Foods to Eat to Help Prevent Diabetes

Oct 26 Foods to Eat copy.jpeg

Why is meat consumption a risk factor for diabetes? Why does there appear to be a stepwise reduction in diabetes rates as meat consumption drops? Instead of avoiding something in meat, it may be that people are getting something protective from plants. Free radicals may be an important trigger for insulin resistance, and antioxidants in plant foods may help. Put people on a plant-based diet, and their antioxidant enzymes shoot up. So not only do plants provide antioxidants, but may boost our own anti-endogenous antioxidant defenses, whereas, on the conventional diabetic diet, they get worse.

In my video, How May Plants Protect Against Diabetes, I discuss how there are phytonutrients in plant foods that may help lower chronic disease prevalence by acting as antioxidants and anti-cancer agents, and by lowering cholesterol and blood sugar. Some, we're now theorizing, may even be lipotropes, which have the capacity to hasten the removal of fat from our liver and other organs, counteracting the inflammatory cascade believed to be directly initiated by saturated-fat-containing foods. Fat in the bloodstream--from the fat on our bodies or the fat we eat--not only causes insulin resistance, but also produces a low-grade inflammation that can contribute to heart disease and non-alcoholic fatty liver disease.

Fiber may also decrease insulin resistance. One of the ways it may do so is by helping to rid the body of excess estrogen. There is strong evidence for a direct role of estrogens in the cause of diabetes, and it's been demonstrated that certain gut bacteria can produce estrogens in our colon. High-fat, low-fiber diets appear to stimulate the metabolic activity of these estrogen-producing intestinal bacteria. This is a problem for men, too. Obesity is associated with low testosterone levels and marked elevations of estrogens produced not only by fat cells but also by some of the bacteria in our gut. Our intestinal bacteria may produce these so-called diabetogens (diabetes-causing compounds) from the fats we eat. By eating lots of fiber, though, we can flush this excess estrogen out of our bodies.

Vegetarian women, for example, excrete two to three times more estrogens in their stools than omnivorous women, which may be why omnivorous women have 50% higher estrogen blood levels. These differences in estrogen metabolism may help explain the lower incidence of diabetes in those eating more plant-based diets, as well as the lower incidence of breast cancer in vegetarian women, who get rid of twice as much estrogen because they get rid of twice as much daily waste in general.

Either way, "[m]eat consumption is consistently associated with diabetes risk. Dietary habits are readily modifiable, but individuals and clinicians will consider dietary changes only if they are aware of the potential benefits of doing so." The identification of meat consumption as a risk factor for diabetes provides helpful guidance that sets the stage for beneficial behavioral changes. Meat consumption is something doctors can easily ask about, and, once identified, at-risk individuals can then be encouraged to familiarize themselves with meatless options.


Plant foods may also protect against diabetes by replacing animal foods. Learn more with my Why Is Meat a Risk Factor for Diabetes? video.

What if your entire diet was filled with plants? See Plant-Based Diets and Diabetes. Find out which plants may be particularly protective with these videos: Amla Versus Diabetes, Flaxseed vs. Diabetes, and Diabetics Should Take Their Pulses.

Unfortunately, cinnamon has fallen out of favor. See my Update on Cinnamon for Blood Sugar Control.

I also have an ever-growing series on the science behind type 2 diabetes:

For more on the estrogen connection, see Relieving Yourself of Excess Estrogen and Breast Cancer and Constipation.

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

Foods to Eat to Help Prevent Diabetes

Oct 26 Foods to Eat copy.jpeg

Why is meat consumption a risk factor for diabetes? Why does there appear to be a stepwise reduction in diabetes rates as meat consumption drops? Instead of avoiding something in meat, it may be that people are getting something protective from plants. Free radicals may be an important trigger for insulin resistance, and antioxidants in plant foods may help. Put people on a plant-based diet, and their antioxidant enzymes shoot up. So not only do plants provide antioxidants, but may boost our own anti-endogenous antioxidant defenses, whereas, on the conventional diabetic diet, they get worse.

In my video, How May Plants Protect Against Diabetes, I discuss how there are phytonutrients in plant foods that may help lower chronic disease prevalence by acting as antioxidants and anti-cancer agents, and by lowering cholesterol and blood sugar. Some, we're now theorizing, may even be lipotropes, which have the capacity to hasten the removal of fat from our liver and other organs, counteracting the inflammatory cascade believed to be directly initiated by saturated-fat-containing foods. Fat in the bloodstream--from the fat on our bodies or the fat we eat--not only causes insulin resistance, but also produces a low-grade inflammation that can contribute to heart disease and non-alcoholic fatty liver disease.

Fiber may also decrease insulin resistance. One of the ways it may do so is by helping to rid the body of excess estrogen. There is strong evidence for a direct role of estrogens in the cause of diabetes, and it's been demonstrated that certain gut bacteria can produce estrogens in our colon. High-fat, low-fiber diets appear to stimulate the metabolic activity of these estrogen-producing intestinal bacteria. This is a problem for men, too. Obesity is associated with low testosterone levels and marked elevations of estrogens produced not only by fat cells but also by some of the bacteria in our gut. Our intestinal bacteria may produce these so-called diabetogens (diabetes-causing compounds) from the fats we eat. By eating lots of fiber, though, we can flush this excess estrogen out of our bodies.

Vegetarian women, for example, excrete two to three times more estrogens in their stools than omnivorous women, which may be why omnivorous women have 50% higher estrogen blood levels. These differences in estrogen metabolism may help explain the lower incidence of diabetes in those eating more plant-based diets, as well as the lower incidence of breast cancer in vegetarian women, who get rid of twice as much estrogen because they get rid of twice as much daily waste in general.

Either way, "[m]eat consumption is consistently associated with diabetes risk. Dietary habits are readily modifiable, but individuals and clinicians will consider dietary changes only if they are aware of the potential benefits of doing so." The identification of meat consumption as a risk factor for diabetes provides helpful guidance that sets the stage for beneficial behavioral changes. Meat consumption is something doctors can easily ask about, and, once identified, at-risk individuals can then be encouraged to familiarize themselves with meatless options.


Plant foods may also protect against diabetes by replacing animal foods. Learn more with my Why Is Meat a Risk Factor for Diabetes? video.

What if your entire diet was filled with plants? See Plant-Based Diets and Diabetes. Find out which plants may be particularly protective with these videos: Amla Versus Diabetes, Flaxseed vs. Diabetes, and Diabetics Should Take Their Pulses.

Unfortunately, cinnamon has fallen out of favor. See my Update on Cinnamon for Blood Sugar Control.

I also have an ever-growing series on the science behind type 2 diabetes:

For more on the estrogen connection, see Relieving Yourself of Excess Estrogen and Breast Cancer and Constipation.

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

Foods to Avoid to Help Prevent Diabetes

Oct 24 Foods to Avoid copy.jpeg

We've known that being overweight and obese are important risk factors for type 2 diabetes, but, until recently, not much attention has been paid to the role of specific foods. I discuss this issue in my video, Why Is Meat a Risk Factor for Diabetes?

A 2013 meta-analysis of all the cohorts looking at the connection between meat and diabetes found a significantly higher risk associated with total meat consumption--especially consumption of processed meat, particularly poultry. But why? There's a whole list of potential culprits in meat: saturated fat, animal fat, trans fats naturally found in meat, cholesterol, or animal protein. It could be the heme iron found in meat, which can lead to free radicals and iron-induced oxidative stress that may lead to chronic inflammation and type 2 diabetes, or advanced glycation end (AGE) products, which promote oxidative stress and inflammation. Food analyses show that the highest levels of these so-called glycotoxins are found in meat--particularly roasted, fried, or broiled meat, though any foods from animal sources (and even high fat and protein plant foods such as nuts) exposed to high dry temperatures can be potent sources of these pro-oxidant chemicals.

In another study, researchers fed diabetics glycotoxin-packed foods, like chicken, fish, and eggs, and their inflammatory markers--tumor necrosis factor, C-reactive protein, and vascular adhesion molecules--shot up. "Thus, in diabetes, environmental (dietary) AGEs promote inflammatory mediators, leading to tissue injury." The good news is that restriction of these kinds of foods may suppress these inflammatory effects. Appropriate measures to limit AGE intake, such as eliminating meat or using only steaming and boiling as methods for cooking it, "may greatly reduce the already heavy burden of these toxins in the diabetic patient." These glycotoxins may be the missing link between the increased consumption of animal fat and meats and the development of type 2 diabetes.

Since the 2013 meta-analysis was published, another study came out in which approximately 17,000 people were followed for about a dozen years. Researchers found an 8% increased risk for every 50 grams of daily meat consumption. Just one quarter of a chicken breast's worth of meat for the entire day may significantly increase the risk of diabetes. Yes, we know there are many possible culprits: the glycotoxins or trans fat in meat, saturated fat, or the heme iron (which could actually promote the formation of carcinogens called nitrosamines, though they could also just be produced in the cooking process itself). However, we did learn something new: There also appears to be a greater incidence of diabetes among those who handle meat for a living. Maybe there are some diabetes-causing zoonotic infectious agents--such as viruses--present in fresh cuts of meat, including poultry.

A "crucial factor underlying the diabetes epidemic" may be the overstimulation of the aging enzyme TOR pathway by excess food consumption--but not by the consumption of just any food: Animal proteins not only stimulate the cancer-promoting hormone insulin growth factor-1 but also provide high amounts of leucine, which stimulates TOR activation and appears to contribute to the burning out of the insulin-producing beta cells in the pancreas, contributing to type 2 diabetes. So, it's not just the high fat and added sugars that are implicated; critical attention must be paid to the daily intake of animal proteins as well.

According to a study, "[i]n general, lower leucine levels are only reached by restriction of animal proteins." To reach the leucine intake provided by dairy or meat, we'd have to eat 9 pounds of cabbage or 100 apples to take an extreme example. That just exemplifies the extreme differences in leucine amounts provided by a more standard diet in comparison with a more plant-based diet.

I reviewed the role endocrine-disrupting industrial pollutants in the food supply may play in a three-part video series: Fish and Diabetes, Diabetes and Dioxins, and Pollutants in Salmon and Our Own Fat. Clearly, the standard America diet and lifestyle contribute to the epidemic of diabetes and obesity, but the contribution of these industrial pollutants can no longer be ignored. We now have experimental evidence that exposure to industrial toxins alone induces weight gain and insulin resistance, and, therefore, may be an underappreciated cause of obesity and diabetes. Consider what's happening to our infants: Obesity in a six-month-old is obviously not related to diet or lack of exercise. They're now exposed to hundreds of chemicals from their moms, straight through the umbilical cord, some of which may be obesogenic (that is, obesity-generating).

The millions of pounds of chemicals and heavy metals released every year into our environment should make us all stop and think about how we live and the choices we make every day in the foods we eat. A 2014 review of the evidence on pollutants and diabetes noted that we can be exposed through toxic spills, but "most of the human exposure nowadays is from the ingestion of contaminated food as a result of bioaccumulation up the food chain. The main source (around 95%) of [persistent pollutant] intake is through dietary intake of animal fats."


For more on the information mentioned here, see the following videos that take a closer look at these major topics:

AGEs: Glycotoxins, Avoiding a Sugary Grave, and Reducing Glycotoxin Intake to Prevent Alzheimer's.

TOR: Why Do We Age?, Caloric Restriction vs. Animal Protein Restriction, Prevent Cancer From Going on TOR, and Saving Lives By Treating Acne With Diet

Viruses: Infectobesity: Adenovirus 36 and Childhood Obesity

Poultry workers: Poultry Exposure and Neurological Disease, Poultry Exposure Tied to Liver and Pancreatic Cancer, and Eating Outside Our Kingdom

Industrial pollutants: Obesity-Causing Pollutants in Food, Fish and Diabetes, Diabetes and Dioxins, and Pollutants in Salmon and Our Own Fat

The link between meat and diabetes may also be due to a lack of sufficient protective components of plants in the diet, which is discussed in my videos How May Plants Protect Against Diabetes?, Plant-Based Diets for Diabetes, Plant-Based Diets and Diabetes, and How Not to Die from Diabetes.

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

Foods to Avoid to Help Prevent Diabetes

Oct 24 Foods to Avoid copy.jpeg

We've known that being overweight and obese are important risk factors for type 2 diabetes, but, until recently, not much attention has been paid to the role of specific foods. I discuss this issue in my video, Why Is Meat a Risk Factor for Diabetes?

A 2013 meta-analysis of all the cohorts looking at the connection between meat and diabetes found a significantly higher risk associated with total meat consumption--especially consumption of processed meat, particularly poultry. But why? There's a whole list of potential culprits in meat: saturated fat, animal fat, trans fats naturally found in meat, cholesterol, or animal protein. It could be the heme iron found in meat, which can lead to free radicals and iron-induced oxidative stress that may lead to chronic inflammation and type 2 diabetes, or advanced glycation end (AGE) products, which promote oxidative stress and inflammation. Food analyses show that the highest levels of these so-called glycotoxins are found in meat--particularly roasted, fried, or broiled meat, though any foods from animal sources (and even high fat and protein plant foods such as nuts) exposed to high dry temperatures can be potent sources of these pro-oxidant chemicals.

In another study, researchers fed diabetics glycotoxin-packed foods, like chicken, fish, and eggs, and their inflammatory markers--tumor necrosis factor, C-reactive protein, and vascular adhesion molecules--shot up. "Thus, in diabetes, environmental (dietary) AGEs promote inflammatory mediators, leading to tissue injury." The good news is that restriction of these kinds of foods may suppress these inflammatory effects. Appropriate measures to limit AGE intake, such as eliminating meat or using only steaming and boiling as methods for cooking it, "may greatly reduce the already heavy burden of these toxins in the diabetic patient." These glycotoxins may be the missing link between the increased consumption of animal fat and meats and the development of type 2 diabetes.

Since the 2013 meta-analysis was published, another study came out in which approximately 17,000 people were followed for about a dozen years. Researchers found an 8% increased risk for every 50 grams of daily meat consumption. Just one quarter of a chicken breast's worth of meat for the entire day may significantly increase the risk of diabetes. Yes, we know there are many possible culprits: the glycotoxins or trans fat in meat, saturated fat, or the heme iron (which could actually promote the formation of carcinogens called nitrosamines, though they could also just be produced in the cooking process itself). However, we did learn something new: There also appears to be a greater incidence of diabetes among those who handle meat for a living. Maybe there are some diabetes-causing zoonotic infectious agents--such as viruses--present in fresh cuts of meat, including poultry.

A "crucial factor underlying the diabetes epidemic" may be the overstimulation of the aging enzyme TOR pathway by excess food consumption--but not by the consumption of just any food: Animal proteins not only stimulate the cancer-promoting hormone insulin growth factor-1 but also provide high amounts of leucine, which stimulates TOR activation and appears to contribute to the burning out of the insulin-producing beta cells in the pancreas, contributing to type 2 diabetes. So, it's not just the high fat and added sugars that are implicated; critical attention must be paid to the daily intake of animal proteins as well.

According to a study, "[i]n general, lower leucine levels are only reached by restriction of animal proteins." To reach the leucine intake provided by dairy or meat, we'd have to eat 9 pounds of cabbage or 100 apples to take an extreme example. That just exemplifies the extreme differences in leucine amounts provided by a more standard diet in comparison with a more plant-based diet.

I reviewed the role endocrine-disrupting industrial pollutants in the food supply may play in a three-part video series: Fish and Diabetes, Diabetes and Dioxins, and Pollutants in Salmon and Our Own Fat. Clearly, the standard America diet and lifestyle contribute to the epidemic of diabetes and obesity, but the contribution of these industrial pollutants can no longer be ignored. We now have experimental evidence that exposure to industrial toxins alone induces weight gain and insulin resistance, and, therefore, may be an underappreciated cause of obesity and diabetes. Consider what's happening to our infants: Obesity in a six-month-old is obviously not related to diet or lack of exercise. They're now exposed to hundreds of chemicals from their moms, straight through the umbilical cord, some of which may be obesogenic (that is, obesity-generating).

The millions of pounds of chemicals and heavy metals released every year into our environment should make us all stop and think about how we live and the choices we make every day in the foods we eat. A 2014 review of the evidence on pollutants and diabetes noted that we can be exposed through toxic spills, but "most of the human exposure nowadays is from the ingestion of contaminated food as a result of bioaccumulation up the food chain. The main source (around 95%) of [persistent pollutant] intake is through dietary intake of animal fats."


For more on the information mentioned here, see the following videos that take a closer look at these major topics:

AGEs: Glycotoxins, Avoiding a Sugary Grave, and Reducing Glycotoxin Intake to Prevent Alzheimer's.

TOR: Why Do We Age?, Caloric Restriction vs. Animal Protein Restriction, Prevent Cancer From Going on TOR, and Saving Lives By Treating Acne With Diet

Viruses: Infectobesity: Adenovirus 36 and Childhood Obesity

Poultry workers: Poultry Exposure and Neurological Disease, Poultry Exposure Tied to Liver and Pancreatic Cancer, and Eating Outside Our Kingdom

Industrial pollutants: Obesity-Causing Pollutants in Food, Fish and Diabetes, Diabetes and Dioxins, and Pollutants in Salmon and Our Own Fat

The link between meat and diabetes may also be due to a lack of sufficient protective components of plants in the diet, which is discussed in my videos How May Plants Protect Against Diabetes?, Plant-Based Diets for Diabetes, Plant-Based Diets and Diabetes, and How Not to Die from Diabetes.

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

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

How to Design a Misleading Study to Show Diet Doesn’t Work

How to Design a Misleading Study to Show Diet Doesn't Work.jpeg

A study out of the University of North Carolina found no association between dietary fiber intake and diverticulosis. They compared those who ate the highest amount of fiber, 25 grams, to those who ate the smallest amount, which was three times lower at only 8 grams. Finding no difference in disease rates, researchers concluded that a low-fiber diet was not associated with diverticulosis.

The university sent out a press release entitled: "Diets high in fiber won't protect against diverticulosis." The media picked it up and ran headlines such as "High-fiber diet may not protect against diverticulosis, study finds." It went all over the paleo blogs and even medical journals, publishing such statements as an "important and provocative paper...calls into question" the fiber theory of the development of diverticulosis. Other editorials, though, caught the study's critical flaw. To understand this, let's turn to another dietary deficiency disease: scurvy.

Medical experiments on prisoners at Iowa State Penitentiary showed that clinical signs of scurvy start appearing after just 29 days without vitamin C. Experiments on pacifists during World War II showed that it takes about 10 mg of vitamin C a day to prevent scurvy. Imagine going back a few centuries when they were still trying to figure scurvy out. Dr. James Linde had this radical theory that citrus fruits could cure scurvy. What if an experiment was designed to test this crazy theory, in which sailors were given the juice of either one wedge of lemon or three wedges of lemon each day? If a month later on the high seas there was no difference in scurvy rates, one might see headlines from printing presses touting that a low-vitamin C diet is not associated with scurvy.

Well, a wedge of lemon only yields about 2 mg of vitamin C, and it takes 10 mg to prevent scurvy. They would have been comparing one vitamin C-deficient dose to another vitamin C-deficient dose. No wonder there would be no difference in scurvy rates. We evolved eating so many plants that we likely averaged around 600 mg of vitamin C a day. That's what our bodies are biologically used to getting.

What about fiber? How much fiber are we used to getting? More than 100 grams a day! The highest fiber intake group in the North Carolina study was only eating 25 grams, which is less than the minimum recommended daily allowance of about 32 grams. The subjects didn't even make the minimum! The study compared one fiber-deficient diet to another fiber-deficient diet--no wonder there was no difference in diverticulosis rates.

The African populations with essentially no diverticulosis ate diets consisting in part of very large platefuls of leafy vegetables--similar, perhaps, to what we were eating a few million years ago. They were eating plant-based diets containing 70 to 90 grams of fiber a day. Most vegetarians don't even eat that many whole plant foods, although some do. At least vegetarians tend to hit the minimum mark, and they have less diverticulosis to show for it. A study of 47,000 people confirmed that "[c]onsuming a vegetarian diet and a high intake of dietary fiber were both associated with a lower risk of admission to hospital or death from diverticular disease." They had enough people to tease it out. As you'll see in my video Does Fiber Really Prevent Diverticulosis?, compared to people eating a single serving of meat a day or more, those who ate less than half a serving appeared to have a 16% lower risk and pescatarians (eating no meat except fish) had a risk down around 23%. Both of these results weren't in and of themselves statistically significant, but eating vegetarian was. Vegetarians had 35% lower risk, and those eating strictly plant-based appeared to be at 78% lower risk.

As with all lifestyle interventions, it only works if you do it. High-fiber diets only work if they're actually high in fiber.

There's more great information in my video Diverticulosis: When Our Most Common Gut Disorder Hardly Existed.

This reminds me of an ancient video I did: Flawed Study Interpretation.

People commonly ask Do Vegetarians Get Enough Protein?, but maybe they should be more concerned where everyone else is getting their fiber. Ninety-seven percent of Americans don't even reach the recommended daily minimum.

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: Yoshihide Nomura / Flickr. This image has been modified.

Original Link

How to Design a Misleading Study to Show Diet Doesn’t Work

How to Design a Misleading Study to Show Diet Doesn't Work.jpeg

A study out of the University of North Carolina found no association between dietary fiber intake and diverticulosis. They compared those who ate the highest amount of fiber, 25 grams, to those who ate the smallest amount, which was three times lower at only 8 grams. Finding no difference in disease rates, researchers concluded that a low-fiber diet was not associated with diverticulosis.

The university sent out a press release entitled: "Diets high in fiber won't protect against diverticulosis." The media picked it up and ran headlines such as "High-fiber diet may not protect against diverticulosis, study finds." It went all over the paleo blogs and even medical journals, publishing such statements as an "important and provocative paper...calls into question" the fiber theory of the development of diverticulosis. Other editorials, though, caught the study's critical flaw. To understand this, let's turn to another dietary deficiency disease: scurvy.

Medical experiments on prisoners at Iowa State Penitentiary showed that clinical signs of scurvy start appearing after just 29 days without vitamin C. Experiments on pacifists during World War II showed that it takes about 10 mg of vitamin C a day to prevent scurvy. Imagine going back a few centuries when they were still trying to figure scurvy out. Dr. James Linde had this radical theory that citrus fruits could cure scurvy. What if an experiment was designed to test this crazy theory, in which sailors were given the juice of either one wedge of lemon or three wedges of lemon each day? If a month later on the high seas there was no difference in scurvy rates, one might see headlines from printing presses touting that a low-vitamin C diet is not associated with scurvy.

Well, a wedge of lemon only yields about 2 mg of vitamin C, and it takes 10 mg to prevent scurvy. They would have been comparing one vitamin C-deficient dose to another vitamin C-deficient dose. No wonder there would be no difference in scurvy rates. We evolved eating so many plants that we likely averaged around 600 mg of vitamin C a day. That's what our bodies are biologically used to getting.

What about fiber? How much fiber are we used to getting? More than 100 grams a day! The highest fiber intake group in the North Carolina study was only eating 25 grams, which is less than the minimum recommended daily allowance of about 32 grams. The subjects didn't even make the minimum! The study compared one fiber-deficient diet to another fiber-deficient diet--no wonder there was no difference in diverticulosis rates.

The African populations with essentially no diverticulosis ate diets consisting in part of very large platefuls of leafy vegetables--similar, perhaps, to what we were eating a few million years ago. They were eating plant-based diets containing 70 to 90 grams of fiber a day. Most vegetarians don't even eat that many whole plant foods, although some do. At least vegetarians tend to hit the minimum mark, and they have less diverticulosis to show for it. A study of 47,000 people confirmed that "[c]onsuming a vegetarian diet and a high intake of dietary fiber were both associated with a lower risk of admission to hospital or death from diverticular disease." They had enough people to tease it out. As you'll see in my video Does Fiber Really Prevent Diverticulosis?, compared to people eating a single serving of meat a day or more, those who ate less than half a serving appeared to have a 16% lower risk and pescatarians (eating no meat except fish) had a risk down around 23%. Both of these results weren't in and of themselves statistically significant, but eating vegetarian was. Vegetarians had 35% lower risk, and those eating strictly plant-based appeared to be at 78% lower risk.

As with all lifestyle interventions, it only works if you do it. High-fiber diets only work if they're actually high in fiber.

There's more great information in my video Diverticulosis: When Our Most Common Gut Disorder Hardly Existed.

This reminds me of an ancient video I did: Flawed Study Interpretation.

People commonly ask Do Vegetarians Get Enough Protein?, but maybe they should be more concerned where everyone else is getting their fiber. Ninety-seven percent of Americans don't even reach the recommended daily minimum.

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: Yoshihide Nomura / Flickr. This image has been modified.

Original Link

How to Design a Misleading Study to Show Diet Doesn’t Work

How to Design a Misleading Study to Show Diet Doesn't Work.jpeg

A study out of the University of North Carolina found no association between dietary fiber intake and diverticulosis. They compared those who ate the highest amount of fiber, 25 grams, to those who ate the smallest amount, which was three times lower at only 8 grams. Finding no difference in disease rates, researchers concluded that a low-fiber diet was not associated with diverticulosis.

The university sent out a press release entitled: "Diets high in fiber won't protect against diverticulosis." The media picked it up and ran headlines such as "High-fiber diet may not protect against diverticulosis, study finds." It went all over the paleo blogs and even medical journals, publishing such statements as an "important and provocative paper...calls into question" the fiber theory of the development of diverticulosis. Other editorials, though, caught the study's critical flaw. To understand this, let's turn to another dietary deficiency disease: scurvy.

Medical experiments on prisoners at Iowa State Penitentiary showed that clinical signs of scurvy start appearing after just 29 days without vitamin C. Experiments on pacifists during World War II showed that it takes about 10 mg of vitamin C a day to prevent scurvy. Imagine going back a few centuries when they were still trying to figure scurvy out. Dr. James Linde had this radical theory that citrus fruits could cure scurvy. What if an experiment was designed to test this crazy theory, in which sailors were given the juice of either one wedge of lemon or three wedges of lemon each day? If a month later on the high seas there was no difference in scurvy rates, one might see headlines from printing presses touting that a low-vitamin C diet is not associated with scurvy.

Well, a wedge of lemon only yields about 2 mg of vitamin C, and it takes 10 mg to prevent scurvy. They would have been comparing one vitamin C-deficient dose to another vitamin C-deficient dose. No wonder there would be no difference in scurvy rates. We evolved eating so many plants that we likely averaged around 600 mg of vitamin C a day. That's what our bodies are biologically used to getting.

What about fiber? How much fiber are we used to getting? More than 100 grams a day! The highest fiber intake group in the North Carolina study was only eating 25 grams, which is less than the minimum recommended daily allowance of about 32 grams. The subjects didn't even make the minimum! The study compared one fiber-deficient diet to another fiber-deficient diet--no wonder there was no difference in diverticulosis rates.

The African populations with essentially no diverticulosis ate diets consisting in part of very large platefuls of leafy vegetables--similar, perhaps, to what we were eating a few million years ago. They were eating plant-based diets containing 70 to 90 grams of fiber a day. Most vegetarians don't even eat that many whole plant foods, although some do. At least vegetarians tend to hit the minimum mark, and they have less diverticulosis to show for it. A study of 47,000 people confirmed that "[c]onsuming a vegetarian diet and a high intake of dietary fiber were both associated with a lower risk of admission to hospital or death from diverticular disease." They had enough people to tease it out. As you'll see in my video Does Fiber Really Prevent Diverticulosis?, compared to people eating a single serving of meat a day or more, those who ate less than half a serving appeared to have a 16% lower risk and pescatarians (eating no meat except fish) had a risk down around 23%. Both of these results weren't in and of themselves statistically significant, but eating vegetarian was. Vegetarians had 35% lower risk, and those eating strictly plant-based appeared to be at 78% lower risk.

As with all lifestyle interventions, it only works if you do it. High-fiber diets only work if they're actually high in fiber.

There's more great information in my video Diverticulosis: When Our Most Common Gut Disorder Hardly Existed.

This reminds me of an ancient video I did: Flawed Study Interpretation.

People commonly ask Do Vegetarians Get Enough Protein?, but maybe they should be more concerned where everyone else is getting their fiber. Ninety-seven percent of Americans don't even reach the recommended daily minimum.

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: Yoshihide Nomura / Flickr. This image has been modified.

Original Link