process in my video What Causes Insulin Resistance? As the level of fat in the blood rises, the body's ability to clear sugar from the blood drops dramatically.

Where does this fat in our blood that's wreaking all this havoc come from? It comes from the fat that we eat and from the fat that we wear.

The number of fat cells we have stays constant in adulthood. The way researchers figured that out is by measuring the amount of radioactive carbon still trapped in our DNA from all the nuclear bomb tests. After massive weight loss, our fat cells shrink as they offload fat, but the number stays the same. Conversely, when we gain weight, our fat cells stretch as we pack more and more into each individual fat cell. So, when our belly, butt, or thighs get big, we're not adding more fat cells, we're just cramming more fat into each cell. At a certain point, our cells become so bloated that they spill fat back into the bloodstream.

This is called the spillover effect. Not only does an obese person have more fat, but they're constantly spilling that fat into their bloodstream. So that could be the link between obesity and diabetes. Fat is spilling out from our fat cells and gets lodged in our muscle cells, leading to the insulin resistance that promotes the onset of type 2 diabetes. I show this in my video The Spillover Effect Links Obesity to Diabetes.

The fat can also enter our bloodstream through our mouth. If you put people on a low carb diet, fat builds up in their muscle within two hours and insulin sensitivity drops. And the more fat found in the muscle, the lower the ability to clear sugar from the blood. It doesn't take years for this to happen, just hours after fatty foods go into our mouths. A fat-rich diet can increase fat in the blood and this increase is accompanied by a decrease in insulin sensitivity.

Studies clearly demonstrate that fat in the blood directly inhibit glucose transport and usage in our muscles, which is responsible for clearing about 85% of the glucose out of blood. These findings indicate that fat consumption can play an important role in the development of insulin resistance.

Normally we only have 10 to 50 micromoles of free fat floating around in our blood stream at any one time, but those who are obese have between 60 to 80. But, we can reach 80 just eating a high fat diet. So a skinny person eating a low-carb diet can have the same level of fat in their blood that obese people do. Similarly, being obese is like eating some horrible bacon and butter diet all day, because obese persons are constantly spilling fat into their bloodstream, no matter what goes in their mouth.

Are all types of fat the same? Find out the answer in my video Lipotoxicity: How Saturated Fat Raises Blood Sugar.

The fat leaking into our bloodstream may also contain fat-soluble pollutants that accumulated from our diet: Pollutants in Salmon and Our Own Fat.

The spillover effect may also help explain the increased heart disease risk associated with obesity: Low Carb Diets and Coronary Blood Flow.

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: [Eugene Bochkarev] © 123RF.com

Original Link

How a Low-Carb Diet is Metabolically Like Being Obese

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Free fatty acids (meaning fat circulating in the bloodstream not packaged into triglycerides) result in inflammation, toxic fat breakdown products, and oxidative stress, which can gum up the insulin receptor pathway and lead to insulin resistance in our muscles. Insulin resistance is what causes prediabetes and type 2 diabetes. I explain the process in my video What Causes Insulin Resistance? As the level of fat in the blood rises, the body's ability to clear sugar from the blood drops dramatically.

Where does this fat in our blood that's wreaking all this havoc come from? It comes from the fat that we eat and from the fat that we wear.

The number of fat cells we have stays constant in adulthood. The way researchers figured that out is by measuring the amount of radioactive carbon still trapped in our DNA from all the nuclear bomb tests. After massive weight loss, our fat cells shrink as they offload fat, but the number stays the same. Conversely, when we gain weight, our fat cells stretch as we pack more and more into each individual fat cell. So, when our belly, butt, or thighs get big, we're not adding more fat cells, we're just cramming more fat into each cell. At a certain point, our cells become so bloated that they spill fat back into the bloodstream.

This is called the spillover effect. Not only does an obese person have more fat, but they're constantly spilling that fat into their bloodstream. So that could be the link between obesity and diabetes. Fat is spilling out from our fat cells and gets lodged in our muscle cells, leading to the insulin resistance that promotes the onset of type 2 diabetes. I show this in my video The Spillover Effect Links Obesity to Diabetes.

The fat can also enter our bloodstream through our mouth. If you put people on a low carb diet, fat builds up in their muscle within two hours and insulin sensitivity drops. And the more fat found in the muscle, the lower the ability to clear sugar from the blood. It doesn't take years for this to happen, just hours after fatty foods go into our mouths. A fat-rich diet can increase fat in the blood and this increase is accompanied by a decrease in insulin sensitivity.

Studies clearly demonstrate that fat in the blood directly inhibit glucose transport and usage in our muscles, which is responsible for clearing about 85% of the glucose out of blood. These findings indicate that fat consumption can play an important role in the development of insulin resistance.

Normally we only have 10 to 50 micromoles of free fat floating around in our blood stream at any one time, but those who are obese have between 60 to 80. But, we can reach 80 just eating a high fat diet. So a skinny person eating a low-carb diet can have the same level of fat in their blood that obese people do. Similarly, being obese is like eating some horrible bacon and butter diet all day, because obese persons are constantly spilling fat into their bloodstream, no matter what goes in their mouth.

Are all types of fat the same? Find out the answer in my video Lipotoxicity: How Saturated Fat Raises Blood Sugar.

The fat leaking into our bloodstream may also contain fat-soluble pollutants that accumulated from our diet: Pollutants in Salmon and Our Own Fat.

The spillover effect may also help explain the increased heart disease risk associated with obesity: Low Carb Diets and Coronary Blood Flow.

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: [Eugene Bochkarev] © 123RF.com

Original Link