The Mediterranean Diet or a Whole Food Plant-Based Diet?

The Mediterranean Diet or a Whole Food Plant-Based Diet.jpg

Recent studies have shown that higher Mediterranean diet adherence scores are associated with a significant reduction of the risk of death, heart disease, cancer, and brain disease. The problem with population studies like these is that people who eat healthier may also live healthier, and so how do we know it's their diet? I examine this in The Mediterranean Diet or a Whole Food Plant-Based Diet?.

As the American Heart Association position states, "Before advising people to follow a Mediterranean diet, we need more studies to find out whether the diet itself or other lifestyle factors account for the lower deaths from heart disease." How do you do that? There are ways you can control for obvious things like smoking and exercise--which many of the studies did--but ideally you'd do an interventional trial, the gold standard of nutritional science. You change people's diets while trying to keep everything else the same and see what happens.

We got that kind of trial 20 years ago with the famous Lyon Diet Heart Study where about 600 folks who had just had their first heart attack were randomized into two groups. The control group received no dietary advice, apart whatever their doctors were telling them, while the experimental group was told to eat more of a Mediterranean-type diet, supplemented with a canola-oil based spread to give them the plant-based omega-3's they'd normally be getting from weeds and walnuts if they actually lived on a Greek isle in the 1950's.

The Mediterranean diet group did end up taking some of the dietary advice to heart. They ate more bread, more fruit, less deli meat, less meat in general, and less butter and cream; other than that, no significant changes in diet were reported in terms of wine, olive oil, or fish consumption. So, they ate less saturated fat and cholesterol, more plant-based omega 3's, but didn't have huge dietary changes. Even so, at the end of about four years, 44 individuals from the control group had a second heart attack, either fatal or nonfatal, but only 14 suffered another attack in the group that changed their diet. So they went from having a 4% chance of having a heart attack every year down to 1%.

A cynic might say that while there was less death and disease, the Mediterranean diet continued to feed their heart disease, so much so that 14 of them suffered new heart attacks while on the diet. Yes, their disease progressed a lot less than the regular diet group (about four times less), but what if there was a diet that could stop or reverse heart disease?

Dr. Caldwell Esselstyn and colleagues at the Cleveland Clinic recently published a case series of 198 consecutive patients with cardiovascular disease counseled to switch to a diet composed entirely of whole plant foods. Of the 198, 177 stuck to the diet, whereas the other 21 fell off the wagon, setting up kind of a natural experiment. What happened to the 21? This was such a sick group of patients that more than half suffered from either a fatal heart attack or needed angioplasty or a heart transplant. In that same time period of about four years, of the 177 that stuck to the plant-based diet, only one had a major event as a result of worsening disease. As Dean Ornish noted in his response to the latest trial, "a Mediterranean diet is better than what most people are consuming"...but even better may be a diet based on whole plant foods.

Dr. Esselstyn's was not a randomized trial, so it can't be directly compared to the Lyon study, and it included very determined patients. Not everyone is willing to dramatically change their diets, even if it may literally be a matter of life or death. In which case, rather than doing nothing, eating a more Mediterranean-type diet may cut risk for heart attack survivors by about two-thirds. Cutting 99% of risk would be better if Esselstyn's results were replicated in a controlled trial, but even a 70% drop in risk could save tens of thousands of lives every year.

For more on the Mediterranean diet, check out:

For more on Dr. Esselstyn's amazing work:

If the short-chain plant-based omega-3s in flax seeds and walnuts appear so beneficial, what about the long-chain omega-3's found in fish and fish oil? There are pros and cons. See, for example, Mercury vs. Omega-3s for Brain Development, Is Fish Oil Just Snake Oil?, and Omega-3's and the Eskimo Fish Tale.

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: wildpixel / Thinkstock. This image has been modified.

Original Link

The Mediterranean Diet or a Whole Food Plant-Based Diet?

The Mediterranean Diet or a Whole Food Plant-Based Diet.jpg

Recent studies have shown that higher Mediterranean diet adherence scores are associated with a significant reduction of the risk of death, heart disease, cancer, and brain disease. The problem with population studies like these is that people who eat healthier may also live healthier, and so how do we know it's their diet? I examine this in The Mediterranean Diet or a Whole Food Plant-Based Diet?.

As the American Heart Association position states, "Before advising people to follow a Mediterranean diet, we need more studies to find out whether the diet itself or other lifestyle factors account for the lower deaths from heart disease." How do you do that? There are ways you can control for obvious things like smoking and exercise--which many of the studies did--but ideally you'd do an interventional trial, the gold standard of nutritional science. You change people's diets while trying to keep everything else the same and see what happens.

We got that kind of trial 20 years ago with the famous Lyon Diet Heart Study where about 600 folks who had just had their first heart attack were randomized into two groups. The control group received no dietary advice, apart whatever their doctors were telling them, while the experimental group was told to eat more of a Mediterranean-type diet, supplemented with a canola-oil based spread to give them the plant-based omega-3's they'd normally be getting from weeds and walnuts if they actually lived on a Greek isle in the 1950's.

The Mediterranean diet group did end up taking some of the dietary advice to heart. They ate more bread, more fruit, less deli meat, less meat in general, and less butter and cream; other than that, no significant changes in diet were reported in terms of wine, olive oil, or fish consumption. So, they ate less saturated fat and cholesterol, more plant-based omega 3's, but didn't have huge dietary changes. Even so, at the end of about four years, 44 individuals from the control group had a second heart attack, either fatal or nonfatal, but only 14 suffered another attack in the group that changed their diet. So they went from having a 4% chance of having a heart attack every year down to 1%.

A cynic might say that while there was less death and disease, the Mediterranean diet continued to feed their heart disease, so much so that 14 of them suffered new heart attacks while on the diet. Yes, their disease progressed a lot less than the regular diet group (about four times less), but what if there was a diet that could stop or reverse heart disease?

Dr. Caldwell Esselstyn and colleagues at the Cleveland Clinic recently published a case series of 198 consecutive patients with cardiovascular disease counseled to switch to a diet composed entirely of whole plant foods. Of the 198, 177 stuck to the diet, whereas the other 21 fell off the wagon, setting up kind of a natural experiment. What happened to the 21? This was such a sick group of patients that more than half suffered from either a fatal heart attack or needed angioplasty or a heart transplant. In that same time period of about four years, of the 177 that stuck to the plant-based diet, only one had a major event as a result of worsening disease. As Dean Ornish noted in his response to the latest trial, "a Mediterranean diet is better than what most people are consuming"...but even better may be a diet based on whole plant foods.

Dr. Esselstyn's was not a randomized trial, so it can't be directly compared to the Lyon study, and it included very determined patients. Not everyone is willing to dramatically change their diets, even if it may literally be a matter of life or death. In which case, rather than doing nothing, eating a more Mediterranean-type diet may cut risk for heart attack survivors by about two-thirds. Cutting 99% of risk would be better if Esselstyn's results were replicated in a controlled trial, but even a 70% drop in risk could save tens of thousands of lives every year.

For more on the Mediterranean diet, check out:

For more on Dr. Esselstyn's amazing work:

If the short-chain plant-based omega-3s in flax seeds and walnuts appear so beneficial, what about the long-chain omega-3's found in fish and fish oil? There are pros and cons. See, for example, Mercury vs. Omega-3s for Brain Development, Is Fish Oil Just Snake Oil?, and Omega-3's and the Eskimo Fish Tale.

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: wildpixel / Thinkstock. This image has been modified.

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Preserving Male Reproductive Health With Diet

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In 1992 a controversial paper was published suggesting sperm counts have been dropping around the world over the last 50 years. However, this remains a matter of debate. It's notoriously difficult to determine sperm counts in the general population for obvious reasons. If you just go ask men for samples, less than 1 in 3 tend to agree to participate.

Finally though, a study of tens of thousands of men studied over a 17-year period was published. It indeed found a significant decline in sperm concentration, about a 30 percent drop, as well as a drop in the percentage of normal looking sperm. Most sperms looked normal in the 90's, but more recently that has dropped to less than half. This may constitute a serious public health warning.

Semen quality may actually be related to life expectancy. In a study of more than 40,000 men visiting a sperm lab during a 40-year period, they found a decrease in mortality was associated with an increase in semen quality, suggesting that semen quality may therefore be a fundamental biomarker of overall male health. Even when defective sperm are capable of fertilizing an egg, creating a child with abnormal sperm may have serious implications for that child's future health.

What role may diet play? I profiled a first-of-its-kind Harvard study suggesting that a small increase in saturated fat intake was associated with a substantially lower sperm count, but not all fat was bad. Higher intakes of omega-3's were associated with a more favorable sperm shape. This may help explain why researchers at UCLA were able to improve sperm vitality, movement, and shape by giving men about 18 walnuts a day for 12 weeks. Walnuts have more than just omega 3's, though. They also contain other important micronutrients. In a study of men aged 22 through 80, older men who ate diets containing lots of antioxidants and nutrients such as vitamin C had the genetic integrity of sperm of much younger men.

The antioxidants we eat not only end up in our semen, but are concentrated there. The amount of vitamin C ends up nearly ten times more concentrated in men's testicles than the rest of their bodies. Why? Because sperm are highly susceptible to damage induced by free radicals, and accumulating evidence suggests that this oxidative stress plays an important role in male infertility. So, more fruits and vegetables and perhaps less meat and dairy, but the Harvard data were considered preliminary. They studied fewer than 100 men, but it was the best we had... until now.

A much larger follow-up study, highlighted in my video, The Role of Diet in Declining Sperm Counts, found that the higher the saturated fat intake the lower the sperm count, up to a 65 percent reduction. These findings are of potentially great public interest because changes in diet over the past decades may be part of the explanation for the recently reported high frequency of subnormal human sperm counts. In any case, the current findings suggest that adapting dietary intake toward eating less saturated fat may be beneficial for both general and reproductive health.

Why is high dietary intake of saturated fat associated with reduced semen quality? What's the connection? Sex steroid hormones in meat, eggs, and dairy may help explain the link between saturated fat intake and declining sperm counts. That's the subject of my video, Dairy Estrogen and Male Fertility.

More on male infertility in my videos Fukushima and Radioactivity in Seafood and Male Fertility and Diet.

Diet also has a role to play in sexual dysfunction:

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Julia Mariani / Flickr

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Children’s Supplements Found Contaminated With Pollutants

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A number of case-control studies have found that giving kids cod liver oil supplements may increase their risk of asthma later in life. Case-control studies are done by asking about past behavior in cases (those with asthma) versus controls (those without asthma) to see if certain past behaviors are more likely among the disease group. The problem is that asking people to remember what they were doing years ago, when most people can't remember what they had for breakfast last week, is unreliable. When interpreting the results from case-control studies, we also can't rule out something called reverse causation. Maybe cod liver oil doesn't lead to asthma, but asthma led to the use of cod liver oil.

It would therefore be nice to see a cohort study. In a cohort study, researchers would take people without asthma and follow them over time to see if those taking cod liver oil are more likely to develop it. Because people without the disease and their diets are followed over time, cohort studies bypass the problems of recall bias and reverse causation.

In 2013, we finally got one such study. 17,000 people free of asthma were followed over 11 years. Researchers knew who was taking cod liver oil and who wasn't, and then sat back and watched to see who got asthma over the subsequent 11 years. The researchers found that cod liver oil intake was indeed significantly associated with the development of asthma. They thought it might be the excessive vitamin A in the cod liver oil that was causing the problem, but there are also a number of substances in fish oil we may not want our children exposed to.

Researchers from Philadelphia University, highlighted in my video PCBs in Children's Fish Oil Supplements, recently looked at 13 over-the-counter children's dietary supplements containing fish oil to assess potential exposure to PCBs, toxic industrial pollutants that have contaminated our oceans. PCBs were detected in all products. Could we just stick to the supplements made from small, short-lived fish like anchovies instead of big predator fish like tuna to reduce the impact of biomagnification? Or use purified fish oils? No, the researchers found no significant difference in PCB levels whether the supplements were labeled as molecularly distilled or how high up the food chain the fish were.

The researchers concluded that while children's dietary supplements containing the long-chain omega-3's from fish oils may claim to benefit young consumers, "daily ingestion of these products may provide a vector for contaminant exposure that may off-set the positive health effects." What positive health benefits are they talking about?

Researchers publishing in the journal, Early Human Development, found that infants given DHA-fortified formula may have better development of their eyes and brains compared to infants getting non DHA-fortified formula. What was the source of the DHA? Not fish, but algae-derived DHA. In that way we can get the benefits of omega 3's without the contaminant risks. But of course, breast milk is the gold standard, significantly better than either of the formula fed infants. So the best source of omega-3's is mom.

It's bad enough when supplement manufacturers exploit adults when they're sick and vulnerable with pills that are often useless or worse, but taking advantage of our parental drive to do what's best for our children with contaminated products that may make them sick, makes me sick.

More on supplements in:

And speaking of which, Is Fish Oil Just Snake Oil?

Also check out these videos on fish oil and DHA: Omega-3's and the Eskimo Fish Tale and Should We Take EPA and DHA Omega-3 For Our Heart?

What about omega 3's for our child's growing brain? See my video Mercury vs. Omega-3s for Brain Development

We can also be exposed to PCBs in food. See Food Sources of PCB Chemical Pollutants.

More on the polluted aquatic food chain in:

What can we do to lower the risk of childhood asthma and other allergic-type diseases? See:

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Lars Plougmann / Flickr

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How to Treat Prediabetes with Diet

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For people with prediabetes, lifestyle modification is considered "the cornerstone of diabetes prevention." Diet-wise, this means individuals with prediabetes or diabetes should aim to reduce their intake of excess calories, saturated fat, and trans fat. Too many of us consume a diet with too many solid fats and added sugars. Thankfully the latest dietary guidelines aim to shift consumption towards more plant-based foods.

Lifestyle modification is now the foundation of the American Association of Clinical Endocrinology guidelines, the European Diabetes Association guidelines, and the official standards of care for the American Diabetes Association. Dietary strategies include reducing intake of fat and increasing intake of fiber (meaning unrefined plant foods, including whole grains).

The recommendation to consume more whole grains is based on research showing that eating lots of whole grains is associated with reduced risk of developing type 2 diabetes. New research even suggests that whole grains may protect against prediabetes in the first place.

According to the American Diabetes Association's official standards of care (which you can see in my video Lifestyle Medicine Is the Standard of Care for Prediabetes), dietary recommendations should focus on reducing saturated fat, cholesterol and trans fat intake (meat, dairy, eggs and junk food). Recommendations should also focus on increasing omega 3's, soluble fiber and phytosterols, all three of which can be found together in flax seeds; an efficient, but still uncommon, intervention for prediabetes. In one study, about two tablespoons of ground flax seed a day decreased insulin resistance (the hallmark of the disease).

If the standards of care for all the major diabetes groups say that lifestyle is the preferred treatment for prediabetes because it's safe and highly effective, why don't more doctors do it? Unfortunately, the opportunity to treat this disease naturally is often unrecognized. Only about one in three patients report ever being told about diet or exercise. Possible reasons for not counseling patients include lack of reimbursement, lack of resources, lack of time, and lack of skill.

It may be because doctors aren't getting paid to do it. Why haven't reimbursement policies been modified? One crucial reason may be a failure of leadership in the medical profession and medical education to recognize and respond to the changing nature of disease patterns.

"The inadequacy of clinical education is a consequence of the failure of health care and medical education to adapt to the great transformation of disease from acute to chronic. Chronic disease is now the principal cause of disability, consuming three quarters of our sickness-care system. Why has there been little academic response to the rising prevalence of chronic disease?"

How far behind the times is the medical profession? A report by the Institute of Medicine on medical training concluded that the fundamental approach to medical education "has not changed since 1910."


I hope my work is helping to fill the gap that medical professionals are not getting during training about preventing and treating chronic disease. That's actually how this all started. I would make trips to Countway at the beginning of every month in medical school to read all the new journal issues. I felt I had a duty to my patients to stay on top of the literature. But hey, since I'm doing so much work, might as well share it! So what started as an email newsletter morphed into a medical school speaking tour into a DVD series and then now all online for everyone.

For more on preventing and treating prediabetes/diabetes, see:

For more on lifestyle medicine:

And for insight into the sad state of nutrition in medical training, Doctors Know Less Than They Think About Nutrition and Medical School Nutrition Training.

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Alden Chadwick / Flickr

Original Link

How to Treat Prediabetes with Diet

NF-May3 Lifestyle Medicine Is the Standard of Care for Prediabetes.jpeg

For people with prediabetes, lifestyle modification is considered "the cornerstone of diabetes prevention." Diet-wise, this means individuals with prediabetes or diabetes should aim to reduce their intake of excess calories, saturated fat, and trans fat. Too many of us consume a diet with too many solid fats and added sugars. Thankfully the latest dietary guidelines aim to shift consumption towards more plant-based foods.

Lifestyle modification is now the foundation of the American Association of Clinical Endocrinology guidelines, the European Diabetes Association guidelines, and the official standards of care for the American Diabetes Association. Dietary strategies include reducing intake of fat and increasing intake of fiber (meaning unrefined plant foods, including whole grains).

The recommendation to consume more whole grains is based on research showing that eating lots of whole grains is associated with reduced risk of developing type 2 diabetes. New research even suggests that whole grains may protect against prediabetes in the first place.

According to the American Diabetes Association's official standards of care (which you can see in my video Lifestyle Medicine Is the Standard of Care for Prediabetes), dietary recommendations should focus on reducing saturated fat, cholesterol and trans fat intake (meat, dairy, eggs and junk food). Recommendations should also focus on increasing omega 3's, soluble fiber and phytosterols, all three of which can be found together in flax seeds; an efficient, but still uncommon, intervention for prediabetes. In one study, about two tablespoons of ground flax seed a day decreased insulin resistance (the hallmark of the disease).

If the standards of care for all the major diabetes groups say that lifestyle is the preferred treatment for prediabetes because it's safe and highly effective, why don't more doctors do it? Unfortunately, the opportunity to treat this disease naturally is often unrecognized. Only about one in three patients report ever being told about diet or exercise. Possible reasons for not counseling patients include lack of reimbursement, lack of resources, lack of time, and lack of skill.

It may be because doctors aren't getting paid to do it. Why haven't reimbursement policies been modified? One crucial reason may be a failure of leadership in the medical profession and medical education to recognize and respond to the changing nature of disease patterns.

"The inadequacy of clinical education is a consequence of the failure of health care and medical education to adapt to the great transformation of disease from acute to chronic. Chronic disease is now the principal cause of disability, consuming three quarters of our sickness-care system. Why has there been little academic response to the rising prevalence of chronic disease?"

How far behind the times is the medical profession? A report by the Institute of Medicine on medical training concluded that the fundamental approach to medical education "has not changed since 1910."


I hope my work is helping to fill the gap that medical professionals are not getting during training about preventing and treating chronic disease. That's actually how this all started. I would make trips to Countway at the beginning of every month in medical school to read all the new journal issues. I felt I had a duty to my patients to stay on top of the literature. But hey, since I'm doing so much work, might as well share it! So what started as an email newsletter morphed into a medical school speaking tour into a DVD series and then now all online for everyone.

For more on preventing and treating prediabetes/diabetes, see:

For more on lifestyle medicine:

And for insight into the sad state of nutrition in medical training, Doctors Know Less Than They Think About Nutrition and Medical School Nutrition Training.

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Alden Chadwick / Flickr

Original Link

Why Would Eating Fish Increase Diabetes Risk?

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In the past two years, six separate meta-analyses have been published on the relationship between fish consumption and type 2 diabetes. The whole point of a meta-analysis is to compile the best studies done to date and see what the overall balance of evidence shows. The fact that there are six different ones published recently highlights how open the question remains. One thread of consistency, though, was that fish consumers in the United States tended to be at greater risk for diabetes.

If we include Europe, then fish eaters appeared to have a 38% increased risk of diabetes. On a per serving basis, that comes out to be about a 5% increase in risk for every serving of fish one has per week. To put that into perspective, a serving of red meat per day is associated with 19% increase in risk. Just one serving per day of fish would be equivalent to a 35% increase in risk. But why might fish be worse than red meat?

Fish intake may increase type 2 diabetes risk by increasing blood sugar levels, as a review of the evidence commissioned by the U.S. government found. The review found that blood sugars increase in diabetics given fish oil. Another possible cause is that omega 3's appear to cause oxidative stress. A recent study, highlighted in my video, Fish and Diabetes, found that the insulin producing cells in the pancreas don't appear to work as well in people who eat two or more servings of fish a week. Or it may not be related to omega 3's at all but rather the environmental contaminants that build up in fish.

It all started with Agent Orange. We sprayed 20 million gallons of the stuff on Vietnam, and some of it was contaminated with trace amounts of dioxins. Though the Red Cross estimates that a million Vietnamese were adversely affected, what about all the servicemen who were exposed spraying it across the countryside? Reports started showing up that veterans exposed to Agent Orange appeared to have higher diabetes rates than unexposed veterans, a link that's now officially recognized.

These so-called "persistent organic pollutants" are mainly man-made industrial chemicals and are among the most hazardous compounds ever synthesized. They include dioxins, PCBs, and certain chlorine-containing pesticides, all of which are highly resistant to breakdown in the environment.

Initially condemned for their deleterious effect on reproductive function and their ability to cause cancer, there is now a growing body of evidence showing that exposure to these pollutants leads to metabolic diseases such as diabetes. This is a breakthrough that "should require our greatest attention."

For more on the role industrial pollutants may play in our diabetes epidemic, see Diabetes and Dioxins and Pollutants in Salmon and Our Own Fat.

More on the changing views surrounding fish oil supplements in Is Fish Oil Just Snake Oil?

Other foods associated with diabetes risk include processed meat and eggs. See Bacon, Eggs, and Gestational Diabetes During Pregnancy and Eggs and Diabetes, while Indian gooseberries and flaxseeds may help (Amla Versus Diabetes and Flaxseed vs. Diabetes).

Other videos on how polluted our oceans now are include:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Gideon / Flickr

Original Link

The Reversal on Fish Oil

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Are the purported benefits of fish oil supplementation for the prevention and treatment of heart disease just a "fish tale"? Thanks to recommendations from organizations such as the American Heart Association that individuals at high risk for heart disease ask their physicians about fish oil supplementation, fish oil has grown into a multibillion dollar industry. We now consume over 100,000 tons of fish oil every year.

But what does the science say? A systematic review and meta-analysis published in the Journal of the American Medical Association, highlighted in my video Is Fish Oil Just Snake Oil? looked at all the best "randomized clinical trials evaluating the effects of omega-3's on lifespan, cardiac death, sudden death, heart attack, and stroke." The studies told the subjects to either eat more oily fish or to take fish oil capsules. What did the study find? Overall, the researchers found no protective benefit for all-cause mortality, heart disease mortality, sudden cardiac death, heart attack, or stroke.

What about for those who already had a heart attack and are trying to prevent another? Still no benefit. Where did we even get this idea that omega 3's were good for the heart? If we look at some of the older studies, the results seemed promising. For example, there was the famous DART trial back in the 80s involving 2,000 men. Those advised to eat fatty fish had a 29% reduction in mortality. Pretty impressive--no wonder it got a lot of attention. But people seemed to have forgotten the sequel, the DART-2 trial. The same group of researchers, and an even bigger study (3,000 men). In DART-2 "those advised to eat oily fish and particularly those supplied with fish oil capsules had a higher risk of cardiac death."

Put all the studies together, and there's no justification for the use of omega 3s as a structured intervention in everyday clinical practice or for guidelines supporting more dietary omega-3's. So what should doctors say when their patients follow the American Heart Association advice to ask them about fish oil supplements? Given this and other negative meta-analyses, "our job as doctors should be to stop highly marketed fish oil supplementation in all of our patients."

I've previously discussed fish oil supplements in the context of risks versus purported cardiovascular benefits:

But if the benefits aren't there, then all one is left with are concerns over the industrial pollutants that concentrate in the fish fat (even in distilled fish oil, see Is Distilled Fish Oil Toxin-Free?).

These same contaminants are found in the fish themselves. This raises concern for adults (Fish Fog), children (Nerves of Mercury), and pregnant moms:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day ,and From Table to Able.

Image Credit: Jo Christian Oterhals / Flickr

Original Link

How "Healthy Fats" Hurt You

Extracted Oils Are the Most Dangerous

The government, the food industry, even doctors may all bombard you with advice to eat so-called "healthy fats," in the form of:

  • olive oil (for monounsaturated fats)
  • other vegetable oils (for polyunsaturated fats)
  • fish oil (for long-chain omega-3 polyunsaturated fats)

But when you start looking closely, you will be faced with an unpleasant surprise. These extracted oils are dangerous in olive oil in cruet_opt.jpgthree major ways.

WHAT ARE EXTRACTED OILS?

No whole food is entirely fat. Instead, fat is mixed in with the thousands of other components of the food, including proteins, carbohydrates, vitamins, minerals, and (if it's a plant) protective phytochemicals that work as antioxidants.

Extracted oils are fats that are forced out of this whole food matrix and put into a capsule, bottle, or tub. Liquid vegetable oils, margarine, and fish oil are all examples of extracted oils.

WHAT FATS DO YOU NEED?

There are two kinds of fats you do need to get from your diet. These are the "short-chain" omega-3 and omega-6 fatty acids (which are polyunsaturated fats). Your daily need is low, only about 3% of your total calories. Extracted oils are not necessary to meet this requirement if you are eating a wide range of whole plant foods.

Given an adequate supply of calories from any source (including carbohydrates and proteins), your body can handily make other kinds of fats you use, including saturated and monounsaturated fat, and can construct long-chain omega-3 and omega-6's from their short-chain precursors.

HOW EXTRACTED OILS HURT YOU

CLICK HERE TO READ THE THREE WAYS THAT EXTRACTED OILS HARM YOU

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How Long to Avoid Fish Before Conception?

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Mothers' increased consumption of fish before and during pregnancy leads to increased exposure to both mercury and the long-chain omega 3 DHA. Mercury may negatively affect brain development in one's unborn baby, whereas DHA may stimulate brain development. However, the negative effect of mercury appears to outweigh the beneficial effect of DHA for most species of fish (see Mercury vs. Omega-3s for Brain Development).

Unfortunately, women of childbearing age appear less aware and knowledgeable about this problem than other women, despite FDA and EPA campaigns to inform every OB/GYN and pediatrician in the country about the potential risks of mercury in fish.

Since mercury sticks around in the body, women may want to avoid fish with high levels of mercury for a year before they get pregnant, not just during pregnancy. The rationale for avoiding fish for a year before pregnancy is because the half-life of mercury in the body is estimated to be about two months. In a study I profile in my video How Long to Detox from Fish Before Pregnancy a group of researchers fed subjects two servings a week of tuna and other high mercury fish to push their mercury levels up, and then stopped the fish. Slowly but surely their levels came back down (see the video for the graph). I know a lot of moms are concerned about exposing their children to mercury containing vaccines, but if they eat even just a serving a week of fish during pregnancy, the latest data shows that their infants end up with substantially more mercury in their bodies than if they were injected with up to six mercury-containing vaccines.

Given the two-month half-life of mercury, within a year of stopping fish consumption our bodies can detox nearly 99% of the mercury. Unfortunately the other industrial pollutants in fish can take longer for our body to get rid of. Certain dioxins, PCBs, and DDT metabolites found in fish have a half-life as long as ten years. So getting that same 99% drop could take 120 years, which is a long time to delay one's first child.

The fact that we can still find DDT in umbilical cord blood decades after the pesticide was banned speaks to the persistence of some pollutants. There's a shortcut for moms, but it's The Wrong Way to Detox.

What effects do these other pollutants have? Well, high concentrations of industrial contaminants are associated with 38 times the odds of diabetes--that's as strong as the relationship between smoking and lung cancer! Isn't diabetes mostly associated with obesity though? Well, these pollutants are fat-soluble, so "as people get fatter the retention and toxicity of persistent organic pollutants related to the risk of diabetes may increase." This suggests the shocking possibility that obesity "may only be a vehicle" for such chemicals.

Now the pollutants could just be a marker for animal product consumption, which may be why there's such higher diabetes risk, since more than 90% of the persistent organic pollutants comes from animal foods. And indeed, in the U.S. every additional serving of fish a week is associated with a 5% increased risk of diabetes, which makes fish consumption about 80% worse than red meat. PCBs are found most concentrated in fish and eggs (Food Sources of PCB Chemical Pollutants), which may be why there are lower levels of Industrial Pollutants in Vegans. This may also help explain the remarkable findings in Eggs and Diabetes.

More on the risks of mercury can be found in these videos:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Tatiana Vdb / Flickr

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