The Natural Human Diet

NF-Nov15 The Problem with the Paleo Diet Argument copy.jpg

Our epidemics of dietary disease have prompted a great deal of research into what humans are meant to eat for optimal health. In 1985, an influential article highlighted in my video The Problem With the Paleo Diet Argument was published proposing that our chronic diseases stem from a disconnect between what our bodies ate while evolving during the Stone Age (about 2 million years ago) and what we're stuffing our face with today. The proposal advocated for a return towards a hunter-gatherer type diet of lean meat, fruits, vegetables, and nuts.

It's reasonable to assume our nutritional requirements were established in the prehistoric past. However, the question of which prehistoric past we should emulate remains. Why just the last 2 million? We've been evolving for about 20 million years since our last common great ape ancestor, during which our nutrient requirements and digestive physiology were set down. Therefore our hunter-gatherer days at the tail end probably had little effect. What were we eating for the first 90% of our evolution? What the rest of the great apes ended up eating--95 percent or more plants.

This may explain why we're so susceptible to heart disease. For most of human evolution, cholesterol may have been virtually absent from the diet. No bacon, butter, or trans fats; and massive amounts of fiber, which pulls cholesterol from the body. This could have been a problem since our body needs a certain amount of cholesterol, but our bodies evolve not only to make cholesterol, but also to preserve it and recycle it.

If we think of the human body as a cholesterol-conserving machine, then plop it into the modern world of bacon, eggs, cheese, chicken, pork, and pastry; it's no wonder artery-clogging heart disease is our #1 cause of death. What used to be adaptive for 90% of our evolution--holding on to cholesterol at all costs since we weren't getting much in our diet--is today maladaptive, a liability leading to the clogging of our arteries. Our bodies just can't handle it.

As the editor-in-chief of the American Journal of Cardiology noted 25 years ago, no matter how much fat and cholesterol carnivores eat, they do not develop atherosclerosis. We can feed a dog 500 eggs worth of cholesterol and they just wag their tail; a dog's body is used to eating and getting rid of excess cholesterol. Conversely, within months a fraction of that cholesterol can start clogging the arteries of animals adapted to eating a more plant-based diet.

Even if our bodies were designed by natural selection to eat mostly fruit, greens and seeds for 90% of our evolution, why didn't we better adapt to meat-eating in the last 10%, during the Paleolithic? We've had nearly 2 million years to get used to all that extra saturated fat and cholesterol. If a lifetime of eating like that clogs up nearly everyone's arteries, why didn't the genes of those who got heart attacks die off and get replaced by those that could live to a ripe old age with clean arteries regardless of what they ate? Because most didn't survive into old age.

Most prehistoric peoples didn't live long enough to get heart attacks. When the average life expectancy is 25 years old, then the genes that get passed along are those that can live to reproductive age by any means necessary, and that means not dying of starvation. The more calories in food, the better. Eating lots of bone marrow and brains, human or otherwise, would have a selective advantage (as would discovering a time machine stash of Twinkies for that matter!). If we only have to live long enough to get our kids to puberty to pass along our genes, then we don't have to evolve any protections against the ravages of chronic disease.

To find a population nearly free of chronic disease in old age, we don't have to go back a million years. In the 20th century, networks of missionary hospitals in rural Africa found coronary artery disease virtually absent, and not just heart disease, but high blood pressure, stroke, diabetes, common cancers, and more. In a sense, these populations in rural China and Africa were eating the type of diet we've been eating for 90% of the last 20 million years, a diet almost exclusively of plant foods.

How do we know it was their diet and not something else? In the 25 year update to their original paleo paper, the authors tried to clarify that they did not then and do not now propose that people adopt a particular diet just based on what our ancient ancestors ate. Dietary recommendations must be put to the test. That's why the pioneering research from Pritikin, Ornish, and Esselstyn is so important, showing that plant-based diets can not only stop heart disease but have been proven to reverse it in the majority of patients. Indeed, it's the only diet that ever has.

For more on the absence of Western diseases in plant-based rural populations, see for example:

I've touched on "paleo" diets in the past:

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: Nathan Rupert / Flickr

Original Link

The Natural Human Diet

NF-Nov15 The Problem with the Paleo Diet Argument copy.jpg

Our epidemics of dietary disease have prompted a great deal of research into what humans are meant to eat for optimal health. In 1985, an influential article highlighted in my video The Problem With the Paleo Diet Argument was published proposing that our chronic diseases stem from a disconnect between what our bodies ate while evolving during the Stone Age (about 2 million years ago) and what we're stuffing our face with today. The proposal advocated for a return towards a hunter-gatherer type diet of lean meat, fruits, vegetables, and nuts.

It's reasonable to assume our nutritional requirements were established in the prehistoric past. However, the question of which prehistoric past we should emulate remains. Why just the last 2 million? We've been evolving for about 20 million years since our last common great ape ancestor, during which our nutrient requirements and digestive physiology were set down. Therefore our hunter-gatherer days at the tail end probably had little effect. What were we eating for the first 90% of our evolution? What the rest of the great apes ended up eating--95 percent or more plants.

This may explain why we're so susceptible to heart disease. For most of human evolution, cholesterol may have been virtually absent from the diet. No bacon, butter, or trans fats; and massive amounts of fiber, which pulls cholesterol from the body. This could have been a problem since our body needs a certain amount of cholesterol, but our bodies evolve not only to make cholesterol, but also to preserve it and recycle it.

If we think of the human body as a cholesterol-conserving machine, then plop it into the modern world of bacon, eggs, cheese, chicken, pork, and pastry; it's no wonder artery-clogging heart disease is our #1 cause of death. What used to be adaptive for 90% of our evolution--holding on to cholesterol at all costs since we weren't getting much in our diet--is today maladaptive, a liability leading to the clogging of our arteries. Our bodies just can't handle it.

As the editor-in-chief of the American Journal of Cardiology noted 25 years ago, no matter how much fat and cholesterol carnivores eat, they do not develop atherosclerosis. We can feed a dog 500 eggs worth of cholesterol and they just wag their tail; a dog's body is used to eating and getting rid of excess cholesterol. Conversely, within months a fraction of that cholesterol can start clogging the arteries of animals adapted to eating a more plant-based diet.

Even if our bodies were designed by natural selection to eat mostly fruit, greens and seeds for 90% of our evolution, why didn't we better adapt to meat-eating in the last 10%, during the Paleolithic? We've had nearly 2 million years to get used to all that extra saturated fat and cholesterol. If a lifetime of eating like that clogs up nearly everyone's arteries, why didn't the genes of those who got heart attacks die off and get replaced by those that could live to a ripe old age with clean arteries regardless of what they ate? Because most didn't survive into old age.

Most prehistoric peoples didn't live long enough to get heart attacks. When the average life expectancy is 25 years old, then the genes that get passed along are those that can live to reproductive age by any means necessary, and that means not dying of starvation. The more calories in food, the better. Eating lots of bone marrow and brains, human or otherwise, would have a selective advantage (as would discovering a time machine stash of Twinkies for that matter!). If we only have to live long enough to get our kids to puberty to pass along our genes, then we don't have to evolve any protections against the ravages of chronic disease.

To find a population nearly free of chronic disease in old age, we don't have to go back a million years. In the 20th century, networks of missionary hospitals in rural Africa found coronary artery disease virtually absent, and not just heart disease, but high blood pressure, stroke, diabetes, common cancers, and more. In a sense, these populations in rural China and Africa were eating the type of diet we've been eating for 90% of the last 20 million years, a diet almost exclusively of plant foods.

How do we know it was their diet and not something else? In the 25 year update to their original paleo paper, the authors tried to clarify that they did not then and do not now propose that people adopt a particular diet just based on what our ancient ancestors ate. Dietary recommendations must be put to the test. That's why the pioneering research from Pritikin, Ornish, and Esselstyn is so important, showing that plant-based diets can not only stop heart disease but have been proven to reverse it in the majority of patients. Indeed, it's the only diet that ever has.

For more on the absence of Western diseases in plant-based rural populations, see for example:

I've touched on "paleo" diets in the past:

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: Nathan Rupert / Flickr

Original Link

How to Prevent Heart Disease

NF-Nov6 What You Need to Know About Preventing Heart Disease.jpg

Many of today's lifestyle medicine doctors, myself included, were greatly influenced by Nathan Pritikin, the nutrition pioneer who started reversing heart disease with a plant-based diet and exercise back in the 70s. (More on Nathan Pritikin in Engineering a Cure, Our Number One Killer Can Be Stopped, and The Answer to the Pritikin Puzzle.) But how did he come up with the idea of opening up arteries without drugs or surgery? We tend to think of rural China as a place with a fraction of our disease rates, but we may forget about Africa.

Pritikin was 43 when he was told by his cardiologist that he was going to die from a heart attack, so he began to live on a diet patterned after the black population in Uganda, a population living off plants that was essentially free from death from heart attacks. After curing his own heart disease with a plant-based diet, he went on to save the lives of thousands of others. What was the data that so convinced him?

Last year, the International Journal of Epidemiology reprinted a landmark article from the '50s that started out with a shocking statement: "In the African population of Uganda, coronary heart disease is almost non-existent." Our number one cause of death almost nonexistent? What were they eating? Plantains and sweet potatoes, other vegetables, corn, millet, pumpkins, tomatoes, and "green leafy vegetables are taken by all." Their protein was almost entirely from plant sources, and they had the cholesterol levels to prove it, similar to modern-day plant-eaters. "Apart from the effects of diet and of the blood cholesterol levels," the researchers couldn't figure out any other reasons for their freedom from heart disease.

These fifty-year-old findings are still relevant today. They showed "dietary intake to be a key, modifiable, established and well-recognized risk factor for heart attacks. This contrasts with the rather desperate search in recent decades for even newer cardiovascular risk factors." We have the only risk factor we need--cholesterol. We've known it for 50 years, and we can do something about it. See One in a Thousand: Ending the Heart Disease Epidemic.

As you can see in the video Cavities and Coronaries: Our Choice, according to the Editor-in-Chief of the American Journal of Cardiology, the only risk factor required for atherosclerotic plaques to form is elevated LDL, or "bad" cholesterol in our blood. Dr. William Clifford Roberts is the distinguished cardiac pathologist who doubles as the Editor-in-Chief of the American Journal of Cardiology. More from him in Eliminating the #1 Cause of Death and Heart Attacks and Cholesterol: Purely a Question of Diet.

To drop our LDL cholesterol, we need to drop our intake of three things: trans fat (found in junk food and animal foods - See Trans Fat in Meat and Dairy); saturated fat (found in mostly animal foods); and dietary cholesterol (found exclusively in animal foods). More on lowering LDL in Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

What Dr. Shaper discovered is that heart disease may be a choice.

Like cavities.

People who lived over 10,000 years before the invention of the toothbrush pretty much had no cavities. Didn't brush a day in their lives, never flossed, no Listerine, no Waterpik--and yet, no cavities. Why? Because candy bars hadn't been invented yet! So why do people continue to get cavities when we know they're preventable though diet? Simple: because the pleasure people derive from dessert may outweigh the cost and discomfort of the dentist.

As long as people understand the consequences of their actions, as a physician what more can I do? If you're an adult and decide that the benefits outweigh the risks for you and your family, then go for it--I certainly enjoy the occasional indulgence (I've got a good dental plan!). But what if instead of the plaque on our teeth, we're talking about the plaque building up in our arteries? Then we're no longer just talking about scraping tarter. We're talking life and death.

The most likely reason our loved ones will die is heart disease. It's still up to each of us to make our own decisions as to what to eat and how to live, but we should make our choices consciously, educating ourselves about the predictable consequences of our actions.

-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: Knar Bedian / Flickr

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How to Treat Multiple Sclerosis With Diet

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Multiple sclerosis is an unpredictable and frightening degenerative autoimmune inflammatory disease of the central nervous system in which our body attacks our own nerves. It often strikes in the prime of life and can cause symptoms in the brain, such as cognitive impairment; in the eye, such as painful loss of vision; as well as tremors, weakness, loss of bladder control, pain, and fatigue.

The most frequently prescribed drug for multiple sclerosis is interferon beta, which can make one feel lousy and cost $30,000 a year. But hey, it might be worthwhile--if it actually worked. We learned recently that it doesn't seem to prevent or delay long-term disability. That leaves chemo drugs like mitoxantrone that causes irreversible heart damage in one out of every eight people who go on the drug and causes cancer (leukemia) in nearly 1% of people who take it. But MS is no walk in the park either.

If only there was a cheap, simple, safe, side-effect free solution that also just so happened to be the most effective treatment for MS ever prescribed...

Dr. Roy Swank, who we lost recently at age 99, was a distinguished neurologist whose research culminated in over 170 scientific papers. In the video, Treating Multiple Sclerosis with the Swank MS Diet, I highlight a few.

As far back as 1950, we knew there were areas in the world that had a lot of MS--North America, Europe--and other places--Africa and Asia--that hardly had any. And migration studies show that those who move from a high risk area to a low risk area significantly drop their risk, and vice versa. So it seems less genetic and more lifestyle.

Dr. Swank had an idea. As he recounts in an interview with Dr. John McDougall at the ripe young age of 84, "it seemed possible to me that this could be a matter of food, because the further north you go the less vegetarian a life is led and the more people are carnivores, you might say--they spend a lot more time eating meat."

After looking at the multiple sclerosis data from World War II in occupied countries where meat and dairy were rationed, along with his famous study in '52 that found that the frequency of MS related directly to the amount of saturated animal fat consumed daily in different areas of Norway, he concluded that it might be the animal fat that was causing the increased risk. He decided to put it to the test by restricting people's intake of saturated animal fat, most commonly coming from dairy and chicken in the U.S. (See Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero).

In Treating Multiple Sclerosis with the Swank MS Diet, you can see data on his first 47 patients before cutting out about 90% of the saturated fat from their diet and after, showing a decrease in both the frequency and severity of MS attacks. Normally, we're lucky if we can get people to stick to a diet for six months, and so that's why most dietary trials last a year at the most. The first study he published reported results from the first three and a half years.

Then came the five and a half year follow-up in which he added about another 100 patients. Then the seven year follow-up, published in the Annals of Internal Medicine. Then the 20 year follow-up, and then the 34 year follow-up.

How did his patients do? If we can get to people early in their disease, when they're only mildly disabled, and restrict their saturated fat intake, Dr. Swank showed he could stop their disease in 95% of cases--no further disability 34 years later. But if they started slacking on their diet--even years in, their disease could become reactivated. They felt so great that some felt that they could cheat a little bit, since they had their disease so well under control. But eating just eight grams of saturated fat more a day was accompanied by a striking increase in disability and a near tripling of their death rate.

How about a 50 year follow-up! They were able to track down 15 of the original patients that stuck to the diet, now in their 70s and 80s, with multiple sclerosis for over 50 years, and 13 out of 15 were walking around normal in all respects. Conclusion: "This study indicated that, in all probability, MS is caused largely by consumption of saturated animal fat."

Dr. Swank thought it was the sludging of the blood caused by even a single meal of saturated fats that can clog tiny capillaries that feed our nervous system. Diets rich in saturated fat and cholesterol can thicken the blood and make our red cells sticky. A single meal of sausage and eggs can stick our blood cells together like rolls of quarters. And that kind of hyperaggregation can lead to a reduction of blood flow and oxygenation of our tissues. What's in sausage and eggs that may cause so much inflammation? See my video series on endotoxins described in my blog How Does Meat Cause Inflammation?

If we put someone's blood through a machine that sucks out about 90% of the cholesterol in their blood, we can demonstrate an immediate improvement in microcirculation in the heart muscle. But what about the brain?

The eyes are the windows... to our brain. We can visualize--in real-time--changes in blood vessel function in the retina at the back of the eye, which gives us a sense of what's happening further back in the brain. And if we lower the cholesterol level in the blood, we can immediately get a significant improvement in vasodilation--the little veins open wider and let the blood flow.

So yes, it could be the animal fat leading to clogging of our capillaries, but now we know animal fats can have all sorts of other deleterious effects such as inflammation, so who knows what the actual mechanism may be by which cutting animal fat can cut MS progression. Regardless, patients with MS that follow a diet with no more than 10 or 15 grams of saturated fat can expect to survive and thrive to a ripe old age. Of course, cutting out saturated fat completely might be better, given that heart disease is our number one killer.

The bottom line is that the results Dr. Swank published remain "the most effective treatment of multiple sclerosis ever reported in the peer reviewed medical literature." In patients with early stage MS, 95% were without progression of their disease 34 years later after adopting his low saturated fat dietary program. Even patients with initially advanced disease showed significant benefit. To date, no medication or invasive procedure has ever even come close, to demonstrating such success.

Doesn't cost $30,000 dollars; doesn't give you leukemia--and works. Better!

This all begs one big obvious question: If Dr. Swanks results are "so stunningly impressive, why haven't other physicians, neurologists, and centers adopted this method of treatment?" One reason may be that MRI machines weren't invented until the 1970s, decades after Dr. Swank's study began. MRIs are how we track the progress of MS today. We don't have to rely on patients' subjective reports or doctor's clinical judgments, we can see the disease get better or worse right there in black and white.

It's like in the 1970s when Nathan Pritikin appeared to reverse heart disease by the thousands but no one took him seriously until angiography was invented and the likes of Ornish and Esselstyn (see Our Number One Killer Can Be Stopped) could hold up angiographic images, proving conclusively that a plant-based diet could help literally open up arteries.

So what we need is someone to repeat Swank's experiment today with MRI scans every step of the way. And I'm happy to report that exact experiment was just completed by Dr. John McDougall. Dr. Swank was one of Dr. McDougall's heroes, and Dr. McDougall is one of mine. Study enrollment was completed last year and we should have the full results soon.

I touched on this in my live 2013 year-in-review lecture More Than an Apple a Day, but I'm excited to be able to take a deeper dive into this extraordinary story.

Those interested in supporting Dr. McDougall's landmark study (headed by Dr. Dennis Bourdette, M.D. and under the supervision of Dr. Vijayshree Yadav) can donate to his nonprofit McDougall Research & Education Foundation (you can also donate to NutritionFacts.org to help keep us bringing you similarly underreported yet life-saving science).

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live 2012 year-in-review presentation Uprooting the Leading Causes of Death.

Image Credit: Theen Moy / Flickr

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