Less than 2% of Americans achieve even the recommended minimum adequate intake of potassium, due primarily to inadequate plant food intake.

If you take any plant, burn it to ash, throw the ash in a pot of water, stir it around, skim it off and then let the water evaporate, you’ll be left with a white residue at the bottom known as pot ash. It has been used since the dawn of history for everything from making soap, glass, fertilizers, and bleach. It was not until 1807, when a new element was discovered in this so-called “vegetable alkali.” They called it pot ashium—potassium. True story, which I bring up only to emphasize the most concentrated source in our diet, plants.

Every cell in the body requires the element potassium to function. As I detail in my 2-min. video 98% of American Diets Potassium Deficient, for much of the last 3 million years or so, we ate so many plants that we probably got 10,000 mg of potassium in our daily diet. Today, we’d be lucky to get 3,000.

Less than 2% of Americans even get the recommended minimum adequate intake of 4,700 a day. To get even the adequate intake, the average American would have to eat like 5 more bananas worth of potassium a day. 98% of Americans eat potassium deficient diets because they don’t eat enough plants.

Why do we care? A review of all the best studies ever done on potassium intake and it’s relationship to two of our top killers, stroke and heart disease, was recently published in the Journal of the American College of Cardiology. A 1600 mg per day higher potassium intake was associated with a 21% lower risk of stroke. That still wouldn’t get the average American up to the minimum adequate intake, but it might be able to wipe out a fifth of their stroke risk. The paper concludes: “These results support recommendations for higher consumption of potassium-rich foods to prevent vascular diseases.”

What does “potassium-rich foods” mean? Find out in my 2-min. video 98% of American Diets Potassium Deficient. Hint: bananas don’t even make it into the top 50 sources!

People eating plant-based diets are often asked where they get their protein (and have to explain that plants are the preferred source). Maybe they should then ask where people eating conventional diets get their potassium–or their fiber for that matter *see Relieving Yourself of Excess Estrogen). For more on what we evolved to eat, see Paleolithic Lessons.

The banana listing reminds me of a similarly humorous finding about the levels of eyesight-saving nutrients in eggs versus greens. See Egg Industry Blind Spot.

Bananas are also kind of pitiful antioxidant-wise (see Best Berries and Which Fruit Fights Cancer Better?). Is it worth going out of our way to eat plants with the most antioxidants, though? See Anti-Inflammatory Antioxidants to find out.

-Michael Greger, M.D.

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

Image credit: 24oranges.nl / Flickr

The distinguished neurologist Roy Swank‘s low saturated fat diet remains the “most effective treatment of multiple sclerosis ever reported in the peer review literature.” In patients with early stage MS, 95% were without progression of their disease 34 years after adopting his meat and dairy-restricted diet. Even patients with initially advanced disease showed significant benefit. To date, no medication or invasive procedure has ever come close to demonstrating such success.

To understand one reason why a plant-based diet may be so successful in treating the disabling auto-immune disease, one has to first understand how the immune system works. This was one of the greatest mysteries in all of biology—solved by a brilliant scientist who won the Nobel in 1960 for figuring it out.

As I illustrate in my 3-min. video Clonal Selection Theory of Immunity, each one of our antibody-producing immune cells, called B-cells, produces only one type of antibody. Antibodies are one of the main weapons our immune system uses to attack foreign invaders. And they’re specific. It’s not just like we have one B-cell that covers grass pollen and another that covers bacteria, we have a B-cell in our body whose only job is to make antibodies against the pollen of purple Siberian oniongrass! (whether or not we ever come in contact with it). Another whose only job is to make antibodies against the tail proteins of bacteria that live only in the thermal vents at the bottom of the ocean…

Wait a second. There must be a billion different things in the world. If each of our B cells produces only one type of antibody, then we’d need to have a billion different types of B cells. And we do!

So, let’s suppose one day you’re walking along and get attacked by a platypus (they have poison spurs on their heels you know). And so for your whole life up until that point the B-cell in your body that produces antibodies against duck-billed platypus venom was just hanging around, twiddling its thumbs, until that very moment. As soon as the venom is detected that specific B-cell starts dividing like crazy, making copies of itself, and soon you have a whole swarm of clones specialized for platypus poison protection. Fending off the toxin, you live happily ever after. That is how the immune system works. Aren’t our bodies spectacular?

If we have a billion different types of antibody-producing B cells, each capable of recognizing a different molecular signature, why then do we tend not to attack ourselves? And how can what we eat sometimes undermine this inherent protection from autoimmune disease?

As I describe in my 3-min video Clonal Deletion Theory of Immunity, the reason that we don’t often fall prey to friendly fire is because before we’re even born we  kill off each and every B cell that recognizes us. That’s what our thymus gland is for. When we’re still a fetus, our body lines up all our immune cells, holds up a picture of our self and asks them one by one: “do you recognize this person?” And if any of our immune cells says yes, they’re killed on the spot, death by apopotosis (programmed cell death) and good riddance.

Turns out this process of ridding our bodies of self-recognizing immune cells happens throughout our lives, mostly in our bone marrow. If you remember, though, in my video series on IGF-1 (starting with The Answer to the Pritikin Puzzle) animal protein consumption increases the level of a cancer-promoting growth hormone that prevents apoptosis, prevents our body’s killing of cells it wants to get rid—that’s why IGF-1 levels are linked to cancer. So IGF-1 might contribute to the inappropriate survival of self-reactive white blood cells in autoimmune or inflammatory conditions. Maybe that’s why people who eat plant-based diets appear protected from autoimmune diseases, explaining, for example, the extraordinary rarity of most autoimmune diseases among sub-Saharan rural blacks following a traditional plant-based diet.   Before they changed their diets, evidently not a single case of MS had been diagnosed among a population of 15 million.

 -Michael Greger, M.D.

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

Image credit: GerryShaw / Wikimedia Commons

Plant-based diets may help rheumatoid arthritis by decreasing exposure to an inflammatory “Trojan horse” compound found in animal products called Neu5Gc. In How Tumors Use Meat to Grow I talked about the inflammatory role Neu5Gc may play in stimulating breast cancer growth, but what about inflammation in our joints?

For those of you who have been following my work since the beginning, you’ll remember back in 2003 I covered a landmark paper in the Proceedings of the National Academy of Sciences entitled “Human intake and incorporation of an immunogenic nonhuman dietary sialic acid.” They took autopsy samples and discovered proof of Neu5Gc in human tumors. In my video The Inflammatory Meat Molecule Neu5Gc you can see it stained brown in human breast cancer, melanoma, brain tumors, and ovarian cancer.

The presence of Neu5Gc in human tumors mystified researchers, because human beings are genetically unable to produce this substance. But other animals can. Maybe, the researchers proposed, human beings absorbed it from eating these other animals? So they put it to the test.

Because Neu5Gc is found in animals and animal products, the researchers had to first eat vegan for a few days to clear their system (including no animal-derived ingredients in foods or drugs or shampoo), and then they basically drank a glass of diluted pig mucous. Within days this invading meat molecule could be found oozing from their bodies, in their saliva, urine—even their hair clippings. They concluded: “Because NeuGc-type compounds are not found in plants, and Neu5Gc is not synthesized by microbes, the dietary source of Neu5Gc must be foods of animal origin.” They proposed that the metabolic incorporation of this molecular “Trojan horse” from animal products may be contributing to the higher rates of cancer and heart disease in those that eat meat and dairy.

Why heart disease too? If you check out my 3-min video Nonhuman Molecules Lining Our Arteries, you’ll see that this foreign meat molecule tends to accumulate not only in the lining of hollow organs (where carcinomas like breast cancer develop inside your glands), but also in the lining of blood vessels. This may be contributing to the hardening of our arteries, the #1 killer of men and women in the United States.

Inflammation is one of the three steps en route to fatal heart disease. See:

• Arterial Acne
• Blocking the First Step of Heart Disease
• Making Our Arteries Less Sticky

Antioxidants found predominantly in plants may also decrease inflammation within the body. Nuts may be particularly useful in this regard.

The absorption of the inflammatory molecule Neu5Gc from animal foods may also explain why vegetarian diets seem to improve rheumatoid arthritis. Maybe the incorporation of this reactive alien molecule into inflamed tissue such as arthritic joints could be aggravating arthritis. That could explain why rheumatoid arthritis is not present in most other great apes. What we do know is that if you take animal products away, rheumatoid sufferers can feel better within weeks–see Diet & Rheumatoid Arthritis and Preventing Arthritis.

Bacterial endotoxins are another reason animal products may trigger an inflammatory immune reaction. See:

• The Leaky Gut Theory of Why Animal Products Cause Inflammation
• The Exogenous Endotoxin Theory Dead Meat Bacteria Endotoxemia

Beyond the putative role of nonhuman Neu5GC as a potential molecular link between diet, autoreactive antibodies, and the progression of human cancer and heart disease, I close out the Neu5Gc story with a 3-min. video entitled Meat May Exceed Daily Allowance of Irony. It turns out that consuming Neu5GC may set children up for life-threatening reactions to E. coli toxins originating in the same animal products. The researchers ask if this is “poetic justice” for meat eaters. Not when it’s a major cause of acute life-threatening kidney failure in children. For more on E. coli, see Fecal Bacteria Survey and Chicken Out of UTIs.

My exploration into Neu5GC spanned a seven video series (starting with Cancer as an Autoimmune Disease). If you’d rather these more extensive probes than my one-off videos, I’ve done similar in-depth series on reversing cancer cell growth, why animal products cause inflammation, changing vitamin D recommendations, arugula athleticism, why nuts don’t appear to cause expected weight gain, as well as the latest dietary guidelines.

-Michael Greger, M.D.

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

Image credit:  Jojo / Wikimedia Commons

Certain cancers—like breast cancer—can be thought of in part as an autoimmune disease.

When people get heart or kidney transplants, they must be given immunosuppressive drugs to prevent rejection of the new organ. What do you suppose happens to cancer rates in those individuals who have their immune systems suppressed? Well, for some types of cancer, like skin cancer, the risk goes up. This supports the so-called immune surveillance theory—the idea that our immune system acts as a natural defense system for keeping cancer under control (see a cool video of immune cells taking on a cancer cell here). This could explain why, as we age and our immune function declines, our risk of cancer goes up.

The problem with the immune surveillance concept is that for some cancers, suppressing immune function decreases risk. After a kidney transplant, though your skin cancer risk may go up, your breast cancer and rectal cancer risk goes down. Why would people with depressed immune systems have less cancer? This led to a new theory of cancer I explore in my 4-min. video Cancer as an Autoimmune Disease.

The only reason the immune system is even able to pick out cancerous cells from noncancerous cells is because tumors express foreign looking molecules that stimulate our immune system. Why would tumors do that? Why would cancer cells go out of their way to wave a red flag around saying, “Hey, come get me!”? We think it’s because cancer tends to thrive in a setting of low level inflammation. In the video I show a number of examples of chronic inflammation leading to cancer–ulcerative colitis to colon cancer, chronic pancreatitis to pancreatic cancer, chronic hepatitis to liver cancer, and stomach inflammation to stomach cancer. Oftentimes the body’s inflammatory immune response can further cancer’s agenda.

By inciting an immune response, cancer creates its own inflammation, which may stimulate angiogenesis, the formation of new blood vessels to bring blood to the tumor and help it grow. This may explain the mystery surrounding Kaposi’s sarcoma, a cancer affecting those with AIDS. When you start treating AIDS and the immune system starts to recover you can actually see a flare in the cancer.

So what are the dietary implications of this new autoimmune theory of cancer? See my 3-min. video How Tumors Use Meat to Grow: Xeno-Autoantibodies. In short, there’s a molecule called Neu5Gc found in nonhuman animals but not made by the human species. Cancerous breast tumors appear to incorporate this molecule that women consume in meat and dairy to trick their immune systems into creating the environment of low-grade inflammation that breast cancer thrives in. Our own cancer may use what we feed on to get what it feeds on.

For more on Neu5Gc, one of the most fascinating topics of modern day nutrition, see my 4-min. video The Inflammatory Meat Molecule Neu5Gc.

Why else might those eating plant-based diets have lower risk of all cancers combined? Kathy Freston wrote a good summary. It could be due to diminished exposure to IGF-1, heme iron, inflammation, viruses, antibiotics, saturated fat, nitrosamines, and arachidonic acid associated with animal product consumption. Or it could be the DNA repair,cellular stress defenses, anti-inflammatory properties, soy, lignans, phytonutrients, and fiber associated with healthy plant food consumption. It’s probably both, so it may not be enough to just eat vegan—we need to eat our veggies too.

-Michael Greger, M.D.

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

Image credit: Pulmonary Pathology / Flickr